This is a script, not a function. The input image is set by INPUT. The variable "bit_slicing" is filled by RAND, then the values are over written by 255 and finally all values are overwritten again - absolutely useless. The last line fails, because "h1" is not defined.
The calculation by BITAND is performed for each element, but it would be much faster and nicer to apply it to the complete matrix at once.
No help, no comments. Neither useful nor usable.
