人工评测

Progress in lighting estimation is tracked by computing existing image quality assessment (IQA) metrics on images from standard datasets. While this may appear to be a reasonable approach we demonstrate that doing so does not correlate to human preference when the estimated lighting is used to relight a virtual scene into a real photograph. To study this we design a controlled psychophysical experiment where human observers must choose their preference amongst rendered scenes lit using a set of lighting estimation algorithms selected from the recent literature and use it to analyse how these algorithms perform according to human perception. Then we demonstrate that none of the most popular IQA metrics from the literature taken individually correctly represent human perception. Finally we show that by learning a combination of existing IQA metrics we can more accurately represent human preference. This provides a new perceptual framework to help evaluate future lighting estimation algorithms. To encourage future research all (anonymised) perceptual data and code are available at https://lvsn.github.io/PerceptionMetric/.

To adequately utilize the available image evidence in multi-view video-based avatar modeling we propose TexVocab a novel avatar representation that constructs a texture vocabulary and associates body poses with texture maps for animation. Given multi-view RGB videos our method initially back-projects all the available images in the training videos to the posed SMPL surface producing texture maps in the SMPL UV domain. Then we construct pairs of human poses and texture maps to establish a texture vocabulary for encoding dynamic human appearances under various poses. Unlike the commonly used joint-wise manner we further design a body-part-wise encoding strategy to learn the structural effects of the kinematic chain. Given a driving pose we query the pose feature hierarchically by decomposing the pose vector into several body parts and interpolating the texture features for synthesizing fine-grained human dynamics. Overall our method is able to create animatable human avatars with detailed and dynamic appearances from RGB videos and the experiments show that our method outperforms state-of-the-art approaches.

Existing 3D mesh shape evaluation metrics mainly focus on the overall shape but are usually less sensitive to local details. This makes them inconsistent with human evaluation as human perception cares about both overall and detailed shape. In this paper we propose an analytic metric named Spectrum Area Under the Curve Difference (SAUCD) that demonstrates better consistency with human evaluation. To compare the difference between two shapes we first transform the 3D mesh to the spectrum domain using the discrete Laplace-Beltrami operator and Fourier transform. Then we calculate the Area Under the Curve (AUC) difference between the two spectrums so that each frequency band that captures either the overall or detailed shape is equitably considered. Taking human sensitivity across frequency bands into account we further extend our metric by learning suitable weights for each frequency band which better aligns with human perception. To measure the performance of SAUCD we build a 3D mesh evaluation dataset called Shape Grading along with manual annotations from more than 800 subjects. By measuring the correlation between our metric and human evaluation we demonstrate that SAUCD is well aligned with human evaluation and outperforms previous 3D mesh metrics.

A long-standing goal of 3D human reconstruction is to create lifelike and fully detailed 3D humans from single-view images. The main challenge lies in inferring unknown body shapes appearances and clothing details in areas not visible in the images. To address this we propose SiTH a novel pipeline that uniquely integrates an image-conditioned diffusion model into a 3D mesh reconstruction workflow. At the core of our method lies the decomposition of the challenging single-view reconstruction problem into generative hallucination and reconstruction subproblems. For the former we employ a powerful generative diffusion model to hallucinate unseen back-view appearance based on the input images. For the latter we leverage skinned body meshes as guidance to recover full-body texture meshes from the input and back-view images. SiTH requires as few as 500 3D human scans for training while maintaining its generality and robustness to diverse images. Extensive evaluations on two 3D human benchmarks including our newly created one highlighted our method's superior accuracy and perceptual quality in 3D textured human reconstruction. Our code and evaluation benchmark is available at https://ait.ethz.ch/sith.

