arXiv subjects

Jakub Maksymilian Fober

Publications and source records attributed to Jakub Maksymilian Fober.

5 recordsLinked to original sources

arXiv2024

Lens Distortion Encoding System Version 1.0

Lens Distortion Encoding System (LDES) allows for a distortion-accurate workflow, with a seamless interchange of high quality motion picture images regardless of the lens source. This system is similar in a concept to the Academy Color Encoding System (ACES), but for distortion. Presented solution is fully compatible with existing software/plug-in tools for STMapping found in popular production software like Adobe After Effects or DaVinci Resolve. LDES utilizes common distortion space and produces single high-quality, animatable STMap used for direct transformation of one view to another, neglecting the need of lens-swapping for each shoot. The LDES profile of a lens consist of two elements; View Map texture, and Footage Map texture, each labeled with the FOV value. Direct distortion mapping is produced by sampling of the Footage Map through the View Map. The result; animatable mapping texture, is then used to sample the footage to a desired distortion. While the Footage Map is specific to a footage, View Maps can be freely combined/transitioned and animated, allowing for effects like smooth shift from anamorphic to spherical distortion, previously impossible to achieve in practice. Presented LDES Version 1.0 uses common 32-bit STMap format for encoding, supported by most compositing software, directly or via plug-ins. The difference between standard STMap workflow and LDES is that it encodes absolute pixel position in the spherical image model. The main benefit of this approach is the ability to achieve a similar look of a highly expensive lens using some less expensive equipment in terms of distortion. It also provides greater artistic control and never seen before manipulation of footage.

cs.CV↗

arXiv2024

Aximorphic Perspective Projection Model for Immersive Imagery

A wide choice of cinematic lenses enables motion-picture creators to adapt image visual-appearance to their creative vision. Such choice does not exist in the realm of real-time computer graphics, where only one type of perspective projection is widely used, a linear perspective. This paper presents an extended perspective imaging model, which can represent distortion and FoV parameters of entire variety of film and photographic lenses (e.g., wide-angle, fisheye, anamorphic), while preserving parametrization in an artistically convincing manner. Self-experimentation with the model revealed that each projection type provides accurate perception of a different aspect of depicted space (e.g., speed, distance, shape). Presented model, enables combination of multiple projections, each on a different axis of the image, to achieve optimal perception for a given scenario. This new projection, named aximorphic, was made available here, under an open license (CC BY-SA 3.0), for a wide and easy adoption.

cs.GR↗

arXiv2023

Calculating Pose with Vanishing Points of Visual-Sphere Perspective Model

The goal of the proposed method is to directly obtain a pose matrix of a known rectangular target, without estimation, using geometric techniques. This method is specifically tailored for real-time, extreme imaging setups exceeding 180° field of view, such as a fish-eye camera view. The introduced algorithm employs geometric algebra to determine the pose for a pair of coplanar parallel lines (ideally a tangent pair as in a rectangle). This is achieved by computing vanishing points on a visual unit sphere, which correspond to pose matrix vectors. The algorithm can determine pose for an extremely distorted view source without prior rectification, owing to a visual-sphere perspective model mapping of view coordinates. Mapping can be performed using either a perspective map lookup or a parametric universal perspective distortion model, which is also presented in this paper. The outcome is a robust pose matrix computation that can be executed on an embedded system using a microcontroller, offering high accuracy and low latency. This method can be further extended to a cubic target setup for comprehensive camera calibration. It may also prove valuable in other applications requiring low latency and extreme viewing angles.

cs.CV↗

arXiv2023

Radiance Textures for Rasterizing Ray-Traced Data

Presenting real-time rendering of 3D surfaces using radiance textures for fast synthesis of complex incidence-variable effects and environment interactions. This includes iridescence, parallax occlusion and interior mapping, (specular, regular, diffuse, total-internal) reflections with many bounces, refraction, subsurface scattering, transparency, and possibly more. This method divides textures into a matrix of radiance buckets, where each bucket represent some data at various incidence angles. Data can show final pixel color, or deferred rendering ambient occlusion, reflections, shadow map, etc. Resolution of the final synthesized output is the radiance bucket matrix size. Technique can be implemented with a simple fragment shader. The computational footprint of this technique is of simple diffuse-only graphics, but with visual fidelity of complex (off-line) ray-traced render at the cost of storage memory footprint. Balance between computational footprint and storage memory footprint can be easily achieved with variable compression ratio of repetitive radiance scene textures.

cs.GR↗

arXiv2020

Perspective picture from Visual Sphere: a new approach to image rasterization

In this paper alternative method for real-time 3D model rasterization is given. Surfaces are drawn in perspective-map space which acts as a virtual camera lens. It can render single-pass 360° angle of view (AOV) image of unlimited shape, view-directions count and unrestrained projection geometry (e.g. direct lens distortion, projection mapping, curvilinear perspective), natively aliasing-free. In conjunction to perspective vector map, visual-sphere perspective model is proposed. A model capable of combining pictures from sources previously incompatible, like fish-eye camera and wide-angle lens picture. More so, method is proposed for measurement and simulation of a real optical system variable no-parallax point (NPP). This study also explores philosophical and historical aspects of picture perception and presents a guide for perspective design.

cs.GR↗