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Abstract
Recently, structured light 3D imaging devices have gained a keen attention due to their potential applications to robotics, industrial manufacturing and medical imaging. Most of these applications require high 3D precision yet high speed in image capturing for hard and/or soft real time environments. This paper presents a method of high speed image capturing for structured light 3D imaging sensors with FPGA based structured light pattern generation and projector-camera synchronization. Suggested setup reduces the time for pattern projection and camera triggering to 16msec from 100msec that should be required by conventional methods.
Keywords: FPGA, structred Light 3D camera, HOC
Copyright © 2017 Universitas Ahmad Dahlan. All rights reserved.
1.Introduction
Structured light 3D acquisition method is one of the renowned methods for high precision 3D measurements. Basic working principle of the structured light system is similar to stereo matching. In stereo matching, we need two passive cameras to grab frame but in structured light system we use only one camera and one projector system to generate 3D depth information. For 3D reconstruction we use projectors that can project patterns on screen, and camera is required to capture those known projected patterns. These known projected patterns are used to find correspondence of common point in projected frame and captured fame, to generate 3D depth information. Basic working mechanism of structured light 3D camera is shown in Figure 1.
Distance between the projector and camera is known as baseline shown in Figure 1, triangulation technique is used to compute depth of scene by using intrinsic and extrinsic parameters of the projector and camera which are obtained by calibration. Structured light depth imaging is gaining attention due to its application in diverse areas e.g. robotics, 3D games, micro inspection systems, 3D finger printing and re-engineering. Especially in the field of robotics, structured light depth imaging system replaced traditional passive stereo systems because of its high accuracy, which is used for object recognition and manipulation.
Potential of structured light system lies in it's capability of capturing 3D point cloud of texture-less objects, and providing higher precision and robustness as compared to passive stereo camera system. Accuracy of depth measurement in structured light system depends upon correct pixel correspondence between the camera and digital mirror device (DMD) of projector....