Open-vocabulary querying in 3D space is challenging but essential for scene understanding tasks such as object localization and segmentation. Language-embedded scene representations have made progress by incorporating language features into 3D spaces. However their efficacy heavily depends on neural networks that are resource-intensive in training and rendering. Although recent 3D Gaussians offer efficient and high-quality novel view synthesis directly embedding language features in them leads to prohibitive memory usage and decreased performance. In this work we introduce Language Embedded 3D Gaussians a novel scene representation for open-vocabulary query tasks. Instead of embedding high-dimensional raw semantic features on 3D Gaussians we propose a dedicated quantization scheme that drastically alleviates the memory requirement and a novel embedding procedure that achieves smoother yet high accuracy query countering the multi-view feature inconsistencies and the high-frequency inductive bias in point-based representations. Our comprehensive experiments show that our representation achieves the best visual quality and language querying accuracy across current language-embedded representations while maintaining real-time rendering frame rates on a single desktop GPU.
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Versatile Medical Image Segmentation Learned from Multi-Source Datasets via Model Self-Disambiguation
PDF ↗A versatile medical image segmentation model applicable to images acquired with diverse equipment and protocols can facilitate model deployment and maintenance. However building such a model typically demands a large diverse and fully annotated dataset which is challenging to obtain due to the labor-intensive nature of data curation. To address this challenge we propose a cost-effective alternative that harnesses multi-source data with only partial or sparse segmentation labels for training substantially reducing the cost of developing a versatile model. We devise strategies for model self-disambiguation prior knowledge incorporation and imbalance mitigation to tackle challenges associated with inconsistently labeled multi-source data including label ambiguity and modality dataset and class imbalances. Experimental results on a multi-modal dataset compiled from eight different sources for abdominal structure segmentation have demonstrated the effectiveness and superior performance of our method compared to state-of-the-art alternative approaches. We anticipate that its cost-saving features which optimize the utilization of existing annotated data and reduce annotation efforts for new data will have a significant impact in the field.
We introduce Florence-2 a novel vision foundation model with a unified prompt-based representation for various computer vision and vision-language tasks. While existing large vision models excel in transfer learning they struggle to perform diverse tasks with simple instructions a capability that implies handling the complexity of various spatial hierarchy and semantic granularity. Florence-2 was designed to take text-prompt as task instructions and generate desirable results in text forms whether it be captioning object detection grounding or segmentation. This multi-task learning setup demands large-scale high-quality annotated data. To this end we co-developed FLD-5B that consists of 5.4 billion comprehensive visual annotations on 126 million images using an iterative strategy of automated image annotation and model refinement. We adopted a sequence-to-sequence structure to train Florence-2 to perform versatile and comprehensive vision tasks. Extensive evaluations on numerous tasks demonstrated Florence-2 to be a strong vision foundation model contender with unprecedented zero-shot and fine-tuning capabilities.
From SAM to CAMs: Exploring Segment Anything Model for Weakly Supervised Semantic Segmentation
PDF ↗Weakly Supervised Semantic Segmentation (WSSS) aims to learn the concept of segmentation using image-level class labels. Recent WSSS works have shown promising results by using the Segment Anything Model (SAM) a foundation model for segmentation during the inference phase. However we observe that these methods can still be vulnerable to the noise of class activation maps (CAMs) serving as initial seeds. As a remedy this paper introduces From-SAM-to-CAMs (S2C) a novel WSSS framework that directly transfers the knowledge of SAM to the classifier during the training process enhancing the quality of CAMs itself. S2C comprises SAM-segment Contrasting (SSC) and a CAM-based prompting module (CPM) which exploit SAM at the feature and logit levels respectively. SSC performs prototype-based contrasting using SAM's automatic segmentation results. It constrains each feature to be close to the prototype of its segment and distant from prototypes of the others. Meanwhile CPM extracts prompts from the CAM of each class and uses them to generate class-specific segmentation masks through SAM. The masks are aggregated into unified self-supervision based on the confidence score designed to consider the reliability of both SAM and CAMs. S2C achieves a new state-of-the-art performance across all benchmarks outperforming existing studies by significant margins. The code is available at https://github.com/sangrockEG/S2C.
