Image Processing of a Black and White Image
in [Matlab]
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From: AZZA Foster on 24 Apr 2010 17:04 I have a Black and White image in which i would like to create a boundary box around a specific part. In order to do this i need to somehow identify this region which has a large L shape around the data. ( The image is a 2D data matrix barcode) I wish to identify this L shape and draw a boundary box around the whole image. I thinking of using the filt2 which is an ROI filter but im not sure how to implement it??? I appreciate any comments made
From: ImageAnalyst on 24 Apr 2010 23:07 Where's your image? Post it to http://drop.io or somewhere, and then we can offer suggestions. It's hard for me to visualize a bar code with some L- shaped region around it, and what you consider the "whole image" to be. I.e. wouldn't a box around the "whole image" just be a box on the top row, bottom row, left column and right column? Or did you mean a box around the bar code, or around the L-shaped region? I'm also unclear as to why you're thinking of using a filter to find the region - a photo would help me understand that.
From: AZZA Foster on 25 Apr 2010 06:15 Here is my image http://drop.io/ifihag5 , i have used the follwing to convert to black and white and extract the corners: %%%%%%%%%%%%%%%%%%%%%%% image(Image3);figure(gcf); Image4 = Image3 >= 100; scaled2 = Image4 * 1.0; level = graythresh (scaled2); bw = im2bw (scaled2, level); bw = bwareaopen (bw, 6); horizontalProfile = max(bw, [], 1); x1 = find(horizontalProfile, 1, 'first'); x2 = find(horizontalProfile, 1, 'last'); verticalProfile =max(bw, [], 2); y1 = find(verticalProfile, 1, 'first'); y2 = find(verticalProfile, 1, 'last'); boxX = [x1 x2 x2 x1 x1]; boxY = [y1 y1 y2 y2 y1]; imshow(bw, []); hold on; plot (boxX,boxY,'r-'); cornerim_adjusted = imadjust (cornerim); corner_peaks = imregionalmax (cornerim_adjusted); corner_idx = find(corner_peaks == true); [r g b] = deal (cornerim); r(corner_idx) = 255; g(corner_idx) = 255; b(corner_idx) = 0; RGB = cat(3,r,g,b); figure,imshow (RGB); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% I Now need to tell Matlab to select an area with say 200 to 300 yellow blobs within a certain area of pixels and draw a box round it. This should pick out only the barcode. I can then overlay that box on the original image.
From: AZZA Foster on 25 Apr 2010 07:23 I think i have to define the yellow pixel areas as a blob definition. so target area of 200x200 pixels, look for 80 - 150 blobs of pixel colour r = 1, g = 1 and b = 0; Then are all the blobs in a 200x200 pixel area. Im looking at something along these lines, just trying to figure out functions and code values.
From: AZZA Foster on 25 Apr 2010 09:45
Sorry the above code is incorrect, try this one LOL. %%%%%%%%%%%%%%%%%%%%%%%%%% image(Image3);figure(gcf); Image4 = Image3 >= 100; scaled2 = Image4 * 1.0; level = graythresh (scaled2); bw = im2bw (scaled2, level); bw = bwareaopen (bw, 6); horizontalProfile = max(bw, [], 1); x1 = find(horizontalProfile, 1, 'first'); x2 = find(horizontalProfile, 1, 'last'); verticalProfile =max(bw, [], 2); y1 = find(verticalProfile, 1, 'first'); y2 = find(verticalProfile, 1, 'last'); boxX = [x1 x2 x2 x1 x1]; boxY = [y1 y1 y2 y2 y1]; imshow(bw, []); hold on; plot (boxX,boxY,'r-'); cornerim = cornermetric (bw); cornerim_adjusted = imadjust (cornerim); corner_peaks = imregionalmax (cornerim_adjusted); corner_idx = find(corner_peaks == true); [r g b] = deal (cornerim); r(corner_idx) = 255; g(corner_idx) = 255; b(corner_idx) = 0; RGB = cat(3,r,g,b); figure,imshow (RGB); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |