We introduce a novel dataset and evaluation approach for long-range depth prediction of small objects that enables consistent comparison across direct time-of-flight (ToF) sensors and learned depth estimation methods. In autonomous driving, accurate depth perception is essential for identifying and locating surrounding elements and determining safe driving paths. Traditional depth metrics focus on distance accuracy but fail to evaluate a key factor at long ranges: distinguishing small, slightly elevated structures from the ground - crucial for anticipating obstacles and making safe driving decisions. At far distances, imagebased systems suffer from resolution limitations that tend to oversmooth the ground plane, causing elevated objects to be mistaken as texture patterns on the surface. Conversely, scanning LiDAR systems may return only a single point from an elevated object due to steep incident angles and sparse returns, preventing accurate differentiation from the ground. This hampers a fair comparison of object presence and shape. To address this, we propose a framework that evaluates how well the estimated point clouds preserve semantic content relative to ground-truth data. We leverage neural network-based feature extraction to assess structural similarity, enabling a modality-agnostic evaluation of object-level fidelity. Our method also supports analysis of the trade-off between resolution and accuracy, investigating performances across sensor types - such as highresolution cameras versus LiDAR - and conditions, including day and night scenarios. This enables a more comprehensive understanding of the capabilities and limitations of current depth prediction approaches in real-world settings.

Depth estimation is a cornerstone computer vision application that is critical for scene understanding and autonomous driving. In real-world scenarios, achieving reliable depth perception under adverse weather—e.g. in fog and rain—is crucial to ensure safety and system robustness. However, quantitatively evaluating the performances of depth estimation methods in these scenarios is challenging due to the difficulty of obtaining ground truth data. A promising approach is using weather chambers to simulate diverse weather conditions in a controlled environment. However, current datasets are limited in distance and lack a dense ground truth. To address this gap, we introduce a novel evaluation benchmark that extends depth evaluation up to 200 meters under clear, foggy, and rainy conditions. To this end, we employ a multimodal sensor setup, including state-of-the-art stereo RGB, RCCB, Gated camera systems, and a long-range LiDAR sensor. Moreover, we record a digital twin of the test facility sampled at a millimeter scale using a high-end geodesic laser scanner. This comprehensive benchmark allows for the evaluation of different models and multiple sensing modalities in a more precise and accurate manner, as well as at far distances. Data and code will be released upon publication.

Reconstructing the geometry and appearance of a given scene is a fundamental task in 3D computer graphics and computer vision. Recently, radiance fields have emerged as a representation of light transport in the scene, allowing, as a byproduct, also to extract 3D geometry solely from multi-view imagery. Initially designed for RGB captures, existing approaches have been extended to other sensor modalities. Among these, transient imaging — measuring the time-of-flight of light at picosecond resolution — has emerged as a promising alternative, offering rich spatio-temporal information to improve reconstruction quality from limited viewpoints and obstructed views. However, its applicability to outdoor scenarios has been highly problematic due to interference from ambient light and the different sensor behavior under high-photon-flux conditions typical of outdoor settings. Addressing this gap, we introduce Transient LASSO, a neural scene reconstruction method operating on raw transient measures of outdoor in-the-wild captures to accurately reconstruct the underlying scene geometry and properties. We demonstrate the effectiveness of our method across a variety of outdoor environments, including complex urban scenes with dense traffic and infrastructure. Finally, we also show the potential use cases of our method for downstream applications such as sensor parameter optimization.

Lidar has become a cornerstone sensing modality for 3D vision, especially for large outdoor scenarios and au-tonomous driving. Conventional lidar sensors are capable of providing centimeter-accurate distance information by emitting laser pulses into a scene and measuring the time- of-flight (ToF) of the reflection. However, the polarization of the received light that depends on the surface orientation and material properties is usually not considered. As such, the polarization modality has the potential to improve scene reconstruction beyond distance measurements. In this work, we introduce a novel long-range polarization wave-front lidar sensor (PolLidar) that modulates the polarization of the emitted and received light. Departing from con-ventional lidar sensors, PolLidar allows access to the raw time-resolved polarimetric wavefronts. We leverage polari-metric wavefronts to estimate normals, distance, and ma-terial properties in outdoor scenarios with a novel learned reconstruction method. To train and evaluate the method, we introduce a simulated and real-world long-range dataset with paired raw lidar data, ground truth distance, and nor-mal maps. We find that the proposed method improves normal and distance reconstruction by 53% mean angular error and 41% mean absolute error compared to existing shape-from-polarization (SfP) and ToF methods. Code and data are open-sourced here11https://light.princeton.edu/pollidar/.