Dilated convolution which expands the receptive field by inserting gaps between its consecutive elements is widely employed in computer vision. In this study we propose three strategies to improve individual phases of dilated convolution from the view of spectrum analysis. Departing from the conventional practice of fixing a global dilation rate as a hyperparameter we introduce Frequency-Adaptive Dilated Convolution (FADC) which dynamically adjusts dilation rates spatially based on local frequency components. Subsequently we design two plug-in modules to directly enhance effective bandwidth and receptive field size. The Adaptive Kernel (AdaKern) module decomposes convolution weights into low-frequency and high-frequency components dynamically adjusting the ratio between these components on a per-channel basis. By increasing the high-frequency part of convolution weights AdaKern captures more high-frequency components thereby improving effective bandwidth. The Frequency Selection (FreqSelect) module optimally balances high- and low-frequency components in feature representations through spatially variant reweighting. It suppresses high frequencies in the background to encourage FADC to learn a larger dilation thereby increasing the receptive field for an expanded scope. Extensive experiments on segmentation and object detection consistently validate the efficacy of our approach. The code is made publicly available at https://github.com/Linwei-Chen/FADC.
We present GALA a framework that takes as input a single-layer clothed 3D human mesh and decomposes it into complete multi-layered 3D assets. The outputs can then be combined with other assets to create novel clothed human avatars with any pose. Existing reconstruction approaches often treat clothed humans as a single-layer of geometry and overlook the inherent compositionality of humans with hairstyles clothing and accessories thereby limiting the utility of the meshes for down-stream applications. Decomposing a single-layer mesh into separate layers is a challenging task because it requires the synthesis of plausible geometry and texture for the severely occluded regions. Moreover even with successful decomposition meshes are not normalized in terms of poses and body shapes failing coherent composition with novel identities and poses. To address these challenges we propose to leverage the general knowledge of a pretrained 2D diffusion model as geometry and appearance prior for humans and other assets. We first separate the input mesh using the 3D surface segmentation extracted from multi-view 2D segmentations. Then we synthesize the missing geometry of different layers in both posed and canonical spaces using a novel pose-guided Score Distillation Sampling (SDS) loss. Once we complete inpainting high-fidelity 3D geometry we also apply the same SDS loss to its texture to obtain the complete appearance including the initially occluded regions. Through a series of decomposition steps we obtain multiple layers of 3D assets in a shared canonical space normalized in terms of poses and human shapes hence supporting effortless composition to novel identities and reanimation with novel poses. Our experiments demonstrate the effectiveness of our approach for decomposition canonicalization and composition tasks compared to existing solutions.
This paper proposes a coupled learning framework to break the performance bottleneck of infrared-visible image fusion and segmentation called MRFS. By leveraging the intrinsic consistency between vision and semantics it emphasizes mutual reinforcement rather than treating these tasks as separate issues. First we embed weakened information recovery and salient information integration into the image fusion task employing the CNN-based interactive gated mixed attention (IGM-Att) module to extract high-quality visual features. This aims to satisfy human visual perception producing fused images with rich textures high contrast and vivid colors. Second a transformer-based progressive cycle attention (PC-Att) module is developed to enhance semantic segmentation. It establishes single-modal self-reinforcement and cross-modal mutual complementarity enabling more accurate decisions in machine semantic perception. Then the cascade of IGM-Att and PC-Att couples image fusion and semantic segmentation tasks implicitly bringing vision-related and semantics-related features into closer alignment. Therefore they mutually provide learning priors to each other resulting in visually satisfying fused images and more accurate segmentation decisions. Extensive experiments on public datasets showcase the advantages of our method in terms of visual satisfaction and decision accuracy. The code is publicly available at https://github.com/HaoZhang1018/MRFS.
While large multimodal models (LMMs) have achieved remarkable progress generating pixel-level masks for image reasoning tasks involving multiple open-world targets remains a challenge. To bridge this gap we introduce PixelLM an effective and efficient LMM for pixel-level reasoning and understanding. Central to PixelLM are a novel lightweight pixel decoder and a comprehensive segmentation codebook. The decoder efficiently produces masks from the hidden embeddings of the codebook tokens which encode detailed target-relevant information. With this design PixelLM harmonizes with the structure of popular LMMs and avoids the need for additional costly segmentation models. Furthermore we propose a token fusion method to enhance the model's ability to differentiate between multiple targets leading to substantially improved mask quality. To advance research in this area we construct MUSE a high-quality multi-target reasoning segmentation benchmark. PixelLM excels across various pixel-level image reasoning and understanding tasks outperforming well-established methods in multiple benchmarks including MUSE and multi-referring segmentation. Comprehensive ablations confirm the efficacy of each proposed component. All code models and datasets will be publicly available.
