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Image Processing: Problems: Exercise 2.2 A Camera With A Focal Length of F 50 MM Is Used To Take A Photo of A Vertical

The document discusses several image processing problems and programs. It provides solutions to problems involving calculating image height and pixel count given focal length and object distance. It also determines file sizes for uncompressed binary, RGB, and black and white television images of various pixel counts and bit depths. Programming problems are presented along with sample code to reduce an image size and quantize an image by setting lowest order bits to zero. Reducing image size and bit depth results in information loss and blurriness when zoomed in, while requiring less storage space.

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512 views5 pages

Image Processing: Problems: Exercise 2.2 A Camera With A Focal Length of F 50 MM Is Used To Take A Photo of A Vertical

The document discusses several image processing problems and programs. It provides solutions to problems involving calculating image height and pixel count given focal length and object distance. It also determines file sizes for uncompressed binary, RGB, and black and white television images of various pixel counts and bit depths. Programming problems are presented along with sample code to reduce an image size and quantize an image by setting lowest order bits to zero. Reducing image size and bit depth results in information loss and blurriness when zoomed in, while requiring less storage space.

Uploaded by

dolinpatel451_457186
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Assignment- 1 1

IMAGE PROCESSING

PROBLEMS:

Exercise 2.2 A camera with a focal length of f = 50 mm is used to take a photo of a vertical
column that is 12 m high and is 95 m away from the camera. Determine its height in the image
in mm (a) and the number of pixels (b) assuming the camera has a resolution of 4000 dots per
inch (dpi).

Answer:

Let,
height of image = h

h = height of object / distance of object away from camera * focal length


h = 12 m / 95 m * 50 mm
h = 12000 mm / 95000 * 50 mm
h = 6.315 mm

Therefore, the height of the image is 6.315 mm.

Number of pixels = height of image * resolution


Number of pixels = 6.315 mm * 4000 dpi
Number of pixels = (6.315 / 25.4) inch * 4000 dpi
Number of pixels = 994 pixels
Assignment- 1 2

Exercise 2.5 Determine the number of bytes necessary to store an uncompressed binary image
of size 4000 × 3000 pixels.

Answer:
Number of bytes = 4000 * 3000 / 8 = 1,500,000 bytes

Exercise 2.6 Determine the number of bytes necessary to store an uncompressed RGB color
image of size 640 × 480 pixels using 8, 10, 12 and 14 bits, respectively, per color channel.

Answer:

Number of bytes necessary to store an uncompressed RGB color image of size 640 × 480 pixels
using:

- 8 bits per color channel = 640 * 480 * 8 * 3 / 8 = 921600 bytes


- 10 bits per color channel = 640 * 480 * 10 * 3 / 8 = 1152000 bytes
- 12 bits per color channel = 640 * 480 * 12 * 3 / 8 = 1382400 bytes
- 14 bits per color channel = 640 * 480 * 14 * 3 / 8 = 1612800 bytes

Exercise 2.7 Assume that a black and white television has a resolution of 160 × 100 4-bit pixels
and a frame rate of 25 images per second. How many different images can this device
ultimately display, and how long would a person have to watch it (assuming no sleeping) in
order to see every possible image at least once?
Answer:

Total number of images = 2160 * 100 * 4 = 2 64000 images

Frame rate = 25 images per second

Total time to view all images = total number of images / frame rate
Total time to view all images = 2 64000 / 25 seconds
Assignment- 1 3

Programs
Programming 1 Write a program that reads the image “rose.raw” (256 x 256), available on
the course homepage, and create three smaller-sized versions of the image, specifically 128 ×
128, 64 × 64 and 32 × 32, respectively. What are the effects of reducing the size of an image?
Solution:
Source code: program1.c

256 * 256 128 * 128

64 * 64 32 * 32
Assignment- 1 4

Effects of reducing the image are:


1. Information is lost which leads to burry image when zoomed.
2. Memory required to store the image is reduced.

Programming 2 Write a program that reads the image “rose.raw” (256 x 256), and create three
different quantized versions of the image. In the first, the 2 lowest order bits are set to 0. In the
second, the 3 lowest order bits are set to 0. In the third, the 4 lowest order bits are set to 0. What
are the effects of reducing the number of bits of each pixel?

Solution:
Source code: program2.c

2 lowest bits are set to 0. 3 lowest bits are set to zero


Assignment- 1 5

4 lowest bits set to zero

Effects of reducing the number of bits of each pixel is that certain grey values are set to zero
which means if we observe the image then not all grey values are present.

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