Detailed Explanation of openCv’s copyTo() Method

In OpenCV, the copyTo() function is used to copy the source image to the destination image. There are several different forms of this function that can be used, and below is a detailed explanation of these forms.

1. This is the basic form of the copyTo() function, where dst is a reference to the target image. This function copies the pixel values of the source image to the target image, while ensuring that both images have consistent types and sizes. If the size and type of dst do not match the source image, the target image will be reallocated and initialized.
2. The function copyTo(Mat &dst, Mat mask) also takes a mask image in addition to the destination image. The mask image must be the same size as the source image, with a single channel and 8-bit unsigned integer type (CV_8UC1). During the copying process, only the pixels in the mask image that have a non-zero value will be copied to the destination image. This allows for partial copying of the source image.
3. In this form, in addition to the target image and mask image, a mask image of the target image is also passed. The mask image of the target image must have the same size as the target image and be a single-channel, 8-bit unsigned integer type. During the copying process, only the positions where the corresponding pixels in the mask image of the target image are non-zero will be overwritten with the value of the corresponding pixels in the source image. This allows for a partial overlay effect on the target image.

In summary, the copyTo() function is used to copy the source image into the target image, and can selectively copy or overlay using a mask image. The choice between these forms depends on whether a mask image is used, as well as the type and purpose of the mask image. Depending on specific needs, the appropriate form of the copyTo() function can be selected.