% !TeX root = ../main.tex

\section{Experiments}
\label{sec:experiments}

% \begin{itemize}
%     \item [1.] Training on RecombiNet
%     \item ImageNet results (large)
%     \item Ablation (TinyImageNet): Foreground position
%     \item Ablation (TinyImageNet): Which background (or part of other ablation table?)
%     \item Ablation (TinyImageNet+ImageNet For edge blur): Design decisions: Which infill model, pruning threshold, p$\to$t /t$\to$p, foreground rotation range (?), edge blur, original image probability/schedule, Foreground size
%     \item With other Data Augmentations
%     \item [2.] More evalution metrics
%     \item Background accuracy (how to frame/sell? Background bias?) / Background robustness (= foreground with all background)?
%     \item Foreground focus
%     \item Position bias
%     \item Size bias
% \end{itemize}

We conduct a comprehensive suit of experiments to validate the effectiveness of our approach,
% We compare training on \name, the ImageNet instantiation of \schemename, to training on ImageNet for 10 different models.
comparing ImageNet-training with and without \schemename for 10 different models.
Furthermore, we assess the impact of using \schemename for pretraining on multiple fine-grained downstream datasets.
Finally, we exploit \schemename's control over the image distribution to quantify model behaviors and biases.
We always report the mean and standard deviation of three independent training runs.

\subsection{Design Choices of ForAug}
\label{sec:ablation}

We start by ablating the design choices of \schemename on TinyImageNet~\cite{Le2015}, a subset of ImageNet containing 200 categories with 500 images each. %, and Tiny\name, the application of \schemename to TinyImageNet.
% \Cref{tab:ablation} presents the results of these ablations.
\Cref{tab:ablation-segment} presents ablations for segmentation and \Cref{tab:ablation-recombine} for recombination.

\begin{table}
    \caption{Ablation of the design decisions in the segmentation phase of \schemename on TinyImageNet.
        The first line is our baseline, while the other lines are using \schemename.
        We use basic settings with the \emph{same} background strategy during recombination for this experiment.
    }
    \label{tab:ablation-segment}
    \centering
    \small
    \resizebox{.9\columnwidth}{!}{
        \begin{tabular}{cccc}
            \toprule
            \multirow{2.5}{*}{\makecell{Detect.                                                                          \\Prompt}} & \multirow{2.5}{*}{\makecell{Infill \\ Model}} & \multicolumn{2}{c}{TinyImageNet Accuracy [\%]}         \\
            \cmidrule{3-4}
                                                      &                                & ViT-Ti         & ViT-S          \\
            \midrule
            \multicolumn{2}{l}{\textbf{TinyImageNet}} & $66.1 \pm 0.5$                 & $68.3 \pm 0.7$                  \\
            specific                                  & LaMa \cite{Suvorov2021}        & $65.5 \pm 0.4$ & $71.2 \pm 0.5$ \\
            general                                   & \gtxt{LaMa \cite{Suvorov2021}} & $66.4 \pm 0.6$ & $72.9 \pm 0.6$ \\
            \gtxt{general}                            & Att. Eraser \cite{Sun2024}     & $67.5 \pm 1.2$ & $72.4 \pm 0.5$ \\
            \bottomrule
        \end{tabular}}
\end{table}

