do-it yourself repro v-cradle for paper books

[ereszet]

Materials: hardwood, glass, steel rods, nuts and bolts, black spray, black cardboard.
Cost (materials and work by a friendly handyman): less than $50
The attached two pictures say it all.

[ereszet]

Part 1 was in my post Do-it-yourself repro v-cradle

1. Why a v-cradle and not a flat bed.
For two reasons: First, you cannot spread the books flat and if you do, the quality of reproduced pages will be compromised. It is especially important if you plan to OCR the book. Second, you avoid light reflections. You need only one lamp with a diffusor just over the v-cradle (picture attached). Lighting is the most difficult part of reproduction. Over the years, I have tried various setups with my semi-profesional Manfrotto repro stand and four lamps at 45 degree angle. It doesn't come close to an overhead lamp and v-cradle. Avoid any other light in the room or take everythig to your terrace and shoot at the sunlight with no artificial light.

2. Where to put the camera
On a tripod, at 90 degree angle to the book page. The camera and the tripod should be masked with a sheet of black cardboard to avoid reflections (picture attached). The best camera is black camera anyway. Same goes about tripod. I use now 8 and 10 megapixel cameras, but 5 megapixels are good enough for most A4 documents.

3. How to shoot fast

Quick and dirty: from hand (or tripod plus remote) if somebody turns the pages for you and keeps them flat (fingers may be visible at margins but you can erase them or the margins later). Takes less than 5 seconds per page.

Precise: from your laptop connected to the camera (My Canon Powershot Pro1 makes it easy - a picture attached). The camera can shoot automatically in regular intervals, so you need no help from your buddy. Takes up to 15 seconds to flatten the page with a glass weight, re-position the cradle if necessary, and shoot. About the same time is required per photo to download (USB 1.1) in a batch after the shooting session. Before shooting use a test page to fix the focus of the camera. Re-positioning of the cradle (rather than the camera), i.e. moving it closer to or further from the tripod, is necessary after shooting 20 or so pages if you do not want the opposite page to get into the picture (a viewfinder on a laptop screen is much better for positioning than using the one on the camera). Alternatively, you can place a black cardboard over the opposite page. Removing black margins aftewards is easy with proper software.

More to follow, if there is any interest.

[ereszet]

Camera setup: view from the front and the back.
Light diffusor.

[NatCh]

That's a very nice system you've got there, I suppose that if you had 2 cameras, and your software could handle it, you could shoot both pages without moving much.

This looks like a pretty viable alternative to the >$10k automatic system that someone posted about a year ago. I'm certainly a lot more likely to do something like this than shell out for the library-grade machine.

The book holder looks like it's the most complicated part of the assembly -- do you find that a particular angle is best for the shots? I'm wondering how much you'd lose by going with a fixed angle holding bed, you see.

Thanks for posting these, ereszet.

[ereszet]

Originally Posted by NatCh

That's a very nice system you've got there, I suppose that if you had 2 cameras, and your software could handle it, you could shoot both pages without moving much.

This looks like a pretty viable alternative to the >$10k automatic system that someone posted about a year ago. I'm certainly a lot more likely to do something like this than shell out for the library-grade machine.

The book holder looks like it's the most complicated part of the assembly -- do you find that a particular angle is best for the shots? I'm wondering how much you'd lose by going with a fixed angle holding bed, you see.

Thanks for posting these, ereszet.

The system with 2 cameras (company name is Atiz) looks very nice and costs now much less but sitll a few thousand USD plus cameras. It is semi-automatic - you turn the pages by hand, but v-shaped glass/plexi? can be moved up and down without removing it, and the shots are taken automatically.

Apart from a v-shaped glass and a mechanism to raise it, my system does exactly the same plus a regulated angle, distance, and room for books of different thickness. Two cameras are no problem technically, they can both shoot automatically every nn seconds (at least my Canon can). The problem is quality. You should concentrate on making every shot picture perfect. Otherwise there is more manual work at the processing stage. Now I shoot all the odd pages and then all even pages just by turning pages and adjusting the distance from the tripod by a few milimeters every 20 or so pages.

The book holder is just two panels with two hinged supports plus a heavy base with a lot of grooves. This is my patent You can regulate the distance between two panels, the angle of each panel, and the distance between the cradle and the tripod. The regulated v design is crucial to ensuring the angle between the lens and the book page at 90 degrees plus avoiding any skewing. Precise correction of angle and skewing with the tripod controls is very cumbersome. Since I installed my system, I do not touch my tripod any more (I miss my 7x zoom when taking photos of my garden birds - like the barbet in my avatar - with other 3x zoom cameras).

