MATLAB: Very Basic Threshold & Edge Detection

edge detectionimage processingthresholding

Hi all, I have a colour image I need to threshold and edge detect. I know this will be quite a simple piece of code however I'm unable to get it working. I was wondering if you could help. Here's what I have so far.

I = imread('p0071.jpeg');
BW = edge(I,'sobel', thresh) 
imshow(BW);

This snippet of code doesn't work, and I assume it's because it's in colour and I need to add some thresholding parameters? How do I add these parameters to get this code to work? Sorry for such a simple question but I've been messing around for over an hour with no success.

Paul

Best Answer

I = imread('p0071.jpg');
J = rgb2gray(I);
BW1 = edge(J,'sobel', 0.5);
imshow(BW1);

Reads a colour image in.
Converts the image to greyscale
Applies Sobel edge detection and thresholding (modify 0.5 to change threshold level 0.1-0.99)
Display the processed image.

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img = imread('diplo000000-L.png');
mask = imread('sdfsd.png');
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MATLAB: How to produce edge detected image

 I = imread('circuit.tif');
 BW1 = edge(I,'prewitt');
 BW2 = edge(I,'canny');
 BW3 = edge(I,'sobel');
 figure, imshow(BW1)
 figure, imshow(BW2)
 figure, imshow(BW3)

Or you can choose manual threshold like,

 BW1 = edge(I,'prewitt',0.4);
 BW2 = edge(I,'canny',0.4);
 BW3 = edge(I,'sobel',0.4);
 figure, imshow(BW1)
 figure, imshow(BW2)
 figure, imshow(BW3)

Best Answer

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