Error with function copyTo() and mask

[Roger Aylagas Torres]

Enviroment

Ubuntu 18.04
OpenCV
C++

Content

The objective of the code is masking the image. To do so I created a mask, invert it and then use the function copyTo() to copy the pixels that are in white in the mask.

Code

capR >> frameR;
 
cvtColor(frameR, imGrayR, CV_RGB2GRAY);

cv::Mat mask2 = cv::Mat::zeros(frameR.size(), frameR.type());

cv::ellipse(mask2, cv::Point(650,700), cv::Size(300,400),
		180,0,180, cv::Scalar(255, 255, 255),-1,8,0);

cv::Mat inv_mask =  cv::Scalar::all(255) - mask2;

imGrayR.copyTo(masked_imGrayR, inv_mask);

imshow("masked image",masked_imGrayR);

waitKey(0);

Error

But while executing an error occur:
OpenCV Error: Assertion failed (mask.depth() == 0 && (mcn == 1 || mcn == cn)) in copyTo, file /home/roger/opencv/modules/core/src/copy.cpp, line 381
terminate called after throwing an instance of 'cv::Exception'
what(): /home/roger/opencv/modules/core/src/copy.cpp:381: error: (-215) mask.depth() == 0 && (mcn == 1 || mcn == cn) in function copyTo

Aborted (core dumped)

I have detected that the issue is in the line 6, in the function copyTo()
Can anyone help me with this issue??
Thank you

[yangjing]

I had the same problem， how did you solve it ？