Segmentation-based scene text detection algorithms that are accurate to the pixel level can satisfy the detection of arbitrary shape scene text and have received widespread attention. On the one hand due to the complexity and diversity of the scene text the convolution with a fixed kernel size has some limitations in extracting the visual features of the scene text. On the other hand most of the existing segmentation-based algorithms only segment the center of the text losing information such as the edges and directions of the text with limited detection accuracy. There are also some improved algorithms that use iterative corrections or introduce other multiple information to improve text detection accuracy but at the expense of efficiency. To address these issues this paper proposes a simple and effective scene text detection method the Kernel Adaptive Convolution which is designed with a Kernel Adaptive Convolution Module for scene text detection via predicting the distance map. Specifically first we design an extensible kernel adaptive convolution module (KACM) to extract visual features from multiple convolutions with different kernel sizes in an adaptive manner. Secondly our method predicts the text distance map under the supervision of a priori information (including direction map and foreground segmentation map) and completes the text detection from the predicted distance map. Experiments on four publicly available datasets prove the effectiveness of our algorithm in which the accuracy and efficiency of both the Total-Text and TD500 outperform the state-of-the-art algorithm. The algorithm efficiency is improved while the accuracy is competitive on ArT and CTW1500.
This paper proposes LLaFS the first attempt to leverage large language models (LLMs) in few-shot segmentation. In contrast to the conventional few-shot segmentation methods that only rely on the limited and biased information from the annotated support images LLaFS leverages the vast prior knowledge gained by LLM as an effective supplement and directly uses the LLM to segment images in a few-shot manner. To enable the text-based LLM to handle image-related tasks we carefully design an input instruction that allows the LLM to produce segmentation results represented as polygons and propose a region-attribute table to simulate the human visual mechanism and provide multi-modal guidance. We also synthesize pseudo samples and use curriculum learning for pretraining to augment data and achieve better optimization. LLaFS achieves state-of-the-art results on multiple datasets showing the potential of using LLMs for few-shot computer vision tasks.
Infer from What You Have Seen Before: Temporally-dependent Classifier for Semi-supervised Video Segmentation
PDF ↗Due to high expense of human labor one major challenge for semantic segmentation in real-world scenarios is the lack of sufficient pixel-level labels which is more serious when processing video data. To exploit unlabeled data for model training semi-supervised learning methods attempt to construct pseudo labels or various auxiliary constraints as supervision signals. However most of them just process video data as a set of independent images in a per-frame manner. The rich temporal relationships are ignored which can serve as valuable clues for representation learning. Besides this per-frame recognition paradigm is quite different from that of humans. Actually benefited from the internal temporal relevance of video data human would wisely use the distinguished semantic concepts in historical frames to aid the recognition of the current frame. Motivated by this observation we propose a novel temporally-dependent classifier (TDC) to mimic the human-like recognition procedure. Comparing to the conventional classifier TDC can guide the model to learn a group of temporally-consistent semantic concepts across frames which essentially provides an implicit and effective constraint. We conduct extensive experiments on Cityscapes and CamVid and the results demonstrate the superiority of our proposed method to previous state-of-the-art methods. The code is available at https://github.com/jfzhuang/TDC.
Existing NeRF-based inverse rendering methods suppose that scenes are exclusively illuminated by distant light sources neglecting the potential influence of emissive sources within a scene. In this work we confront this limitation using LDR multi-view images captured with emissive sources turned on and off. Two key issues must be addressed: 1) ambiguity arising from the limited dynamic range along with unknown lighting details and 2) the expensive computational cost in volume rendering to backtrace the paths leading to final object colors. We present a novel approach ESR-NeRF leveraging neural networks as learnable functions to represent ray-traced fields. By training networks to satisfy light transport segments we regulate outgoing radiances progressively identifying emissive sources while being aware of reflection areas. The results on scenes encompassing emissive sources with various properties demonstrate the superiority of ESR-NeRF in qualitative and quantitative ways. Our approach also extends its applicability to the scenes devoid of emissive sources achieving lower CD metrics on the DTU dataset.
