COM1370 Computer Graphics -- Quiz 2 -- Thursday, July 12th

Summer 2001 -- Professor Futrelle
College of Computer Science, Northeastern U., Boston, MA

PRINT your name clearly ________________________________________________ Your ID no. ________________

Question 1.

Assume that a CLUT has a three-bit RGB color index and produces a 24-bit (3 byte) color output. Write out a CLUT that transforms the input colors into approximately correct grey levels. Some of the following decimal-binary pairs might help you and you can interpolate your own to get values that are a bit more appropriate: 

      0: 00000000 
      8: 00001000 
     16: 00010000 
     32: 00100000 
     64: 01000000 
    128: 10000000 
    255: 11111111

That is, you should write each entry of the CLUT table as a 24 bit value made up of three bytes.

Question 2.

Compute the square of the following transformation matrix where A = sqrt(2)/ 2. Apply the original matrix to the point 1,0 and also apply the product matrix to the point 1,0. Discuss your result -- what is going on? What type of transformations are these? Hint: "square" simply means multiplying the matrix by (a copy of) itself. 

 _        _
|          |
| A    - A |
|          |
|          |
| A      A |
|          |
 -        -
ANSWERS HERE AND ON THE REVERSE SIDE: