Nameless

PP Rocks

Team Members

1. Rene Anderson, researching
2. Francis Chau, researching on Image Processing
3. Yiqi Liu, Researching on DCRaw — a commonly used open source RAW image processing library

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Progress

Assignment 1

Francis' discoveries After doing some research and going through the trouble of building through windows command-line on the latest GNU compiler, I've managed to compile it.

I've downloaded and chose one of the sample projects that CImg carries, "tutorial.cpp" from http://cimg.eu/. Based on my observations through running it, it measures the amount of Red, Green and Blue values (RGB, primary colours) of a picture; there is one window displaying an image in this case a parrot and the other window to measure RGB values.

Performing some execution tests, I've found that CImgDisplay function consumes the most amount of time at 1.57 seconds.

Here's the flat diagram:

As well as the call graph diagram:

Yiqi's Findings

• The subject: RAW photo processing using the (commonly used) open source DCRaw library by Dave Coffin
• Library/program source file web page: https://www.cybercom.net/~dcoffin/dcraw/dcraw.c
• The script runProfile.sh in the submitted zip file executes the make command, run the profiling, and display the result
• Findings: the hot spot of the dcraw library is the ahd_interpolate() function, which contains large amount of loops, thus should be suitable of parallelization using GPU
• Although the time to process an individual image is not really long, for a batch of images, the time saving could be significant
• Here is the profiling result:

real    0m15.020s
user    0m13.653s
sys     0m1.016s

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls  ms/call  ms/call  name
 30.34      3.68     3.68                             ahd_interpolate()
 26.71      6.92     3.24 45411856     0.00     0.00  cielab(unsigned short*, short*)
  9.40      8.06     1.14                             convert_to_rgb()
  8.74      9.12     1.06                             write_ppm_tiff()
  8.57     10.16     1.04                             lossless_jpeg_load_raw()
  4.29     10.68     0.52                             scale_colors()
  3.54     11.11     0.43                             crop_masked_pixels()
  3.22     11.50     0.39 23384000     0.00     0.00  getbithuff(int, unsigned short*)
  3.13     11.88     0.38     3950     0.10     0.24  ljpeg_row(int, jhead*)
  1.48     12.06     0.18 23384000     0.00     0.00  kodak_c603_load_raw()
  0.49     12.12     0.06                             pre_interpolate()
  0.08     12.13     0.01        1    10.00    10.00  border_interpolate(int)
  0.00     12.13     0.00       42     0.00     0.00  tiff_get(unsigned int, unsigned int*, unsigned int*, unsigned int*, unsigned int*)
  0.00     12.13     0.00       26     0.00     0.00  get2()
  0.00     12.13     0.00       26     0.00     0.00  get4()
  0.00     12.13     0.00        5     0.00     0.00  getreal(int)
  0.00     12.13     0.00        4     0.00     0.00  parse_tiff_ifd(int)
  0.00     12.13     0.00        3     0.00     0.00  parse_tiff(int)
  0.00     12.13     0.00        3     0.00     0.00  ljpeg_start(jhead*, int)
  0.00     12.13     0.00        2     0.00     0.00  make_decoder_ref(unsigned char const**)
  0.00     12.13     0.00        1     0.00     0.00  apply_tiff()
  0.00     12.13     0.00        1     0.00     0.00  parse_exif(int)
  0.00     12.13     0.00        1     0.00     0.00  adobe_coeff(char const*, char const*)
  0.00     12.13     0.00        1     0.00     0.00  cam_xyz_coeff(float (*) [4], double (*) [3])
  0.00     12.13     0.00        1     0.00     0.00  pseudoinverse(double (*) [3], double (*) [3], int)
  0.00     12.13     0.00        1     0.00     0.00  parse_makernote(int, int)
  0.00     12.13     0.00        1     0.00     0.00  parse_gps(int)