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September 2002
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2002.09.19 00:20 "Re: Reading 16bits from a gray scale image", by Marti Maria
> I am displaying the image in 8bits so the final number
> needs to be only 8bits, that is why I shifted the pixels
> the opposite direction at the end. I am not sure if I am
> doing this step correct either. I was thinking of dividing
> by 257 but am unsure of the rounding process and think
> that this is probably just as good because it is easier.
The correct method would be to divide by 257 and then round:
r = floor(c / 257.0 + 0.5)
However this is painfull slow. If you don't care about memory,
you could use a table of 64K for speeding up... other options
would be to use fixed point.
Anyway, for most usages a simple >> 8 is enough.
Regards,
Marti.