Cameras for a business project

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kamina
Posts: 13
Joined: 20 Jul 2014, 10:24
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Country: Spain

Cameras for a business project

Post by kamina »

Hi

I'm searching a nice book scanner for digitalize several books which has been discountinued and put them available again in digital format. Commercial scanners, like Atiz ones, aren't an options because they are very (very) expensive. The DIY Book Scanner Kit seems the best option to me as it's easy to setup/use and relatively cheap. I'm new to book scanning and I have some doubts about what cameras to use.
It seems that the full DIY Book Scanner Kit comes with two 16Mpx cameras (Canon A2500??) and CHDK firmware preloaded on two sd cards. I think this will be fine to do the job, but as I have a quite nice budget for the rig (around 1600$) I want to consider other options to make the job easier and faster.
I will be OCR'ing the books through a Abby Fine Reader so it could be awesome to get the images at best quality in order to avoid most OCR errors as possible.

I was thinking in a pair of DLSR cameras for the scanner. Reasons for this are:

Pros:
  • Better image quality (better optics, sensor, more megapixels)
  • Native support for remote triggering, downloading to computer, preview...
  • Faster shooting (?)
  • Not have to deal with CHDK and possible issues here
Cons:
  • Way more expensive
  • More weight and size (I don't know if DIY chassis was thinked for this kind of setup)
It looks that there are a lot of work on Canon compact cameras that allows you to remote shoot, download directly to computer, control the cameras by a computer... but thinking about this, it looks very complex. Most of this functions are directly available on a DSLR camera (ex, a remote trigger could be done with a connector and two cables) without need special firmware. It's fine to me do some things manually, for example, to scan a book and join the photos from the two sd cards in my computer to process it (also looks easier and less error prone).

As the scanner will be used for a business work, I would like to reduce the chances of something stop working or not work properly. There's no problem in make some extra job (manual zooming the cameras before start scanning, adjusting the photo parameters, download photos to computer, etc), but things need to work fine.

As I said, book scanning is new to me, so if you could give me some advice or tell me your experience with this matter I will be very thankful.
qv_
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Re: Cameras for a business project

Post by qv_ »

I am also new to this and like to have "the best" quality so I am looking for two Canon 550D for my setup.
I have start to build the scanner (my thread is "laser cut version")
I have assambly the scanner body and I see no problems that it can take the load of a DLSR camera.

I have not yet check that the "standard" 18-55mm lens will work.

/Jan
dpc
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Location: Issaquah, WA

Re: Cameras for a business project

Post by dpc »

I ended up using two Canon T2i DSLRs with the 18-55mm lens for my scanner. I initially tried to use some compact Canons but the lenses were soft near the outer edges which tended to blur the text near the borders of the page.

The other selling point was the free Canon SDK that allowed me to write some custom camera control and image retrieval software to manage the cameras from a laptop. I didn't have to worry about CHDK support and updating camera firmware, custom scripts, and whatnot.

Another reason that convinced me to break open my wallet and buy two DSLRs was camera control. Everything is configurable with a DSLR. F-stop, exposure, ISO, shutter speed, white balance, you name it. I can play around with all of these in order to get good images. That wasn't the case with the digital compacts.

Finally, I've chosen PDF as the format for digital archiving of books in my library. I want the digital copies to look like the books' pages because I have a lot of books with illustrations, charts, photos, etc. along with some novels that only have black text on a white page. For this reason, I want the best image I can get from my cameras and the cheap compacts just wouldn't cut it.
kamina
Posts: 13
Joined: 20 Jul 2014, 10:24
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Country: Spain

Re: Cameras for a business project

Post by kamina »

qv_ wrote:I am also new to this and like to have "the best" quality so I am looking for two Canon 550D for my setup.
I have start to build the scanner (my thread is "laser cut version")
I have assambly the scanner body and I see no problems that it can take the load of a DLSR camera.

I have not yet check that the "standard" 18-55mm lens will work.

/Jan
Watching the build in more details looks that it will handle quite nice a big cameras (~600gr). Thanks for the tip.
kamina
Posts: 13
Joined: 20 Jul 2014, 10:24
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Country: Spain

Re: Cameras for a business project

Post by kamina »

dpc wrote:I ended up using two Canon T2i DSLRs with the 18-55mm lens for my scanner. I initially tried to use some compact Canons but the lenses were soft near the outer edges which tended to blur the text near the borders of the page.
Did you have issues with with distortion at the border of the pages with the T2i? Looking at the lens review in Ken Rockwell site for the 18-55 bundled with Rebel T2i (18-55 IS), it seems to have a little distortion at 18 or 28mm of distance. I don't know what is the distance between the camera and the cristal on the DIY Kit, but i think it's around 30 or 40mm.
Did also you have any problems with focusing?
dpc wrote:The other selling point was the free Canon SDK that allowed me to write some custom camera control and image retrieval software to manage the cameras from a laptop. I didn't have to worry about CHDK support and updating camera firmware, custom scripts, and whatnot.
I agree with you on the CHDK point, I don't want to mess around with custom firmwares.
About the Canon SDK it looks awesome. I'm a programmer so it will be a good point to write something to improve my workflow. Did you upload somewhere the code to control the cameras? It will be nice to see what possibilities provides the SDK, like auto naming the photos of left and right cameras.
There's also a SDK for Nikon and a program called DigiCamControl which looks very great and will save to write anything to start working.

