We present a new method for efficient high-quality image segmentation of objects and scenes. By analogizing classical computer graphics methods for efficient rendering with over-and undersampling challenges faced in pixel labeling tasks, we develop a unique perspective of image segmentation as a rendering problem. From this vantage, we present the PointRend (Point-based Rendering) neural network module: a module that performs point-based segmentation predictions at adaptively selected locations based on an iterative subdivision algorithm. PointRend can be flexibly applied to both instance and semantic segmentation tasks by building on top of existing state-ofthe-art models. While many concrete implementations of the general idea are possible, we show that a simple design already achieves excellent results. Qualitatively, PointRend outputs crisp object boundaries in regions that are oversmoothed by previous methods. Quantitatively, PointRend yields significant gains on COCO and Cityscapes, for both instance and semantic segmentation. PointRend's efficiency enables output resolutions that are otherwise impractical in terms of memory or computation compared to existing approaches. Code has been made available at https:// github.com/facebookresearch/detectron2/ tree/master/projects/PointRend.

我们提出了一个令人尴尬的简单点注释方案，以收集弱监督，例如分割。除了边界框外，我们还收集了在每个边界框内均匀采样的一组点的二进制标签。我们表明，为完整的掩模监督开发的现有实例细分模型可以通过我们的方案收集基于点的监督而无缝培训。值得注意的是，接受了可可，Pascal VOC，CityScapes和LVI的面具R-CNN，每个物体只有10个带注释的随机点可实现94％ - 占其完全监督的性能的98％，为弱化的实例细分定下了强大的基线。新点注释方案的速度比注释完整的对象掩码快5倍，使高质量实例分割在实践中更容易访问。受基于点的注释形式的启发，我们提出了对Pointrend实例分割模块的修改。对于每个对象，称为隐式pointrend的新体系结构生成一个函数的参数，该函数可以使最终的点级掩码预测。隐式Pointrend更加简单，并使用单点级掩蔽丢失。我们的实验表明，新模块更适合基于点的监督。

两阶段和基于查询的实例分段方法取得了显着的结果。然而，他们的分段面具仍然非常粗糙。在本文中，我们呈现了用于高质量高效的实例分割的掩模转发器。我们的掩模转发器代替常规密集的张量，而不是在常规密集的张量上进行分解，并表示作为Quadtree的图像区域。我们基于变换器的方法仅处理检测到的错误易于树节点，并并行自我纠正其错误。虽然这些稀疏的像素仅构成总数的小比例，但它们对最终掩模质量至关重要。这允许掩模转换器以低计算成本预测高精度的实例掩模。广泛的实验表明，掩模转发器在三个流行的基准上优于当前实例分段方法，显着改善了COCO和BDD100K上的大型+3.0掩模AP的+3.0掩模AP的大余量和CityScapes上的+6.6边界AP。我们的代码和培训的型号将在http://vis.xyz/pub/transfiner提供。

The recently introduced panoptic segmentation task has renewed our community's interest in unifying the tasks of instance segmentation (for thing classes) and semantic segmentation (for stuff classes). However, current state-ofthe-art methods for this joint task use separate and dissimilar networks for instance and semantic segmentation, without performing any shared computation. In this work, we aim to unify these methods at the architectural level, designing a single network for both tasks. Our approach is to endow Mask R-CNN, a popular instance segmentation method, with a semantic segmentation branch using a shared Feature Pyramid Network (FPN) backbone. Surprisingly, this simple baseline not only remains effective for instance segmentation, but also yields a lightweight, topperforming method for semantic segmentation. In this work, we perform a detailed study of this minimally extended version of Mask R-CNN with FPN, which we refer to as Panoptic FPN, and show it is a robust and accurate baseline for both tasks. Given its effectiveness and conceptual simplicity, we hope our method can serve as a strong baseline and aid future research in panoptic segmentation.