\begin{table}[t]
    \caption{Ablation of the recombination phase of \schemename on TinyImageNet (top) and ImageNet (bottom). The first experiments use the initial segmentation settings with LaMa \cite{Suvorov2021}.}
    \label{tab:ablation-recombine}
    \centering
    \resizebox{\columnwidth}{!}{
        \begin{tabular}{ccccccccccc}
            \toprule
            % FG.          & Augment.              & BG.         & BG.        & Edge                             & Original     & \multicolumn{2}{c}{Accuracy [\%]}                \\
            % Size         & Order                 & Strat.      & Prune      & Smoothing                        & Mixing       & ViT-Ti                            & ViT-S        \\
            \multirow{2.5}{*}{\makecell{FG.                                                                                                                                                      \\size}} & \multirow{2.5}{*}{\makecell{Augment.\\Order}} & \multirow{2.5}{*}{\makecell{BG\\Strat.}} & \multirow{2.5}{*}{\makecell{BG.\\Prune}} & \multirow{2.5}{*}{\makecell{Original\\Mixing}} & \multirow{2.5}{*}{\makecell{Edge\\Smooth.}} & \multicolumn{2}{c}{Accuracy [\%]} \\
            \cmidrule{7-8}
                                                      &                       &                     &            &              &                                  & ViT-Ti       & ViT-S        \\
            \midrule
            % TinyImageNet             &              &                                 &             &            &                                  &              & $66.1\pm0.5$                 & $68.3\pm0.7$ \\
            \multicolumn{6}{l}{\textbf{TinyImageNet}} & \gtxt{$66.1\pm0.5$}   & \gtxt{$68.3\pm0.7$}                                                                                              \\
            mean                                      & crop$\to$paste        & same                & -          & -            & \gtxt{-}                         & $64.6\pm0.5$ & $70.0\pm0.6$ \\
            range                                     & \gtxt{crop$\to$paste} & \gtxt{same}         & \gtxt{-}   & \gtxt{-}     & \gtxt{-}                         & $65.5\pm0.4$ & $71.2\pm0.5$ \\
            \midrule
            % \gtxt{range} & \gtxt{crop$\to$paste} & \gtxt{same} & \gtxt{-}   & \gtxt{-}     & \gtxt{-}                         & $66.4\pm0.6$ & $72.9\pm0.6$ \\
            {range}                                   & {crop$\to$paste}      & {same}              & {-}        & {-}          & {-}                              & $67.5\pm1.2$ & $72.4\pm0.5$ \\
            \gtxt{range}                              & paste$\to$crop        & \gtxt{same}         & \gtxt{-}   & \gtxt{-}     & \gtxt{-}                         & $67.1\pm1.2$ & $72.9\pm0.5$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & 1.0        & \gtxt{-}     & \gtxt{-}                         & $67.0\pm1.2$ & $73.0\pm0.3$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & 0.8        & \gtxt{-}     & \gtxt{-}                         & $67.2\pm1.2$ & $72.9\pm0.8$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & 0.6        & \gtxt{-}     & \gtxt{-}                         & $67.5\pm1.0$ & $72.8\pm0.7$ \\
            % \gtxt{range} & \gtxt{paste$\to$crop} & \gtxt{same} & \gtxt{0.8} & $\sigma_\text{max} = 2.0$        & \gtxt{-}     & $67.2\pm0.4$ & $72.9\pm0.5$ \\
            % \gtxt{range} & \gtxt{paste$\to$crop} & \gtxt{same} & \gtxt{0.8} & $\sigma_\text{max} = 4.0$        & \gtxt{-}     & $65.9\pm0.5$ & $72.4\pm0.6$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & $p=0.2$      & \gtxt{-}                         & $69.8\pm0.5$ & $75.0\pm0.3$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & $p=0.33$     & \gtxt{-}                         & $69.5\pm0.4$ & $75.2\pm1.0$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & $p=0.5$      & \gtxt{-}                         & $70.3\pm1.0$ & $74.2\pm0.2$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & linear       & \gtxt{-}                         & $70.1\pm0.7$ & $74.9\pm0.8$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & reverse lin. & \gtxt{-}                         & $67.6\pm0.2$ & $73.2\pm0.3$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & cos          & \gtxt{-}                         & $71.3\pm1.0$ & $75.7\pm0.8$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & \gtxt{cos}   & $\sigma_\text{max} = 4.0$        & $70.0\pm0.8$ & $75.5\pm0.7$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & orig.               & \gtxt{0.8} & \gtxt{cos}   & \gtxt{$\sigma_\text{max} = 4.0$} & $67.2\pm0.9$ & $69.9\pm1.0$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & all                 & \gtxt{0.8} & \gtxt{cos}   & \gtxt{$\sigma_\text{max} = 4.0$} & $70.1\pm0.7$ & $77.5\pm0.6$ \\
            \midrule
            \multicolumn{6}{l}{\textbf{ImageNet}}     & \gtxt{-}              & \gtxt{$79.1\pm0.1$}                                                                                              \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & \gtxt{cos}   & \gtxt{-}                         & -            & $80.5\pm0.1$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & \gtxt{same}         & \gtxt{0.8} & \gtxt{cos}   & $\sigma_\text{max} = 4.0$        & -            & $80.7\pm0.1$ \\
            \gtxt{range}                              & \gtxt{paste$\to$crop} & all                 & \gtxt{0.8} & \gtxt{cos}   & \gtxt{$\sigma_\text{max} = 4.0$} & -            & $81.4\pm0.1$ \\
            \bottomrule
        \end{tabular}}
\end{table}


\textbf{Prompt.}
% We present the ablation of our main design decisions in \Cref{tab:ablation}.
First, we evaluate the type of prompt used to detect the foreground object.
Here, the \emph{general} prompt, which contains the class and the more general object category, outperforms only having the class name (\emph{specific}).

\textbf{Inpainting.} Among inpainting models, Attentive Eraser~\cite{Sun2024} produces slightly better results compared to LaMa~\cite{Suvorov2021} ($+0.5$ p.p. on average).
For inpainting examples, see the supplementary material.
% (see the supplementary material for examples).
% When comparing the infill models, the GAN-based LaMa \cite{Suvorov2021} gets outperformed by the Attentive Eraser \cite{Sun2024}.

\textbf{Foreground size}
% We observe that LaMa's often infills unnatural textures compared to Attentive Eraser.
% The size of foreground objects during training has a significant impact on the performance.
% Here, using the greater variability of the \emph{range} strategy increases the performance by $\approx 1\%$ compared to the \emph{mean} strategy.
significantly impacts performance.
Employing a \emph{range} of sizes during recombination, rather than a fixed \emph{mean} size, boosts accuracy by approximately 1 p.p.
This suggests that the added variability is beneficial.

\textbf{Order of data augmentation.}
% (1) Applying the image crop related augmentations \emph{before} pasting the foreground object and the color-based ones \emph{after} pasting or (2) applying all data augmentations after pasting the foreground object.
% While results are ambiguous, we choose the second strategy, as it improves the performance of ViT-S, although not the one of ViT-Ti.
Applying all augmentations after foreground-background recombination (\emph{paste$\to$crop$\to$color}) improves ViT-S's performance compared to applying crop-related augmentations before pasting (\emph{crop$\to$paste$\to$color}).
ViT-Ti results are ambiguous.

\textbf{Background pruning.}
When it comes to the backgrounds to use, we test different pruning thresholds ($t_\text{prune}$) to exclude backgrounds with large inpainting.
% and only use backgrounds with an relative size of the infilled region of at most $t_\text{prune}$ (exclusive).
A threshold of $t_\text{prune}=1.0$ means that we use all backgrounds that are not fully infilled.
% We find that the background pruning does not significantly impact the models' performance.
% We choose $t_\text{prune}=0.8$ for the following experiments to exclude backgrounds that are mostly artificial.
Varying $t_\text{prune}$ has minimal impact.
We choose $t_\text{prune} = 0.8$ to exclude predominantly artificial backgrounds.

