CS 474/674 Midterm Examination, October, 2001, Prof. Carl G. Looney
[1] (a) Draw a graph of a nonlinear transformation that contracts very dark and very light shades of gray but stretches the middle gray levels out to a wider range. (b) Draw a transformation that outputs the negative of the input image.
(a) (b)
[2] Check which of the following image properties can be determined from a histogram.
(a) ___ gray level range is too small (b) ___ too many pixels are too light (c) ___ too many pixels are too dark
(d) ___ edges are not sharp enough (d) ___ image is too smooth (e) ___ there is a lot of noise
[3] An 8-bit pixel value in a color image file is 10001110. How does this value determine the R, G and B colors for a pixel?
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[4] Images A and B are to be put on a Web site. The first is a medical image whose details are important and the second is a photograph of a mountain scene. It is desired to compress these as much as possible. What type of file should be used for each? (a) The file format for A should be ______________. (b) The file format for B should be ________________. (c) Is there an alternative format for either of these?
______________________________________________________________________________________[5] Design a 3x3 mask that detects edges in when moving from left to right (horizontally). Design a 3x3 mask that detects edges when moving from top to bottom (vertically). Show the sum of these masks below on the right.
Clearly and briefly, what does the sum mask do? __________________________________________________________
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[6] Consider the mask given below. (a) Describe what it does to an image under mask convolution.__________
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(b) Break this mask into two masks whose sum is the mask shown and the first mask boosts the original image
by a standard amount.
