Three-Dimensional Measurement for Specular Reflection Surface Based on Reflection Component Separation and Priority Region Filling Theory

Abstract

Due to the strong reflection property of materials with smooth surfaces like ceramic and metal, it will cause saturation and the highlight phenomenon in the image when taking pictures of those materials. In order to solve this problem, a new algorithm which is based on reflection component separation (RCS) and priority region filling theory is designed. Firstly, the specular pixels in the image are found by comparing the pixel parameters. Then, the reflection components are separated and processed. However, for ceramic, metal and other objects with strong specular highlight, RCS theory will change color information of highlight pixels due to larger specular reflection component. In this situation, priority region filling theory was used to restore the color information. Finally, we implement 3D experiments on objects with strong reflecting surfaces like ceramic plate, ceramic bottle, marble pot and yellow plate. Experimental results show that, with the proposed method, the highlight caused by the strong reflecting surface can be well suppressed. The highlight pixel number of ceramic plate, ceramic bottle, marble pot and yellow plate, is decreased by 43.8 times, 41.4 times, 33.0 times, and 10.1 times. Three-dimensional reconstruction results show that highlight areas were significantly reduced.

Investigation of TLS Intensity Data and Distance Measurement Errors from Target Specular Reflections

“…Results indicate that the distance measurement accuracy can be improved significantly after establishing the function between intensity and distance errors, which is of great importance to TLS data quality, reliability, and subsequent processing. Additionally, target specular reflections can lead to intensity highlight phenomena [19,22]. The proposed method can provide accurate distance information for the estimation of the incidence angle.…”

“…However, these errors can significantly increase to centimeter and even decimeter levels [8,10] for smooth surfaces because diffuse and specular reflections exist in all-natural surfaces and the type of reflection affects the direction and strength of backscattered light. For targets with a relatively smooth or glossy surface (e.g., water [11][12][13], fresh ice [14][15][16], foliage/leaves [17,18], metal [19], porcelain, and plastic [20,21]), specular reflections are dominant over diffuse reflections. For a generally smooth surface of multiple facets with different orientations, specular reflections are distributed in the surroundings of the reflection angle direction [22].…”

“…For a generally smooth surface of multiple facets with different orientations, specular reflections are distributed in the surroundings of the reflection angle direction [22]. The target specular reflections can significantly change the amplitude, width, or shape of the backscattered signal, especially in the case of small incidence angles that are close to zero due to the coincidence of the emitter and receiver [19,23]. A deformed signal influences the scanner system's determination of the arrival time of the backscattered echo or the phase comparison between the emitted and received signals.…”

“…A deformed signal influences the scanner system's determination of the arrival time of the backscattered echo or the phase comparison between the emitted and received signals. Thus, target specular reflections can lead to errors in distance observations and even in the saturation effect [10,[19][20][21]23,24] of photodetectors due to the extremely high amplitude of returned pulses.…”

A Calibration Method for System Parameters in Direct Phase Measuring Deflectometry

“…In the area of structured light techniques, phase-calculation-based fringe pattern projection has made rapid progress so far, because it has the advantages of full-field measurement, non-contact operation, automatic data processing, and fast data acquisition [10][11][12][13]. Nevertheless, there are a large number of specular objects that need to be measured [14]. Current fringe pattern projection techniques cannot deal with this demand, especially in the measurement of specular objects that have discontinuous and/or isolated surfaces.…”