How to get the barcode region to red color??

How can I write the code to get the red region works on vertical barcode image shown on figure 1(a&b).

Figure 2(a&b) is what I want.

I also attach my coding for your reference.

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Figure 1a (Original image)

Figure 1b (Processed Image)

Figure 2a (Original Image)

Figure 2b (Processed Image)

Coding

rgb = imread('barcode12.jpg');
% Resize Image
rgb = imresize(rgb,0.33);
figure(),imshow(rgb);
% Convert from RGB to Gray
Igray = rgb2gray(rgb);
Igray = double(Igray);
% Calculate the Gradients
[dIx, dIy] = gradient(Igray);
B = abs(dIx) - abs(dIy);
% Low-Pass Filtering
H = fspecial('gaussian', 20, 10);
C = imfilter(B, H);
figure(),imagesc(C); colorbar;

Answer 1

[Chandra Kurniawan]

When use the first image (vertical barcode image),

I just simply try to change the position of abs(dIx) and abs(dIy) into :

B = abs(dIy) - abs(dIx);

But when I use the second image (horizontal barcode image),

I have the same problem.

Then, I decide to use this command :

B = imabsdiff(abs(dIx),abs(dIy));

[Kim]

Thanks its works! But I don't know whether is it a good coding for other images.

Btw how can make the image turning fully blue leaving the barcode in red region?

[Chandra Kurniawan]

This is not exact way to do, but I use the max value of C as threshold.

rgb = imread('av672a.jpg');

Iresize = imresize(rgb,0.33);

Igray = double(rgb2gray(Iresize));

[dIx dIy] = gradient(Igray);

B = imabsdiff(abs(dIx),abs(dIy));

H = fspecial('gaussian', 20, 10);

C = imfilter(B, H);

Th = max(C(:));

D = C < Th-10;

figure, imagesc(D); colorbar;

Then you can remove the rest of unwanted objects will bwareaopen.

[Kim]

After I did a 'imfilter(B, H)' , how can I convert the image to the colorbar image so that I can do a bwareaopen. Thereafter, draw a box or a line across to determine the barcode. I don't know whether my idea is it good or not.

Anyway, thanks for the code, really appreciate it! Just that not the thing that I wanted.

Answer 2

[Chandra Kurniawan]

Hi, Kim

I agree with you. To determine the barcode just use boundingbox from regionprops :)

Irgb = imread('15wmqe9.jpg');
Irgb = imread('av672a.jpg');
Iresize = imresize(Irgb,0.33);
Igray = double(rgb2gray(Iresize));

[dIx dIy] = gradient(Igray);
B = imabsdiff(abs(dIx),abs(dIy));

H = fspecial('gaussian', 20, 10);
C = imfilter(B, H);
Th = max(C(:));
D = C < Th-10;

stat = regionprops(~D,'Area','BoundingBox');
for i = 1 : numel(stat), 
    Iarea(i) = stat(i).Area;
end
[C I] = max(Iarea);
bb = stat(I).BoundingBox;

imshow(Iresize); hold on
rectangle('position',bb,'edgecolor','r');

[Elysi Cochin]

i'm not getting it... my error is

??? Index exceeds matrix dimensions.

Error in ==> Untitled6 at 20 bb = stat(I).BoundingBox;

please can u rectify for me..

[Image Analyst]

This is not a robust algorithm. It's fine tuned for these particular images. It may need to be tweaked for your images. Reply to the thread you started with the URL to your image.