Alexandria Univeristy
Faculty of Engineering
Computer and Communications Program
CCE: Computer Vision
Assigned: Tue, Oct 27, 2020
Due: Sat, Oct 31, 2020
Homework # 1
Image Formation, Histograms, and Point Operations
1. Consider the following 4 × 4 image f (x, y), in which pixel intensity values are represented
using 3 bits only.

1
2
f (x, y) = 
1
3
3
6
2
1
1
1
3
4

2
3

2
1
(a) Construct the intensity histogram of the image.
(b) Compute the contrast value of the image.
(c) Compute the dynamic range of the image.
(d) Construct a binning histogram for the image using B = 4 bins. Can you still compute
the contrast and dynamic range from the binning histogram?
2. Consider the 16-bin histogram below, which is constructed for a gray scale image.
i
0
h(i) 0
1 2 3 4 5 6
0 0 5 15 20 18
7 8 9 10 11 12
16 10 5 8 20 25
13 14 15
30 20 48
(a) Which of the following image defects can be found in this histogram: under exposure
or over exposure?
(b) Construct the histogram h0 , which represents the same image as h after applying a
point operation that reduces brightness by 2 units. Does this operation affect the
contrast or dynamic range of the image?
(c) Construct the histogram h00 , which represents the same image as h after applying
a point operation that multiplies all intensity values by 1.1 . Does this operation
affect the contrast or dynamic range of the image? [Note that you will need to round
the resulting intensity values to the closest 4-bit integer.]
(d) Construct the equalized histogram heq for the histogram h.
Good Luck!
Dr. Marwan Torki
Eng. Shereen Elkordi
Alexandria Univeristy
Faculty of Engineering
Computer and Communications Program
CCE: Computer Vision
Assigned: Tue, Oct 27, 2020
Due: Sat, Oct 31, 2020
3. Explain which thresholding method is suitable for each of the images having the following
histograms.
(a)
Good Luck!
(b)
Dr. Marwan Torki
Eng. Shereen Elkordi