find gradient using sobel mask operator in matlab

2017 2 25
1 个回答
更新时间：2017 2 26
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I am using following code to mask image using sobel mask .
%------------------- C is an image
for i=1:size(C,1)-2
for j=1:size(C,2)-2
%Sobel mask for x-direction:
Gx=((2*C(i+2,j+1)+C(i+2,j)+C(i+2,j+2))-(2*C(i,j+1)+C(i,j)+C(i,j+2)));
%Sobel mask for y-direction:
Gy=((2*C(i+1,j+2)+C(i,j+2)+C(i+2,j+2))-(2*C(i+1,j)+C(i,j)+C(i+2,j)));
%The gradient of the image
%B(i,j)=abs(Gx)+abs(Gy);
B(i,j)=sqrt(Gx.^2+Gy.^2);
direction = atan(Gy./Gx)
end
end
My question is that sometimes gradient direction value is giving as "NaN", how to avoid it?
Second, how to quantize gradient direction into eight zone and find feature vector for the image? Please someone help me.

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回答（1 个）

Image Analyst
Image Analyst 2017-2-25

0 个投票

Why? Why not simply use imgradient() to get the Sobel filtered image?

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DIWAKAR KUMAR
DIWAKAR KUMAR 2017-2-25
please tell me how to quantize gradient direction into eight zone and find feature vector for the image?
Image Analyst
Image Analyst 2017-2-26
What features do you want to measure?

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