MATLAB: Position Of pixel

image processingMATLAB

heyy.. can anyone help me out in finding out the position of pixel of an binaryimage and the grayscale value of pixel

Best Answer

Igray(Ibinary); %extract gray values of true binary values
true_locations = find(Ibinary); %indices of binary values

You'll have to be more specific if you want more information.

EDIT per comment/clarification:

%Ibinary is your logical map
%Igray is your grayscale image  
%Conversions as necessary
if ~isa(Igray,'double');Igray = double(Igray);end
if ~islogical(Ibinary);Ibinary = logical(Ibinary);end
wtrr = bsxfun(@times,(1:size(Igray,1)).',Igray); %weighted Igray by rows
wtrr = sum(wtrr(Ibinary)); %Sum the ones that matter
wtcc = bsxfun(@times,1:size(Igray,2),Igray); %weighted Igray by columns
wtcc = sum(wtcc(Ibinary)); %sum the ones that matter
Gtot = sum(Igray(:));
CGr = sum(wtrr(:))/Gtot;
CGc = sum(wtcc(:))/Gtot;

%CGr is the CG amongst rows (y) and CGc is the CG amongst columns (x)

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MATLAB: For a binay image, how to plot a circle by using the centroid of the white pixel region for any given radius.

Hi!

It appears to me that you want to calculate the centroid of the white spot in your image, and using this centroid value as the center, plot a circle of any radius.

The first part of the question, i.e. finding the centroid of the circle can be evaluate as follows –

im = imread('figure.jpeg'); % Your figure
imBin = imbinarize(im);
imBin = imfill(imBin, 'holes');
BW = regionprops(logical(imBin), 'centroid');
imshow(imBin); 
hold on; 
plot(BW.Centroid(1),BW.Centroid(2),'bx')

The value of the centroid of this image is stored in the variable ‘BW’.

The output is -

(I snipped this output to enhance readability)

Coming to the second part of your question, please refer to this link here to get the relevant steps to plotting a circle with a given center and radius.

MATLAB: Assign black pixels to binary image

If "mask" is your binary image, and you want the white parts to be black (and the original pixels in the black areas of your binary image left unaltered) in your original grayscale or rgb image , called "yourImage", do this:

% Mask the image using bsxfun() function to multiply the mask by each channel individually.
maskedImage = bsxfun(@times, yourImage, cast(~mask, 'like', yourImage));

Best Answer

Related Solutions

MATLAB: For a binay image, how to plot a circle by using the centroid of the white pixel region for any given radius.

MATLAB: Assign black pixels to binary image

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