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High-speed 3D imaging by DMD technology

2004; SPIE; Volume: 5303; Linguagem: Inglês

10.1117/12.528341

1996-756X

Roland Hoefling,

Surface Roughness and Optical Measurements

The paper presents an advanced solution for capturing the height of an object in addition to the 2D image as it is frequently desired in machine vision applications. Based upon the active fringe projection methodology, the system takes advantage of a series of patterns projected onto the object surface and observed by a camera to provide reliable, accurate and highly resolved 3D data from any scattering object surface. The paper shows how the recording of a projected image series can be significantly accelerated and improved in quality to overcome current limitations. The key is ALP - a metrology dedicated hardware design using the Discovery 1100 platform for the DMD micromirror device of Texas Instruments Inc. The paper describes how this DMD technology has been combined with latest LED illumination, high-performance optics, and recent digital camera solutions. The ALP based DMD projection can be exactly synchronized with one or multiple cameras so that gray value intensities generated by pulse-width modulation (PWM) are recorded with high linearity. Based upon these components, a novel 3D measuring system with outstanding properties is described. The " z- Snapper " represents a new class of 3D imaging devices, it is fast enough for time demanding in-line testing, and it can be built completely mobile: laptop based, hand-held, and battery powered. The turnkey system provides a "3D image" as simple as an usual b/w picture is grabbed. It can be instantly implemented into future machine vision applications that will benefit from the step into the third dimension.