We present a new, embarrassingly simple approach to instance segmentation. Compared to many other dense prediction tasks, e.g., semantic segmentation, it is the arbitrary number of instances that have made instance segmentation much more challenging. In order to predict a mask for each instance, mainstream approaches either follow the "detect-then-segment" strategy (e.g., Mask R-CNN), or predict embedding vectors first then use clustering techniques to group pixels into individual instances. We view the task of instance segmentation from a completely new perspective by introducing the notion of "instance categories", which assigns categories to each pixel within an instance according to the instance's location and size, thus nicely converting instance segmentation into a single-shot classification-solvable problem. We demonstrate a much simpler and flexible instance segmentation framework with strong performance, achieving on par accuracy with Mask R-CNN and outperforming recent single-shot instance segmenters in accuracy. We hope that this simple and strong framework can serve as a baseline for many instance-level recognition tasks besides instance segmentation. Code is available at https://git.io/AdelaiDet

本文提出了一种用于对象和场景的高质量图像分割的新方法。灵感来自于形态学图像处理技术中的扩张和侵蚀操作，像素级图像分割问题被视为挤压对象边界。从这个角度来看，提出了一种新颖且有效的\ textBF {边界挤压}模块。该模块用于从内侧和外侧方向挤压对象边界，这有助于精确掩模表示。提出了双向基于流的翘曲过程来产生这种挤压特征表示，并且设计了两个特定的损耗信号以监控挤压过程。边界挤压模块可以通过构建一些现有方法构建作为即插即用模块，可以轻松应用于实例和语义分段任务。此外，所提出的模块是重量的，因此具有实际使用的潜力。实验结果表明，我们简单但有效的设计可以在几个不同的数据集中产生高质量的结果。此外，边界上的其他几个指标用于证明我们对以前的工作中的方法的有效性。我们的方法对实例和语义分割的具有利于Coco和CityCapes数据集来产生重大改进，并且在相同的设置下以前的最先进的速度优于先前的最先进的速度。代码和模型将在\ url {https:/github.com/lxtgh/bsseg}发布。

We present a conceptually simple, flexible, and general framework for object instance segmentation. Our approach efficiently detects objects in an image while simultaneously generating a high-quality segmentation mask for each instance. The method, called Mask R-CNN, extends Faster R-CNN by adding a branch for predicting an object mask in parallel with the existing branch for bounding box recognition. Mask R-CNN is simple to train and adds only a small overhead to Faster R-CNN, running at 5 fps. Moreover, Mask R-CNN is easy to generalize to other tasks, e.g., allowing us to estimate human poses in the same framework. We show top results in all three tracks of the COCO suite of challenges, including instance segmentation, bounding-box object detection, and person keypoint detection. Without tricks, Mask R-CNN outperforms all existing, single-model entries on every task, including the COCO 2016 challenge winners. We hope our simple and effective approach will serve as a solid baseline and help ease future research in instance-level recognition. Code will be made available.

现代方法通常将语义分割标记为每个像素分类任务，而使用替代掩码分类处理实例级分割。我们的主要洞察力：掩码分类是足够的一般，可以使用完全相同的模型，丢失和培训过程来解决语义和实例级分段任务。在此观察之后，我们提出了一个简单的掩模分类模型，该模型预测了一组二进制掩码，每个模型与单个全局类标签预测相关联。总的来说，所提出的基于掩模分类的方法简化了语义和Panoptic分割任务的有效方法的景观，并显示出优异的经验结果。特别是，当类的数量大时，我们观察到掩码形成器优于每个像素分类基线。我们的面具基于分类的方法优于当前最先进的语义（ADE20K上的55.6 miou）和Panoptic Seation（Coco）模型的Panoptic Seationation（52.7 PQ）。

