Optical range-finding system using a single-image sensor with liquid crystal display aperture

Abstract

This Letter presents an optical range-finding camera using a liquid crystal display (LCD) to generate multiple, off-axis color-filtered apertures in a flexible manner. The disparity between the different color channels is measured from a pair of stereo images acquired by two off-axis apertures, and the distance of a scene point from the camera is then estimated from the pre-specified relationship between the color disparity and distance.

Depth Camera Using High-Transmittance Off-Axis Dual Electro-Optical Irises

“…ToF utilizes a laser scanner to scan the environment and infers the depth map from the phase differences between the emitted and received signals [9]. The advantage of ToF is its high speed thanks to laser scanning, whereas the limited working distance and weak detection capability over transparent objects are the major demerits [10]. In SI, analysis based on the spatially and temporally coded patterns can render the depth information [11], [12].…”

“…The distance between these two sub-cameras is the stereo baseline which determines the farthest distance a depth camera is expected to sense. One alternative to such a stereo camera is using a combination of a single image sensor and off-axis dual irises [10], [15], [16]. A triangular geometry, similar to that between the object and two sub-cameras, can be found with this combination.…”

“…However, the separation of color channels may result in very different grayscale intensities between the two stereo images. The disparity error due to this effect is significant so that the estimated depth would deviate drastically [10]. An alternative approach is using a liquid crystal panel to generate stereo images with the same color response [10].…”

“…The disparity error due to this effect is significant so that the estimated depth would deviate drastically [10]. An alternative approach is using a liquid crystal panel to generate stereo images with the same color response [10]. The liquid crystal panel, placed at the optical aperture, had dense grids, and was switchable by adjusting voltage to sample the light on the aperture.…”

Segmentation-Based Color Channel Registration for Disparity Estimation of Dual Color-Filtered Aperture Camera

“…Lee et al presented a novel computational imaging system for disparity estimation by inserting a dual color-filtered aperture (DCA) into an ordinary single camera [ 6 ]. The DCA camera generates a pair of color-filtered stereo images in a single shot and then estimates the disparity by registrating the pair of color images [ 7 , 8 ]. A salient region-based local disparity extraction method was proposed for robust cross-channel disparity estimation using phase correlation matching (PCM) in [ 9 ].…”