% One of the most important design decisions is the mixing of the original dataset with \name.
\textbf{Mixing} \schemename-augmented samples with the original ImageNet data proves crucial.
While constant and linear mixing schedules improve performance over no mixing by $2-3$ p.p. compared to only augmented samples, the cosine annealing schedule proves optimal, boosting accuracy by $3-4$ p.p.

\textbf{Edge smoothing.}
We evaluate the impact of using Gaussian blurring to smooth the edges of the foreground masks.
% Similarly, applying edge smoothing to foreground masks with Gaussian blurring actually hurts performance on Tiny\name, but slightly improves it on \name.
For larger models, this gives us a slight performance boost on the full ImageNet (second to last line in \Cref{tab:ablation-recombine}).

\textbf{Background strategy.}
Another point is the allowed choice of background image for each foreground object.
% We evaluate three different strategies.
% (1) Picking the background from which that specific foreground was originally extracted.
% The major difference to ImageNet when using this setup is the variability in size and position of the foreground object.
% (2) Picking a background that originally had a foreground object of the same class in it.
% Here, we have backgrounds where objects of this type can typically appear while also creating a wider variety of samples due to pairing each foreground object with different backgrounds each time.
% (3) Picking any background.
% This choice has the largest variety of backgrounds, but the backgrounds are not semantically related to the foreground object anymore.
% We find in \Cref{fig:bg-strategy} that choosing only a foreground's original background is the worst choice.
We compare using the original background, a background from the same class, and any background.
These strategies go from low diversity and high shared information content between the foreground and background to high diversity and low shared information content.
For \emph{ViT-Ti}, the latter two strategies perform comparably, while \emph{ViT-S} benefits from the added diversity of using any background.
The same is true when training on the full ImageNet.


\begin{table}
    \caption{Accuracy of ViT-S on TinyImageNet (TIN) in percent using \schemename with different foreground position distributions by varying the Bates parameter $\eta$.
        The best performance is achieved when using the uniform distribution ($\eta=1$) for training.}
    \label{tbl:foreground-eta}
    \centering
    \small
    \resizebox{.9\columnwidth}{!}{
        \begin{tabular}{ccccccc}
            \toprule
            \multirow{2.5}{*}{\makecell{Bates Parameter                  \\during training}} & \multirow{2.5}{*}{\makecell{TIN                                           \\w/o \schemename}} & \multicolumn{5}{c}{TIN w/ \schemename}                               \\
            \cmidrule(l){3-7}
                        &      & $\eta=-3$ & $-2$ & $1/-1$ & $2$  & $3$  \\
            \midrule
            Baseline    & 68.9 & 60.5      & 60.2 & 60.8   & 62.6 & 63.1 \\
            $\eta=-3$   & 71.3 & 79.3      & 79.5 & 79.1   & 79.3 & 79.1 \\
            $\eta=-2$   & 71.5 & 80.0      & 78.7 & 79.3   & 79.1 & 78.8 \\
            $\eta=1/-1$ & 72.3 & 79.5      & 78.9 & 80.2   & 79.7 & 80.4 \\
            $\eta=2$    & 71.3 & 78.2      & 77.8 & 79.1   & 79.6 & 79.9 \\
            $\eta=3$    & 71.4 & 77.2      & 76.9 & 78.6   & 79.6 & 79.7 \\
            \bottomrule
        \end{tabular}}
\end{table}

\textbf{Foreground position.}
Finally, we analyze the foreground object's positioning in the image, using a
generalization of the Bates distribution~\cite{Bates1955} with parameter $\eta \in \Z$.
The Bates distribution presents an easy way to sample from a bounded domain with just one hyperparameter that controls its concentration.
$\eta = 1/-1$ corresponds to the uniform distribution; $\eta > 1$ concentrates the distribution around the center; and for $\eta < -1$, the distribution is concentrated at the borders (see supplementary material for details).
% We utilize an extended Bates distribution to sample the position of the foreground object.
% The Bates distribution with parameter $\eta \geq 1$ is the mean of $\eta$ independent uniformly distributed random variables \cite{Jonhson1995}.
% The larger $\eta$, the more concentrated the distribution is at the center, $\eta < -1$ concentrates the distribution at the edges.
% We extend this concept to $\eta \leq -1$, shifting the distribution away from the center and towards the edges.
When sampling more towards the center of the image, the difficulty of the task is reduced, which reduces performance on TinyImageNet (\Cref{tbl:foreground-eta}).
This is reflected in the performance when evaluating using \schemename with $\eta=2$ and $\eta=3$ compared to $\eta=-1/1$.
We observe a similar reduction for $\eta < -1$.
% This experiment is conducted using the LaMa infill model.

\begin{table}
    \caption{Dataset statistics for TinyImageNet and ImageNet with and without \schemename. For \schemename we report the number of foreground/background pairs.}
    \label{tab:dataset-stats}
    \centering
    \resizebox{.9\columnwidth}{!}{
        \begin{tabular}{l S[table-format=4.0] S[table-format=7.0] S[table-format=5.0]}
            \toprule
            Dataset                    & {Classes} & {\makecell{Training         \\ Images}} & {\makecell{Validation \\ Images}} \\
            \midrule
            TinyImageNet               & 200       & 100000              & 10000 \\
            TinyImageNet + \schemename & 200       & 99404               & 9915  \\
            ImageNet                   & 1000      & 1281167             & 50000 \\
            ImageNet + \schemename     & 1000      & 1274557             & 49751 \\
            \bottomrule
        \end{tabular}}
\end{table}
After fixing the optimal design parameters in \Cref{tab:ablation-segment,tab:ablation-recombine} (last rows), we run \schemename's segmentation step on the entire ImageNet dataset.
\Cref{tab:dataset-stats} shows the resulting dataset statistics.
% The slightly lower number of images in \name is due to \emph{Grounded SAM} returning no or invalid detections for some images.
The slightly reduced image count for \schemename is due to instances where Grounded SAM fails to produce valid segmentation masks.


