Hot answers tagged document-reproduction
35
I've had to preserve whiteboard scribbles a few times. The problem is that you usually can't control the lighting and it's rarely good. The technique I've converged on is to take two pictures. With the camera on a tripod, take the first picture of the board as is. Then erase the board and take the second picture with exactly the same settings.
Now ...
10
I regularly take photos of whiteboards sized 3' x 4' or larger with my cell phone camera to record meeting notes, and it produces passable results. The D90 should absolutely kick butt on this.
The two factors you want to avoid are glare and motion blur. As Guffa mentioned, you want to avoid glare from ambient (room) lighting, so get into a position as ...
8
As others have already mentioned, a little image processing is a good solution. However, I have two different suggestions
Take a image when only a blank area is on the screen. Set up the camera on a tripod so that all images are taken with the viewer screen in the same position relative to the camera. Then subtract the blank image from the real images. ...
6
Consideration of dimensions of input art work and the likly dpi required in the final image and the available resolution of current cameras it seems that an A3 scanner with 600 dpi or better resolution would be a superior solution to using a camera in this application.
A recent stack exchange question discussed requisite scanning and print resolutions ...
6
You can certainly get much better results than you're experiencing now, but it's going to take a bit of fiddling around to do it.
The "real world" has a lot bigger range of light-to-dark than typical ink on paper. The paper isn't nearly as white as you think it is, and the ink reflects a lot more light than you probably think it does. In pictures of the ...
5
The standard solution is to use two (or sometimes four) lights set at about 45 degree angles to the surface you are copying, and at a distance great enough that (a) there isn't a huge degree of falloff or an obvious bright spot from either light; and (b) that the angle of the light at the surface closest to the light is not so high that you get direct ...
5
Minimum focus distance is related to several aspects (e.g. sensor size, lens type, etc). I will try to give you a general answer however, I do not guarantee any exact results (use it at your risk!).
Here is a basic formula to calculate focus length, given the size and distance of the object (you can try to minimize the value by trying different parameters).
...
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This is a textbook example of image processing that we give the students as an assignment.
You do a large mean-filter on the images and subtract it, and fix the contrast, maybe even threshold it.. I implemented it in Image View Plus More 2 as a standalone function called "Local Normalisation -> Remove Gradients e.g. from paper". I assume you have matlab and ...
5
Your camera should definitely be able to capture the entire board without having to stitch images together, as long as you are using the highest resolution.
You should use lighting that falls at an angle on the board. Make sure that you don't have a light behind you, that would reflect in the board.
If you use the built-in flash, the reflection will of ...
4
If you need to illuminate documents that you are "scanning" in such a manner, and you wish to filter UV light, a sheet of your average picture framing glass between the bulb and the document should filter out most UV light. If you are intent on filtering out as much of it as you can, you could pick up a small piece of multi-coated museum glass, which will ...
3
If there is often sufficient natural light, as John points out you have a tripod/stand and can do longer exposures.
You would want light on at least two sides to avoid dark shadows. If you are using window light, you could use a reflector to provide fill.
If you want to capture the feel of old paper, you would want to place lights low, raking across the ...
3
I don't want to skirt the question, but I take photos of white boards frequently but using a different method then you suggested. I use my iPhone to take the photo using one of three different applications:
Genius Scan App
Built in Camera App
Microsoft Photosynth App
My favorite is the Genius scan app. It is designed for doing things like this, and has ...
3
If you can center the bright spot, you may be able to use an vignette tool. Lightroom can apply this easily, it is usually done to adjust for lens aberrations, but it may work in this case. But certainly, use RAW.
It doesn't appear that Photoshop has this feature. There are tons of tutorials, but I suspect they all seem geared to loosing data, rather than ...
3
If there is a bright spot, your camera will record it regardless of its settings, I'm not sure if changing the light metering method to center-weighted average will do any help or not.
But since your camera can shoot raw image, I suggest you to shoot in raw and then edit it in Photoshop.
In Photoshop when you use an adjustment layer, click on its layer ...
2
As @Russell says, you are going to need a lot of pixels. One pro's approach to this is to go medium format: http://strobist.blogspot.com/2012/01/bailing-on-nikon-d4.html
However, he describes a $10,000 purchase, and he is "settling" for the P25+ sensor back, not the newer and more expensive P40+ backs.
A rig such as this, with lenses, will rent for about ...
2
You have a D800 which has enormous resolution, so I think the way I would tackle this is to pull back a little and crop the result rather than filling the full frame. Your 50 f/1.8 was designed for a full frame camera (if I recall correctly) which means that on the T2i, you were hitting the lens center sweet spot. That's basically what I'm suggesting with ...
2
There's a somewhat similar question here, although it was more geared towards which camera was better I still think there's some value in looking into it for other misc info.
As for distortion, pretty much every lens has distortion, the difference is that it's sometimes a bit more obvious in certain lens due to its design. Fortunately something like this ...
2
I think you want simple, so I'd recommend using Program mode, which gives you the greatest control without making you learn about exposure. Program mode (the 'P' on the Auto-P-S-A-M dial) gives you these advantages:
it sets exposure correctly for the lighting conditions, so you won't get a too-dark or too-light image, and you don't have to think about ...
2
It looks like a document camera set up. You can see some examples at this link.
Here's some more info on copy stands:
NOTE: A copy stand is a device used to copy images and/or text with a camera.
The stand consists of a board onto which the media is
placed and a camera mount above it, usually with an adjustable height.
Light is provided by either ...
1
First my advice to you is to use the tripod. Second 580exII is fast enough but in old places with old gravings and painting you can not and should not use flash light because it damages them. 2 Leds will help you out with a reflector in the hardest situations. Also I think you should not use ring led since it's to homogenous. About long exposure you'll get ...
1
Use a wide angle lens that has a close near-focal distance.
You will have a distance of around or less than 50cm from Paper to Camera. The closest that I think could be feasible would still be around 20cm, you are clearly not going to get 4cm...
Use multiple cameras. You could get OmniVision camera modules or other mini cameras. They are cheap, you can get ...
1
The integrated lights will be easier, but something similar on stands beside a larger surface would work as well. As for lights, you really don't need anything special. Household incandescents will work just fine (and won't be too hot). You could also use compact fluorescents if they have a high CRI (over 90). Most LEDs that aren't horribly expensive ...
1
I also have to make mention of a shooting technique to reduce the distortion to whatever the optical design presents by ensuring you have a PERFECTLY level camera in a perfect parallel plane with the artwork.
An extreme example is tilting your camera upwards and shooting a skyscraper. It makes those buildings look very tilted.
1
The technique you are looking for is called "panorama", which in the digital age normally consists of stitching together a number of image tiles into a single larger image. As long as you have the entire board covered with about a 20% overlap between the pictures, you should be able to get a single coherent image using any of the panorama software packages ...
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