CODEWITHSUNDEEP
opencv
user349026
user349026

Reputation:

cvErode Error- Unknown Array Type

I am trying to perform an erosion of a JPEG image after converting the image to YCrCb image space. Using the following code

 YCrCbMin.val[0] = 0;
 YCrCbMin.val[1] = 131;
 YCrCbMin.val[2] = 80;

 YCrCbMax.val[0] = 255;
 YCrCbMax.val[1] = 185;
 YCrCbMax.val[2] = 135;

 imshow("img",Img);// Img is the JPEG image I load off the disk. 
 waitKey(0);

 Mat YCrCbImg;
 cvtColor(Img, YCrCbImg, CV_BGR2YCrCb);

 Mat erodedImg;
 inRange(YCrCbImg, YCrCbMin, YCrCbMax, erodedImg);

 Mat InterMediateImg     = YCrCbImg;
 IplConvKernel* element  = new IplConvKernel();

 element->nCols      = 12;   element->nRows      = 12;   element->anchorX    = 6;    element->anchorY    = 6;

  cvErode(&erodedImg, &InterMediateImg, element, 1);
  element->nCols      = 6;    element->nRows      = 6;    element->anchorX    = 3;    element->anchorY    = 3;
  cvDilate(&InterMediateImg, &erodedImg, element, 2);

On the first erosion, I get the following error as shown in the screenshot.

Error Image

I have used the following image as input

index.jpg

What am I doing wrong here??

Upvotes: 0

Views: 2758

Answers (1)

Sassa
Sassa

Reputation: 3334

The error appears probably when you call cvErode and cvDilate. You are mixing the C and C++ interface. So, for example, in

cvErode(&erodedImg, &InterMediateImg, element, 1);

erodedImg and InterMediateImg are of type cv::Mat when they should be of type cvMat. The same thing for cvDilate.

You can either use the new interface:

cv::erode

void erode(const Mat& src, Mat& dst, const Mat& element, Point anchor=Point(-1, -1), int iterations=1, int borderType=BORDER_CONSTANT, const Scalar& borderValue=morphologyDefaultBorderValue())

and

cv::dilate

void dilate(const Mat& src, Mat& dst, const Mat& element, Point anchor=Point(-1, -1), int iterations=1, int borderType=BORDER_CONSTANT, const Scalar& borderValue=morphologyDefaultBorderValue())

or convert from cv::Mat to cvMat (link to cheatsheet):

CvMat cvmat = img; // convert cv::Mat -> CvMat


Also notice that when you call those functions, the destination matrix is not empty and probably does not have the same type as the source matrix so there is a chance you will run in an error there too if I am not mistaken.


Nice erosion and dilation tutorial in OpenCV 2.4.2

Upvotes: 2

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