198:443 Digital Imaging and Multimedia

Spring 2008

Assignment 3

Due Date – in class: Tuesday April 8th

Submission instruction:

1- Report: You need to prepare a report containing all your answers, results, images, plots, and codes you wrote in one document. For example, you can use MS Word or any similar software to create a document and copy and paste the resulting images into it. Print the report and submit a hard copy of it as well as email it to the TA.

2- Code: You also need to submit an electronic copy of your code. This applies only to any code you write. Zip all your code in one file and email it to the TA.

3- You can use ImageJ or Matlab for your implementation. Useful implementations of ImageJ plugins can be found at:

http://rsb.info.nih.gov/ij/developer/source/

- Late submission policy: 20% off the grade for each day late.

The images for this assignment are available at

ftp://ftp.cs.rutgers.edu/pub/elgammal/CS443/HW3

[Q 1 – 30 points]

In the exercise, the goal is to use the image “flowers.” To experiment with color spaces. Convert the image to the following color spaces and show the color components as indicated. Show the results in a form

1. Show the R,G,B components for RGB

2. Convert the image to HSV and show the H, S, and V components.

3. Convert the image to YUV and show the Y, U, and V components.

4. Convert the image to YIQ and show the Y, I, and Q components.

5. Convert the image to YcbCr and show the Y, Cb, and Cr components.

6. Convert the image to CMYK and show the C, M, Y, and K components. Use equation 12.40 for this conversion.

7. Convert the image to CIE XYZ and show the X, Y, and Z components.

8. Convert the image to CIE xy and show the x, and y components.

9. Convert the image to L*a*b* and show the L*, a*, and b* components.

[Q2 – 30 points]

In this exercise, the goal is to experiment with color quantization. Use the median cut algorithm to quantize the image “Fruits-RGB.tif” into:

1) quantize the image to 128 colors

2) quantize the image to 64 colors

3) quantize the image to 16 colors

- In each of the cases, show the quantize images

- In each of the cases, plot the CIE-xy color space with the representative colors plotted as points in that space.

Note: an imageJ implementation of median cut can be found at:

http://rsb.info.nih.gov/ij/developer/source/