27th September 1999

Due Friday, 8th October 1999

* READ CHAPTER 6

in Digital Image Processing by Gonzalez and Woods

* Solve the following problems:

1. For the three colour images of the lip region (clipped from a full face image), lip1.ppm, lip2.ppm, and lip3.ppm, obtain six gray-level images of each lip image as follows: Red only component, Green only component, Blue only component, Hue component, Saturation component and Intensity component. Based on these images suggest a scheme for isolating only the upper and lower lips (minus teeth, face skin etc). Do you think your scheme is robust? Mail me the saturation image corresponding to lip1.ppm. Submit your suggestions as a written assignment (maybe a flow chart).

   You will notice that the same thresholds may not work for all images. So it may not be possible to hardcode a threshold value into your program that will work with all images. In that case you may have to threshold based on image histograms.

2. For the image squares.ppm suggest a compression scheme. You may want to do requantization of graylevels, run-length coding etc. etc. You should write two programs, one for encoding the image for compression and another for decoding the image for viewing. The decoder program should take as input the output of the compression program. Give the compression ratio achieved by your compression scheme. Submit the details of your compression scheme as a written assignment. Will your compression scheme applied on the images in Problem 1 above, result in any data reduction? If yes describe how you have modified the compression algorithm to work on those images. If no then suggest a scheme that would work on those images.

   Send me all code that you write to solve these problems.