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ter on GeoImageNet has more of a uniform distribution. For
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fMoW, we can conclude that each cluster contain samples
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from most of the classes. Finally, when adding the geo-
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location classification task into the contrastive learning we
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tuneαandβto be 1.
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Methods We compare our unsupervised learning approach
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tosupervised learning for image recognition task. For ob-
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ject detection, and semantic segmentation we compare them
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Figure 8: Top andBottom show the distributions of the
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fMoW and GeoImageNet clusters.
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6
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to pre-trained weights obtained using (a) supervised learn-
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ing, and (b) random initilization while fine-tuning on the
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target task dataset. Finally, for ablation analysis we provide
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results using different combinations of our methods. When
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appending only geo-location classification task or temporal
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positives into MoCo-v2 we use MoCo-v2+Geo andMoCo-
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v2+TP . When adding both of our approaches into MoCo-
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v2we use MoCo-v2+Geo+TP .
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5.1. Experiments on fMoW
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We first perform experiments on fMoW image recogni-
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tion task. Similar to the common protocol of evaluating un-
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supervised pre-training methods [3, 13], we freeze the fea-
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tures and train a supervised linear classifier. However, in
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practice, it is more common to finetune the features end-to-
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end in a downstream task. For completeness and a better
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comparison, we report end-to-end finetuning results for the
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62-class fMoW classification as well. We report both top-1
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accuracy and F1-scores for this task.
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BackboneF1-Score↑
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(Frozen/Finetune)Accuracy↑
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(Frozen/Finetune)
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Sup. Learning (IN wts. init.) *ResNet50 -/64.72 -/69.07
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Sup. Learning (Scratch) * ResNet50 -/64.71 -/69.05
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Geoloc. Learning * ResNet50 48.96/52.23 52.40/56.59
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MoCo-V2 (pre. on IN) ResNet50 31.55/57.36 37.05/62.90
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MoCo-V2 ResNet50 55.47/60.61 60.69/64.34
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MoCo-V2+Geo ResNet50 61.60/66.60 64.07/69.04
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MoCo-V2+TP ResNet50 64.53/67.34 68.32/71.55
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MoCo-V2+Geo+TP ResNet50 63.13/66.56 66.33/70.60
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Table 1: Experiments on fMoW on classifying single im-
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ages. * indicates a model trained up to epoch with the high-
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est accuracy on the validation set. We use the same set up
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for Sup. Learning and Geoloc. Learning in the remaining
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experiments. Frozen corresponds to linear classification on
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frozen features. Finetune corresponds to end-to-end fine-
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tuning results for the fmow classification.
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Classifying Single Images In Table 1, we report the results
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on single image classification on fMoW. We would like to
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highlight that in this case we classify each image individ-
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ually. In other words, we do not use the prior information
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that multiple images over the same area (x1
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i,x2
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i,...,xTi
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i)
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have the same labels (yi,yi,...,yi). For evaluation, we
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use 53,041 images. Our results on this task (linear classi-
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fication on frozen features) show that MoCo-v2 performs
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reasonably well on a large-scale dataset with 60.69% accu-
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racy, 8%less than the supervised learning methods. Sup.
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Learning (IN wts. init.) andSup. Learning (Scratch) cor-
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respond to supervised learning method starting from ima-
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genet pre-trained weights and random weights respectively.
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This result aligns with MoCo-v2’s performance on the Ima-
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geNet dataset [3]. Next, by incorporating geo-location clas-
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sification task into MoCo-v2, we improve by 3.38% in top-
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1 classification accuracy. We further improve the resultsto68.32% using temporal positives, bridging the gap be-
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tween the MoCo-v2 baseline and supervised learning to less
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than1%. However, when we perform end-to-end finetun-
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ing for the classification task, we observe that our method
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surpasses the supervised learning methods by more than
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2%. For completeness, we also include results for MoCo-
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v2 pre-trained on Imagenet dataset (4th row in Table 1) and
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find that the distribution shift between Imagenet and down-
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stream dataset leads to suboptimal performance.
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Classifying Temporal Data In the next step, we change
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how we perform testing across multiple images over an
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area at different times. In this case, we predict labels
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from images over an area i.e. make a prediction for each
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t∈{1,...,Ti}, and average the predictions from that area.
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We then use the most confident class prediction to get area-
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specific class predictions. In this case, we evaluate the per-
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formance on 11,231 unique areas that are represented by
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multiple images at different times. Our results in Table 2
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show that doing area-specific inference improves the classi-
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fication accuracies by 4-8%over image-specific inference.
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Even incorporating temporal positives, we can improve the
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accuracy by 6.1%by switching from image classification to
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temporal data classification. Overall, our methods outper-
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form the baseline Moco-v2 by 4-6%and supervised learn-
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ing by 1-2%. Here we only report temporal classification
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on top of frozen features.
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Backbone F1-Score↑ Accuracy↑
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Sup. Learning (IN wts. init.) *ResNet50 68.72 (+4.01) 73.22 (+4.15)
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Sup. Learning (Scratch) * ResNet50 68.73 (+4.02) 73.24 (+4.19)
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Geoloc. Learning * ResNet50 52.01 (+3.05) 56.12 (+3.72)
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MoCo-V2 (pre. on IN) ResNet50 35.93 (+4.38) 42.56 (+5.51)
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MoCo-V2 ResNet50 63.96 (+8.49) 68.64 (+7.95)
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MoCo-V2+Geo ResNet50 66.93 (+5.33) 70.48 (+6.41)
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MoCo-V2+TP ResNet50 70.11 (+5.58) 74.42 (+6.10)
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