Current autonomous driving technologies are being rolled out in geo-fenced areas with well-defined operation conditions such as time of operation, area, weather conditions and road conditions. In this way, challenging conditions as adverse weather, slippery road or densely-populated city centers can be excluded. In order to lift the geo-fenced restriction and allow a more dynamic availability of autonomous driving functions, it is necessary for the vehicle to autonomously perform an environment condition assessment in real time to identify when the system cannot operate safely and either stop operation or require the resting passenger to take control. In particular, adverse-weather challenges are a fundamental limitation as sensor performance degenerates quickly, prohibiting the use of sensors such as cameras to locate and monitor road signs, pedestrians or other vehicles. To address this issue, we train a deep learning model to identify outdoor weather and dangerous road conditions, enabling a quick reaction to new situations and environments. We achieve this by introducing an improved taxonomy and label hierarchy for a state-of-the-art adverse-weather dataset, relabelling it with a novel semi-automated labeling pipeline. Using the novel proposed dataset and hierarchy, we train RECNet, a deep learning model for the classification of environment conditions from a single RGB frame. We outperform baseline models by relative 16% in F1-Score, while maintaining a real-time capable performance of 20 Hz. The code is published here1.

Although lidar sensors have emerged as a cornerstone sensing modality in autonomous driving, they face significant challenges in adverse weather conditions. A particularly detrimental effect is spray — a phenomenon where water particles are whirled up by vehicles driving with high velocities on wet roads. Spray often causes clutter points in lidar data that are falsely classified as vehicles by downstream object detectors. In this work, a phenomenological spray simulation model, suitable as an augmentation method for object detection algorithms, is presented. Two distinct datasets featuring real-world spray scenarios are recorded and analyzed, with the first serving for calibrating the simulation model through extensive experiments that vary vehicle speeds, types, and pavement wetness levels. The second dataset functions as a spray test set to evaluate the effectiveness of the simulation model in the context of object detection. Employing the simulation model as an augmentation tool reveals an improvement of up to 17% in Average Precision for state-of-the-art object detection methods in real spray conditions.

LiDAR has become a cornerstone sensing modality for 3D vision. LiDAR systems emit pulses of light into the scene, take measurements of the returned signal, and rely on hardware digital signal processing (DSP) pipelines to construct 3D point clouds from these measurements. The resulting point clouds output by these DSPs are input to downstream 3D vision models - both, in the form of training datasets or as input at inference time. Existing LiDAR DSPs are composed of cascades of parameterized operations; modifying configuration parameters results in significant changes in the point clouds and consequently the output of downstream methods. Existing methods treat LiDAR systems as fixed black boxes and construct downstream task networks more robust with respect to measurement fluctuations. Departing from this approach, the proposed method directly optimizes LiDAR sensing and DSP parameters for downstream tasks. To investigate the optimization of LiDAR system parameters, we devise a realistic LiDAR simulation method that generates raw waveforms as input to a LiDAR DSP pipeline. We optimize LiDAR parameters for both 3D object detection IoU losses and depth error metrics by solving a nonlinear multi-objective optimization problem with a 0th-order stochastic algorithm. For automotive 3D object detection models, the proposed method outperforms manual expert tuning by 39.5% mean Average Precision (mAP).

Vision in adverse weather conditions, whether it be snow, rain, or fog is challenging. In these scenarios, scattering and attenuation severly degrades image quality. Handling such inclement weather conditions, however, is essential to operate autonomous vehicles, drones and robotic applications where human performance is impeded the most. A large body of work explores removing weather-induced image degradations with dehazing methods. Most methods rely on single images as input and struggle to generalize from synthetic fully-supervised training approaches or to generate high fidelity results from unpaired real-world datasets. With data as bottleneck and most of today’s training data relying on good weather conditions with inclement weather as outlier, we rely on an inverse rendering approach to reconstruct the scene content. We introduce ScatterNeRF, a neural rendering method which adequately renders foggy scenes and decomposes the fog-free background from the participating media – exploiting the multiple views from a short automotive sequence without the need for a large training data corpus. Instead, the rendering approach is optimized on the multi-view scene itself, which can be typically captured by an autonomous vehicle, robot or drone during operation. Specifically, we propose a disentangled representation for the scattering volume and the scene objects, and learn the scene reconstruction with physics-inspired losses. We validate our method by capturing multi-view In-the-Wild data and controlled captures in a large-scale fog chamber. Our code and datasets are available at https://light.princeton.edu/scatternerf.

Autonomous vehicles rely on a variety of sensors to gather information about their surrounding. The vehicle’s behavior is planned based on the environment perception, making its reliability crucial for safety reasons. The active LiDAR sensor is able to create an accurate 3D representation of a scene, making it a valuable addition for environment perception for autonomous vehicles. Due to light scattering and occlusion, the LiDAR’s performance change under adverse weather conditions like fog, snow or rain. This limitation recently fostered a large body of research on approaches to alleviate the decrease in perception performance. In this survey, we gathered, analyzed, and discussed different aspects on dealing with adverse weather conditions in LiDAR-based environment perception. We address topics such as the availability of appropriate data, raw point cloud processing and denoising, robust perception algorithms and sensor fusion to mitigate adverse weather induced shortcomings. We furthermore identify the most pressing gaps in the current literature and pinpoint promising research directions.