Search found 3 matches

by stereoMatching
2013-01-25T07:54:31-07:00
Forum: Digital Image Processing
Topic: future of image enlargement?
Replies: 61
Views: 206918

Re: future of image enlargement?

The SR result about the alphabets are very good
I could tell what are the alphabets of the last line
even with my eyes without relying on OCR, pretty amazing.

I remember our professor said that fractal base algorithm is patent?
Do that mean we have to pay money if we want to implement
this ...
by stereoMatching
2013-01-20T01:17:20-07:00
Forum: Bugs
Topic: Sigmoidal equation(bug?) of image magick
Replies: 7
Views: 10203

Re: Sigmoidal equation(bug?) of image magick

Thanks, the result are much more closer to the equation --(1/(1+exp(10*(.5-u)))-0.0066928509)*1.0092503

Although the last one has some different(precision problem?But double also give the same answer).

exponential version

inline float sigmoidal(float contrast, float threshold, float signal ...
by stereoMatching
2013-01-19T06:49:16-07:00
Forum: Bugs
Topic: Sigmoidal equation(bug?) of image magick
Replies: 7
Views: 10203

Sigmoidal equation(bug?) of image magick

According to this page
http://www.imagemagick.org/Usage/color_mods/#sigmoidal

The equation of the sigmoidal should be
(1/(1+exp(β*(α-u))) - 1/(1+exp(β))) / (1/(1+exp(β*(α-1)))/(1+exp(β)))

In general, the Beta is 10 and the alpha is 0.5, IM give us a simple
command "-fx" with default Beta and ...