Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Do we actually need portable cameras ?

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
CCDeye
Posts: 17
Joined: 20 Apr 2011, 12:28

Do we actually need portable cameras ?

Post by CCDeye » 11 May 2011, 12:34

Hi guys..
Few things about the digital cameras I hate, when it comes to scanning books to a PC

0.They aren't meant to be used beside a computer.
1.They need power supply. See 0
2.They store pictures on a SD. See 0
3.They need time to focus. They aren't meant to shoot objects in a fixed distance.
4.They need special triggers for remote control. They are meant so, that the creature that takes pictures, actually hold them in their hands.
5.They have a shutter mechanism and mechanical moving parts that wears out after several thousands of shots.

The closest alternative I can think of is a web camera !
They are cheap, small, light, no shutters, no power supply, directly upload the picture to the PC via USB, no automatic focus, no mechanical moving parts, out of the box remote - hit SPACE to take picture etc..
The problem is I can't find a web camera that actually takes good pictures. I need 3-5 Megapixels (not interpolated ) for my needs ( the books I scan are rather small)
Am I missing something ? If no, can you point me to a web camera, suitable for 3 Megapixels or more resolution ? The one I bouth Logitech C310 shoots worse than my old cell phone with 2 Megapixels.

spamsickle
Posts: 596
Joined: 06 Jun 2009, 23:57

Re: Do we actually need portable cameras ?

Post by spamsickle » 11 May 2011, 22:17

I've worn out a couple of shutters myself. Reading your post, I wonder if it might be possible, using CHDK, to pop the shutter open once per session, then pull timed exposures out of a webcam-like stream. The idea hadn't occurred to me before, and I'm not going to have time to explore it in the near term, but it seems worth pursuing. If it works, it should extend the life of a shutter.

I already use fixed focus for a session, so I'm extending the zoom/focus mechanism a bit by not trying to have each shot pull focus. If it was possible to clear the pixel array, let it soak up light for a specified interval, dump the data to the SD card, and clear the pixel array again, all under the control of a CHDK script, I can see how that might have uses that extend beyond our simple scanning needs.

Something to think about.

jgreely

Re: Do we actually need portable cameras ?

Post by jgreely » 12 May 2011, 03:37

CCDeye wrote:The problem is I can't find a web camera that actually takes good pictures.
I doubt you'll find one. I recently spent a merry hour trying to find actual spec sheets for HD webcams, and most of them are evasive to the point of deception. Bottom line: 2 megapixels or less, and all claims of high-resolution stills were based on software interpolation. Useless for book-scanning anyway, since almost all of the lenses are wide-angle enough that you couldn't fill the frame with a book page and have it be in focus.

Thanko and Novac have portable USB bus-powered, fixed-focus, A4-size document scanners with built-in LED lights, but after poking around their web sites, they're using 2MP sensors as well. Novac's Simply Scan A3 ($340) has a 5MP sensor, but with the adjustable arm at minimum height, it manages 4.1MP on an A4 page. Smaller pages are just crops of that (down to a quoted 0.5MP for a business card).

[update: I found the PDF manual for the A3 scanner, and it has a manual focus dial. It also gives the scan time, ~1 second. The spec page also had links to sample A3 and A4 output that isn't terribly impressive.]

-j

dtic
Posts: 461
Joined: 06 Mar 2010, 18:03

Re: Do we actually need portable cameras ?

Post by dtic » 13 May 2011, 14:16

Hi CCDeye, I'm with you on this. It should only be a matter of time until webcams will be up for the task image quality wise.

It is frustratingly hard to find clear information on webcam still image quality - specs and reviews are very uninformative for that.

The C910 looks promising - has a 5 Mpx sensor (interpolates to 10 Mpx):
http://forums.quickcamteam.net/showthread.php?tid=1492

Ryan_phx
Posts: 63
Joined: 29 Dec 2010, 14:51
E-book readers owned: Nook, Kindle DX
Number of books owned: 0
Country: USA
Location: Sandusky, OH

Re: Do we actually need portable cameras ?

Post by Ryan_phx » 13 May 2011, 16:22

I'm not a camera expert, but it seems to me that the quality of the optics is just as important--if not more so--than the pixel count. I can't see webcams that are designed to capture relatively low-quality images for transmission ever being good enough for book scanning, especially with small print or image-heavy books. It's not a question of the technology being available, it's a question of the purpose of the device. You wouldn't expect a cheap cell phone designed just for text and voice to run apps like a smartphone. They're just different kinds of devices, optimized for different tasks.

dtic
Posts: 461
Joined: 06 Mar 2010, 18:03

Re: Do we actually need portable cameras ?

Post by dtic » 14 May 2011, 11:57

Ryan: Keep in mind that webcams do list still pictures as a spec and it seems pretty common to use them to take portraits. So it makes sense for webcam producers to go for better quality there too. I'd bet still image quality will keep getting better, but lagging several years behind compact cameras of course.

We can speculate more, but I'd rather see some test shots of book pages with good lighting taken by the currently best webcams. From those images we could estimate if webcam use is feasible know and, if not, how far from it they are.

recaptcha
Posts: 61
Joined: 03 Sep 2010, 13:23
Number of books owned: 0
Location: Calgary, Alberta, Canada

Re: Do we actually need portable cameras ?

Post by recaptcha » 14 May 2011, 14:18

I've often wondered about the feasibility of using a video camera., which could be set up overhead to film both open pages. This would allow hands free turning of pages. One could pause at each page. Of course this would involve more post-processing to capture the stills from each page, so, not sure about any time saved in the overall workflow.

