[ros-users] cvToImgMsg for ROI images

[Kei Okada]

Dear, James,

Thanks for the response!

        CvMat subframe;
        {
          cvGetSubRect(frame, &subframe, cvRect(0, 0, height/2, height/2));
          pub_omni_.publish(bridge.cvToImgMsg((IplImage *)&subframe, "bgr8"));
        }

works fine for me. (I need to add (IplImage *) before &subframe)

FYI. Another option is to use cv::Mat in  fromIpltoRosImage

@@ -359,7 +359,11 @@
       dest.height = cvm->height;
       dest.step = cvm->step;
       dest.data.resize(cvm->step * cvm->height);
-      memcpy((char*)(&dest.data[0]), source->imageData, cvm->step *
cvm->height);
+
+      //memcpy((char*)(&dest.data[0]), source->imageData, cvm->step *
cvm->height);
+      cv::Mat m = cv::cvarrToMat(source);
+      memcpy((char*)(&dest.data[0]), m.data, cvm->step *
cvm->height);
+
       return true;
     }

or copy from source->imageData to dest.data for every line.



On Fri, Apr 23, 2010 at 10:07 PM, James Bowman <jamesb at willowgarage.com> wrote:
> Hmm, suggest instead of IplImage you use CvMat, as in
>
> CvMat subframe;
> cvGetSubRect(frame, &subframe, cvRect(width/2, height/2, width/2,
> height/2));
> pub_narrow_.publish(bridge.cvToImgMsg(&subframe, "bgr8"));
>
> (I think you are right; cv_bridge does not handle IplImage with ROI
> correctly.  But IplImage is deprecated in OpenCV in favor of CvMat.)
>
> On Fri, Apr 23, 2010 at 4:57 AM, Kei Okada <k-okada at jsk.t.u-tokyo.ac.jp>
> wrote:
>>
>> Hi,
>>
>> Does cv_bridge support converting ROI image to ROS msg?
>>
>> I'm trying to publish ROI cropped image as followings, however the
>> hoge.ppm and published image message are differ.
>> hoge.ppm start from (width/2 height/2) of the original image but
>> published image starts from (0 0).Both image size are width/2 and
>> height/2.
>>
>>          IplImage *frame = ....;
>>          int width = frame->width, height = frame->height;
>>          cvSetImageROI(frame, cvRect(width/2, height/2, width/2,
>> height/2));
>>          cvSaveImage("hoge.ppm", frame);
>>          pub_narrow_.publish(bridge.cvToImgMsg(frame, "bgr8"));
>>
>> ==
>> Kei Okada
>> _______________________________________________
>> ros-users mailing list
>> ros-users at code.ros.org
>> https://code.ros.org/mailman/listinfo/ros-users
>
>
>
> --
> J.
>
>
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