MATLAB: How to remove background from an image

background correctionbackground subtractionImage Processing Toolbox

I want to know how to remove background from an image and edge detection of the rest of the image

Best Answer

There are many ways do remove background. If you have a colored image, then you can try this

http://www.mathworks.com/help/images/examples/color-based-segmentation-using-k-means-clustering.html

If you have a gray scale image, then you can try this

http://www.mathworks.com/help/images/ref/graythresh.html

Hope it helps you.

Meshoo

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MATLAB: How to visually isolate and measure a round object within the MATLAB image

Here is an example on how to visually isolate and measure a round object within an image in MATLAB:

I = imread('eight.tif');
imshow(I)
BW = roipoly(I);
% manually select region here
BW1 = not(BW);
J = roifill(I,BW1); imshow(J)
% using ipexsegcell demo
% type 'ipexsegcell' from the MATLAB command prompt
% to view documentation for this demo
BWs = edge(J, 'sobel', (graythresh(I) * .1));
figure, imshow(BWs), title('binary gradient mask');
se90 = strel('line', 3, 90);
se0 = strel('line', 3, 0);
BWsdil = imdilate(BWs, [se90 se0]);
figure, imshow(BWsdil), title('dilated gradient mask');
BWdfill = imfill(BWsdil, 'holes');
figure, imshow(BWdfill);
title('binary image with filled holes');
BWnobord = imclearborder(BWdfill, 4);
figure, imshow(BWnobord), title('cleared border image');
seD = strel('diamond',1);
BWfinal = imerode(BWnobord,seD);
BWfinal = imerode(BWfinal,seD);
figure, imshow(BWfinal), title('segmented image');
BWoutline = bwperim(BWfinal);
Segout = I; 
Segout(BWoutline) = 255; 
figure, imshow(Segout), title('outlined original image');
% find diameter and center of the selected coin
[i,j] = find(BWfinal);
i1 = unique(i);
j1 = unique(j);
diameter = max(i)-min(i)
center_i = floor(mean(i1))
center_j = floor(mean(j1))
Additionally, another demonstration you can look into is the following MathWorks FileExchange submission:
http://www.mathworks.com/matlabcentral/fileexchange/25157-image-segmentation-tutorial

MATLAB: After using Edging and morphological operation i got the following Image. how can i now extract the number plate region. image is attached.

Fill the regions with imfill(). Then call bwareafilt(bw, 1) to extract the largest blob. Erode if a bit to get inside the outer rectangular edge, and use it as a mask on the initial binary image.

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Related Solutions

MATLAB: How to visually isolate and measure a round object within the MATLAB image

MATLAB: After using Edging and morphological operation i got the following Image. how can i now extract the number plate region. image is attached.

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