University of Technology and Education
Faculty of Electrical & Electronic Engineering
Lecture:
IMAGE PROCESSING
Chapter 2:
Fundamentals
Nguyen Thanh Hai, PhD
2.1 Image Representation
- Gray-level images
or color images.
- The light intensity or brightness of an object shown at coordinates (x,y) of the image
- The maximum value on the range of gray level corresponding to a completely bright point and a point
with a gray level of zero is a completely
dark point
- The most popular ranges of gray level often used in typical images: 0 to 255, 0 to 511, 0 to 1023,
etc.
- The gray levels are almost always set to be nonnegative integer numbers (real numbers)
- This saves a lot of digital storage
spaces and significantly in processing
digital images
0 and 255 is white and 254 gray levels are in between. For example, in
one 8 bit image, one gray level value is in the range (0 to 255). For color
images, in the system with 8-bit, there are 256 gray levels on one color
Each pixel can be represented on a byte (8-bit ) and the maximum number
of colors displayed at any point to 256. For 8-bit format, based on three standard
colors and it is divided as follows: 3-bit red, green and 2 bit 3 bit is blue
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