Just a thought.

dpc
Posts: 304
Joined: 01 Apr 2011, 18:05
Number of books owned: 0
Location: Issaquah, WA

Re: Do we actually need portable cameras ?

Post by dpc » 14 May 2011, 15:21

I've often wondered about the feasibility of using a video camera., which could be set up overhead to film both open pages. This would allow hands free turning of pages. One could pause at each page. Of course this would involve more post-processing to capture the stills from each page, so, not sure about any time saved in the overall workflow.

Just a thought.
I thought about this a while back as well. I was going to keep the video running during the entire scanning process and output an audio signal to denote when the page was stabilized for the photo. I would parse the video in a post processing step and retrieve the frame of video where the audio signal appeared.
HD video cameras are only 2MP though (if you could even get access to the uncompressed video frame), and that is nowhere near the resolution that I need for what I'm trying to scan so I bagged that idea.

If the makers of compact digital cameras would enable them to work as a webcam via USB, that would certainly help. I'm not holding my breath on that one though. There's may be more chance of something like this working on a smartphone device. They claim to have 8MP cameras in some of the newer smartphones which is about 300 DPI for an 8x10 page and the SDKs would likely allow more control over the camera compared to what you'd get with a webcam. They also have wi-fi, which would be handy for getting images off the device and displaying previews on your PC. The lenses are usually crap, but you were thinking about using a webcam so maybe that's not a big deal. ;)

There is an "open source" digital camera out there that is very customizable (hw & sw) - www.elphel.org. It's the same camera that Google used for digitizing all their eBooks. The latest version of Elphel's "document" camera is a Model 363 with 11MP 35mm Kodak CCD sensor. Not cheap though.

CCDeye
Posts: 17
Joined: 20 Apr 2011, 12:28

Re: Do we actually need portable cameras ?

Post by CCDeye » 16 May 2011, 01:33

jgreely wrote:
CCDeye wrote:The problem is I can't find a web camera that actually takes good pictures.
I doubt you'll find one. I recently spent a merry hour trying to find actual spec sheets for HD webcams, and most of them are evasive to the point of deception. Bottom line: 2 megapixels or less, and all claims of high-resolution stills were based on software interpolation. Useless for book-scanning anyway, since almost all of the lenses are wide-angle enough that you couldn't fill the frame with a book page and have it be in focus.
-j
Yep, I'm afraid so.. Actually I only need true 2 MP photos for my needs. I can't believe, there's no web cam that can deliver this. I bought a Logitech C310 and the "true" 2MP photos were just awful, compared to the 2 MP from my Canon A495. It was even worse than my old SonyEricsson K750 cell phone photos. I guess it has something to do with the lack of manual focus of the Logitech C310 (and other cameras), so I assumne the image was just out of focus. I'm thinking of putting some external lenses to "shorten" the focus for book scanning or someting.

dtic wrote:Hi CCDeye, I'm with you on this. It should only be a matter of time until webcams will be up for the task image quality wise.

It is frustratingly hard to find clear information on webcam still image quality - specs and reviews are very uninformative for that.

The C910 looks promising - has a 5 Mpx sensor (interpolates to 10 Mpx):
http://forums.quickcamteam.net/showthread.php?tid=1492
Thanks. I'm afraid to buy the C910 as it\s more expensive than a Canon 495 digital camera. And my experience with the C310 from Logitech isn't that great. I'm afraid even this camera would take worse pictures than my cell phone :lol:
We'll see about that, anyway :)

Ryan_phx wrote:I'm not a camera expert, but it seems to me that the quality of the optics is just as important--if not more so--than the pixel count.
Well, I can try to disassemble an old photo camera(not even digital) and put the web camera sensor where the tape is, behind the lens. Then focus manually etc.I don't know if the sensor matrix size of the web camera is too small for the objective to project cover the entire picture.
dpc wrote:
I've often wondered about the feasibility of using a video camera., which could be set up overhead to
I thought about this a while back as well. I was going to keep the video running during the entire scanning process and output an audio signal to denote when the page was stabilized for the photo. I would parse the video in a post processing step and retrieve the frame of video where the audio signal appeared.
HD video cameras are only 2MP though (if you could even get access to the uncompressed video frame), and that is nowhere near the resolution that I need for what I'm trying to scan so I bagged that idea.
I don't get it. How could you know that the page is stabilized for the photo ? Are you going to use a Canon camera with CHDK that could sense when the focus is OK and then "beep"?

Edit:
I think I understood what you meant...
You put an HD camera above the book and start recording a video. When you turn the page you press a button. That button isn't connected to the camera, it's just a beeper/zoomer what ever ringing device. The sound is recorded and then you post process the video and extract the frames where the sound appears. That's a brilliant idea and I think it could be automated quite well.

Thank you all.(That doesn't mean the thread is to be closed :))

dpc
Posts: 304
Joined: 01 Apr 2011, 18:05
Number of books owned: 0
Location: Issaquah, WA

Re: Do we actually need portable cameras ?

Post by dpc » 16 May 2011, 10:48

You put an HD camera above the book and start recording a video. When you turn the page you press a button. That button isn't connected to the camera, it's just a beeper/zoomer what ever ringing device. The sound is recorded and then you post process the video and extract the frames where the sound appears. That's a brilliant idea and I think it could be automated quite well.
Yep, that's it.

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