How to replace part of the image with another image ROI

asked 2015-03-26 06:27:15 -0600

RB
90 ●2 ●6 ●10

updated 2015-03-27 03:41:52 -0600

using opencv2.4.11 java API i am trying to truncate part of an image and then place it on another image.

the code posted below shows, the truncate Mat object is a truncated part of the img_1 posted below. and img_2 is the image that should host the truncated part of the "truncated" Mat object.

When i run the code, the result is the img_3, and i exepected to see img_2 overlapped with the "truncated" Mat object img_3.

please let me know how to achieve this properly.

Highgui.imwrite(path2, destImg);
static final String PATH5 = "c:.../images/CannyDest.jpg";
static final String PATH6 = "c:.../images/BlurredDest.jpg";

public static void main(String[] args) {
    ....
    ....
    ....

    Mat temp = Highgui.imread(PATH5);//img_1
    Mat trunctaed = temp.submat(new Rect(0, 0, 30, 30));
    Mat target = Highgui.imread(PATH6);//img_2
    trunctaed.copyTo(target);
    Highgui.imwrite(PATH6, trunctaed);//img_3
}

update:

    Mat destImg = Highgui.imread(path0, Highgui.IMREAD_COLOR);
    Mat srcImg = Highgui.imread(path1);

    srcImg.copyTo(destImg.submat(0, 30, 0, 30));
     Highgui.imwrite(path2, destImg);

    /*          //Also i tried the following 
     * srcImg.submat(new Rect(0, 0, 30, 30)).copyTo(destImg.submat(0,30,0,30));
        Highgui.imwrite(path2, destImg);

        srcImg.submat(new Rect(0, 0, 30, 30)).copyTo(destImg.submat(new Rect(0, 0, 30, 30)));
        Highgui.imwrite(path2, destImg);*/

img_1

img_2

img_3

Comments

I think you really need to iterate through all the pixels you want to change and assign them a new value.

Pedro Batista ( 2015-03-26 06:45:32 -0600 )edit

Could you also post the result you want? I am not sure I am understanding what you want. Is it: You want the result to be img_2 with a cropped region, or img_2 with img_3 inside in a specific place, or something else?

thdrksdfthmn ( 2015-03-26 07:32:56 -0600 )edit

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answered 2015-03-26 07:30:58 -0600

bvbdort
115 ●3 ●7

updated 2015-03-27 06:52:59 -0600

change

trunctaed.copyTo(target);   // erases all content  of target and keeps truncated image only.

trunctaed.copyTo(target(cv::Rect(0, 0, 30, 30))); // replace specified rect of target with truncate image.
Highgui.imwrite(PATH6, target); //img_3  result is in target.

above change gives.

image description

Update :

    Mat temp = Highgui.imread(PATH5);//img_1
    Mat trunctaed = temp.submat(new Rect(0, 0, 30, 30));
    Mat target = Highgui.imread(PATH6);//img_2
    trunctaed.copyTo(target(cv::Rect(0, 0, 30, 30))); 
    Highgui.imwrite(PATH6, target); //img_3

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Comments

i tried your answer but unfortunately i always receive the same result

RB ( 2015-03-26 08:07:08 -0600 )edit

This will create a ROI on target and then will copy truncated to that image. OP wants to replace pixels of ROI in the main image, keeping the other pixels the same.

Pedro Batista ( 2015-03-26 08:10:49 -0600 )edit

what is OP please

RB ( 2015-03-26 08:39:25 -0600 )edit

So what do you want? the inverse: colors in the edges? Or do you want edges on colors, but keeping the colors? Have you really changed the 2 lines of code in the answer? Strange if it gives the same result as in your case... Aren't you overwriting the image with just the ROI?

thdrksdfthmn ( 2015-03-26 10:09:02 -0600 )edit

please have alook at the update section..i still have the same problem to copy part of the image over anothe rimage, though, i have solved this issue with pixel by pixel replacement

RB ( 2015-03-27 03:43:18 -0600 )edit

i just put complete code lines, let me know it its working and gives you required result.

bvbdort ( 2015-03-27 06:53:59 -0600 )edit

The submat is cropping the image, so you'll have just the copied region...Aren't simple parenthesis working (srcImg.submat(new Rect(0, 0, 30, 30)).copyTo(destImg(new Rect(0, 0, 30, 30)));)?

thdrksdfthmn ( 2015-03-27 11:46:59 -0600 )edit

On java you can't do destImg(new Rect(0, 0, 30, 30). I tried with destImg.adjustROI(dtop, dbottom, dleft, dright) before copyTo but still not work.

jotapdiez ( 2017-11-08 13:10:22 -0600 )edit

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How to replace part of the image with another image ROI

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