As with many machine learning problems the progress of image generation methods hinges on good evaluation metrics. One of the most popular is the Frechet Inception Distance (FID). FID estimates the distance between a distribution of Inception-v3 features of real images and those of images generated by the algorithm. We highlight important drawbacks of FID: Inception's poor representation of the rich and varied content generated by modern text-to-image models incorrect normality assumptions and poor sample complexity. We call for a reevaluation of FID's use as the primary quality metric for generated images. We empirically demonstrate that FID contradicts human raters it does not reflect gradual improvement of iterative text-to-image models it does not capture distortion levels and that it produces inconsistent results when varying the sample size. We also propose an alternative new metric CMMD based on richer CLIP embeddings and the maximum mean discrepancy distance with the Gaussian RBF kernel. It is an unbiased estimator that does not make any assumptions on the probability distribution of the embeddings and is sample efficient. Through extensive experiments and analysis we demonstrate that FID-based evaluations of text-to-image models may be unreliable and that CMMD offers a more robust and reliable assessment of image quality.

Multimodal Large Language Models (MLLMs) have recently demonstrated impressive capabilities in multimodal understanding reasoning and interaction. However existing MLLMs prevalently suffer from serious hallucination problems generating text that is not factually grounded in associated images. The problem makes existing MLLMs untrustworthy and thus impractical in real-world (especially high-stakes) applications. To address the challenge we present RLHF-V which enhances MLLM trustworthiness via behavior alignment from fine-grained correctional human feedback. Specifically RLHF-V collects human preference in the form of segment-level corrections on hallucinations and performs dense direct preference optimization over the human feedback. Comprehensive experiments on five benchmarks in both automatic and human evaluation show that RLHF-V can enable substantially more trustworthy MLLM behaviors with promising data and computation efficiency. Remarkably using 1.4k annotated data samples RLHF-V significantly reduces the hallucination rate of the base MLLM by 34.8% outperforming the concurrent LLaVA-RLHF trained on 10k annotated data. The final model achieves state-of-the-art performance in trustworthiness among open-source MLLMs and shows better robustness than GPT-4V in preventing hallucinations aroused from over-generalization. All the data code and model weights will be released to facilitate future research.

Establishing an automatic evaluation metric that closely aligns with human judgments is essential for effectively developing image captioning models. Recent data-driven metrics have demonstrated a stronger correlation with human judgments than classic metrics such as CIDEr; however they lack sufficient capabilities to handle hallucinations and generalize across diverse images and texts partially because they compute scalar similarities merely using embeddings learned from tasks unrelated to image captioning evaluation. In this study we propose Polos a supervised automatic evaluation metric for image captioning models. Polos computes scores from multimodal inputs using a parallel feature extraction mechanism that leverages embeddings trained through large-scale contrastive learning. To train Polos we introduce Multimodal Metric Learning from Human Feedback (M2LHF) a framework for developing metrics based on human feedback. We constructed the Polaris dataset which comprises 131K human judgments from 550 evaluators which is approximately ten times larger than standard datasets. Our approach achieved state-of-the-art performance on Composite Flickr8K-Expert Flickr8K-CF PASCAL-50S FOIL and the Polaris dataset thereby demonstrating its effectiveness and robustness.

Recent advances in text-to-image generation have made remarkable progress in synthesizing realistic human photos conditioned on given text prompts. However existing personalized generation methods cannot simultaneously satisfy the requirements of high efficiency promising identity (ID) fidelity and flexible text controllability. In this work we introduce PhotoMaker an efficient personalized text-to-image generation method which mainly encodes an arbitrary number of input ID images into a stack ID embedding for preserving ID information. Such an embedding also empowers our method to be applied in many interesting scenarios such as when replacing the corresponding class word and when combining the characteristics of different identities. Besides to better drive the training of our PhotoMaker we propose an ID-oriented data creation pipeline to assemble the training data. Under the nourishment of the dataset constructed through the proposed pipeline our PhotoMaker demonstrates comparable performance to test-time fine-tuning-based methods yet provides significant speed improvements strong generalization capabilities and a wide range of applications.

