Image Crop

Cropping

asked 2014-02-26 12:12:25 -0600

dondan1976
50 ●2 ●2 ●5

Hello there,

I have an image that's 320 x 240 in size. I draw a rectangle area over the image that needs to be cropped. I get 4 values from the rectangle and they are,

X = X-axis value from top left of rectangle.
Y = Y-axis value from top left of rectangle.
Width = Width of rectangle.
Height = Height of rectangle.

Now what am doing is,

Rect r(X, Y, Width, Height); Mat orig_Image; Mat cropped_Image = orig_Image(r).clone();

I tried some other approaches also. But what i see is that the cropping is not 100% accurate.

It looks like the Y axis seems to be off by few pixels.

Is there a different approach to cropping?

I am working on a C++ project.

Thanks in advance.

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Comments

Refer to this link,It uses c :http://kristou.com/2009/08/01/opencv-image-cropping/

Abhishek Kumar Annamraju ( 2014-02-26 14:01:32 -0600 )edit

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answered 2014-03-02 22:42:39 -0600

Amit
63 ●1 ●1 ●6

croping should be done by this method in C++, i got accurate croping image.

Rect roi(r.x, r.y, r.width, r.height);
Mat image_roi = image(roi);
image_roi.copyTo(cropimage);
imwrite("cropimage.jpg",image_roi);

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I try this code posted by @Amit

    Rect roi(r.x, r.y, r.width, r.height);
Mat image_roi = image(roi);
image_roi.copyTo(cropimage);
imwrite("cropimage.jpg",image_roi);

Error on image(roi) method could you please explain the image(roi) method? Is it is built-in method or the programmer want to write the definition for that image(roi) method? Help me to solve the error I am working in java project Thanks