why resizing with a minus 127.5 and multiply 0.0078125

[flankechen]

in the detect_face.m line 34:
im_data=(imResample(img,[hs ws],'bilinear')-127.5)*0.0078125;

how to understand this magic number?

[ilyanelken]

@flankechen 0.0078125 = 1 / 128

[lx-onism]

in the detect_face.m line 34:
im_data=(imResample(img,[hs ws],'bilinear')-127.5)*0.0078125;

how to understand this magic number?

hello, my matlab meet an errot while excute the above code: Undefined function or variable 'imResample'. I don't know why and can not get answer by searching on the net.Could you help me? thanks a lot