We present GigaPose a fast robust and accurate method for CAD-based novel object pose estimation in RGB images. GigaPose first leverages discriminative "templates" rendered images of the CAD models to recover the out-of-plane rotation and then uses patch correspondences to estimate the four remaining parameters. Our approach samples templates in only a two-degrees-of-freedom space instead of the usual three and matches the input image to the templates using fast nearest-neighbor search in feature space results in a speedup factor of 35x compared to the state of the art. Moreover GigaPose is significantly more robust to segmentation errors. Our extensive evaluation on the seven core datasets of the BOP challenge demonstrates that it achieves state-of-the-art accuracy and can be seamlessly integrated with existing refinement methods. Additionally we show the potential of GigaPose with 3D models predicted by recent work on 3D reconstruction from a single image relaxing the need for CAD models and making 6D pose object estimation much more convenient. Our source code and trained models are publicly available at https://github.com/nv-nguyen/gigaPose
Perception plays a crucial role in various robot applications. However existing well-annotated datasets are biased towards autonomous driving scenarios while unlabelled SLAM datasets are quickly over-fitted and often lack environment and domain variations. To expand the frontier of these fields we introduce a comprehensive dataset named MCD (Multi-Campus Dataset) featuring a wide range of sensing modalities high-accuracy ground truth and diverse challenging environments across three Eurasian university campuses. MCD comprises both CCS (Classical Cylindrical Spinning) and NRE (Non-Repetitive Epicyclic) lidars high-quality IMUs (Inertial Measurement Units) cameras and UWB (Ultra-WideBand) sensors. Furthermore in a pioneering effort we introduce semantic annotations of 29 classes over 59k sparse NRE lidar scans across three domains thus providing a novel challenge to existing semantic segmentation research upon this largely unexplored lidar modality. Finally we propose for the first time to the best of our knowledge continuous-time ground truth based on optimization-based registration of lidar-inertial data on large survey-grade prior maps which are also publicly released each several times the size of existing ones. We conduct a rigorous evaluation of numerous state-of-the-art algorithms on MCD report their performance and highlight the challenges awaiting solutions from the research community.
LiDAR localization is a fundamental task in robotics and computer vision which estimates the pose of a LiDAR point cloud within a global map. Scene Coordinate Regression (SCR) has demonstrated state-of-the-art performance in this task. In SCR a scene is represented as a neural network which outputs the world coordinates for each point in the input point cloud. However SCR treats all points equally during localization ignoring the fact that not all objects are beneficial for localization. For example dynamic objects and repeating structures often negatively impact SCR. To address this problem we introduce LiSA the first method that incorporates semantic awareness into SCR to boost the localization robustness and accuracy. To avoid extra computation or network parameters during inference we distill the knowledge from a segmentation model to the original SCR network. Experiments show the superior performance of LiSA on standard LiDAR localization benchmarks compared to state-of-the-art methods. Applying knowledge distillation not only preserves high efficiency but also achieves higher localization accuracy than introducing extra semantic segmentation modules. We also analyze the benefit of semantic information for LiDAR localization. Our code is released at https://github.com/Ybchun/LiSA.
We introduce the new setting of open-vocabulary object 6D pose estimation in which a textual prompt is used to specify the object of interest. In contrast to existing approaches in our setting (i) the object of interest is specified solely through the textual prompt (ii) no object model (e.g. CAD or video sequence) is required at inference and (iii) the object is imaged from two RGBD viewpoints of different scenes. To operate in this setting we introduce a novel approach that leverages a Vision-Language Model to segment the object of interest from the scenes and to estimate its relative 6D pose. The key of our approach is a carefully devised strategy to fuse object-level information provided by the prompt with local image features resulting in a feature space that can generalize to novel concepts. We validate our approach on a new benchmark based on two popular datasets REAL275 and Toyota-Light which collectively encompass 34 object instances appearing in four thousand image pairs. The results demonstrate that our approach outperforms both a well-established hand-crafted method and a recent deep learning-based baseline in estimating the relative 6D pose of objects in different scenes. Code and dataset are available at https://jcorsetti.github.io/oryon.
