True object material quality reflecting attribute modeling approach based on linear light

Abstract

A method for modeling a reflection attribute of a real object material based on a linear light source comprises the following steps: (1) a data collection device based on the linear light source collects and process data; the linear light source is taken as a light source system of the data collection device; the linear light emitted by the linear light source shines a collected plane object, a control system drives an automatic translation system to move forwards; meanwhile, an industrial camera collects images of the collected plane object, a computer performs subsequent processing of the collected image data to obtain a trajectory curve of pixel values and store the trajectory curve; (2) a reflection table is generated; (3) BRDF attribute is modeled to obtain rhod of a Ward illumination model, and then obtain alpha, and finally obtain rhos according to the trajectory curve of the pixel values obtained in the step (1) and the reflection generated in the step (2), wherein, the rhod is a diffuse reflection parameter, the rhos is a mirror reflection parameter and the alpha is a material roughness coefficient. The method can efficiently collect data and quickly solve the parameters of the BRDF model, and is easy to be realized.

Description

technical field [0001] The invention belongs to the technical field of computer virtual reality, and specifically relates to a method for modeling reflection properties of flat object materials using linear light sources, which is used for modeling and drawing material BRDF in a realistic virtual environment. Background technique [0002] 3D modeling of real objects is an important part of computer graphics. 3D modeling is divided into geometric modeling and attribute modeling. Geometric modeling can be well realized by modeling software and 3D scanners, while attribute modeling has become a difficult point in computer graphics modeling. Accurate acquisition and modeling of real object surface reflection properties is a hot issue in computer graphics. The appearance of an object is the result of light and the material of the object. Modeling reflection properties is all about describing how light interacts with surfaces. At present, the most commonly used model to describ...

AI Technical Summary

Problems solved by technology

There are two main types of BRDF modeling methods: one is the modeling method based on parametric mathematical expressions, through sparse sampling of material samples, using the acquired data to match the known analytical BRDF model parameters, in the drawing process In , the reflection phenomenon is simulated by analyzing the real-time calculation. For example, the simple cosine lobe (cosine lobe) is used in the literature 6-B.T.Phong, Illumination for computer generated pictures, Communications of ACM vol. ) Phong model for approximate specular reflection, literature 7-E.Lafortune, S.-C.Foo, etc.Non-linear approximation of reflectance functions, Computer Graphics, 1997, no.Annual Conference Series: pp.117-126 in Phong model Based on the improved, physically more realistic Lafortune model and literature 8-Ward, G.J. Measuring and modeling anisotropic reflection. In SIGGRAPH, 1992, pp.265-272 uses Gaussian instead of cosine Ward model; the other is based on data-driven (Data-Driven) BRDF modeling method, such as literature 4, densely samples materials, uses linear and nonlinear analysis, generates new BRDF data through interpolation and extrapolation methods, and provides some intuitive parameters for users to modify interactively BRDF, this type of method is complex in modeling and needs to collect a large amount of data

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