how to crop image from detected rectangle.?

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Nimisha
Nimisha on 16 Feb 2016
Commented: bhagyashri kapre on 12 Sep 2019
clear all;clc
boxImage = imread('IMG.jpg');
boxImage = boxImage(:,:,3);
figure; imshow(boxImage);
title('Image of a Box');
sceneImage = imread('IMG1.jpg');
sceneImage = sceneImage(:,:,3);
figure; imshow(sceneImage);
title('Image of a Cluttered Scene');
boxPoints = detectSURFFeatures(boxImage);
scenePoints = detectSURFFeatures(sceneImage);
figure; imshow(boxImage);
title('100 Strongest Feature Points from Box Image');
hold on;
plot(boxPoints.selectStrongest(100));
figure; imshow(sceneImage);
title('300 Strongest Feature Points from Scene Image');
hold on;
plot(scenePoints.selectStrongest(300));
[boxFeatures, boxPoints] = extractFeatures(boxImage, boxPoints);
[sceneFeatures, scenePoints] = extractFeatures(sceneImage, scenePoints);
boxPairs = matchFeatures(boxFeatures, sceneFeatures);
matchedBoxPoints = boxPoints(boxPairs(:, 1), :);
matchedScenePoints = scenePoints(boxPairs(:, 2), :);
figure;
showMatchedFeatures(boxImage, sceneImage, matchedBoxPoints, ...
matchedScenePoints, 'montage');
title('Putatively Matched Points (Including Outliers)');
[tform, inlierBoxPoints, inlierScenePoints] = ...
estimateGeometricTransform(matchedBoxPoints, matchedScenePoints, 'affine');
figure;
showMatchedFeatures(boxImage, sceneImage, inlierBoxPoints, ...
inlierScenePoints, 'montage');
title('Matched Points (Inliers Only)');
boxPolygon = [1, 1;... % top-left
size(boxImage, 2), 1;... % top-right
size(boxImage, 2), size(boxImage, 1);... % bottom-right
1, size(boxImage, 1);... % bottom-left
1, 1]; % top-left again to close the polygon
newBoxPolygon = transformPointsForward(tform, boxPolygon);
figure; imshow(sceneImage);
hold on;
line(newBoxPolygon(:, 1), newBoxPolygon(:, 2), 'Color', 'y');
title('Detected Box');
After ruuning this code, i am able to detect features of one image into another and it draws a rectange at detected portion. Now i want to crop that detected portion and want to save.. How to crop it and save it.?

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Accepted Answer

Image Analyst
Image Analyst on 16 Feb 2016
Have you tried imcrop() and imwrite()?
  6 Comments
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Sharmin Akhter
Sharmin Akhter on 20 Feb 2019
thanx.. i am also facing the same problem..
bhagyashri kapre
bhagyashri kapre on 12 Sep 2019
xLeft = min(newBoxPolygon(:, 1))
xRight = max(newBoxPolygon(:, 1))
yTop = min(newBoxPolygon(:, 2))
yBottom = max(newBoxPolygon(:, 2))
height = abs(yBottom - yTop)
width = abs(xRight - xLeft);
croppedImage = imcrop(sceneImage, [xLeft, yTop, width, height])
imshow(croppedImage);
Thank you above answer is helful for me in my project

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