Problems with uint8 and double in image processing

Matlab provides a special data type uint8 (8-bit unsigned integer) for images, and images stored in this way are called 8-bit images.
imread stores the grayscale image in an 8-bit matrix, and when it is an RGB image, it is stored in an 8-bit RGB matrix.
Therefore, the data that matlab reads into the image is uint8, and the values ​​in matlab are generally stored and operated in double type (64 bits). Therefore, it is necessary to convert the image to double format before operation,
I2=im2double(I1) % Convert image I1 to double precision type (assuming the graphics matrix range is 0~255)
or
I64=double(I8)/255; %uint conversion If it is not converted into double
, the calculation will overflow.
That is to say, when using uint8 for display, use double
im2double(): convert the image array to double precision type
im2uint8(): convert the image array to unit8 type
im2uint16(): convert the image array to unit16 type