How to find directional Map for intensity values

Please help me to findout directional quantized value of intensity value of an image like following.

Answer 1

[Image Analyst]

You can use imgradient() or imgradientxy().

[Anu G]

Sir, i dono how to compute qantized map value and to storred in four directional value like 0, 45, -45 and 90 degree. Kindly help me

[Image Analyst]

The gradient vectors will not necessarily point only in those directions. They could point at any angle.