find an inverse log transformation of an image in matlab

matlab image-processing transformation imagefilter
user461127 picture user461127 · Oct 16, 2011 · Viewed 15.2k times · Source

I have been searching for this almost all day. The general form of the log transformation is 

s = clog(1+r)

where

c = 0.1

The opposite is inverse log transformation(book). What will be the inverse log transformation? Is it

s = exp(r)?

Could not get right output.

Answer

sarnold picture sarnold · Oct 16, 2011

Exp() will only be an inverse of Log() if Log() is the natural logarithm. If your Log() is using a different base (base 2, base 10, any other arbitrary base), then you will need to use the different base in place of e in Exp().

Update

Try 10^(x/0.1)-1. x/0.1 undoes the 0.1 * operation, 10^ undoes the log(), and -1 undoes the +1.

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