Reviewerly/exHarmony huggingface dataset:
EventPoint: Self-Supervised Interest Point Detection and Description for Event-based Camera

This paper proposes a self-supervised learned local detector and descriptor, called EventPoint, for event stream/camera tracking and registration. Event-based cameras have grown in popularity because of their biological inspiration and low power consumption. Despite this, applying local features directly to the event stream is difficult due to its peculiar data structure. We propose a new time-surface-like event stream representation method called Ten-code. The event stream data processed by Tencode can obtain the pixel-level positioning of interest points while also simultaneously extracting descriptors through a neural network. Instead of using costly and unreliable manual annotation, our network leverages the prior knowledge of local feature extraction on color images and conducts self-supervised learning via homographic and spatio-temporal adaptation. To the best of our knowledge, our proposed method is the first research on event-based local features learning using a deep neural network. We provide comprehensive experiments of feature point detection and matching, and three public datasets are used for evaluation (i.e. DSEC, N-Caltech101, and HVGA ATIS Corner Dataset). The experimental findings demonstrate that our method outperforms SOTA in terms of feature point detection and description.
Cut-Paste Consistency Learning for Semi-Supervised Lesion Segmentation

Semi-supervised learning has the potential to improve the data-efficiency of training data-hungry deep neural networks, which is especially important for medical image analysis tasks where labeled data is scarce. In this work, we present a simple semi-supervised learning method for lesion segmentation tasks based on the ideas of cut-paste augmentation and consistency regularization. By exploiting the mask information available in the labeled data, we synthesize partially labeled samples from the unlabeled images so that the usual supervised learning objective (e.g., binary cross entropy) can be applied. Additionally, we introduce a background consistency term to regularize the training on the unlabeled background regions of the synthetic images. We empirically verify the effectiveness of the proposed method on two public lesion segmentation datasets, including an eye fundus photograph dataset and a brain CT scan dataset. The experiment results indicate that our method achieves consistent and superior performance over other self-training and consistency-based methods without introducing sophisticated network components.
Efficient Reference-based Video Super-Resolution (ERVSR): Single Reference Image Is All You Need

Reference-based video super-resolution (RefVSR) is a promising domain of super-resolution that recovers high-frequency textures of a video using reference video. The multiple cameras with different focal lengths in mobile devices aid recent works in RefVSR, which aim to super-resolve a low-resolution ultra-wide video by utilizing wide-angle videos. Previous works in RefVSR used all reference frames of a Ref video at each time step for the super-resolution of low-resolution videos. However, computation on higher-resolution images increases the runtime and memory consumption, hence hinders the practical application of RefVSR. To solve this problem, we propose an Efficient Reference-based Video Super-Resolution (ERVSR) that exploits a single reference frame to super-resolve whole low-resolution video frames. We introduce an attention-based feature align module and an aggregation upsampling module that attends LR features using the correlation between the reference and LR frames. The proposed ERVSR achieves 12× faster speed, 1/4 memory consumption than previous state-of-the-art RefVSR networks, and competitive performance on the RealMCVSR dataset while using a single reference image.
360MVSNet: Deep Multi-view Stereo Network with 360° Images for Indoor Scene Reconstruction

Recent multi-view stereo methods have achieved promising results with the advancement of deep learning techniques. Despite of the progress, due to the limited fields of view of regular images, reconstructing large indoor environments still requires collecting many images with sufficient visual overlap, which is quite labor-intensive. 360° images cover a much larger field of view than regular images and would facilitate the capture process. In this paper, we present 360MVSNet, the first deep learning network for multi-view stereo with 360° images. Our method combines uncertainty estimation with a spherical sweeping module for 360° images captured from multiple viewpoints in order to construct multi-scale cost volumes. By regressing volumes in a coarse-to-fine manner, high-resolution depth maps can be obtained. Furthermore, we have constructed EQMVS, a large-scale synthetic dataset that consists of over 50K pairs of RGB and depth maps in equirectangular projection. Experimental results demonstrate that our method can reconstruct large synthetic and real-world indoor scenes with significantly better completeness than previous traditional and learning-based methods while saving both time and effort in the data acquisition process.
Are Straight-Through gradients and Soft-Thresholding all you need for Sparse Training?

