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Advice on best camera for large data acquisition project

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Offline Last Chance

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Advice on best camera for large data acquisition project
« on: 13 / May / 2010, 05:12:51 »
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Hi everyone,

I have a specific need to run two cameras simultaneously with them having certain features. This is to allow both pages of a book, which cannot lie flat, to be digitised in one go. The idea is to build a contraption (such things exist on the web) to hold the volumes in a V-shaped support, with camera and lighting angled respectively.

This is a large project and the first batch of 50-odd volumes will require about 20,000 shots - you get an idea of the magnitude of such a task when a total of 400 volumes and ledgers are available! This is a proposed project working in conjunction with the local library archive. The first batch of volumes are handwritten order books, dating from 1851 to 1953, and relate to a company that I am currently researching for a new book. Here are the the desired features, not necessarily in order. I appreciate not all will be available...

  • Remote trigger (via USB?)
  • Download each shot to a laptop, or remote USB hard drive?
  • 10MP or better - should give 300dpi for an A4 page
  • Preview each camera on a monitor, prior to being 'snapped', i.e. live output
  • AC adaptor

Ideally an inexpensive compact would suffice, so I have thought about the IXUS 100 (SD780) or (gasp!) even an A480. So can anyone suggest the best camera to go for, with respect to price, availability, and usability with CHDK in mind? Ideally they need to be new cameras, when bearing in mind the heavy task-load, but will the feature list of CHDK for the IXUS and A480 be expanded further in the future?

See ChanceGlass.net for details of my work - follow the link to Laura Brett's log, who is the archivist in charge of the project.

Any help would be much appreciated!  :)

David
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Offline Microfunguy

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Re: Advice on best camera for large data acquisition project
« Reply #1 on: 14 / May / 2010, 07:46:29 »
Look at the image and link at top right of this page :

http://stereo.jpn.org/eng/sdm/index.htm

Contact Daniel Reetz, I will be able to give you assistance.


David
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Offline Last Chance

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Re: Advice on best camera for large data acquisition project
« Reply #2 on: 14 / May / 2010, 12:52:03 »
Thanks for the response. I was already aware of Daniel's work - the one link I gave (http://www.wired.com/gadgetlab/2009/12/diy-book-scanner/) shows various images of his device in action and this gave me the impetus to build one. Also I think this is his own web site and this site details how he built one step-by-step.

So I should be fine building one (or perhaps two if the library asks!), having been an instrument mechanic at some time in my life. But my only real problem is which cameras to purchase, and ideally a new or very recent model. That of course means the CHDK firmware is likely to be less mature... so any help is welcomed in this matter.
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Offline whoever

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Re: Advice on best camera for large data acquisition project
« Reply #3 on: 14 / May / 2010, 14:11:45 »
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But my only real problem is which cameras to purchase, and ideally a new or very recent model. That of course means the CHDK firmware is likely to be less mature... so any help is welcomed in this matter.
You need an already CHDK'ed camera, the CHDK software being (almost) equally mature on all of them. And you definitely should NOT expect any new not-yet-supported camera to become supported in a foreseeable future, -- in fact, it may never happen.

Talking about already CHDK'ed cams, all of them should support remote USB triggering (NOT via PC though!), and then you can use Eye-fi cards to satisfy your automatic downloading requirements. Preview on PC will not be available in this case.

It may be possible to satisfy all your stated needs (including live preview, PC-controlled trigger, and downloading via USB) with the experimental CHDK versions that use certain "PTP extensions". Here, however, the choice of supported cameras is rather limited, the openly available builds being privately developed by ewavr. The A480 is already supported and, as far as I understand, the guy who ported to SD780 can easily add similar support. Going this way, you will probably need to do some additional coding to satisfy your specific needs.

Good luck!
« Last Edit: 14 / May / 2010, 14:13:18 by whoever »
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Offline Microfunguy

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Re: Advice on best camera for large data acquisition project
« Reply #4 on: 14 / May / 2010, 14:13:53 »
Yes, after posting I noticed that your link pointed to exactly the same information.

Not sure what you mean by CHDK being LESS mature with a new or recent camera model.

So far, no cameras introduced in 2010 have even had their firmware dumped.

Unless some clever hacker can solve that problem, this may be the 'end-of-the-road'.

Daniel is a member of this Forum but I doubt if he reads the posts very often.

I am no expert on cameras so all I can say is be aware that some cameras have an AV/USB combined connector .. that makes life difficult but not impossible.

A single A/V output is easier to deal with.

WIA loader will upload the images at regular intervals:-

http://stereo.jpn.org/eng/sdm/upload2.htm

All the cameras can be triggered by USB.

Although this information is for developers, you can quickly see the supported cameras and look-up which ones are 10MB or bigger:-

http://tools.assembla.com/chdk/browser/trunk/include/camera.h

Check DPReview site for detailed evaluation of the cameras.


The manuals (that give AC adapter details at the end) can be downloaded from Canon USA.

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Offline Last Chance

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Re: Advice on best camera for large data acquisition project
« Reply #5 on: 16 / May / 2010, 06:59:21 »
Thanks for the feedback.

You will appreciate that I am new to this and am not a software guru, so sorry if I misunderstood the way CHDK works. I assumed the firmware was downloaded from the camera, reprogrammed and then uploaded to the camera card? The "maturity" I talk of really means the features available to each camera with CHDK, which I understand is always 'work in progress'.

