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Computer System Laboratory

Computer System Laboratory. Lab14 – Camera. Experimental Goal. Learn how to use DSP and CMOS sensor to take pictures on PXA270 by using the miniGUI from GPRS driver. CMOS Sensor. TIDSP-5502. Environment. Host System Windows XP Build System VirtualBox + Ubuntu 8.04 Target System

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Computer System Laboratory

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  1. Computer System Laboratory Lab14 – Camera

  2. Experimental Goal • Learn how to use DSP and CMOS sensor to take pictures on PXA270 by using the miniGUI from GPRS driver. CMOS Sensor TIDSP-5502 / 14

  3. Environment • Host System • Windows XP • Build System • VirtualBox + Ubuntu 8.04 • Target System • Creator XScale PXA270 • Software • LCD, GPRS and DSP Drivers • JPEG library and GPRS program • You can download all software from RSWiki CSL Course Software / 14

  4. Hardware Connection TIDSP-5502 • PXA270 • TIDSP-5502 • CMOS Sensor CMOS / 14

  5. Introduction to DSP • A digital signal processor (DSP) is a specialized microprocessor with an architecture optimized for the operational needs of digital signal processing. • Digital signal processing algorithms typically require a large number of mathematical operations to be performed quickly and repeatedly on a series of data samples. Reference: wiki info: DSP, en.wikipedia.org/wiki/Digital_signal_processor / 14

  6. Introduction to CMOS • An active-pixel sensor (APS) is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. • There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web cameras, etc. • Such an image sensor is produced by a CMOS process (and is hence also known as a CMOS sensor), and has emerged as an alternative to charge-coupled device (CCD) image sensors. Reference: wiki info: APS, en.wikipedia.org/wiki/Active_pixel_sensor / 14

  7. Lab Steps (1/5) • Step 1: Download drivers2.tar.bz2 and refer to Lab12 to add the following drivers to the kernel. • Creator-pxa270 DSP5502 • Creator-pxa270 LCD • Creator-pxa270 GPRS • You can build them as modules. • Step 2: Create related device files if they does not exist. • % mknod /dev/lcd c 120 0 • % mknod /dev/gprs c 122 0 • % mknod /dev/mtdsp c 123 0 / 14

  8. Lab Steps (2/5) • Step 3: Download gprs-remote-ctrl.tar.bz2. • Step 4: Modify configuration files and Makefile. • In gprs-ctrl-build/jpeg-6b/microtime_configure, • Delete “.$HOME/bin/microtime”. • Modify “--enable-shared” to “--enable-static”. • Add the following to the front of the file. MICROTIME_USR_LOCAL_DIR=<jpeg-6b installation path> mkdir -p $MICROTIME_USR_LOCAL_DIR mkdir -p $MICROTIME_USR_LOCAL_DIR/bin mkdir -p $MICROTIME_USR_LOCAL_DIR/include mkdir -p $MICROTIME_USR_LOCAL_DIR/lib mkdir -p $MICROTIME_USR_LOCAL_DIR/man mkdir -p $MICROTIME_USR_LOCAL_DIR/man/man1 / 14

  9. Lab Steps (3/5) • In gprs-ctrl-build/creator-pxa270-gprs-1.0/microtime_configure, • Delete “.$HOME/bin/microtime”. • Delete “export LINUXDIR=$MICROTIME_LINUX_DIR”. • Add the following to the front of the file. export MICROTIME_USR_LOCAL_DIR=<jpeg-6b installation path> export MICROTIME_BUILD_PACKAGE_DIR=<path of gprs-ctrl-build> export LINUXDIR=<path of pxa270/linux> • In gprs-ctrl-build/creator-pxa270-gprs-1.0/Makefile, • Add a new flags “-static” at the end of “CFLAGS”. • In gprs-ctrl-build/creator-pxa270-gprs-1.0/creator-pxa270-gprs.c, • Delete the code of initializing UART about 5 lines at line 227. / 14

  10. Lab Steps (4/5) • Step 5: Compile the JPEG library. • Execute “gprs-ctrl-build/jpeg-6b/microtime_configure”. • Modify the generated Makefile, where “AR= arm-unknown-linux-gnu-arrc”, but not “AR= arrc”. • % make libjpeg.a • % cplibjpeg.a<jpeg-6b installation path>/lib • Step 6: Compile the GPRS program. • Execute “gprs-ctrl-build/creator-pxa270-gprs-1.0/microtime_configure”. • Copy “cmosr.out.bin” and “creator-pxa270-gprs” to PXA270. • Step 7: Connect DSP module and CMOS to PXA270 and execute. • $ ./creator-pxa270-gprs • If you use drivers as modules, don’t forget to insmod modules before executing. • By pressing keypad 7, the CMOS sensor will take a picture, and store it to PXA270 which is named “dsp_data.jpg”. / 14

  11. Lab Steps (5/5) • Step 8: Display the image on the LCD at the same time. • On PXA270, there is a LCD device which can display not only messages but also a 128*128 image with 4 gray levels. • We take a colored picture by CMOS and save the image in JPEG format. / 14

  12. Hint (1/2) • The LCD driver has already provided an ioctl command to display image on LCD. • You can implement a new function in creator_lib.c, and use this command in GPRS program. • You can refer to the example source code, i.e., lcd.c, to see how to set data to a LCD image buffer. • Since the captured image is colored, i.e., each pixel consists of three components: red(R), green(G) and blue(B), if you want to display on the LCD, please convert it to 4 gray levels. • Any reasonable conversion is acceptable. • E.g., convert RGB color space to YUV color space, then quantize the luminance Y to 4 gray levels or apply edge detection filter, then convert the edges to black and white, etc. / 14

  13. Hint (2/2) • For more information, please refer to the following sites: • Grayscale, http://en.wikipedia.org/wiki/Grayscale • RGB, http://en.wikipedia.org/wiki/RGB_color_model • YUV, http://en.wikipedia.org/wiki/YUV • Edge detection, http://en.wikipedia.org/wiki/Edge_detection • Note that the resolution of image (320*240) is different from LCD (128*128), so you can scale the resolution before you display. • Any reasonable scaling method is acceptable. • E.g., nearest neighbor, http://tech-algorithm.com/articles/nearest-neighbor-image-scaling/or bilinear, http://tech-algorithm.com/articles/bilinear-image-scaling/ / 14

  14. Lab Requirement • Take pictures by the CMOS. • Please modify the DSP driver (creator-pxa270-dsp5502.c) and GPRS program (dsp.c) to take 320*240 pictures. • The default resolution is 160*120. • Display the image on PC and on the LCD. • You can use tftp to upload your image file. • $ tftp -p -l <file><ip address> / 14

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