| 摘要 |
A range imaging system in which a moving periodic pattern is projected onto the scene to be imaged. The phase by which variations in range cause portions of the pattern to shift are monitored to develop range data. A television camera offset from the axis of illumination generates four frames of intensity values. The moving pattern shifts one-quarter cycle with respect to the pattern between each of the frames. The data from the third frame is subtracted from the first frame and the data from the fourth frame is subtracted from the data of the second frame to cancel the effects of background illumination. The first difference represents a sine signal and the second difference represents a cosine signal. The arc tangent of the quotient of these values represents the phase, and thus the relative range of various points in the image. The moving pattern can be generated by either a translating plate or rotating disk which has a periodic variation in transmissiveness. An ambiguity exists when a change in range causes the phase to shift by one complete cycle. By employing a second moving pattern projected on the scene with a larger spatial period, the range in which no ambiguity occurs can be increased.
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