[sane-devel] SniffUSB: URB direction and TransferFlags IN/OUT confusion

[Gernot Hassenpflug]

On Sat, Feb 27, 2010 at 12:38 AM, Gernot Hassenpflug
<aikishugyo at gmail.com> wrote:
> On Fri, Feb 26, 2010 at 11:12 PM, m. allan noah <kitno455 at gmail.com> wrote:
>> On Thu, Feb 25, 2010 at 10:03 PM, Gernot Hassenpflug
>> <aikishugyo at gmail.com> wrote:
>>> On Fri, Feb 26, 2010 at 11:56 AM, m. allan noah <kitno455 at gmail.com> wrote:
>>>> On Thu, Feb 25, 2010 at 9:17 PM, Gernot Hassenpflug
>>>> <aikishugyo at gmail.com> wrote:
>>>>> On Fri, Feb 26, 2010 at 12:38 AM, m. allan noah <kitno455 at gmail.com> wrote:
>>
>> for initial work, I usually write a small libusb program that just
>> sends the basic commands required to get image data out. Then I can
>> play with that program, and watch how the image changes. Once I
>> understand what each command does, then I pick a backend and clone it.
>
> OK great advice for this newbie, here progress, not much but a start:
> 1)  got a small program running with libusb that gives me the handle
> to the device.
> 2)  took usbsniff log of several small scans with different parameters
>     (greyscale photo, colour photo, greyscale text, colour text,
> colour magazine, OCR, B/W text).
> Plan to spend part of weekend seeing how to setup device to do each
> such image acquisition.

I thought it might be interesting to note that the resolutions
supported by the applications made by Canon for its 8800F scanner are
as follows:

for paper/photos:
50, 75, 100, 150, 200, 300, 400, 600, 800, 1200

additional resolutions only for color and monochrome negative or positive film:
1600, 2400, 3200, 4800, 6400, 9600

I have no idea what the max resolution of the CCDs is in such a case,
if the stepper motor is responsible for the suppsoed increase, for
example. I'm sticking to 50dpi and 75dpi for now, varying image sizes
by 1 pixel in each direction and changing individual parameters of the
scanner software settings.

Regards,
Gernot