Have Canon something else that makes you decide for that model?
dpc wrote:Another reason that convinced me to break open my wallet and buy two DSLRs was camera control. Everything is configurable with a DSLR. F-stop, exposure, ISO, shutter speed, white balance, you name it. I can play around with all of these in order to get good images. That wasn't the case with the digital compacts.
+1
dpc wrote:Finally, I've chosen PDF as the format for digital archiving of books in my library. I want the digital copies to look like the books' pages because I have a lot of books with illustrations, charts, photos, etc. along with some novels that only have black text on a white page. For this reason, I want the best image I can get from my cameras and the cheap compacts just wouldn't cut it.
It looks that 16 megapixels is enough for any scan, so 18Mpx of the T2i should be fine. Have you tried different Mpx configurations? Does it makes any differences?
dpc
Posts: 379
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Location: Issaquah, WA

Re: Cameras for a business project

Post by dpc »

I haven't noticed any lens distortion at the edges of my images, but realize that I'm framing an entire page with margins, and even then the aspect ratio of the image may not match those of the page so that could result in more "dead space" that might have distortion but I'm cropping that off anyway.
...it seems to have a little distortion at 18 or 28mm of distance. I don't know what is the distance between the camera and the cristal on the DIY Kit, but i think it's around 30 or 40mm.
Did you mean to type 'cm' above? What distance are you referring to? From the lens to the page?

The T2i is an older camera (I bought one new and one refurb from Canon). I think the T5i is the latest and might be a better choice today unless you want to save money by purchasing a refurbished unit (one of my T2i was a refurb from Canon).

I have to keep the code that I write to myself as my employer has to give approval for any sort of moonlighting projects and I'd rather not go through that approval process. If you get the Canon SDK and have questions about something I'm happy to answer them if I can. Canon provides some nice software to control their DSLR cameras (built using the same SDK), but it can only control a single camera connected to the PC via USB. I suppose you could run that software on two different machines for a scanner, but then you've got two DSLRs and two computers and that can get pricey.

I always shoot at the highest camera resolution possible. I haven't tried shooting at a lower resolution as I'm not overly concerned about image file size (storage is cheap). Again, I do some custom post processing on my images, so the more I can get out of the camera before I start that processing the better.

Before you purchase expensive cameras, you might want to look at renting a DSLR with the lens you'll be using and shoot some pages and then try to run that through your OCR app. That will tell you whether or not you'll get the results you need from the camera. You don't need a scanner built for this test. Get a tripod and a light and shoot about 20 pages and then see what happens. You may find that you don't need a DSLR for what you're doing.
kamina
Posts: 13
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Country: Spain

Re: Cameras for a business project

Post by kamina »

dpc wrote:
...it seems to have a little distortion at 18 or 28mm of distance. I don't know what is the distance between the camera and the cristal on the DIY Kit, but i think it's around 30 or 40mm.
Did you mean to type 'cm' above? What distance are you referring to? From the lens to the page?
Yes, I mean cm, sorry for the typo. I was talking about the minimum focus distance from the camera. It looks that there're more than 25cm from the camera (25cm it's the minimum distance for that lens) to the glass and you're shooting withouth problem, but want to ask it just in case.
dpc wrote: I have to keep the code that I write to myself as my employer has to give approval for any sort of moonlighting projects and I'd rather not go through that approval process. If you get the Canon SDK and have questions about something I'm happy to answer them if I can. Canon provides some nice software to control their DSLR cameras (built using the same SDK), but it can only control a single camera connected to the PC via USB. I suppose you could run that software on two different machines for a scanner, but then you've got two DSLRs and two computers and that can get pricey.
Thank you for the offering.
Definetly two machines will be a lot. It looks that DigiCamControl can handle two cameras at the same time, by the way.
dpc wrote: Before you purchase expensive cameras, you might want to look at renting a DSLR with the lens you'll be using and shoot some pages and then try to run that through your OCR app. That will tell you whether or not you'll get the results you need from the camera. You don't need a scanner built for this test. Get a tripod and a light and shoot about 20 pages and then see what happens. You may find that you don't need a DSLR for what you're doing.
Great tip, I will make some experiments and then see.

Thank you a lot dpc!
markvdb
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Country: Belgium

Re: Cameras for a business project

Post by markvdb »

Just fyi, the current diybookscanner rig can carry a dslr no problem. There is also at least basic support for Canon DSLRs in the software we use (gphoto2 based).
Mark
http://diybookscanner.eu - official EU diybookscanner kits - subscribe to our newsletter
kamina
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Country: Spain

Re: Cameras for a business project

Post by kamina »

Thanks for the confirmation markvdb. Are you using a DSLR camera for the scanner?
markvdb
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Country: Belgium

Re: Cameras for a business project

Post by markvdb »

kamina wrote:Thanks for the confirmation markvdb. Are you using a DSLR camera for the scanner?
We used this with an older, more experimental software version. I know of people using more recent versions, but we don't do that ourselves (Powershot cameras are sufficient for our purposes).

I am testing the dslr setup with the latest software version extensively later this week. I get back to you as soon as possible. Probably later this week, worst case early next week.
Mark
http://diybookscanner.eu - official EU diybookscanner kits - subscribe to our newsletter
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