\subsection{Image Classification Results}

\begin{table}
    \caption{ImageNet results of models trained on ImageNet with and without \schemename. \schemename improves the performance of most models, with a larger gain for larger models.}
    \label{tab:imagenet-results}
    \centering
    \small
    \resizebox{.8\columnwidth}{!}{\begin{tabular}{lccc}
            \toprule
            \multirow{2.5}{*}{Model} & \multicolumn{2}{c}{\makecell{ImageNet Accuracy [\%]}} & \multirow{2.5}{*}{Delta}                   \\
            \cmidrule(lr){2-3}
                                     & w/o \schemename                                       & w/ \schemename           &                 \\
            \midrule
            ViT-S                    & $79.1\pm0.1$                                          & $81.4\pm0.1$             & \grntxt{$+2.3$} \\
            ViT-B                    & $77.6\pm0.2$                                          & $81.1\pm0.4$             & \grntxt{$+3.5$} \\
            ViT-L                    & $75.3\pm0.4$                                          & $79.8\pm0.1$             & \grntxt{$+4.5$} \\
            \midrule
            DeiT-S                   & $80.1 \pm 0.1$                                        & $80.0\pm0.3$             & \gtxt{$-0.1$}   \\
            DeiT-B                   & $81.9 \pm 0.3$                                        & $81.9\pm0.2$             & \gtxt{$\pm0.0$} \\
            DeiT-L                   & $79.3\pm2.3$                                          & $82.4\pm0.1$             & \grntxt{$+3.1$} \\
            \midrule
            Swin-Ti                  & $77.9\pm0.2$                                          & $79.7\pm0.1$             & \grntxt{$+1.8$} \\
            Swin-S                   & $79.4\pm0.1$                                          & $80.6\pm0.1$             & \grntxt{$+1.2$} \\
            \midrule
            ResNet-50                & $78.3\pm0.1$                                          & $78.8\pm0.1$             & \grntxt{$+0.5$} \\
            ResNet-101               & $79.4\pm0.1$                                          & $80.4\pm0.1$             & \grntxt{$+1.0$} \\
            \bottomrule
        \end{tabular}}
\end{table}

\Cref{tab:imagenet-results} compares the ImageNet performance of models trained with and without \schemename.
We adopt the training setup of \cite{Nauen2025} and \cite{Touvron2022} for training ViT \cite{Dosovitskiy2021}, Swin \cite{Liu2021} and ResNet \cite{He2016} (representing CNNs) models as well as the setup of DeiT \cite{Touvron2021b} for that model.
Both setups are using strong data augmentations like RandAugment, CutMix, and Mixup optimized for Transformers (details in supplementary material).
Notably, \schemename improves performance across all tested architectures, including the ResNet models, % (up to $1$ p.p.), 
demonstrating benefits beyond Transformers.
For DeiT we only observe benefits on ImageNet for the larger models.
For other transformers, we observe improvements from $1.2$ p.p. to $4.5$ p.p. with increasing gains for larger models.
% This improvement is more substantial for the larger models, with ViT-L gaining $4.5$ p.p. in accuracy.
\schemename's improvements counteract the drop in performance for increasing model sizes.
Without \schemename this drop is $3.8$ p.p. (ViT-S to L), while with \schemename it is reduced to $1.6$ p.p.
For DeiT there is a drop of $0.8$ p.p. from small to large while when using \schemename there is a \emph{gain} of $2.4$ p.p.

\begin{table}
    \caption{Comparison of \schemename and simple Copy-Paste methods. We train ViT-S on ImageNet using the same 3-augment data augmentation on top of the copy-paste augmentation.}
    \label{tab:copy-paste-comparison}
    \centering
    \resizebox{\columnwidth}{!}{
        \begin{tabular}{lcc S[table-format=+2.1,retain-explicit-plus,detect-inline-weight=math,detect-weight=true]}
            \toprule
            Augmentation                                 & labels    & \makecell{     Accuracy [\%]} & {\makecell{Delta \\to Prev.}} \\
            \midrule
            % Baseline                                     &           & $79.1 \pm 0.1$                                   \\
            Baseline + \textbf{Simple Copy-Paste}        & bg        & $31.3 \pm 0.6$                &                  \\
            + mixed labels                               & fg + bg   & $32.0 \pm 0.8$                & +0.7             \\
            + fg labels                                  & fg        & $31.6 \pm 0.9$                & -0.4             \\
            + \emph{range} foreground size variation     & \gtxt{fg} & $43.0 \pm 1.2$                & \bfseries +11.4  \\
            + infilled backgrounds                       & \gtxt{fg} & $68.7 \pm 0.2$                & \bfseries +25.7  \\
            + \emph{cos} mixing strategy                 & \gtxt{fg} & $81.2 \pm 0.1$                & \bfseries +12.5  \\
            + edge smoothing                             & \gtxt{fg} & $81.3 \pm 0.1$                & +0.1             \\
            + background pruning$=$ \textbf{\schemename} & \gtxt{fg} & $81.4 \pm 0.1$                & +0.1             \\
            \bottomrule
        \end{tabular}}
\end{table}
\textbf{Comparison to Simple Copy-Paste.}
We compare \schemename to a simple adaption of the Copy-Paste augmentation inspired by \cite{Ge2023,Ghiasi2020,Shermaine2025} in \Cref{tab:copy-paste-comparison}.
Contrary to semantic segmentation we do not have foreground masks available.
Thus, we paste the extracted foreground objects from \emph{\schemename's segmentation stage} onto normal ImageNet images.
% Since such images do not have straight forward classification labels, we test multiple possibilities.
We observe 3 large jumps in accuracy: (\textbf{1}) From our \emph{range} foreground size variation (+11.4\%), (\textbf{2}) from using our infilled backgrounds instead of images from the dataset (+25.7\%), and (\textbf{3}) from our \emph{cos} mixing strategy with non-augmented images (+12.5\%).
\schemename's changes to the naive copy-paste augmentation are thus imperative for good classification performance.

