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.
DSpider

Re: Do we actually need portable cameras ?

Post by DSpider » 29 Aug 2011, 15:44

They said it's basically mechanical and that the quality of the image plus enhancement will all depend on the driver provided by the OS. They seem to have dodged the question about the effective megapixel count there, but that's ok, mechanical autofocus is a deal breaker for me. I don't doubt that it may be a (more than) fine webcam, I'm just sceptical about the durability of scanning ~1200 books x ~200 pages on average, over the course of several years.

What other alternatives are there? Anything besides any Logitech, Microsoft or HP products. None. Most of them are 1.3 or 2.0 MP crap, which is ok for their intended purpose vs price, I guess... Just like the OP said about cameras, they were meant to be used under certain conditions too.

CCDeye
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Joined: 20 Apr 2011, 12:28

Re: Do we actually need portable cameras ?

Post by CCDeye » 01 Sep 2011, 09:31

Hmm... You know what, I'll just send them an email inquiring about it and about what megapixel count I can expect if I'm not using Windows (tho I could use VirtualBox and a lighter, custom version of Windows XP just for the damn "enhancing" software). They'll probably get back to me next week, since it's the weekend and all...

Yep, no big deal about "software enhancing". As far as I know, it's as simple as linear interpolation. They take any adjacent pixels and generate the inbetween pixels by interpolation using something like : (A+t*(B-A)); where t lies between {0-1.0}.
There are some kind image based enhancing algorithm, like those seen on pixel shaders effects, Photoshop filters. Edge detection, sharpness, color correction etc. There a lots of free pixel shader(post process) algorithms out there, so out of the box software enhancing under Linux won't be such a big deal, I guess.

Personally I need a raw hardware sensor power with > 3 Mpx, no mechanical parts, autofocus, shutters etc.
My old web camera was with a manual focusing system, via rotating objective. I need this, but with lots of megapixels. Nothing more.
We can write DirectShow application and automate lots of stuff on the PC side.
I don't need to hack a Canon cameras and write scripts only to make remote stutter, timelapse pictures etc. I need a laptop with a nice long life web camera and a PC side DirectShow application + pixel shader application that could do whatever I need in real time.

DSpider

Re: Do we actually need portable cameras ?

Post by DSpider » 02 Sep 2011, 16:31

Autofocus would be nice (not manual/mechanical but digital).

Anything that can OCR properly because too much detail and the OCR could start to separate "d" into "cl", place printing imperfections as punctuation marks or other strange things. For extra detail such as covers, drawings, graphs, etc., a mid-range flatbed scanner will do the job much better than a digital camera. Today's cheaper scanners are like the high-end scanners from a few years ago. Same detail could be captured by a D-SLR (except it doesn't cost 3-4x as much).

Like someone said earlier on page 1, cellphone cameras will probably hit the spot, and soon. Especially rooted/jailbroken smartphones (Android, iOS). They probably already do.

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

Re: Do we actually need portable cameras ?

Post by CCDeye » 03 Sep 2011, 02:00

DSpider wrote:Autofocus would be nice (not manual/mechanical but digital).

Anything that can OCR properly because too much detail and the OCR could start to separate "d" into "cl", place printing imperfections as punctuation marks or other strange things. For extra detail such as covers, drawings, graphs, etc., a mid-range flatbed scanner will do the job much better than a digital camera. Today's cheaper scanners are like the high-end scanners from a few years ago. Same detail could be captured by a D-SLR (except it doesn't cost 3-4x as much).
Hi and thanks for the comment.
I don't want autofocus, because it's takes time to find the focus, it wears out the mechanism after a few tens of thousands shots etc. For a book scanner, where the focus is always fixed, an autofocus is a "deal breaker for me" as you said in a previous post. Digital as you mentioned. I don't know how it works, (maybe I shouls google it), but most probably it needs extra hardware to keep something like a depth buffer. In computer graphics and depth of field effects, focusing in different ranges is done that way.
For a flat-bed scanner. Yes, I have several flat-bed scanners(budget devices) but they are slow for my needs, and most page turning mechanisms will not work with them. I need to take pictures fast and automate the page turning.

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daniel_reetz
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Re: Do we actually need portable cameras ?

Post by daniel_reetz » 03 Sep 2011, 02:02

CCDeye, are you familiar with machine vision cameras? It sounds like you want some variant on a machine vision camera with a C-mount lens.

The problem is that they only ever reach into the low megapixels and are expensive. I have personally played with stuff from Allied and Point Grey. Not bad, but very clunky overall.

CCDeye
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Re: Do we actually need portable cameras ?

Post by CCDeye » 07 Sep 2011, 02:19

Thanks, I did not consider machine vision camera as alternatives until now. Will definatelty take a look, moreover they seem to use fast FireWire 1394 interface.
Fortunately, USB 3.0 PCs and devices are already on the market, so I hope fast, cheap and hi-res web cameras would flood the market. USB 3.0 claims to be 10 times faster than USB 2.0, and I suspect one of the reason we can't find a hi-res web-camera is the speed limit of the USB bus. For a 2 megapixel sensor, that shoots video with 30 fps it would be 1920*1080 = 2 073 600 pixels * 24 bits per pixel is approximately 6 megabytes per frame * 30 frames per second = 180 mb/sec wich is more that USB 2.0 - 40 mb/sec, so I hope USB 3.0 claimed 400 mb/sec would be fast enough for hi-res web-camers to flood the market.

reece.arnott
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Re: Do we actually need portable cameras ?

