[PM] mean vs scale

[joyhuang9473]

reference: happynear/FaceVerification

剪去 mean 的 data 不是用 scale 1/255 ?

Ans:

happynear:

But i don't understand why you set 0.0078125 scale in CASIA_train_test.prototxt. Why is not 0.00390625.Should it normalized -1 to 1 not 0 to 1? But input image is 0 - 255 , if scale set 0.0078125 it get 0-2 isn't it? So why scale is 0.0078125. Do you do any image process before you train model? Thank your answer!

Since I have substracted the mean image, divide by 128 (1/128=0.0078125) scales the pixels' graylevel to [-1, 1]. I have also minused the mean image. So every pixel's range is [-1 1].