\begin{table}[t]
    \caption{Downstream accuracy in percent when finetuning on other datasets. Models are pretrained on ImageNet with and without \schemename. Pretraining using \schemename increases transformer downstream accuracy.
        % on all datasets.
    }
    \label{tab:downstream-results}
    \centering
    \resizebox{\columnwidth}{!}{\begin{tabular}{lcccccc}
            \toprule
            Model      & \schemename & Aircraft        & Cars            & Flowers         & Food            & Pets                    \\
            \midrule
            ViT-S      & \xmark      & $72.4\pm1.0$    & $89.8\pm0.3$    & $94.5\pm0.2$    & $89.1\pm0.1$    & $93.8\pm0.2$            \\
            ViT-S      & \cmark      & $78.6\pm0.5$    & $92.2\pm0.2$    & $95.5\pm0.2$    & $89.6\pm0.1$    & $94.5\pm0.2$            \\
                       &             & \grntxt{$+6.2$} & \grntxt{$+2.4$} & \grntxt{$+1.0$} & \grntxt{$+0.5$} & \grntxt{$+0.7$}         \\
            \cmidrule(r){1-1}
            ViT-B      & \xmark      & $71.7\pm0.5$    & $90.0\pm0.2$    & $94.8\pm0.4$    & $89.8\pm0.2$    & $94.1\pm0.4$            \\
            ViT-B      & \cmark      & $79.0\pm2.2$    & $93.3\pm0.1$    & $ 96.5\pm0.1$   & $90.9\pm0.1$    & $95.1\pm0.4$            \\
                       &             & \grntxt{$+7.3$} & \grntxt{$+3.3$} & \grntxt{$+1.7$} & \grntxt{$+1.1$} & \grntxt{$+1.0$}         \\
            \cmidrule(r){1-1}
            ViT-L      & \xmark      & $72.1\pm1.0$    & $88.8\pm0.3$    & $94.4\pm0.3$    & $90.1\pm0.2$    & $94.2\pm0.4$            \\
            ViT-L      & \cmark      & $77.6\pm1.2$    & $89.1\pm0.2$    & $96.6\pm0.1$    & $91.3\pm0.1$    & $95.1\pm0.1$            \\
                       &             & \grntxt{$+5.5$} & \grntxt{$+0.3$} & \grntxt{$+2.2$} & \grntxt{$+1.2$} & \grntxt{$+0.9$}         \\
            \midrule
            DeiT-S     & \xmark      & $75.3\pm0.4$    & $91.1\pm0.2$    & $94.8\pm0.4$    & $89.2\pm0.2$    & $92.4\pm0.2$            \\
            DeiT-S     & \cmark      & $76.8\pm0.8$    & $91.9\pm0.2$    & $95.2\pm0.3$    & $89.1\pm0.2$    & $92.3\pm0.4$            \\
                       &             & \grntxt{$+1.5$} & \grntxt{$+0.8$} & \grntxt{$+0.4$} & \gtxt{$-0.1$}   & \gtxt{$-0.1$}           \\
            \cmidrule(r){1-1}
            DeiT-B     & \xmark      & $77.0\pm1.2$    & $92.9\pm0.2$    & $96.1\pm0.2$    & $91.2\pm0.1$    & $93.3\pm0.4$            \\
            DeiT-B     & \cmark      & $79.3\pm0.3$    & $93.1\pm0.1$    & $96.4\pm0.2$    & $91.3\pm0.1$    & $93.3\pm0.1$            \\
                       &             & \grntxt{$+2.3$} & \gtxt{$+0.2$}   & \grntxt{$+0.3$} & \gtxt{$+0.1$}   & \gtxt{$\pm0.0$}         \\
            \cmidrule(r){1-1}
            DeiT-L     & \xmark      & $72.8\pm5.5$    & $92.8\pm1.0$    & $95.8\pm1.5$    & $90.5\pm2.6$    & $92.4\pm2.0$            \\
            DeiT-L     & \cmark      & $78.8\pm0.8$    & $93.8\pm0.2$    & $97.0\pm0.2$    & $92.0\pm0.2$    & $93.5\pm0.2$            \\
                       &             & \grntxt{$+6.0$} & \grntxt{$+1.0$} & \grntxt{$+1.2$} & \grntxt{$+1.5$} & \grntxt{$+1.1$}         \\
            \midrule
            Swin-Ti    & \xmark      & $77.0\pm0.1$    & $91.3\pm0.6$    & $95.9\pm0.1$    & $90.0\pm0.2$    & $94.2\pm0.1$            \\
            Swin-Ti    & \cmark      & $81.1\pm0.8$    & $92.8\pm0.4$    & $96.2\pm0.1$    & $90.4\pm0.3$    & $94.8\pm0.5$            \\
                       &             & \grntxt{$+4.1$} & \grntxt{$+2.5$} & \grntxt{$+0.3$} & \grntxt{$+0.4$} & \grntxt{$+0.6$}         \\
            \cmidrule(r){1-1}
            Swin-S     & \xmark      & $75.7\pm1.4$    & $91.0\pm0.3$    & $95.9\pm0.5$    & $91.1\pm0.2$    & $94.4\pm0.1$            \\
            Swin-S     & \cmark      & $81.4\pm0.2$    & $93.1\pm0.2$    & $96.3\pm0.3$    & $91.2\pm0.2$    & $94.9\pm0.3$            \\
                       &             & \grntxt{$+5.7$} & \grntxt{$+2.1$} & \grntxt{$+1.4$} & \gtxt{$+0.1$}   & \grntxt{$+0.5$}         \\
            \midrule
            ResNet-50  & \xmark      & $78.2\pm0.5$    & $89.8\pm0.2$    & $91.7\pm0.4$    & $84.4\pm0.2$    & $93.7\pm0.3$            \\
            ResNet-50  & \cmark      & $80.3\pm0.4$    & $90.4\pm0.2$    & $91.7\pm0.2$    & $84.5\pm0.2$    & $93.7\pm0.3$            \\
                       &             & \grntxt{$+2.1$} & \grntxt{$+0.6$} & \gtxt{$\pm0.0$} & \gtxt{$+0.1$}   & \gtxt{$\pm0.0$}         \\
            \cmidrule(r){1-1}
            ResNet-101 & \xmark      & $78.4\pm0.6$    & $90.3\pm0.1$    & $91.2\pm0.5$    & $86.0\pm0.2$    & $94.3\pm0.2$            \\
            ResNet-101 & \cmark      & $81.4\pm0.5$    & $91.3\pm0.1$    & $92.9\pm0.2$    & $86.3\pm0.1$    & $94.0\pm0.3$            \\
                       &             & \grntxt{$+3.0$} & \grntxt{$+1.3$} & \grntxt{$+1.7$} & \grntxt{$+0.3$} & \textcolor{red}{$-0.3$} \\
            \bottomrule
        \end{tabular}}
\end{table}

