June 15, 2014
June 15, 2014
June 18, 2014
Computers in Education
24.1062.1 - 24.1062.12
RT-DSP Using “See Through”Digital signal processing (DSP) has become one of the “must know” topics that many employersexpect of new electrical and computer engineering graduates. It has been found that a trueunderstanding of many fundamental DSP topics can be more fully realized by a student whenthey attempt to implement various DSP algorithms in real-time (typically in C), when comparedto non-real-time implementations with tools such as MATLAB or LabVIEW. In order to helpstudents successfully transition from theory to real-time practice, there needs to be both apedagogical method and an infrastructure in place to support them and target as many modes oflearning as are reasonably possible.The authors have long advocated a three-step method of teaching DSP. First, we teach the theoryalong with interesting and motivating real-time demonstrations. We then have studentsimplement a particular concept using MATLAB , until they are comfortable with the basictopic. Finally, we have them “de-vectorize” their MATLAB code and convert it to C, in order tocompile and run it in real-time on high-performance DSP hardware.Most of our previous efforts have involved audio signals, and these signals were digitized by astereo audio codec (e.g., TVL320AIC3106). In this paper, we extend our coding framework toallow for real-time image capture, processing, and display. A composite video signal from acamera is digitized by a video digital decoder (TVP5147M1). Once digitized, the signal must beconverted to red-green-blue (RGB) format. This conversion is currently accomplished in aninterrupt service routine (ISR) of the DSP code, which executes once per image frame. Whileformat conversion is only required just prior to the signal being displayed, we choose to performthe RGB conversion at this early point because our students are more familiar with RGB-basedimage processing techniques.At this point in the process, porting the RGB signal via the video digital-to-analog converter(DAC, THS8135) using the standard 15-pin VGA connector, accomplishes what we call seethrough. That is, the image processing equivalent of talk through is see through. Both talkthrough and see through demonstrate that a working, end-to-end system, has been achieved. Thisbasic step has been shown to eliminate many learning barriers for students who are just learningreal-time DSP.We have also made available the necessary algorithm insertion points for either student code orlibraries from the OpenCV  library of open source routines. All of this code runs outside ofthe challenging DSP/BIOS or SYS/BIOS  environment. A block diagram of the OMAP-L138Development Kit (LCDK)  is provided in Figure 1.During our presentation at the Annual ASEE Conference in Indianapolis, we will provide a real-time demonstration of the effectiveness of the see through system. The MathWorks, Inc., MATLAB: The Language of Technical Computing, 2013. OpenCV, http://opencv.org/ SYS/BIOS real-time kernel, http://www.ti.com/tool/sysbios OMAP-L138 Development Kit (LCDK), additional information, http://www.ti.com/tool/tmdxlcdk138 Figure 1. OMAP-L138 C6748 low cost development kit functional block diagram .
Wright, C. H. G., & Welch, T. B., & Morrow, M. G. (2014, June), RT-DSP Using “See Through” Paper presented at 2014 ASEE Annual Conference & Exposition, Indianapolis, Indiana. https://peer.asee.org/22995
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