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Image treshold

Can anyone give me an example how to apply a threshold value to an
image?

(everything above a certain brightness level becomes white, and
everything below the
level becomes black.)

I was told I should use 256-item mapping table and pass it to the
"point" method.

But how should the 256-item mapping table look like, if the threshold
is 18( found from the histogram)
Thank you for any hint.
L.

Nov 10 '07 #1
1 1024
Johny wrote:
Can anyone give me an example how to apply a threshold value to an
image?
(everything above a certain brightness level becomes white, and
everything below the level becomes black.)
I was told I should use 256-item mapping table and pass it to the
"point" method.
But how should the 256-item mapping table look like, if the threshold
is 18( found from the histogram)
Sounds like homework. You have the tools, and are close to the answer.
Experiment and look at the results.

-Scott
Nov 10 '07 #2

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