在本文中，我们专注于探索有效的方法，以更快，准确和域的不可知性语义分割。受到相邻视频帧之间运动对齐的光流的启发，我们提出了一个流对齐模块（FAM），以了解相邻级别的特征映射之间的\ textit {语义流}，并将高级特征广播到高分辨率特征有效地，有效地有效。 。此外，将我们的FAM与共同特征的金字塔结构集成在一起，甚至在轻量重量骨干网络（例如Resnet-18和DFNET）上也表现出优于其他实时方法的性能。然后，为了进一步加快推理过程，我们还提出了一个新型的封闭式双流对齐模块，以直接对齐高分辨率特征图和低分辨率特征图，在该图中我们将改进版本网络称为SFNET-LITE。广泛的实验是在几个具有挑战性的数据集上进行的，结果显示了SFNET和SFNET-LITE的有效性。特别是，建议的SFNET-LITE系列在使用RESNET-18主链和78.8 MIOU以120 fps运行的情况下，使用RTX-3090上的STDC主链在120 fps运行时，在60 fps运行时达到80.1 miou。此外，我们将四个具有挑战性的驾驶数据集（即CityScapes，Mapillary，IDD和BDD）统一到一个大数据集中，我们将其命名为Unified Drive细分（UDS）数据集。它包含不同的域和样式信息。我们基准了UDS上的几项代表性作品。 SFNET和SFNET-LITE仍然可以在UDS上取得最佳的速度和准确性权衡，这在如此新的挑战性环境中是强大的基准。所有代码和模型均可在https://github.com/lxtgh/sfsegnets上公开获得。

We propose a simple yet effective instance segmentation framework, termed CondInst (conditional convolutions for instance segmentation). Top-performing instance segmentation methods such as Mask R-CNN rely on ROI operations (typically ROIPool or ROIAlign) to obtain the final instance masks. In contrast, we propose to solve instance segmentation from a new perspective. Instead of using instancewise ROIs as inputs to a network of fixed weights, we employ dynamic instance-aware networks, conditioned on instances. CondInst enjoys two advantages: 1) Instance segmentation is solved by a fully convolutional network, eliminating the need for ROI cropping and feature alignment.2) Due to the much improved capacity of dynamically-generated conditional convolutions, the mask head can be very compact (e.g., 3 conv. layers, each having only 8 channels), leading to significantly faster inference. We demonstrate a simpler instance segmentation method that can achieve improved performance in both accuracy and inference speed. On the COCO dataset, we outperform a few recent methods including welltuned Mask R-CNN baselines, without longer training schedules needed.

我们呈现Fouriermask，它采用傅立叶系列与隐式的神经表示结合起来，以产生实例分段掩模。我们将傅里叶映射（FM）应用于坐标位置，并利用映射特征作为隐式表示的输入（基于坐标的多层Perceptron（MLP））。 FouriMASK学习为特定实例预测FM的系数，因此将FM适应特定对象。这允许Fouriermask广泛化以预测来自自然图像的实例分段掩模。由于隐式功能在输入坐标的域中是连续的，因此我们说明通过对输入像素坐标进行分采样，因此我们可以在推理期间生成更高的分辨率掩码。此外，我们在Fourimask的不确定预测上培训渲染器MLP（Fourrierrend），并说明它显着提高了面具的质量。与在相同输出分辨率的基线掩模R-CNN相比，Fourimask在MS Coco DataSet上显示竞争结果，并在更高分辨率上超越它。

在语义细分中，将高级上下文信息与低级详细信息集成至关重要。为此，大多数现有的分割模型都采用双线性启动采样和卷积来具有不同尺度的地图，然后以相同的分辨率对齐。但是，双线性启动采样模糊了这些特征地图和卷积中所学到的精确信息，这会产生额外的计算成本。为了解决这些问题，我们提出了隐式特征对齐函数（IFA）。我们的方法的灵感来自隐式神经表示的快速扩展的主题，在该主题中，基于坐标的神经网络用于指定信号字段。在IFA中，特征向量被视为表示2D信息字段。给定查询坐标，附近的具有相对坐标的特征向量是从多级特征图中获取的，然后馈入MLP以生成相应的输出。因此，IFA隐含地将特征图在不同级别对齐，并能够在任意分辨率中产生分割图。我们证明了IFA在多个数据集上的功效，包括CityScapes，Pascal环境和ADE20K。我们的方法可以与各种体系结构的改进结合使用，并在共同基准上实现最新的计算准确性权衡。代码将在https://github.com/hzhupku/ifa上提供。

