Re: Lower-cost IIDC cameras

Hi again Arne,

I was just looking at the Datasheet for the TI chipset and the errata for
the chip. I quote the following paragraph:

<begin quote>
5. color_bw Bit Cannot Be Configured for Monochrome Operation

Problem:

The camera works properly when the color_bw bit in the VIDEO_OPTIONS_CNFG
register (0F22h) is set to 1, indicating that the TSB15LV01 is to assume
the CCD is a color CCD and process it accordingly. However, if set to 0,
the resulting image has a cross-hatched appearance.

Workaround:

As a result of this problem, TSB15LV01 cannot be used with a monochrome
sensor. It only works with the Sony or Sharp color sensors. If a
monochrome image is desired, the monochrome transfer mode can be used.
Note that with this setting, the image from the sensor is processed as a
color image including interpolation of a presupposed Bayer pattern
and then only the luminance data is transmitted to the host.
<end quote>

You stated:
> IIRC you need to program the following register:
> 0xF20 VIDEO_OPTIONS_CNFG
> If you clear bit 30: color_bw, you should get the bayer pattern.

Aren't these the same things? The documentation says that if this bit is
set to "0" then the image has a "cross-hatched" appearance. Is this
simply the bayer pattern or is it some sort of interpolated version of the
bayer pattern?

Thanks,

-- Andrew

On Sat, 13 Nov 2004, Arne Caspari wrote:

> Andrew Hogue wrote:
>
> >Hi Arne,
> >
> >I would love to hear any advice on 'tuning' the TI chipset you may have.
> >
> >
> >
> >>If you are not happy with the debayering code of the TI chipset, you can
> >>tell the chip to use a monochrome CCD ( get the spec of the TI TSB15Lv01
> >>). This will give you the raw bayer pattern of the CCD. Then you can do
> >>the bayer processing on the host PC and use a better algorithm ( you
> >>need to do another workaround for a bug in the chipset then but I can
> >>give you details if you ask for it ;-) ).
> >>
> >>
> >
> >I would be grateful for any information you would be willing to provide
> >about this. It would be wonderful to have access to the raw bayer image
> >so I could do the processing my self... some of the work I do requires
> >offline computation anyways.
> >
> >
>
> Andrew,
>
> At first, you should go to www.ti.com and get the datasheet of the
> "TSB15LV01" ( do a part search on this part ID ).
>
> I assume you already know about debayering algorithms.
>
> IIRC you need to program the following register:
> 0xF20 VIDEO_OPTIONS_CNFG
> If you clear bit 30: color_bw, you should get the bayer pattern.
>
> Now you should set "WhiteBalance", Saturation etc to the value 64 which
> should be the "neutral" values for this DSP.
>
> Then you might come across the next issue: The DSP will change the
> starting row of the output randomly on every startup. The solution I
> found for this is to turn on the Test-Pattern using the register:
> 0xF04 TEST_CNFG
>
> Locate eg. the red bar of this test pattern. In bayer mode, check if you
> get red pixels in the location where the red bar is. If it is not, you
> need to alter your debayer code to compensate for the changed starting row.
>
> I hope this information helps. Otherwise, ask ;-)
>
>
> -Arne
>
>
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Received on Sun Nov 14 18:40:14 2004