Turning the weights to zero when training a neural network helps in reducing the computational complexity at inference. To progressively increase the sparsity ratio in the network without causing sharp weight discontinuities during training, our work combines soft-thresholding and straight-through gradient estimation to update the raw, i.e. non-thresholded, version of zeroed weights. Our method, named ST-3 for straight-through/soft-thresholding/sparse-training <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , obtains SoA results, both in terms of accuracy/sparsity and accuracy/FLOPS trade-offs, when progressively increasing the sparsity ratio in a single training cycle. In particular, despite its simplicity, ST-3 favorably compares to the most recent methods, adopting differentiable formulations [42] or bio-inspired neuroregeneration principles [25]. This suggests that the key ingredients for effective sparsification primarily lie in the ability to give the weights the freedom to evolve smoothly across the zero state while progressively increasing the sparsity ratio.
I See-Through You: A Framework for Removing Foreground Occlusion in Both Sparse and Dense Light Field Images

Light field (LF) camera captures rich information from a scene. Using the information, the LF de-occlusion (LF-DeOcc) task aims to reconstruct the occlusion-free center view image. Existing LF-DeOcc studies mainly focus on the sparsely sampled (sparse) LF images where most of the occluded regions are visible in other views due to the large disparity. In this paper, we expand LF-DeOcc in more challenging datasets, densely sampled (dense) LF images, which are taken by a micro-lens-based portable LF camera. Due to the small disparity ranges of dense LF images, most of the background regions are invisible in any view. To apply LF-DeOcc in both LF datasets, we propose a framework, ISTY, which is defined and divided into three roles: (1) extract LF features, (2) define the occlusion, and (3) inpaint occluded regions. By dividing the framework into three specialized components according to the roles, the development and analysis can be easier. Furthermore, an explainable intermediate representation, an occlusion mask, can be obtained in the proposed framework. The occlusion mask is useful for comprehensive analysis of the model and other applications by manipulating the mask. In experiments, qualitative and quantitative results show that the proposed framework outperforms state-of-the-art LF-DeOcc methods in both sparse and dense LF datasets.
Nested Deformable Multi-head Attention for Facial Image Inpainting

Extracting adequate contextual information is an important aspect of any image inpainting method. To achieve this, ample image inpainting methods are available that aim to focus on large receptive fields. Recent advancements in the deep learning field with the introduction of transformers for image inpainting paved the way toward plausible results. Stacking multiple transformer blocks in a single layer causes the architecture to become computationally complex. In this context, we propose a novel lightweight architecture with a nested deformable attention-based transformer layer for feature fusion. The nested attention helps the network to focus on long-term dependencies from encoder and decoder features. Also, multi-head attention consisting of a deformable convolution is proposed to delve into the diverse receptive fields. With the advantage of nested and deformable attention, we propose a lightweight architecture for facial image inpainting. The results comparison on Celeb HQ [25] dataset using known (NVIDIA) and unknown (QD-IMD) masks and Places2 [57] dataset with NVIDIA masks along with extensive ablation study prove the superiority of the proposed approach for image inpainting tasks. The code is available at: https://github.com/shrutiphutke/NDMA_Facial_Inpainting.
Elimination of Non-Novel Segments at Multi-Scale for Few-Shot Segmentation

Few-shot segmentation aims to devise a generalizing model that segments query images from unseen classes during training with the guidance of a few support images whose class tally with the class of the query. There exist two domain-specific problems mentioned in the previous works, namely spatial inconsistency and bias towards seen classes. Taking the former problem into account, our method compares the support feature map with the query feature map at multi scales to become scale-agnostic. As a solution to the latter problem, a supervised model, called as base learner, is trained on available classes to accurately identify pixels belonging to seen classes. Hence, subsequent meta learner has a chance to discard areas belonging to seen classes with the help of an ensemble learning model that coordinates meta learner with the base learner. We simultaneously address these two vital problems for the first time and achieve state-of-the-art performances on both PASCAL-5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sup> and COCO-20 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sup> datasets.
Image Segmentation-based Unsupervised Multiple Objects Discovery

Unsupervised object discovery aims to localize objects in images, while removing the dependence on annotations required by most deep learning-based methods. To address this problem, we propose a fully unsupervised, bottom-up approach, for multiple objects discovery. The proposed approach is a two-stage framework. First, instances of object parts are segmented by using the intra-image similarity between self-supervised local features. The second step merges and filters the object parts to form complete object instances. The latter is performed by two CNN models that capture semantic information on objects from the entire dataset. We demonstrate that the pseudo-labels generated by our method provide a better precision-recall trade-off than existing single and multiple objects discovery methods. In particular, we provide state-of-the-art results for both unsupervised class-agnostic object detection and unsupervised image segmentation.
Rethinking the Data Annotation Process for Multiview 3D Pose Estimation with Active Learning and Self-Training

