Question

How to normalize images when converting AI models.

Answer

Can be set with IN_MEAN and IN_SCALE in setting.conf file.

• IN_MEAN : Parameters for subtractive normalization

  • Values that have an average of 0 (For 0-255, it is 127.5)

  • If the values are different in RGB, enter them separated by commas without spaces. (103.94,116.78,123.68)

• IN_SCALE : Parameters for division normalization

  • Value that gives a variance of 1 (For 0-255, it is 255)

If normalization is performed with the above parameters specified, processing is performed in the following order. (Standardization)
subtraction (IN_MEAN) ⇒ division (IN_SCALE) ⇒ inference
If you want to normalize using a procedure other than the above, create a preprocessing script and set it to "PREPRO".

Setting Example :

• When normalizing 0 - 255 to 0.0 - 1.0 :

  • IN_MEAN : 0

  • IN_SCALE : 255

• When normalizing 0 - 255 to -1.0 - 1.0 :

  • IN_MEAN : 127.5

  • IN_SCALE : 127.5

• When normalization is performed in the preprocessing script (Not include preprocessing in post-conversion model)：

  • IN_MEAN : 0

  • IN_SCALE : 1

  • PREPRO : Preprocessing script path