Paper
26 February 1997 Hyperspeed data acquisition for 3D computer vision metrology as applied to law enforcement
Author Affiliations +
Proceedings Volume 2962, 25th AIPR Workshop: Emerging Applications of Computer Vision; (1997) https://doi.org/10.1117/12.267834
Event: 25th Annual AIPR Workshop on Emerging Applications of Computer Vision, 1996, Washington, DC, United States
Abstract
The use of conventional video cameras at standard broadcast rates permits 30 frame per second videocapture and recording. Even when moving events are recorded with fast shuttering to preclude blurring (e.g. 1000th second) each recorded consecutive stopped action still has a 33 millisecond interval between them. The reason for this is the finite time necessary to serially dump recorded information from the microchip sensor, and reinitialize the sensor for the next capture event. By designing a parallel video chip with multiple, independently capable segments for sensor input/output/re-initialization, the duration of the interval required for unloading and resetting the entire sensor is decreased by the number of discrete segments in the chip, and the number of unloading ports to transfer data. Silicon Mountain Design, Inc. (SMD) developed a 16 parallel channel output 512 by 512 by 8 bit digital video camera, and a suitable memory buffer to absorb 256 full images. This camera has the uniquely advantageous feature that no image data is absorbed while the camera discharges its image to the parallel output ports. With this parallel video camera it is possible to record events at 1000th second (or faster) continuously, or at least until the memory buffer fills. The use of structured light stereo numerical camera technology requires the collection of a series of video images, each video-image containing a different 'exposure' of an object with a different pattern of structured laser beams projected onto it. The complete series of images creates a temporal-spatial encoding of the laser beams necessary to calculate a 3-D numerical recreation of the object. By using a parallel video camera, the collection of a complete series is limited by the time it takes to expose each video-image, plus the time it takes to change the light pattern being projected. Using a rapid ferric liquid crystal electro-optic modulator with a 1 millisecond cycle time, and an SMD parallel video camera cycling at 1 millisecond, each pattern is projected and recorded in a cycle time of 1/500th second. An entire set of patterns can then be recorded within 1/60th second. This pattern set contains all the information necessary to calculate a 3-D map. The use of hyper-speed parallel video cameras in conjunction with high speed modulators enables video data rate acquisition of all data necessary to calculate numerical digital 3-D metrological surface data. Thus a 3-D video camera can operate at the rate of a conventional 2-D video camera. The speed of actual 3-D output information is a function of the speed of the computer, a parallel processor being preferred for the task. With video rate 3-D data acquisition law enforcement could survey crime scenes, obtain evidence, watch and record people, packages, suitcases, and record disaster scenes very rapidly.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Bruce R. Altschuler "Hyperspeed data acquisition for 3D computer vision metrology as applied to law enforcement", Proc. SPIE 2962, 25th AIPR Workshop: Emerging Applications of Computer Vision, (26 February 1997); https://doi.org/10.1117/12.267834
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KEYWORDS
Video

3D acquisition

Cameras

3D image processing

3D vision

Data acquisition

Robotics

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