Papers for

imaging system engineers

Papers whose findings have a practical use for this group, as judged from the abstract. Open a paper to read what it means in practice.

UniPolar restores images and polarization info amid mixed distortions

UniPolar: Joint Image and Polarimetric Restoration under Compound Degradations via Physical Consistency Learning

Abstract: Polarimetric image restoration aims to recover polarization angle images and reliable polarimetric quantities from degraded observations. Beyond visual fidelity, it also requires preserving the physical relationships underlying reliable polarimetric estimation. However, existing methods typically address either device- or environment-induced degradations in isolation, limiting their applicability to color polarization filter array (CPFA) imaging, where both often coexist. Such compound degradations jointly perturb image intensities and cross angle polarization differences. Consequently, improved image fidelity alone does not necessarily ensure accurate Stokes, DoLP, and AoLP recovery. To address this challenge, we propose UniPolar, a coupled Image Stokes framework for joint image polarimetric restoration from compound-degraded CPFA observations. Specifically, UniPolar employs two complementary streams to reconstruct four polarization-angle images and directly predict Stokes difference components. To coordinate these streams, Degradation Conditioned Cross Domain Interaction combines Dual Domain Frequency Interaction for frequency selective evidence exchange with Degradation Conditioned Modulation for condition adaptive feature correction. Furthermore, at the output level, Image Stokes Physical Consistency Learning aligns image derived and directly predicted Stokes components while regularizing angular fidelity and the physical feasibility of DoLP. On the compound-degradation benchmark, UniPolar achieves average image and DoLP PSNR of 31.522 dB and 24.097 dB, respectively, with an average AoLP error of 16.833 degree. These results underscore the importance of jointly considering visual fidelity and polarimetric reliability, offering a physically grounded perspective on learning based restoration under compound degradations.

Fri 16 OctComputer Vision and Pattern Recognition
The gist
Polarimetric images show how light waves are oriented, which helps in many scientific and technical fields. But images from sensors can be blurry or noisy due to device issues and environmental effects at the same time. The authors introduce UniPolar, a method that fixes these images and recovers important polarization details by learning physical rules about the light's behavior. This approach improves both the quality of the image and the accuracy of the recovered polarization data.
Open → 2610.23360v1

Modeling event camera responses improves dynamic optical system analysis

Modelling dynamic systems transfer functions from events in computational neuromorphic imaging

Abstract: Event Vision Sensing (EVS) report threshold crossings of log-irradiance, so a static optical system imaging a static scene produces no output at all. The classical procedure for measuring a Point Spread Function (PSF), illuminating the system with a constant point source, therefore has no event-based equivalent: the probe must carry a temporal profile, and that profile becomes part of the measurement. A growing body of Computational Neuromorphic Imaging (CNI) work already exploits this, pairing engineered or modulated optics with event sensing, but each system adopts a particular excitation together with a particular reading of the event stream without the correspondence between the two being stated. We examine that correspondence directly within a analytical framework of an Linear Shift-Invariant (LSI) optical system with a specified Modulation Transfer Function (MTF), a first-order filter EVS pixel model, and three different temporal probes: a step function, a linear ramp and an exponential ramp. By analysing the inverse of the entire chain for different event-statistic, and comparing the results to the specified MTF, we identify the context where each probe is most relevant. We consider how photon-noise and cross-array threshold mismatch effects the analytical accuracy of the probe-inverse. Results show that the widely used step probe is highly susceptible to mismatch while resilient to photon shot-noise, while a linear rise probe and exponential rise probe retain their ability to infer signal levels even with high mismatch. We discuss the potential of dynamic-PSFs as components of a full forward operator from scene to events. In this, we use this analytical description to define dynamic-PSFs around EVS, and discuss the gaps toward a unified pixel model and a scene-composition framework required for CNI.

Thu 24 SeptComputer Vision and Pattern Recognition
The gist
Event vision sensors only respond to changes in light rather than steady illumination, making traditional testing methods invalid for these devices. The authors study how different types of light changes, like steps or ramps, affect the sensor’s output and how well these outputs can be used to understand the system’s behavior. They find that some light change patterns are better at overcoming sensor mismatches and noise than others. This work helps clarify how to model and interpret event camera data for better imaging system designs. It points toward building better tools that link scenes, sensors, and their dynamic responses.
Open → 2609.29863v1