Xref: utzoo comp.graphics:16953 rec.photo:19632
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!milano.sw.mcc.com!uudell!loft386!dpi
From: dpi@loft386.uucp (Doug Ingraham)
Newsgroups: comp.graphics,rec.photo
Subject: Re: Digital Photography
Summary: Built our own scanner.
Message-ID: <1991Mar30.182645.1949@loft386.uucp>
Date: 30 Mar 91 18:26:45 GMT
References: <1991Mar22.234502.4783@ux1.cso.uiuc.edu>
Followup-To: comp.graphics,rec.photo
Organization: Lofty Pursuits Public Access Unix for Rapid City, SD USA
Lines: 58


> I would like to find out what the current state of the market is (I know
> for certain the technology exists) for ways to do digital photography.
> 
> 1.  Do any of these digital video still cameras have a direct digital to
>     digital interface so that you can load the photos you took directly
>     into the computer WITHOUT a video step along the way?

Not yet.  They will eventually.  The current systems record the data on the
floppy using analog techniques or as pulse width encoding (Still analog).

> 
> 2.  Are there any digitizer/scanners that can work directly from 35mm
>     slides (again, not via any video)?

Nikon makes a wonderful unit that has 4096x6144x24 bits resolution.  Its
about $10,000.  I wanted one of these pretty bad, but for home use, I
couldn't justify it.  So a friend of mine and I are building our own.
Total parts costs are about $300.  We are using my Bessler enlarger
to project the Slides/Negatives onto a front surface mirror that is
mounted on a stepper motor.  Using 2 12 bit D/A converters we can microstep
the stepper motor to rotate the image across a linear ccd array.  The 
ccd array we are currently using came from an abandoned cannon scanner
and has 2592 bits.  We are converting the output of the ccd array using a
12 bit A/D converter.  We don't have everything working yet, but all the
remaining problems are with software.  The hardware is working well.
I am getting the Utah RLE package running and will use that as the
storage format until I find something better.  This is not fast.  It
takes about 12 minutes/pass so about 36 minutes for a full color image
to be scanned in at 2592x3888x36.  The image is increasingly noisy from
the left to the right because of the speed at which we scan, so we discard
the least significant 4 bits to eliminate the noise.  This problem
will be solved when we obtain an A/D converter that is faster than 25us
convert.  I am looking at several parts, but am waiting until everything
else is working before I pop for a new part.  Also, we will probably get
a larger ccd array at some future time.  NEC and TI both make larger units.

> I want color images to be in an RGB format, i.e. so that I can do my own
> processing on them.  I do NOT want to be stuck with some program that
> someone else thinks everyone wants.  I want to process the images with
> tools like PBMPLUS.  B&W grayscales systems are OK, too.  The higher the

Exactly!

> resolution the better.  640x480 is an absolute minimum.  1280x1024 would
> be nice.  The equivalent of a 8x10 photo enlargement scanned at 300 DPI
> would be really great (from the slide).

This is currently 324dpi at 8x10 resolution.  Eventually, I might offer to
scan images in for people.  I dont know what I would charge.  This is a lot
of data and real images dont compress all that well.  Something like 30mb
per image is a lot of data.

-- 
Doug Ingraham (SysAdmin)
Lofty Pursuits (Public Access for Rapid City SD USA)
bigtex!loft386!dpi
uunet!loft386!dpi