BITDEPTH 48 (more than 8bit per chanel)

[gfaitwain]

Hi,

I need more then 24 bit (RGB) images from a scanner but be not sure if TWAIN supports more than 8 bit per channel by spezification.
I’m using TWAIN without GUI-interaction by using MSG_SET …

I tried getting 48 bits with an Hp scanner. By asking the driver for supported BITDEPTH I got max 16, means 16 bit per channel. Therefor I set the BITHDEPTH to 16 without any error. But when I launch the aquisation of the image, using nativ transfer, I got TWCC_OPERATIONERROR.
Asking the TWAIN driver just before starting aquisation by calling DAT_IMAGEINFO/MSG_GET, the driver says 48 bit image. I also set some other image caps like gamma and the area. Maybe the driver has problems by applying image processing on 48 bit images?
Are 48 bit not supported by NATIVTRANSFER or does the problem layes with in the specific twain driver of hp?

Does anybody else has experiences with getting images more then 24 bit fri?m twain?
________
ROLL A JOINT

[jimwatters]

Native transfer only offers a handle to a Device Independent Bitmaps (DIB). DIB are not 16bit per channel.

You are better using memory or file transfer.

The order you want to set these items are.
XFERMECH
ICAP_IMAGEFILEFORMAT (if using file)
ICAP_PIXELTYPE
ICAP_BITDEPTH
ICAP_COMPRESSION

Jim Watters

[spike]

I’m also trying to scan 48-bit color, but working with a Plustek OptiCard 820, and driving it through EZTwain.

The scanner driver definitely offers 16 as a value of ICAP_BITDEPTH, and I can set ICAP_PIXELTYPE=TWPT_RGB and then ICAP_BITDEPTH=16 (and I verify the bitdepth=16 setting with a following MSG_GET)
Then I set XFERMECH to memory, and compression=none.
I enable the DS, and when XFERREADY arrives I do a DAT_IMAGEINFO/MSG_GET – which tells me the image is 24 bit color!

Jim – I can try juggling the order of cap setting around to match your suggestion. Is your cap ordering specifically for HP or is that extracted from the TWAIN recommended capability ordering? Have you used that to do 48-bit scanning and if so from what scanner?

Anybody have a positive experience doing 48-bit color scanning with an under-100$US scanner that can do 48-bit color? Under 200$US?? Any scanner at all???

[jimwatters]

If the scanner is enabled with the UI, are those settings chosen? With UI open, if you choose 16 bit, is that what you get? If the transfers produce 16 bit in this case then it is a problem with the DS.

Regards,
Jim Watters

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[spike]

Hey Jim – I’ll ask my customer, who is the one actually trying to do this.

[Author]

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