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Re: Conversion floating point to byte or integer [message #56315 is a reply to message #56296]

Thu, 11 October 2007 06:22

beardown911
Messages: 21
Registered: March 2007

Junior Member

On Oct 11, 3:05 am, Maarten <maarten.sn...@knmi.nl> wrote:
> On Oct 10, 11:32 pm, go cats <beardown...@gmail.com> wrote:
>
>> Hello Gurus,
>
>> I've been trying to write a code to correct imagery data. Original
>> imagery data format is byte format.
>> Steps for the processing includes reading the original data,
>> subtracting dark current, and multiplying calibration coefficients and
>> saving the results. The two values; dark current and calibration
>> coefficients are given by arrays with floationg point format.
>> The code seemes to work without any problem. But in the resulting
>> image saved in binary format , numbers higher than 255 store only
>> remants of what is subtracted from 256. The reason I want to convert
>> to byte is to save some disk space. In the image saved as floating
>> point format pixel values look ok.
>> Could you give some advice what part of program I have to look at? and
>> what causes this problem?
>
> Why bother with dark-current correction and calibration, if you are
> destructing the data afterwards by scaling to byte again? I'd suggest
> to save as floating point in a format that supports internal
> compression (hdf4/hdf5), and play with the compression settings. You'l
> still end up with the minimal data set on disk, but you won't
> introduce artefacts.
>
> Maarten

Maarten,

Thank you for the idea. I will try it.

Kim

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[Message index]

		Re: Conversion floating point to byte or integer By: beardown911 on Thu, 11 October 2007 18:44
		Re: Conversion floating point to byte or integer By: M. Katz on Thu, 11 October 2007 14:04
		Re: Conversion floating point to byte or integer By: beardown911 on Thu, 11 October 2007 06:22
		Re: Conversion floating point to byte or integer By: beardown911 on Thu, 11 October 2007 06:20
		Re: Conversion floating point to byte or integer By: Maarten[1] on Thu, 11 October 2007 01:05
		Re: Conversion floating point to byte or integer By: Jean H. on Wed, 10 October 2007 23:08
		Re: Conversion floating point to byte or integer By: beardown911 on Wed, 10 October 2007 21:20
		Re: Conversion floating point to byte or integer By: Jean H. on Wed, 10 October 2007 16:44

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