Question on ISPs CFA interpolation coefficients

Question on ISPs CFA interpolation coefficients

[Matthias Schwarz]

Hi all,

i just wondered how the camera interface's, especially the previewer 
module's CFA coefficients are setup on OMAP3530.

The TRM also does not give too much information about it:
> In the generic mode, CFA interpolation is implemented using 
> programmable filter coefficients that operate
> on a 5x5 grid:
> · Each coefficient is coded in S8Q6 format.
> · Each output color , G, and B) has its own set of coefficients.
> · There are 4 phases. Each pixel is associated with a phase.
> · Different sets of filter coefficients are provided, depending on the 
> tendency (gradient in the data:
> horizontal, vertical, or neutral).
> · So there are 3 color x 4 phase x 3 tendencies x 16 taps = 576 
> coefficients (each coefficient is 8 bits
> wide).
> Note: Coefficients are based on sensor type. However, users can use a 
> different methods of
> defining an optimal coefficient set.

Also drivers/media/video/isp/cfa_coef_table.h does not provide 
information on what the inserted values mean and how they are arrenged.

My question now is: is there anyone on the list who would provide me 
with information on how to compose these coefficients correctly?

Thank you very much,
Matthias
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Re: Question on ISPs CFA interpolation coefficients

[matthias schwarz]

2009/8/27 Matthias Schwarz <matthias.schw@googlemail.com>:
> Hi all,
>
> i just wondered how the camera interface's, especially the previewer
> module's CFA coefficients are setup on OMAP3530.
>
> The TRM also does not give too much information about it:
>>
>> In the generic mode, CFA interpolation is implemented using programmable
>> filter coefficients that operate
>> on a 5x5 grid:
>> · Each coefficient is coded in S8Q6 format.
>> · Each output color , G, and B) has its own set of coefficients.
>> · There are 4 phases. Each pixel is associated with a phase.
>> · Different sets of filter coefficients are provided, depending on the
>> tendency (gradient in the data:
>> horizontal, vertical, or neutral).
>> · So there are 3 color x 4 phase x 3 tendencies x 16 taps = 576
>> coefficients (each coefficient is 8 bits
>> wide).
>> Note: Coefficients are based on sensor type. However, users can use a
>> different methods of
>> defining an optimal coefficient set.
>
> Also drivers/media/video/isp/cfa_coef_table.h does not provide information
> on what the inserted values mean and how they are arrenged.
>
> My question now is: is there anyone on the list who would provide me with
> information on how to compose these coefficients correctly?
>
> Thank you very much,
> Matthias
>

What i guess from no answers is that this part clearly lacks
information. I also created a thread in TI's e2e forums:
http://e2e.ti.com/forums/t/9565.aspx

Best regards,
Matthias
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