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## Gradient using first order derivative of Gaussian

version 1.0 (1.63 KB) by

Output the gradient image of a grayscale image

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Updated

image IM using a 2-D Gaussian kernel. Sigma is the standard deviation of
this kernel along both directions.

Atif Anwer

PRATIK GAUDANI

### PRATIK GAUDANI (view profile)

Hey, nice job man! I can easily visulaize the variations in my image.
But what if i m in 3D. With image in 2D and a time factor that is adds to the third dimenstion ?

Ernesto

### Ernesto (view profile)

thanks, it show clearly gx and gy

Karthik MSwamy

Karthik MSwamy

### Karthik MSwamy (view profile)

Real nice work!!!

Gustaf Kylberg

### Gustaf Kylberg (view profile)

Seems like you are calculating too small kernel sizes when higher values of sigma are used, e.g., when sigma>10 the kernels are clearly truncated. With sigma>40 your kernel size becomes imaginary.

samur piere

### samur piere (view profile)

can you mention the mathematical basis for kernel size and normalization steps. thx.

epsilon = 1e-2;
halfsize = ceil( sigma * sqrt(-2*log(sqrt(2*pi)*sigma*epsilon)) );

hx = hx/sqrt(sum(sum( abs(hx).*abs(hx) )));

hbu 

good

Yaroslav Bulatov

### Yaroslav Bulatov (view profile)

Prakash Manandhar

### Prakash Manandhar (view profile)

Andrea Tagliasacchi

Works perfectly it seems, Thanks

masha yusrina

there was a problem using the function imshow(fim(1:50,1:50),'InitialMagnification','fit'); in 'fit'

i can't solve it

renuka patnaik

there was a problem using the function imshow(fim(1:50,1:50),'InitialMagnification','fit'); in 'fit'

Michal Kujalowicz

Theare is a problem with fim=mat2gray(im); instruction,in "testgaussgradient.m" (matlab R14)I got "matrix im should be a double error".
It can be solved by adding im=double(im);

H N

Image processing toolbox is not required if you use conv2 instead of imfilt.

 31 Mar 2016 1 BSD
MATLAB 7 (R14)