Human avatar has become a novel type of 3D asset with various applications. Ideally a human avatar should be fully customizable to accommodate different settings and environments. In this work we introduce NECA an approach capable of learning versatile human representation from monocular or sparse-view videos enabling granular customization across aspects such as pose shadow shape lighting and texture. The core of our approach is to represent humans in complementary dual spaces and predict disentangled neural fields of geometry albedo shadow as well as an external lighting from which we are able to derive realistic rendering with high-frequency details via volumetric rendering. Extensive experiments demonstrate the advantage of our method over the state-of-the-art methods in photorealistic rendering as well as various editing tasks such as novel pose synthesis and relighting. Our code is available at https://github.com/iSEE-Laboratory/NECA.

Human matting is a foundation task in image and video processing where human foreground pixels are extracted from the input. Prior works either improve the accuracy by additional guidance or improve the temporal consistency of a single instance across frames. We propose a new framework MaGGIe Masked Guided Gradual Human Instance Matting which predicts alpha mattes progressively for each human instances while maintaining the computational cost precision and consistency. Our method leverages modern architectures including transformer attention and sparse convolution to output all instance mattes simultaneously without exploding memory and latency. Although keeping constant inference costs in the multiple-instance scenario our framework achieves robust and versatile performance on our proposed synthesized benchmarks. With the higher quality image and video matting benchmarks the novel multi-instance synthesis approach from publicly available sources is introduced to increase the generalization of models in real-world scenarios. Our code and datasets are available at https://maggie-matt.github.io

The capacity of existing human keypoint localization models is limited by keypoint priors provided by the training data. To alleviate this restriction and pursue more general model this work studies keypoint localization from a different perspective by reasoning locations based on keypiont clues in text descriptions. We propose LocLLM the first Large-Language Model (LLM) based keypoint localization model that takes images and text instructions as inputs and outputs the desired keypoint coordinates. LocLLM leverages the strong reasoning capability of LLM and clues of keypoint type location and relationship in textual descriptions for keypoint localization. To effectively tune LocLLM we construct localization-based instruction conversations to connect keypoint description with corresponding coordinates in input image and fine-tune the whole model in a parameter-efficient training pipeline. LocLLM shows remarkable performance on standard 2D/3D keypoint localization benchmarks. Moreover incorporating language clues into the localization makes LocLLM show superior flexibility and generalizable capability in cross dataset keypoint localization and even detecting novel type of keypoints unseen during training.

Current metrics for text-to-image models typically rely on statistical metrics which inadequately represent the real preference of humans. Although recent work attempts to learn these preferences via human annotated images they reduce the rich tapestry of human preference to a single overall score. However the preference results vary when humans evaluate images with different aspects. Therefore to learn the multi-dimensional human preferences we propose the Multi-dimensional Preference Score (MPS) the first multi-dimensional preference scoring model for the evaluation of text-to-image models. The MPS introduces the preference condition module upon CLIP model to learn these diverse preferences. It is trained based on our Multi-dimensional Human Preference (MHP) Dataset which comprises 918315 human preference choices across four dimensions (i.e. aesthetics semantic alignment detail quality and overall assessment) on 607541 images. The images are generated by a wide range of latest text-to-image models. The MPS outperforms existing scoring methods across 3 datasets in 4 dimensions enabling it a promising metric for evaluating and improving text-to-image generation. The model and dataset will be made publicly available to facilitate future research.