Pose estimation of the human body and hands is a fundamental problem in computer vision, and learning-based solutions require a large amount of annotated data. In this work, we improve the efficiency of the data annotation process for 3D pose estimation problems with Active Learning (AL) in a multiview setting. AL selects examples with the highest value to annotate under limited annotation budgets (time and cost), but choosing the selection strategy is often nontrivial. We present a framework to efficiently extend existing single-view AL strategies. We then propose two novel AL strategies that make full use of multiview geometry. Moreover, we demonstrate additional performance gains by incorporating pseudo-labels computed during the AL process, which is a form of self-training. Our system significantly outperforms simulated annotation baselines in 3D body and hand pose estimation on two large-scale benchmarks: CMU Panoptic Studio and InterHand2.6M. Notably, on CMU Panoptic Studio, we are able to reduce the turn-around time by 60% and annotation cost by 80% when compared to the conventional annotation process.
Intention-Conditioned Long-Term Human Egocentric Action Anticipation

To anticipate how a person would act in the future, it is essential to understand the human intention since it guides the subject towards a certain action. In this paper, we propose a hierarchical architecture which assumes a sequence of human action (low-level) can be driven from the human intention (high-level). Based on this, we deal with long-term action anticipation task in egocentric videos. Our framework first extracts this low- and high-level human information over the observed human actions in a video through a Hierarchical Multi-task Multi-Layer Perceptrons Mixer (H3M). Then, we constrain the uncertainty of the future through an Intention-Conditioned Variational Auto-Encoder (I-CVAE) that generates multiple stable predictions of the next actions that the observed human might perform. By leveraging human intention as high-level information, we claim that our model is able to anticipate more time-consistent actions in the long-term, thus improving the results over the baseline in Ego4D dataset. This work results in the state-of-the-art for Long-Term Anticipation (LTA) task in Ego4D by providing more plausible anticipated sequences, improving the anticipation scores of nouns and actions. Our work ranked first in both CVPR@2022 and ECCV@2022 Ego4D LTA Challenge.
Attribution-aware Weight Transfer: A Warm-Start Initialization for Class-Incremental Semantic Segmentation

In class-incremental semantic segmentation (CISS), deep learning architectures suffer from the critical problems of catastrophic forgetting and semantic background shift. Although recent works focused on these issues, existing classifier initialization methods do not address the background shift problem and assign the same initialization weights to both background and new foreground class classifiers. We propose to address the background shift with a novel classifier initialization method which employs gradient-based attribution to identify the most relevant weights for new classes from the classifier’s weights for the previous background and transfers these weights to the new classifier. This warm-start weight initialization provides a general solution applicable to several CISS methods. Furthermore, it accelerates learning of new classes while mitigating forgetting. Our experiments demonstrate significant improvement in mIoU compared to the state-of-the-art CISS methods on the Pascal-VOC 2012, ADE20K and Cityscapes datasets.
CountNet3D: A 3D Computer Vision Approach to Infer Counts of Occluded Objects

3D scene understanding is an important problem that has experienced great progress in recent years, in large part due to the development of state-of-the-art methods for 3D object detection. However, the performance of 3D object detectors can suffer in scenarios where extreme occlusion of objects is present, or the number of object classes is large. In this paper, we study the problem of inferring 3D counts from densely packed scenes with heterogeneous objects. This problem has applications to important tasks such as inventory management or automatic crop yield estimation. We propose a novel regression-based method, CountNet3D, that uses mature 2D object detectors for finegrained classification and localization, and a PointNet backbone for geometric embedding. The network processes fused data from images and point clouds for end-to-end learning of counts. We perform experiments on a novel synthetic dataset for inventory management in retail, which we construct and make publicly available to the community. Our results show that regression-based 3D counting methods systematically outperform detection-based methods, and reveal that directly learning from raw point clouds greatly assists count estimation under extreme occlusion. Finally, we study the effectiveness of CountNet3D on a large dataset of real-world scenes where extreme occlusion is present and achieve an error rate of 11.01% .
Couplformer: Rethinking Vision Transformer with Coupling Attention

