Opencv converts 16 bit image data to 8 bits and 8 to 16

1、16 Bit image data is converted to 8 position

function Mat(int rows, int cols, int type, void* data, size_t step=AUTO_STEP);

    /** @overload @param rows Number of rows in a 2D array. @param cols Number of columns in a 2D array. @param type Array type. Use CV_8UC1, ..., CV_64FC4 to create 1-4 channel matrices, or CV_8UC(n), ..., CV_64FC(n) to create multi-channel (up to CV_CN_MAX channels) matrices. @param data Pointer to the user data. Matrix constructors that take data and step parameters do not allocate matrix data. Instead, they just initialize the matrix header that points to the specified data, which means that no data is copied. This operation is very efficient and can be used to process external data using OpenCV functions. The external data is not automatically deallocated, so you should take care of it. @param step Number of bytes each matrix row occupies. The value should include the padding bytes at the end of each row, if any. If the parameter is missing (set to AUTO_STEP ), no padding is assumed and the actual step is calculated as cols*elemSize(). See Mat::elemSize. */
Mat(int rows, int cols, int type, void* data, size_t step=AUTO_STEP);
rows  The number of rows in a two-dimensional array  
cols  The number of columns in a two-dimensional array 
type  The type of array 
data  Pointer to user data 
step  The number of bytes occupied by each row of the matrix . This value must contain the data supplemented by each row . If you don't provide this parameter , Just assume that there is no supplement , The actual step size is equal to cols*elemSize()

Mat tmp;
Mat mat(dwCount, dwProfileDataCount, CV_16UC1, (void*)pHeightProfileArray, image_info.width*2);
mat.convertTo(tmp, CV_8UC1, 255.0 / 65535, 0.5);

2、8 Bit image data is converted to 16 position

Mat mat(1000, 3200, CV_8UC1, (void*)image->getMatPtr()->data, 3200);
Mat tep;
mat.convertTo(tep, CV_16UC1, 255.0);