| Summary: | 碩士 === 國立暨南國際大學 === 資訊工程學系 === 93 === The optical 3-D scanning technique has played an important role in reverse engineering.In recent years, it has also been widely used in the fields of the movie and entertainment industry,military applications, surgical planning, virtual reality, and digital museums.Popular optical 3-D scanning systems, such as the stereo vision system and the laser triangulation system,need to be calibrated precisely beforehand. Furthermore, most of the optical 3-D scanning systems require expensive frame grabbers for image acquisition. In the thesis, we designed two hardware image processing modules, i.e., the single point laser scanner (SPLS) module and the single line laser scanner (SLLS) module,for image feature extraction. These image processing modules can extract image features directly from the video signal. Therefore, it can be used to replace the frame grabber and the software feature extraction program of a laser scanning system. We also developed a procedure for building a look-up table to simplify the system calibration task. In the SPLS module, we binarize the input video signal with a voltage comparator to obtain the position of the light spot and the detected light spot position is converted to a depth measurement by an 8051 microcontroller. The SPLS circuit is extremely simple and stable although it can only provide 30 measurements per second. To increase the measurement speed, one can use a line generator to project a bright light stripe onto the object surface. However, the image processing hardware for detecting the projected laser light stripe is more complicated than that for detecting a single light spot.Our SLLS image processing module can extract at most 480 bright points for each image frame using a turbo 8051 microcontroller and a CPLD circuit. The experiment results show that the digital circuitries of our image processing modules work properly.
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