With the development of the self-attention mechanism, the Transformer model has demonstrated its outstanding performance in the computer vision domain. However, the massive computation brought from the full attention mechanism became a heavy burden for memory consumption. Sequentially, the limitation of memory consumption hinders the deployment of the Transformer model on the embedded system where the computing resources are limited. To remedy this problem, we propose a novel memory economy attention mechanism named Couplformer, which decouples the attention map into two sub-matrices and generates the alignment scores from spatial information. Our method enables the Transformer model to improve time and memory efficiency while maintaining expressive power. A series of different scale image classification tasks are applied to evaluate the effectiveness of our model. The result of experiments shows that on the ImageNet-1K classification task, the Couplformer can significantly decrease 42% memory consumption compared with the regular Transformer. Meanwhile, it accesses sufficient accuracy requirements, which outperforms 0.56% on Top-1 accuracy and occupies the same memory footprint. Besides, the Couplformer achieves state-of-art performance in MS COCO 2017 object detection and instance segmentation tasks. As a result, the Couplformer can serve as an efficient backbone in visual tasks and provide a novel perspective on deploying attention mechanisms for researchers.
Surface normal estimation from optimized and distributed light sources using DNN-based photometric stereo

Photometric stereo (PS) is a major technique to recover surface normal for each pixel. However, since it assumes Lambertian surface and directional light to estimate the value, a large number of images are usually required to avoid the effects of outliers and noise. In this paper, we propose a technique to reduce the number of images by using distributed light sources, where the patterns are optimized by a deep neural network (DNN). In addition, to efficiently realize the distributed light, we use an optical diffuser with a video projector, where the diffuser is illuminated by the projector from behind, the illuminated area on the diffuser works as if an arbitrary-shaped area light. To estimate the surface normal using the distributed light source, we propose a near-light photometric stereo (NLPS) using DNN. Since optimization of the pattern of distributed light is achieved by a differentiable renderer, it is connected with NLPS network, achieving end-to-end learning. The experiments are conducted to show the successful estimation of the surface normal by our method from a small number of images.
IFQA: Interpretable Face Quality Assessment

Existing face restoration models have relied on general assessment metrics that do not consider the characteristics of facial regions. Recent works have therefore assessed their methods using human studies, which is not scalable and involves significant effort. This paper proposes a novel face-centric metric based on an adversarial framework where a generator simulates face restoration and a discriminator assesses image quality. Specifically, our per-pixel discriminator enables interpretable evaluation that cannot be provided by traditional metrics. Moreover, our metric emphasizes facial primary regions considering that even minor changes to the eyes, nose, and mouth significantly affect human cognition. Our face-oriented metric consistently surpasses existing general or facial image quality assessment metrics by impressive margins. We demonstrate the generalizability of the proposed strategy in various architectural designs and challenging scenarios. Interestingly, we find that our IFQA can lead to performance improvement as an objective function. The code and models are available at https://github.com/VCLLab/IFQA.
Two-level Data Augmentation for Calibrated Multi-view Detection

Data augmentation has proven its usefulness to improve model generalization and performance. While it is commonly applied in computer vision application when it comes to multi-view systems, it is rarely used. Indeed geometric data augmentation can break the alignment among views. This is problematic since multi-view data tend to be scarce and it is expensive to annotate.In this work we propose to solve this issue by introducing a new multi-view data augmentation pipeline that preserves alignment among views. Additionally to traditional augmentation of the input image we also propose a second level of augmentation applied directly at the scene level. When combined with our simple multi-view detection model, our two-level augmentation pipeline outperforms all existing baselines by a significant margin on the two main multi-view multi-person detection datasets WILD-TRACK and MultiviewX.
Continual Learning with Dependency Preserving Hypernetworks

Humans learn continually throughout their lifespan by accumulating diverse knowledge and fine-tuning it for future tasks. When presented with a similar goal, neural networks suffer from catastrophic forgetting if data distributions across sequential tasks are not stationary over the course of learning. An effective approach to address such continual learning (CL) problems is to use hypernetworks which generate task dependent weights for a target network. However, the continual learning performance of existing hypernetwork based approaches are affected by the assumption of independence of the weights across the layers in order to maintain parameter efficiency. To address this limitation, we propose a novel approach that uses a dependency preserving hypernetwork to generate weights for the target network while also maintaining the parameter efficiency. We propose to use recurrent neural network (RNN) based hypernetwork that can generate layer weights efficiently while allowing for dependencies across them. In addition, we propose novel regularisation and network growth techniques for the RNN based hypernetwork to further improve the continual learning performance. To demonstrate the effectiveness of the proposed methods, we conducted experiments on several image classification continual learning tasks and settings. We found that the proposed methods based on the RNN hypernetworks outperformed the baselines in all these CL settings and tasks.