Recent state-of-the-art one-stage instance segmentation model SOLO divides the input image into a grid and directly predicts per grid cell object masks with fully-convolutional networks, yielding comparably good performance as traditional two-stage Mask R-CNN yet enjoying much simpler architecture and higher efficiency. We observe SOLO generates similar masks for an object at nearby grid cells, and these neighboring predictions can complement each other as some may better segment certain object part, most of which are however directly discarded by non-maximum-suppression. Motivated by the observed gap, we develop a novel learning-based aggregation method that improves upon SOLO by leveraging the rich neighboring information while maintaining the architectural efficiency. The resulting model is named SODAR. Unlike the original per grid cell object masks, SODAR is implicitly supervised to learn mask representations that encode geometric structure of nearby objects and complement adjacent representations with context. The aggregation method further includes two novel designs: 1) a mask interpolation mechanism that enables the model to generate much fewer mask representations by sharing neighboring representations among nearby grid cells, and thus saves computation and memory; 2) a deformable neighbour sampling mechanism that allows the model to adaptively adjust neighbor sampling locations thus gathering mask representations with more relevant context and achieving higher performance. SODAR significantly improves the instance segmentation performance, e.g., it outperforms a SOLO model with ResNet-101 backbone by 2.2 AP on COCO \texttt{test} set, with only about 3\% additional computation. We further show consistent performance gain with the SOLOv2 model.

Feature pyramids are a basic component in recognition systems for detecting objects at different scales. But recent deep learning object detectors have avoided pyramid representations, in part because they are compute and memory intensive. In this paper, we exploit the inherent multi-scale, pyramidal hierarchy of deep convolutional networks to construct feature pyramids with marginal extra cost. A topdown architecture with lateral connections is developed for building high-level semantic feature maps at all scales. This architecture, called a Feature Pyramid Network (FPN), shows significant improvement as a generic feature extractor in several applications. Using FPN in a basic Faster R-CNN system, our method achieves state-of-the-art singlemodel results on the COCO detection benchmark without bells and whistles, surpassing all existing single-model entries including those from the COCO 2016 challenge winners. In addition, our method can run at 6 FPS on a GPU and thus is a practical and accurate solution to multi-scale object detection. Code will be made publicly available.

在重建掩码的实例分段网络的设计中，分段通常是其文字定义 - 分配每个像素标签。这导致了将问题视为匹配一个问题，其中一个目标是最小化重建和地面真相像素之间的损耗。重新思考重建网络作为发电机，我们定义了预测掩模作为GAN游戏框架的问题：分割网络生成掩码，鉴别器网络决定掩码的质量。为了演示这个游戏，我们对掩模R-CNN的普通分段框架显示了有效修改。我们发现，在特征空间中播放游戏比导致鉴别器和发电机之间的稳定训练的像素空间更有效，应该通过预测对象的上下文区域来替换预测对象坐标，并且整体对抗性损失有助于性能和消除每个不同数据域的任何自定义设置都需要。我们在各个域中测试我们的框架并报告手机回收，自动驾驶，大规模对象检测和医用腺体。我们观察到一般的GANS产生掩模，该掩模占克里克里德界，杂乱，小物体和细节，处于规则形状或异质和聚结形状的领域。我们的再现结果的代码可公开提供。

Image segmentation is a key topic in image processing and computer vision with applications such as scene understanding, medical image analysis, robotic perception, video surveillance, augmented reality, and image compression, among many others. Various algorithms for image segmentation have been developed in the literature. Recently, due to the success of deep learning models in a wide range of vision applications, there has been a substantial amount of works aimed at developing image segmentation approaches using deep learning models. In this survey, we provide a comprehensive review of the literature at the time of this writing, covering a broad spectrum of pioneering works for semantic and instance-level segmentation, including fully convolutional pixel-labeling networks, encoder-decoder architectures, multi-scale and pyramid based approaches, recurrent networks, visual attention models, and generative models in adversarial settings. We investigate the similarity, strengths and challenges of these deep learning models, examine the most widely used datasets, report performances, and discuss promising future research directions in this area.

