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Resolution
Resolution refers to the dimensions that determine the number of pixels present on a screen or in an image. It is
often measured by multiplying the width with height of the image in pixels, such as 1920×1080 (HD resolution),
which means the image has 1920 pixels across the width and 1080 pixels along the height.
In the context of displays or digital images, higher resolution means more pixels are used to represent the image,
leading to sharper and clearer details.
Resolution can also be expressed as a single number, such as in megapixels (for cameras), where one megapixel
equals one million pixels. For example, a 50-megapixel camera captures images with 50 million pixels, which
affects the level of detail that can be captured in the photograph.
In the case of our 1920×1024 monitors, it could also be expressed as 1920 × 1024 = 1,966,080 pixels.
In megapixels:
1,966,080
= 1.97 MP.
1,000,000
Pixel value
Each pixel in an image stored on a computer has a specific value that determines its brightness and/or colour.
The most common pixel format is the byte image, where the pixel value is stored as an 8-bit integer, allowing
for a range of values from 0 to 255. In this system, a value of 0 typically represents no colour or black, while 255
represents full colour or white.
But why do we use a value of 255?
In computer systems, data is represented using the binary system, which consists of ones and zeros. Each bit in
a computer's memory can hold one of these two values. Since each pixel is represented by 1 byte of data, which
consists of 8 bits, the total number of possible values for a pixel is 2 raised to the power of 8 (2^8), resulting
in 256 possible values. These values range from 0 to 255, providing a nuanced spectrum of pixel intensities for
representing colours and brightness levels.
Number of Bits Different Patterns No. of Patterns
1 0 1 2^1=2
2 00 01 10 11 2^2=4
000 001 010 011 100
3 2^3=8
101 110 111
0000 0001 0010 0011
0100 0101 0110 0111
4 2^4=16
1000 1001 1010 1011
1100 1101 1110 1111
Similarly, for when the number of bits is 8, then the total patterns are 2^8=256. Where, ^ represent the exponent.
Additionally, the use of 8 bits for each pixel allows for the efficient storage and processing of images in a variety
of applications, from simple graphics to high-definition photographs. With 256 possible values, this system can
represent different shades of gray or multiple colour channels in formats such as RGB (Red, Green, Blue), where
each colour channel is also represented by an 8-bit value. This binary representation ensures that images are both
stored and displayed with a rich depth of colour and brightness while remaining computationally manageable.
Computer Vision (Theory) 315

