As @AldurDisciple said, Mat::convertTo()
is intended to be used for changing the data type of a Mat
, not for changing the number of channels.
To work out, you should split it into two steps:
cvtColor(image, image, CV_BGRA2BGR); // 1. change the number of channels
image.convertTo(image, CV_32FC3, 1/255.0); // 2. change type to float and scale