Learning 3D human-object interaction relation is pivotal to embodied AI and interaction modeling. Most existing methods approach the goal by learning to predict isolated interaction elements e.g. human contact object affordance and human-object spatial relation primarily from the perspective of either the human or the object. Which underexploit certain correlations between the interaction counterparts (human and object) and struggle to address the uncertainty in interactions. Actually objects' functionalities potentially affect humans' interaction intentions which reveals what the interaction is. Meanwhile the interacting humans and objects exhibit matching geometric structures which presents how to interact. In light of this we propose harnessing these inherent correlations between interaction counterparts to mitigate the uncertainty and jointly anticipate the above interaction elements in 3D space. To achieve this we present LEMON (LEarning 3D huMan-Object iNteraction relation) a unified model that mines interaction intentions of the counterparts and employs curvatures to guide the extraction of geometric correlations combining them to anticipate the interaction elements. Besides the 3D Interaction Relation dataset (3DIR) is collected to serve as the test bed for training and evaluation. Extensive experiments demonstrate the superiority of LEMON over methods estimating each element in isolation. The code and dataset are available at https://yyvhang.github.io/LEMON/

The analysis of the ubiquitous human-human interactions is pivotal for understanding humans as social beings. Existing human-human interaction datasets typically suffer from inaccurate body motions lack of hand gestures and fine-grained textual descriptions. To better perceive and generate human-human interactions we propose Inter-X a currently largest human-human interaction dataset with accurate body movements and diverse interaction patterns together with detailed hand gestures. The dataset includes 11K interaction sequences and more than 8.1M frames. We also equip Inter-X with versatile annotations of more than 34K fine-grained human part-level textual descriptions semantic interaction categories interaction order and the relationship and personality of the subjects. Based on the elaborate annotations we propose a unified benchmark composed of 4 categories of downstream tasks from both the perceptual and generative directions. Extensive experiments and comprehensive analysis show that Inter-X serves as a testbed for promoting the development of versatile human-human interaction analysis. Our dataset and benchmark will be publicly available for research purposes.

To date the quest to rapidly and effectively produce human-object interaction (HOI) animations directly from textual descriptions stands at the forefront of computer vision research. The underlying challenge demands both a discriminating interpretation of language and a comprehensive physics-centric model supporting real-world dynamics. To ameliorate this paper advocates HOIAnimator a novel and interactive diffusion model with perception ability and also ingeniously crafted to revolutionize the animation of complex interactions from linguistic narratives. The effectiveness of our model is anchored in two ground-breaking innovations: (1) Our Perceptive Diffusion Models (PDM) brings together two types of models: one focused on human movements and the other on objects. This combination allows for animations where humans and objects move in concert with each other making the overall motion more realistic. Additionally we propose a Perceptive Message Passing (PMP) mechanism to enhance the communication bridging the two models ensuring that the animations are smooth and unified; (2) We devise an Interaction Contact Field (ICF) a sophisticated model that implicitly captures the essence of HOIs. Beyond mere predictive contact points the ICF assesses the proximity of human and object to their respective environment informed by a probabilistic distribution of interactions learned throughout the denoising phase. Our comprehensive evaluation showcases HOIanimator's superior ability to produce dynamic context-aware animations that surpass existing benchmarks in text-driven animation synthesis.

Incorporating human feedback has been shown to be crucial to align text generated by large language models to human preferences. We hypothesize that state-of-the-art instructional image editing models where outputs are generated based on an input image and an editing instruction could similarly benefit from human feedback as their outputs may not adhere to the correct instructions and preferences of users. In this paper we present a novel framework to harness human feedback for instructional visual editing (HIVE). Specifically we collect human feedback on the edited images and learn a reward function to capture the underlying user preferences. We then introduce scalable diffusion model fine-tuning methods that can incorporate human preferences based on the estimated reward. Besides to mitigate the bias brought by the limitation of data we contribute a new 1.1M training dataset a 3.6K reward dataset for rewards learning and a 1K evaluation dataset to boost the performance of instructional image editing. We conduct extensive empirical experiments quantitatively and qualitatively showing that HIVE is favored over previous state-of-the-art instructional image editing approaches by a large margin.

