It is a graph showing the number of pixels in an image at each different intensity value.
Eg. 256 different possible intensities for an eight-bit grayscale image.
Histogram equalization:
- It is the technique by which the dynamic range of the DN values of an image is increased.
- It assigns the intensity values of pixels in the input image to show a uniform distribution of intensities.
- It improves contrast and obtains a uniform histogram
Histogram Stretching:
- It is a simple image enhancement technique that improves the contrast image.
- It uses methods like linear and nonlinear contrast stretching for image enhancement.