The two cameras mentioned, A480 and SD780 are both current models with a certain amount of features available to them. I will investigate the ewavr developments - thanks for the link. Sadly I have to consider 10MP or better, otherwise the A590 would be a sure choice (8MP...)

I take the point about a single A/V output. The other option is to snap the pages and preview the result. I'd hate to digitise entire volumes only to find I'd cropped off the top, or whatever!

While I think about it, as most of the volumes are hand-written, then 16-grey-scale would suffice. Saves on memory and upload/download times if the pages ever go online.

Thanks again.
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Offline reyalp

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Re: Advice on best camera for large data acquisition project
« Reply #6 on: 16 / May / 2010, 17:21:52 »
Quote from: Last Chance on 16 / May / 2010, 06:59:21
You will appreciate that I am new to this and am not a software guru, so sorry if I misunderstood the way CHDK works. I assumed the firmware was downloaded from the camera, reprogrammed and then uploaded to the camera card?
Not exactly. CHDK runs from the card and hooks itself into various parts of the existing firmware.
Quote
The "maturity" I talk of really means the features available to each camera with CHDK, which I understand is always 'work in progress'.
In general, most features are supported on most cameras that have the relevant hardware. There are some exceptions: cameras that have specific quirks, features that need additional code for each camera, differences between canon OS generations. However, most of this doesn't depend on the maturity of the port.

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I will investigate the ewavr developments - thanks for the link. Sadly I have to consider 10MP or better, otherwise the A590 would be a sure choice (8MP...)
Have you verified this by experiment ? Optical quality and sensor noise can be a bigger factor than MP. For example, a sub-compact ixus is more likely to have bad distortion near the edge of the frame, you probably won't get 10mp worth of resolution out there. An 8MP frame without as much distortion may give you more usable data total.

Quote
While I think about it, as most of the volumes are hand-written, then 16-grey-scale would suffice. Saves on memory and upload/download times if the pages ever go online.
If you are thinking CHDK will allow you to shoot 16 bit gray scale, this is not a realistic option. It would be technically possible to do from raw but it would be very slow and require some code to be written. Realistically, you should shoot normal jpegs and do whatever you need in post processing.
« Last Edit: 16 / May / 2010, 18:09:13 by reyalp »
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Offline Last Chance

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Re: Advice on best camera for large data acquisition project
« Reply #7 on: 16 / May / 2010, 17:47:02 »
Quote from: reyalp on 16 / May / 2010, 17:21:52
Quote from: Last Chance on 16 / May / 2010, 06:59:21
You will appreciate that I am new to this and am not a software guru, so sorry if I misunderstood the way CHDK works. I assumed the firmware was downloaded from the camera, reprogrammed and then uploaded to the camera card?
Not exactly. CHDK runs from the card and hooks itself into various parts of the existing firmware.
Thanks.

Quote
Quote
The "maturity" I talk of really means the features available to each camera with CHDK, which I understand is always 'work in progress'.
In general, most features are supported on most cameras that have the relevant hardware. There are some exceptions: cameras that have specific quirks, features that need additional code for each camera, differences between canon OS generations. However, most of this doesn't depend on the maturity of the port.
Understood.

Quote
Quote
I will investigate the ewavr developments - thanks for the link. Sadly I have to consider 10MP or better, otherwise the A590 would be a sure choice (8MP...)
Have you verified this by experiment ? Optical quality and sensor noise can be a bigger factor than MP. For example, a sub-compact ixus is more likely to have bad distortion near the edge of the frame, you probably won't get 10mp worth of resolution out there. An 8MP frame without as much distortion may give you more usable data total.
Not by experiment, but to reproduce an A4 page at 300dpi (for printing) requires something like 3500x2500, which is equivalent to 8.75MP, however some of the ledgers will be larger than this: I think 'Royal' is something like 14x10-in. (4200x3000, or 12.6MP, although the aspect ratio is incorrect). Whilst many pages might not require such a high resolution, this cannot be assumed across the board.

I also have to consider price and performance, hence my consideration for the IXUS 100. Perhaps someone can advise on the relative performance of this?

Quote
Quote
While I think about it, as most of the volumes are hand-written, then 16-grey-scale would suffice. Saves on memory and upload/download times if the pages ever go online.
If you are thinking CHDK will allow you to shoot 16 bit grey scale, this is not a realistic option. It would be technically possible to do from raw but it would be very slow and require some code to be written. Realistically, you should shoot normal jpegs and do whatever you need in post processing.
No, 16-grey-scale (I should have said 4-bit!) but I appreciate this would be a post-processing operation anyway. I was assuming JPEG as well, but a batch conversion shouldn't take too long.
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Offline reyalp

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Re: Advice on best camera for large data acquisition project
« Reply #8 on: 16 / May / 2010, 18:08:50 »
Quote from: Last Chance on 16 / May / 2010, 17:47:02
No, 16-grey-scale (I should have said 4-bit!) but I appreciate this would be a post-processing operation anyway. I was assuming JPEG as well, but a batch conversion shouldn't take too long.
Ooops. I actually understood that as I was typing, but the "bit" slipped in by habit. Either way, the answer is is pretty much the same.

edit:
Quote
I also have to consider price and performance, hence my consideration for the IXUS 100. Perhaps someone can advise on the relative performance of this?
Many camera reviews contain detailed resolution tests which should give you a decent starting point, e.g. http://www.dpreview.com/reviews/

Assuming you can arrange for enough light to use minimum ISO, noise should be too much of an issue.
« Last Edit: 16 / May / 2010, 18:12:47 by reyalp »
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