The creation of personalized anatomical digital twins is important in the fields of medicine computer graphics sports science and biomechanics. To observe a subject's anatomy expensive medical devices (MRI or CT) are required and the creation of the digital model is often time-consuming and involves manual effort. Instead we leverage the fact that the shape of the body surface is correlated with the internal anatomy; e.g. from surface observations alone one can predict body composition and skeletal structure. In this work we go further and learn to infer the 3D location of three important anatomic tissues: subcutaneous adipose tissue (fat) lean tissue (muscles and organs) and long bones. To learn to infer these tissues we tackle several key challenges. We first create a dataset of human tissues by segmenting full-body MRI scans and registering the SMPL body mesh to the body surface. With this dataset we train HIT (Human Implicit Tissues) an implicit function that given a point inside a body predicts its tissue class. HIT leverages the SMPL body model shape and pose parameters to canonicalize the medical data. Unlike SMPL which is trained from upright 3D scans MRI scans are acquired with subjects lying on a table resulting in significant soft-tissue deformation. Consequently HIT uses a learned volumetric deformation field that undoes these deformations. Since HIT is parameterized by SMPL we can repose bodies or change the shape of subjects and the internal structures deform appropriately. We perform extensive experiments to validate HIT's ability to predict a plausible internal structure for novel subjects. The dataset and HIT model are available at https://hit.is.tue.mpg.de to foster future research in this direction.

Despite recent advances in text-to-3D generative methods there is a notable absence of reliable evaluation metrics. Existing metrics usually focus on a single criterion each such as how well the asset aligned with the input text. These metrics lack the flexibility to generalize to different evaluation criteria and might not align well with human preferences. Conducting user preference studies is an alternative that offers both adaptability and human-aligned results. User studies however can be very expensive to scale. This paper presents an automatic versatile and human-aligned evaluation metric for text-to-3D generative models. To this end we first develop a prompt generator using GPT-4V to generate evaluating prompts which serve as input to compare text-to-3D models. We further design a method instructing GPT-4V to compare two 3D assets according to user-defined criteria. Finally we use these pairwise comparison results to assign these models Elo ratings. Experimental results suggest our metric strongly align with human preference across different evaluation criteria.

The robust generalization of models to rare in-distribution (ID) samples drawn from the long tail of the training distribution and to out-of-training-distribution (OOD) samples is one of the major challenges of current deep learning methods. For image classification this manifests in the existence of adversarial attacks the performance drops on distorted images and a lack of generalization to concepts such as sketches. The current understanding of generalization in neural networks is very limited but some biases that differentiate models from human vision have been identified and might be causing these limitations. Consequently several attempts with varying success have been made to reduce these biases during training to improve generalization. We take a step back and sanity-check these attempts. Fixing the architecture to the well-established ResNet-50 we perform a large-scale study on 48 ImageNet models obtained via different training methods to understand how and if these biases - including shape bias spectral biases and critical bands - interact with generalization. Our extensive study results reveal that contrary to previous findings these biases are insufficient to accurately predict the generalization of a model holistically. We provide access to all checkpoints and evaluation code at https://github.com/paulgavrikov/biases_vs_generalization/

We propose CG-HOI the first method to address the task of generating dynamic 3D human-object interactions (HOIs) from text. We model the motion of both human and object in an interdependent fashion as semantically rich human motion rarely happens in isolation without any interactions. Our key insight is that explicitly modeling contact between the human body surface and object geometry can be used as strong proxy guidance both during training and inference. Using this guidance to bridge human and object motion enables generating more realistic and physically plausible interaction sequences where the human body and corresponding object move in a coherent manner. Our method first learns to model human motion object motion and contact in a joint diffusion process inter-correlated through cross-attention. We then leverage this learned contact for guidance during inference to synthesize realistic and coherent HOIs. Extensive evaluation shows that our joint contact-based human-object interaction approach generates realistic and physically plausible sequences and we show two applications highlighting the capabilities of our method. Conditioned on a given object trajectory we can generate the corresponding human motion without re-training demonstrating strong human-object interdependency learning. Our approach is also flexible and can be applied to static real-world 3D scene scans.