Crop an image using coordinates

props = regionprops(verticalProfile, 'PixelIdxList');
for k = 1 : length(props)
    row1 = props(k).PixelIdxList(1, 1)
    row2 = props(k).PixelIdxList(1, end)
    croppedImage = grayImage(row1:row2, :)
    imshow(croppedImage);
    drawnow;
end

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Image Analyst 2019-11-3

在 MATLAB Online 中打开

Hopefully you tried what I told you about removing the inner loop. Did you? If not, why not?

Here is what you should have gotten:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 14;
% cd('F:\Matlab Research\Images\Codes');
% myFolder = 'F:\Matlab Research\Images\Codes';
myFolder = pwd;
pathname = pwd;
% [filename, pathname] = uigetfile('*.png','Select image to be read');
filename = 'image.png';
grayImage= imread(fullfile(pathname,filename));
if ndims(grayImage) > 1
	% Take blue channel
	grayImage = grayImage(:, :, 3);
end
grayImage=padarray(grayImage,[0 1]);
letterLocations = any(grayImage > 128, 1);
subplot(2, 2, 1);
imshow(grayImage);
subplot(2,2, 3:4);
plot(letterLocations, 'b-', 'LineWidth', 2);
title('Projection down vertically');
grid on;
% Find Rising and falling edges
d = diff(letterLocations);
startingColumns = find(d>0)
% disp (startingColumns)
endingColumns = find(d<0)
% disp (endingColumns)
% Extract each letter.
numLetters = length(startingColumns)
plotRows = ceil(sqrt(numLetters + 3))
subplot(plotRows, plotRows, 1);
imshow(grayImage);
impixelinfo;
title('Original Image', 'FontSize', fontSize);
subplot(plotRows, plotRows, 2:3);
plot(letterLocations, 'b-');
title('Projection down vertically');
grid on;
% Extract each letter.
for k = 1 : numLetters
	% Get sub image of just one character...
	subImage = grayImage(:, startingColumns(k):endingColumns(k));
	[L, numberOfBlobsInThisBand] = bwlabel(subImage);
	baseFileName = sprintf('c%d.png', k);
	% Prepend the folder to make the full file name.
	fullFileName = fullfile(myFolder, baseFileName);
	% Do the write to disk.
	% 		imwrite(bw, fullFileName);
	subplot(plotRows, plotRows, k + 3);
	imshow(subImage);
	caption = sprintf('Letter %d of %d', k, numLetters);
	title(caption);
end

Image Analyst 2019-11-4

在 MATLAB Online 中打开

It should only get to that line if it's an RGB image. What does this say?

ndims(grayImage)
whos grayImage
[rows, columns, numberOfColorChannels] = size(grayImage)

Don't use semicolons and look to see what it reports to the command window.

Anonymous26 2019-11-8

@Image Analyst

Thank you so much for your support. I made some modifications in the code and made it work, according to my need.

Thanks a lot again!

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Answer 2

darova 2019-11-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/488817-crop-an-image-using-coordinates#answer_399492

在 MATLAB Online 中打开

Capture.jpeg

Here is an attempt

clc,clear
I = imread('Capture.jpeg');
I1 = im2bw(I);                  % convert to binary
I2 = bwareaopen(~I1,100);       % remove numbers (small areas)
[row,col] = find(I2);
I3 = I2*0;
h = 1;                          % crop thickness
ii = row(1)+h:row(end)-h;
jj = col(1)+h:col(end)-h;
I3(ii,jj) = I2(ii,jj);          % crop
I4 = bwareaopen(I3,200);        % remove small areas
[L,n] = bwlabel(I4);            % label image
for i = 1:4
    subplot(2,2,i)
    I5 = L == i;                % find part of a curve
    I6 = imdilate(I5,ones(5));  % highlight the part
    II = cat(3,~I6,I1,I1)*255;
    imshow(II)                  % show original image and part of a curve
end