This paper presents an optical path analysis performed with a vision system comprising an array of LEDs as the light source, a half mirror, and an image sensor. We propose an effective approximation method to estimate three-dimensional (3-D) surfaces of specular objects. This paper demonstrates the practicality of the proposed method by approximating the 3-D surface of a specular object using the displacement of the point lights in the acquired image.
We propose a method using a machine vision technique to detect the defects caused by spatially non-uniform brightness on LCD panels. The detection method is based on human vision, so subjective experiments were conducted to investigate the correlation between the parameters related to non-uniformity and the degree of easy observability. The visibility of the defects depends mainly on the spatial gradient of luminance variation. The proposed method uses the spatial gradient calculated using extracted contours to detect the defects caused by non-uniform brightness. The detection method is composed of four parts: the extraction of contours, the calculation of spatial gradient, the decision about defects, and the display of defects. Finally, the spatial gradient has a near-logarithmic relationship to the observability in judging the degree of how easily the detected defects are observed by the human inspector.
We propose a method to detect defects due to spatially non-uniform brightness on LCD panels by using a machine vision technique. The detection method is based on human vision so that proper subjective assessment experiments were conducted to investigate the correlation between the parameters related to non-uniformity and the degree how easily observable it is. The visibility of the defects reveals to depend mainly on the spatial gradient of brightness variation. Thus, in the proposed method, the spatial gradient that is calculated by using extracted contours will be utilized to detect the defects due to non-uniform brightness. The detection method comprises four parts: contour extraction, spatial gradient calculation, decision of defects, and display of defects. We applied the method to the images captured from practical LCD panels with non-uniformity defects and the results were consistent with detection by a human inspector.
A new design method of the dichroic mirrors is proposed for color separation/composition in 3-LCD projection systems. In this method, the design parameters were optimized by maximizing the volume of the reproducible color gamut in a CIELUV uniform color space for 2 typical viewing conditions.