\textbf{Downstream tasks.} To assess the transferability of \schemename-trained models, we finetune models pretrained on ImageNet with and without \schemename on five fine-grained datasets:
FGVC-Aircraft \cite{Maji2013}, Stanford Cars~\cite{Dehghan2017}, Oxford Flowers \cite{Nilsback2008}, Food-101 \cite{Kaur2017}, and Oxford-IIIT Pets \cite{Parkhi2012}.
% While for ResNets, the performance of both training datasets is about the same, 
In \Cref{tab:downstream-results} we see transformer accuracies improve on all these datasets by up to 7.3 p.p.
% and a reduction of error rate of up to $39.3\%$.
% Notably, training with \name increases the downstream performance of DeiT-S and DeiT-B, even though the ImageNet results were the same.
% This demonstrates that the improved representations from training on \name translate to superior performance beyond gains from better ImageNet performance.
Notably, training with \schemename boosts the downstream performance of DeiT-S and DeiT-B, despite similar ImageNet results.
This shows the improved representations from training with \schemename translate to gains beyond better ImageNet scores.
% not only on ImageNet, but also on fine-grained image classification tasks.


\subsection{Bias and Robustness Evaluation}
% Additional to just using \name for training, its special properties and posibilities for adjustment of the data distribution make it a valuable tool for evaluating other model properties and biases.
Beyond its use for training, \schemename's unique properties and controlled data generation capabilities make it a powerful tool for analyzing behavior and biases of black-box models.

\begin{figure*}
    \centering
    \includegraphics[width=.95\textwidth]{img/bg_robustness.pdf}
    \caption{Evaluation of background robustness on ImageNet + \schemename, ImageNet9 and CounterAnimal.
        We plot the in-distribution (top of arrow) and the out-of-distribution (bottom of arrow) accuracy when training with and without \schemename.
        We annotate each arrow with its length $\Delta$.
        Training with \schemename improves the background robustness of all transformers by mostly boosting the out-of-distribution accuracy.
    }
    \label{fig:background-robustness}
\end{figure*}

\textbf{Background Robustness.}
% By adjusting the background distribution from using a background from an image of the same class as the foreground to using any background, we can evaluate the robustness of models to shifts in the background distribution.
% We assess background robustness by changing the background distribution, comparing accuracy with backgrounds of the same class as the foreground to using any background.
We assess the robustness of models to shifts in the background distribution from a class-related background to any background.
% We define the background robustness coefficient to be the accuracy of a model on \name when using the same class background divided by the accuracy when using any background:
% Background robustness is defined to be the ratio of accuracy on \name with same-class backgrounds to accuracy with any background:
% \begin{align}
%     \text{Background Robustness} = \frac{\text{Acc}(\name_\text{all})}{\text{Acc}(\name_\text{same})}
% \end{align}
% It represents the relative drop in performance under a background distribution shift.
\Cref{fig:background-robustness} presents the background robustness results for three datasets: ImageNet with \schemename (all backgrounds vs. backgrounds of same class), ImageNet9 \cite{Xiao2020} (random backgrounds vs. original backgrounds), and CounterAnimal \cite{Wang2024f} (counter vs. common background).
The top triangle of each arrow represents the in-distribution backgrounds and the bottom triangle represents the out-of-distribution ones.
We follow ImageNet9 and CounterAnimal and assess the background robustness in terms of the accuracy gap when evaluating a model on images of normal background distribution compared to out-of-distribution backgrounds (length of each arrow; $\Delta$).
% When trained on ImageNet, smaller models generally exhibit greater robustness to changes in the background distribution than larger models and ResNet is more robust than the tested Transformer models.
Crucially, \schemename improves the background robustness of all models and across datasets, reducing the background-gap by boosting the performance on the out-of-background-distribution samples more than the in-distribution ones.
% to $\approx1.00$, meaning that these models are agnostic to the choice of background and only classify based on the foreground.
These findings highlight the generalization benefits of \schemename to unusual image compositions.

