How can I compute the direction of gradient at each pixel of an image I ??

I need MatLab code to compute gradient direction atan(y/x) for image at each pixel

Answer 1

[Image Analyst]

Not sure what your difficulty was, but I spent a few minutes and threw together this code to take the tangent of the gradient images. See attached code.

Answer 2

[Walter Roberson]

atan2() accepts matrix parameters.

I have no idea what your x and y values are going to be, though, unless you are looking at a sequence of images and tracking the fluctuation in each pixel over time.

Have you considered imgradient ? It use a different definition of gradient.

[Abdelrahiem Hashem]

what is the meaning of angle of direction? I need numerical exam.

Answer 3

[Image Analyst]

Try imgradient() and/or imgradientxy().

Answer 4

[Abdelrahiem Hashem]

I established matrix im0 and try to understand the values in Gmag and Gdir but I can not.!!??

im0=[110 54 36 255 0;255 255 0 0 1;0 0 1 255 120;255 4 87 66 0;0 0 0 0 0]

[Gmag, Gdir] = imgradient(im0)

Please, I need to understand how be computed the first value in Gmag and Gdir (657.8146 and -104.7968) which corresponding to first value 110 in im0.

How can I compute the gradient of an image? - ResearchGate. Available from: https://www.researchgate.net/post/How_can_I_compute_the_gradient_of_an_image#5788522796b7e435a8434272 [accessed Jul 15, 2016].