"Dot indexing is not supported for variables of this type" in blockproc(I_STRUCT.coef_arrays{1},[8 8],fun);

Question

After imread into a variable and sending it to the function, it returns an error "Dot indexing is not supported for variables of this type."

Not sure why, it seemed to work with jpg, but with pgm it fails despite using same function

stego = imread('1.pgm');
quality_factor = 75;

fun = @(x)x.data .*stego.quant_tables{1};
I_spatial = blockproc(stego.coef_arrays{1},[8 8],fun)

Answer 1

Bad attempt at using pmg instead of jpg, assumed that jpeg_read was equal to imgread. Instead of sending a struct to the function sent array.