Dispel Darkness for Better Fusion: A Controllable Visual Enhancer based on Cross-modal Conditional Adversarial Learning
PDF ↗We propose a controllable visual enhancer named DDBF which is based on cross-modal conditional adversarial learning and aims to dispel darkness and achieve better visible and infrared modalities fusion. Specifically a guided restoration module (GRM) is firstly designed to enhance weakened information in the low-light visible modality. The GRM utilizes the light-invariant high-contrast characteristics of the infrared modality as the central target distribution and constructs a multi-level conditional adversarial sample set to enable continuous controlled brightness enhancement of visible images. Then we develop an information fusion module (IFM) to integrate the advantageous features of the enhanced visible image and the infrared image. Thanks to customized explicit information preservation and hue fidelity constraints the IFM produces visually pleasing results with rich textures significant contrast and vivid colors. The brightened visible image and the final fused image compose the dual output of our DDBF to meet the diverse visual preferences of users. We evaluate DDBF on the public datasets achieving state-of-the-art performances of low-light enhancement and information integration that is available for both day and night scenarios. The experiments also demonstrate that our DDBF is effective in improving decision accuracy for object detection and semantic segmentation. Moreover we offer a user-friendly interface for the convenient application of our model. The code is publicly available at https://github.com/HaoZhang1018/DDBF.
Segmenting affordance in 3D data is key for bridging perception and action in robots. Existing efforts mostly focus on the visual side and overlook the affordance knowledge from a semantic aspect. This oversight not only limits their generalization to unseen objects but more importantly hinders their synergy with large language models (LLMs) which are excellent task planners that can decompose an overarching command into agent-actionable instructions. With this regard we propose a novel task Language-guided Affordance Segmentation on 3D Object (LASO) which challenges a model to segment a 3D object's part relevant to a given affordance question. To facilitate the task we contribute a dataset comprising 19751 point-question pairs covering 8434 object shapes and 870 expert-crafted questions. As a pioneer solution we further propose PointRefer which highlights an adaptive fusion module to identify target affordance regions at different scales. To ensure a text-aware segmentation we adopt a set of affordance queries conditioned on linguistic cues to generate dynamic kernels. These kernels are further used to convolute with point features and generate a segmentation mask. Comprehensive experiments and analyses validate PointRefer's effectiveness. With these efforts We hope that LASO can steer the direction of 3D affordance guiding it towards enhanced integration with the evolving capabilities of LLMs.
The integration of visual inputs with large language models (LLMs) has led to remarkable advancements in multi-modal capabilities giving rise to vision large language models (VLLMs). However effectively harnessing LLMs for intricate visual perception tasks such as detection and segmentation remains a challenge. Conventional approaches achieve this by transforming perception signals (e.g. bounding boxes segmentation masks) into sequences of discrete tokens which struggle with the precision errors and introduces further complexities for training. In this paper we present a novel end-to-end framework named PerceptionGPT which represent the perception signals using LLM's dynamic token embedding. Specifically we leverage lightweight encoders and decoders to handle the perception signals in LLM's embedding space which takes advantage of the representation power of the high-dimensional token embeddings. Our approach significantly eases the training difficulties associated with the discrete representations in prior methods. Furthermore owing to our compact representation the inference speed is also greatly boosted. Consequently PerceptionGPT enables accurate flexible and efficient handling of complex perception signals. We validate the effectiveness of our approach through extensive experiments. The results demonstrate significant improvements over previous methods with only 4% trainable parameters and less than 25% training time.
Accurate 3D neuron segmentation from electron microscopy (EM) volumes is crucial for neuroscience research. However the complex neuron morphology often leads to over-merge and over-segmentation results. Recent advancements utilize 3D CNNs to predict a 3D affinity map with improved accuracy but suffer from two challenges: high computational cost and limited input size especially for practical deployment for large-scale EM volumes. To address these challenges we propose a novel method to leverage lightweight 2D CNNs for efficient neuron segmentation. Our method employs a 2D Y-shape network to generate two embedding maps from adjacent 2D sections which are then converted into an affinity map by measuring their embedding distance. While the 2D network better captures pixel dependencies inside sections with larger input sizes it overlooks inter-section dependencies. To overcome this we introduce a cross-dimension affinity distillation (CAD) strategy that transfers inter-section dependency knowledge from a 3D teacher network to the 2D student network by ensuring consistency between their output affinity maps. Additionally we design a feature grafting interaction (FGI) module to enhance knowledge transfer by grafting embedding maps from the 2D student onto those from the 3D teacher. Extensive experiments on multiple EM neuron segmentation datasets including a newly built one by ourselves demonstrate that our method achieves superior performance over state-of-the-art methods with only 1/20 inference latency.