Segmentation is the underlying concept for creating objects from pixels. The segmentation process involves dividing the image into regions or objects have common properties.

Typical image segmentation techniques involve one of the two process:

• Region merging according to some measure of homogeneity
• Separation of objects by finding edges using the gradient of digital numbers (DNs) between neighboring pixels.

Region- margining approaches can be divided into two approaches:

• Region Growing
• Region split and merging

Detection of Discontinuities in Digital Image– Point Detection, Line Detection and Edge Detection.