Post by reece.arnott » 11 Sep 2011, 20:05

<Partial repost from another thread with bits added for this thread>
I've decided that if I can get something working via the UVC standard then a lot of webcams will 'just work' with the same process. The easiest way to do this is not to have a continuous stream of video (which will be downgraded from the full sensor resolution and then compressed anyway - probably in a lossy way) but to actually just ask the camera for an image when you want it so you do not need to invest in fast USB 3.0 or Firewire etc. and you can get the raw sensor data before the 'software enhanced' image stage. Another advantage of this is that you can query the camera and get back a list of supported resolutions up to the full sensor size. Not so good for making a decision on what to buy but after you've bought it you can post the results for others to see.

I have got something working on Linux which works quite well but I won't get around to doing a Windows version for a few weeks at least (I only have 1 Windows machine out of the 6 or 7 I have lying around and it is basically there because I haven't got around to upgrading it yet) as I want to get a working system before spending time enhancing it for others .

I am documenting what I'm doing at http://dspace.org.nz/2011/09/11/bookscanner-project/

The basic idea is that you set up the webcam parameters like manual focus settings, pan, tilt, zoom at the start of the run and then sequentially take an image left,right,wait,left,right,wait etc.
With manual focus settings I am getting a 5 megapixel image in less than a second. With autofocus I have to let the auto-focus do its job for a couple of seconds before taking the picture. There is a little wrinkle for my particular webcams that the webcam is only active when the image is being taken and after the image is taken the lens physically goes back to a park position so I had to add in a little something to put the lens back in the correct focus position before taking the next shot, hence why auto-focus needs additional time to sort itself out.

CCDeye
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Re: Do we actually need portable cameras ?

Post by CCDeye » 12 Sep 2011, 03:45

Thank you for the post.
Yes, that's something that looks like it would fulfill my needs. If you have any Windows progress, please keep us in touch, although I will check the possibilties to interface a UVC compilant camera under Windows via a custom application to automate things out.
Another advantage of this is that you can query the camera and get back a list of supported resolutions up to the full sensor size. Not so good for making a decision on what to buy but after you've bought it you can post the results for others to see.
I used this tool to find out, that my Logitech C310 camera is bellow 1.3 MP raw sensor. No wonder why it takes crappy pictures compared to my 2 MP cell-phone.
http://www.quickcamteam.net/documentati ... vc-webcams
As you say, a 5 MP image could be taken and written on disk under a second, with no auto-focus, and the standard and driver support more than one device at a time, so writting a script or program like this would be very useful for PC scanner to be implemented, avoiding digital point and shoot cameras for PC-book scanning.
I can imagine a desktop application that sends commands to some port that controls the page turner, takes pictures, rename them accordingly, runs OCR etc. You lay down the book, and go have a cup of coffee. :)

Edit :

I just tried to write a simple C++ application that takes pictures over an adjustable time interval (for ex. 2 seconds), kinda like time lapse, using Windows XP SP2++ UVC driver and it works. It uses my Logitech C310 full sensor capacity.
I will buy a more decent C910 (raw 5 MP sensor) and try to make 2 cameras capture under Windows.

Edit2 :
@reece.arnottm are you sure that Logitech C910 web camera has real 5 MP sensor ? I think it's more like 2 MP, because it cannot capture video with resolution greater than 1920x1080. Interpolation will get us nowhere. :(

reece.arnott
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Re: Do we actually need portable cameras ?

Post by reece.arnott » 14 Sep 2011, 02:26

The problem is not the sensor, it is the streaming video component. Standard HD streaming of 1080p at 24 frames a second, assuming a 16:9 aspect ratio,give a frame resolution of 1920x1080 (the approx 2MP you are getting) giving 48MB/s or 384Mb/s (thats B=bytes vs. b=bits). USB 2.0 maxs out at 480 Mb/s so to get higher resolution per frame, you need to take the framerate down (until USB 3 takes off and we can push 5 Gigabits per second down the USB line).

Edit: technically 1 pixel could be equal to 3 or 4 bytes depending on format but with good compression, a good rule of thumb is that 1 pixel=1 byte.

There may be options to decrease the framerate and increase the resolution in some software but not in others as I can get higher in guvcview - it does 15 frames a second at 2048x1536 as well as 10 fps at full 2592x1944 (although presumably because of the max resolution of my monitor or some weird issue in guvcview it screwed up showing the largest).

Edit: The partial output of a command line query I ran to get valid MJPEG resolution/framerate options (1/30 means 30 frames every second 2/15 means 15 frames every 2 seconds etc.) as reported by my Logitech C910.

{ discrete: width = 1280, height = 720 }
Time interval between frame: 1/30, 1/24, 1/20, 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1392, height = 768 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1504, height = 832 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1600, height = 896 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1280, height = 960 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1712, height = 960 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1792, height = 1008 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1920, height = 1080 }
Time interval between frame: 1/30, 1/24, 1/20, 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 1600, height = 1200 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 2048, height = 1536 }
Time interval between frame: 1/15, 1/10, 2/15, 1/5,
{ discrete: width = 2592, height = 1944 }
Time interval between frame: 1/10, 2/15, 1/5,
Last edited by reece.arnott on 14 Sep 2011, 06:28, edited 1 time in total.

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

Re: Do we actually need portable cameras ?

Post by CCDeye » 14 Sep 2011, 03:53

I'm thinking to buy a Logitech C910 web cam, but I'm affraid it won't perform much better than my Logitech C310.
Can you post a picture of something world known to compare. I'm thinking of posting a picture from my C310 of a standart(not mini) USB plug like the one I connect my camera to the computer. If you do the same, we can compare roghly the image quality difference between the two models.
I was thinking to go to thje store and ask the sales-man to plug the camera and take few pictures of a book, or something.

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