\begin{figure*}
    \centering
    \includegraphics[width=.95\textwidth]{img/fg_focus.pdf}
    \caption{Evaluation of the foreground focus (\Cref{eq:fg-focus}) using GradCam, GradCam++ and IntegratedGradients (IG) of models trained on ImageNet. Training with \schemename improves the foreground focus of almost all models.}
    \label{fig:foreground-focus}
\end{figure*}

\textbf{Foreground Focus.}
Leveraging our inherent knowledge of the foreground masks when using \schemename, as well as common XAI techniques~\cite{Selvaraju2016,Chattopadhay2018,Sundararajan2017}, we can evaluate a model's focus on the foreground object.
% I.e. we measure how much the model's decision depends on the foreground.
We can directly evaluate ImageNet-trained models, but this technique can also be extended to other datasets without relying on manually annotated foreground masks.
To evaluate the foreground focus, we employ Grad-CAM \cite{Selvaraju2016}, Grad-CAM++ \cite{Chattopadhay2018} and IntegratedGradients (IG) \cite{Sundararajan2017} to compute the per-pixel importance of an image for the model's prediction.
The foreground focus is defined to be the ratio of the foreground's relative importance to its relative size in the image:
\begin{align} \label{eq:fg-focus}
    \text{FG Focus}(\text{img}) = \frac{\text{Area}(\text{img}) \hspace{3pt} \text{Importance}(\text{fg})}{\text{Area}(\text{fg}) \hspace{3pt} \text{Importance}(\text{img})}
\end{align}
If all pixels uniformly receive the same importance value, the foreground focus is one.
The foreground focus of a model is its average focus over all test images.
\Cref{fig:foreground-focus} presents our findings.
Using \schemename significantly increases the foreground focus of ViT, DeiT and ResNet across all XAI metrics.
% I.e. \schemename-trained models base their decision more on the foreground object compared to the background than models trained without \schemename.
% For Swin, the foreground focus stagnates when measured using GradCam and GradCam++, but almost doubles when using IG.
% We hypothesize that Swin's below-uniform foreground focus reported with GradCam is due to its specific implementation for Swin.
We hypothesize Swin's below-uniform foreground focus with GradCam is due to its specific implementation.
% These differences might be due to the way GradCam is calculated for Swin \todo{cite package website where this is from} and the \todo{common critique of GradCam}.

\begin{table}[t]
    \caption{
        % Evaluation of the center bias. 
        Accuracy relative to the center accuracy of multiple instantiations of the models when the foreground objects is in different cells of a $3 \times 3$ grid.
        We calculate center bias according to \Cref{eq:center-bias}.
        Using \schemename significantly reduces models' center bias.}
    \label{tab:center-bias}
    \centering
    \resizebox{.78\columnwidth}{!}{
        \begin{tabular}{lccc}
            \toprule
            \multirow{2.5}{*}{Model} & \multicolumn{2}{c}{\makecell{Center Bias [\%] when trained}}                                                                                                                                                                          & \multirow{2.5}{*}{Delta}                                                                                                                                                                                                                                                   \\
            \cmidrule(lr){2-3}
                                     & w/o \schemename                                                                                                                                                                                                                       & w/ \schemename                                                                                                                                                                                                                                                             \\
            \midrule
            ViT-S                    & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ViT-S_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-S_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-S_ImageNet_v3.pdf}}             & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ViT-S_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-S_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-S_RecombNet_all_v3.pdf}}                                   \\
                                     & $25.5\pm0.8$                                                                                                                                                                                                                          & $22.0\pm0.3$                                                                                                                                                                                                                                            & \grntxt{$-3.5$}  \\
            ViT-B                    & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ViT-B_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-B_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-B_ImageNet_v3.pdf}}             & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ViT-B_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-B_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-B_RecombNet_all_v3.pdf}}                                   \\
                                     & $25.4\pm0.4$                                                                                                                                                                                                                          & $19.0\pm0.2$                                                                                                                                                                                                                                            & \grntxt{$-6.4$}  \\
            ViT-L                    & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ViT-L_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-L_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-L_ImageNet_v3.pdf}}             & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ViT-L_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-L_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ViT-L_RecombNet_all_v3.pdf}}                                   \\
                                     & $24.3\pm1.1$                                                                                                                                                                                                                          & $11.7\pm0.7$                                                                                                                                                                                                                                            & \grntxt{$-12.6$} \\
            \midrule
            DeiT-S                   & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/DeiT-S_ImageNet_vNone.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-S_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-S_ImageNet_v3.pdf}  }     & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/DeiT-S_fornet_all_linear_v1.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-S_fornet_all_linear_v2.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-S_fornet_all_linear_v3.pdf}}                    \\
                                     & $20.4 \pm 0.2$                                                                                                                                                                                                                        & $21.2 \pm 0.1$                                                                                                                                                                                                                                          & \gtxt{$+0.8$}    \\
            DeiT-B                   & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/DeiT-B_ImageNet_vNone.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-B_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-B_ImageNet_v3.pdf}     }  & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/DeiT-B_fornet_all_cos_v1.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-B_fornet_all_cos_v2.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-B_fornet_all_cos_v3.pdf}}                             \\
                                     & $19.0 \pm 0.7$                                                                                                                                                                                                                        & $19.0 \pm 0.2$                                                                                                                                                                                                                                          & \gtxt{$\pm0.0$}  \\
            DeiT-L                   & \raisebox{-6pt}{ \includegraphics[width=.08\columnwidth]{img/DeiT-L_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-L_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-L_ImageNet_v3.pdf}   }      & \raisebox{-6pt}{ \includegraphics[width=.08\columnwidth]{img/DeiT-L_fornet_all_cos_v1.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-L_fornet_all_cos_v2.pdf} \includegraphics[width=.08\columnwidth]{img/DeiT-L_fornet_all_cos_v3.pdf} }                           \\
                                     & $21.2 \pm 0.2$                                                                                                                                                                                                                        & $18.0 \pm 0.2$                                                                                                                                                                                                                                          & \grntxt{$-3.2$}  \\
            \midrule
            Swin-Ti                  & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/Swin-Ti_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-Ti_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-Ti_ImageNet_v3.pdf}}       & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/Swin-Ti_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-Ti_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-Ti_RecombNet_all_v3.pdf}}                             \\
                                     & $25.0\pm0.7$                                                                                                                                                                                                                          & $16.5\pm0.2$                                                                                                                                                                                                                                            & \grntxt{$-8.5$}  \\
            Swin-S                   & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/Swin-S_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-S_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-S_ImageNet_v3.pdf}}          & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/Swin-S_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-S_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/Swin-S_RecombNet_all_v3.pdf}}                                \\
                                     & $23.2\pm0.1$                                                                                                                                                                                                                          & $15.6\pm0.2$                                                                                                                                                                                                                                            & \grntxt{$-7.6$}  \\
            \midrule
            ResNet50                 & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ResNet50_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet50_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet50_ImageNet_v3.pdf}}    & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ResNet50_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet50_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet50_RecombNet_all_v3.pdf}}                          \\
                                     & $26.3\pm0.3$                                                                                                                                                                                                                          & $19.7\pm0.3$                                                                                                                                                                                                                                            & \grntxt{$-6.6$}  \\
            ResNet101                & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ResNet101_ImageNet_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet101_ImageNet_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet101_ImageNet_v3.pdf}} & \raisebox{-6pt}{\includegraphics[width=.08\columnwidth]{img/ResNet101_RecombNet_all_v1.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet101_RecombNet_all_v2.pdf} \includegraphics[width=.08\columnwidth]{img/ResNet101_RecombNet_all_v3.pdf}}                       \\
                                     & $23.0\pm0.3$                                                                                                                                                                                                                          & $19.9\pm0.2$                                                                                                                                                                                                                                            & \grntxt{$-3.1$}  \\
            \bottomrule
        \end{tabular} }
    \includegraphics[width=.8\columnwidth]{img/colorbar_horizontal.pdf}
\end{table}

