### Highlights from Gradient using first order derivative of Gaussian

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# Gradient using first order derivative of Gaussian

### Guanglei Xiong (view profile)

19 Jul 2005 (Updated )

Output the gradient image of a grayscale image

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Description

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

Required Products Image Processing Toolbox
MATLAB release MATLAB 7 (R14)
24 Nov 2012 Atif Anwer

### Atif Anwer (view profile)

29 May 2012 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 ?

22 Mar 2010 Ernesto

### Ernesto (view profile)

thanks, it show clearly gx and gy

07 Jan 2010 Karthik MSwamy

### Karthik MSwamy (view profile)

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04 Jan 2010 Karthik MSwamy

### Karthik MSwamy (view profile)

Real nice work!!!

13 Aug 2009 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.

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10 Aug 2009 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) )));

12 Jun 2009 hbu 

### hbu  (view profile)

good

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23 Apr 2009 Yaroslav Bulatov

### Yaroslav Bulatov (view profile)

10 Feb 2009 Prakash Manandhar

### Prakash Manandhar (view profile)

02 Oct 2008 Andrea Tagliasacchi

Works perfectly it seems, Thanks

19 Sep 2008 masha yusrina

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

i can't solve it

06 Jul 2006 renuka patnaik

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

25 Nov 2005 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);