图像分割是关于使用不同语义的分组像素，例如类别或实例成员身份，其中每个语义选择定义任务。虽然只有每个任务的语义不同，但目前的研究侧重于为每项任务设计专业架构。我们提出了蒙面关注掩模变压器（Mask2Former），这是一种能够寻址任何图像分段任务（Panoptic，实例或语义）的新架构。其关键部件包括屏蔽注意，通过限制预测掩模区域内的横向提取局部特征。除了将研究工作减少三次之外，它还优于四个流行的数据集中的最佳专业架构。最值得注意的是，Mask2Former为Panoptic semonation（Coco 57.8 PQ）设置了新的最先进的，实例分段（Coco上50.1 AP）和语义分割（ADE20K上的57.7 miou）。

In this paper, we propose a unified panoptic segmentation network (UPSNet) for tackling the newly proposed panoptic segmentation task. On top of a single backbone residual network, we first design a deformable convolution based semantic segmentation head and a Mask R-CNN style instance segmentation head which solve these two subtasks simultaneously. More importantly, we introduce a parameter-free panoptic head which solves the panoptic segmentation via pixel-wise classification. It first leverages the logits from the previous two heads and then innovatively expands the representation for enabling prediction of an extra unknown class which helps better resolve the conflicts between semantic and instance segmentation. Additionally, it handles the challenge caused by the varying number of instances and permits back propagation to the bottom modules in an end-to-end manner. Extensive experimental results on Cityscapes, COCO and our internal dataset demonstrate that our UPSNet achieves stateof-the-art performance with much faster inference. Code has been made available at: https://github.com/ uber-research/UPSNet. * Equal contribution.† This work was done when Hengshuang Zhao was an intern at Uber ATG.

The way that information propagates in neural networks is of great importance. In this paper, we propose Path Aggregation Network (PANet) aiming at boosting information flow in proposal-based instance segmentation framework. Specifically, we enhance the entire feature hierarchy with accurate localization signals in lower layers by bottom-up path augmentation, which shortens the information path between lower layers and topmost feature. We present adaptive feature pooling, which links feature grid and all feature levels to make useful information in each feature level propagate directly to following proposal subnetworks. A complementary branch capturing different views for each proposal is created to further improve mask prediction.These improvements are simple to implement, with subtle extra computational overhead. Our PANet reaches the 1 st place in the COCO 2017 Challenge Instance Segmentation task and the 2 nd place in Object Detection task without large-batch training. It is also state-of-the-art on MVD and Cityscapes. Code is available at https://github. com/ShuLiu1993/PANet.

建模长期依赖关系对于理解计算机视觉中的任务至关重要。尽管卷积神经网络（CNN）在许多视觉任务中都表现出色，但由于它们通常由当地核层组成，因此它们仍然限制捕获长期结构化关系。但是，完全连接的图（例如变形金刚中的自我发项操作）对这种建模是有益的，但是，其计算开销非常有用。在本文中，我们提出了一个动态图形消息传递网络，与建模完全连接的图形相比，该网络大大降低了计算复杂性。这是通过在图表中自适应采样节点（以输入为条件）来实现的，以传递消息传递。基于采样节点，我们动态预测节点依赖性滤波器权重和亲和力矩阵，以在它们之间传播信息。这种公式使我们能够设计一个自我发挥的模块，更重要的是，我们将基于变压器的新骨干网络用于图像分类预处理，并用于解决各种下游任务（对象检测，实例和语义细分）。使用此模型，我们在四个不同任务上的强，最先进的基线方面显示出显着改进。我们的方法还优于完全连接的图形，同时使用较少的浮点操作和参数。代码和型号将在https://github.com/fudan-zvg/dgmn2上公开提供。