\textbf{Center Bias.}
With \schemename we have unique control over the position of the foreground object in the image.
This lets us quantify the center bias of models trained with and without \schemename.
We divide the image into a $3 \times 3$ grid and evaluate model accuracy when the (scaled-down) foreground object is in each of the $9$ grid cells.
Each cell's accuracy is divided by the accuracy in the center cell for normalization, which gives us the relative performance drop when the foreground is in each part of the image.
The center bias is calculated as one minus the average of the minimum performance of a corner cell and the minimum performance of a side cell:
% \begin{align}
%     \begin{split}
%         & \text{Center Bias} =                                                                                                                                                          \\
%         & \hspace{7pt} 1 - \frac{\min\limits_{a, b \in \{0, 2\}} \text{Acc}(\text{cell}_{(a, b)}) + \min\limits_{\substack{a=1 \text{ or } b=1 \\ a \neq b}} \text{Acc}(\text{cell}_{(a, b)})}{2 \text{Acc}(\text{cell}_{(1, 1)})}
%     \end{split}
% \end{align}
\begin{align} \label{eq:center-bias}
    \text{Center Bias} = 1 - \frac{\min\limits_{c \in \text{sides}} \text{Acc}(c) + \min\limits_{c \in \text{corners}} \text{Acc}(c)}{2 \text{Acc}(c_\text{center})}
\end{align}
\Cref{tab:center-bias} visualizes the center bias of three instantiations of each model.
Performance is generally highest in the center and lowest in the four corners.
Interestingly, ImageNet-trained models perform slightly better when the foreground object is on the right side of the image, compared to the left side, despite our use of random flipping with a probability of $0.5$ during training.
% Training on \name reduces the center bias of all models by at least half.
Using \schemename significantly reduces center bias across models, with a more uniform performance especially across the middle row.
% Their accuracy is higher in the center left and right cells than in the center top and bottom ones, which is not the case for ImageNet-trained models.
% This demonstrates that \schemename promotes a more uniform spatial attention distribution, counteracting the center-bias of ImageNet.
Thus, \schemename makes the model recognize objects across a wider spatial distribution, counteracting the center-bias of ImageNet.

\begin{figure}[t!]
    \centering
    \includegraphics[width=\columnwidth]{img/size_bias_grid.pdf}
    \caption{Evaluation of the size bias of models trained on ImageNet. We plot the accuracy relative to the accuracy when using the default size ($f_\text{size} = 1.0$).}
    \label{fig:size-bias}
\end{figure}

\textbf{Size Bias.}
Finally, we evaluate the impact of different sized foreground objects on the accuracy.
For this evaluation, we use the \emph{mean} foreground size strategy.
We introduce a size factor $f_\text{size}$ by which we additionally scale the foreground object before pasting it onto the background.
Results are normalized by the accuracy when using $f_\text{size} = 1.0$.
\Cref{fig:size-bias} shows the size bias curves of models trained with and without \schemename.
% When training on \name, the resulting model keeps it's good performance on smaller foreground objects, while models trained on ImageNet fall of faster and lower.
Models trained using \schemename maintain perform better, especially with smaller foreground objects.
%, when ImageNet-trained models exhibit a more rapid performance decline.
Therefore, \schemename-training improves robustness to variations in object scale, especially for larger models.