As for cheap and dirty alternative you can make something similar from a cardboard. It was my first design. My wife used her scissors to make it in one hour or so. It worked perfectly. Remember, the devil is in the lighting and reflections, especially for color and glossy pages (or pages under glass). The disadvantages of cheap and dirty solution are: it is very light and therefore unstable, and you have to change tripod postion controls frequently to accomodate for various sizes of original pages, since moving the cradle further away creates a trapezoidal effect. You can avoid it with changing the angle in the v-cradle. The focus is quite forgiving in such a case (+/- a few milimeters difference in distance between the lens and upper and lower parts of the page do not show in repro).
The advantage of the cardboard cradle is portability.
Finally, you can always use the simplest solution: a friend or a document holder (picture attached) and soft flash plus a lot of processing to get pictures straight. You need a steady hand and a camera with a good automatic focus (out of my two Casios, ex-z850 does a better job than ex-z1000).

Thanks for asking NatCh.

[ereszet]

The angle between the lamp and the book page can be anything (usually 45 degrees) as long as the reflected at 90 degrees light does not go into the camera lens.
For uniformity of lighting the best thing is natural light outside, an apartment corner with two windows at 90 degrees or a bright lamp as high as possible (a bright ceiling lamp will do) over the cradle plus a diffusor. The v-cradle assures the proper angle.
Typical setting of two or four repro lamps at 45 degrees to the book page may work with very expensive lamps that I cannot find even in best photo shops (however there are some ads on the net). But in my experience, even if you see no bright spots on the page, the reproduction will show them. Human eyes provide for automatic correction, while the camera is not forgiving at all (photographers who deal with RAW pictures know it too well).

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Cradle distance and angles

First picture to the left is a setup with camera lens at 90 degrees to the book page placed in the v-cradle.

The middle picture shows that moving the v-cradle closer to the lens helps to maintain 90 degrees angle for pages of bigger sizes. The zoom in the camera has to be adjusted accordingly.

The last picture shows what happens when the distance between the cradle and the lens stays the same despite a bigger page size. The distances between upper and lower parts of the page and the lens differ considerably, which causes a trapezoidal effect.

Not shown in the pictures but an obvious solution for bigger pages is to change the lens angle in order to keep the focus in the middle of the page. But when the lens angle changes then it is no longer 90 degrees to the page. That is why you can change the inclination of v-cradle panels.

[ereszet]

Cost: nothing (just a diamond ring for my wife, but I would buy it anyway)

Enclosed pictures are worth a thousand words (and bucks if you had considered to buy an expensive substitute ).

[phrodod]

Originally Posted by ereszet

Cost: nothing (just a diamond ring for my wife, but I would buy it anyway)

Enclosed pictures are worth a thousand words (and bucks if you had considered to buy an expensive substitute ).

This one looks doable, even for me. Does anyone have OCR software recommendations that work with camera images?

Phrodod

[ereszet]

Originally Posted by phrodod

This one looks doable, even for me. Does anyone have OCR software recommendations that work with camera images?

Phrodod

Finereader 8
Takes images with resolution from 96 dpi upwards (I tried 72 dpi with success). Ingenious recognition algorithm with all imaginable languages. Splits double pages. Converts to black and white. Can save blocks of text and images only (removing any useless white or other space around - requires some trick though to do it in batch). Finally, saves as text under picture pdf format.

IMHO The best available OCR software. I have bought it. I put my money where my mouth is.

BTW I am considering posting some hints on processing photos to a book format but I am not sure if this is a right forum/thread. Any ideas?

[Szczurek]

That's a very nice system but do you use special software to handle it.
Can you give us hints to make the best results.

[ereszet]

Originally Posted by Szczurek

That's a very nice system but do you use special software to handle it.
Can you give us hints to make the best results.

You either take time to position the book right in the cradle (no distortion, no background behind the page, uniform lighting - just rectangular page in your viewfinder) and then no processing is required apart from conversion of images to pdf or djvu with any freely available software. Or you shoot fast with the black background and don't care about photo quality, which you improve later with proper software. I prefer shooting fast because processing later is fun.

In both cases free Google Picasa can be very useful (downloading the pictures from the camera, automatic contrast and colour corection in batch processing, individual deskewing and cropping, etc.). Free Irfanview may be useful as well, especially for batch conversion between image formats.

I will post my suggestions for more sophisticated photo processing software (for low quality photos like the ones offered by google books in pdf format or a number of digital libraries in djvu format - you know dLibra, don't you) over the weekend.

[ereszet]

Before photoscanning hundreds of pages, it is worth making sure that the lighting is uniform. Neither your visual inspection of the original paper document nor the camera LCD display or the computer screen (if you shoot from a camera connected to a computer) are good enough to see the bright and shadow areas due to non-uniform lighting (unless shadows and bright spots are very discernible).

There is a commercial program (Psremote) that in its preview mode can highlight the areas that are too bright according to a selected level of luminosity. However its use is limited to cameras that can shoot from the computer and it can only show which areas are too bright at a chosen threshold rather then areas with different levels of brightness.

I deviced a method which is simple and effective to check the lighting uniformity before shooting hundreds of photos.

You just take a test photo as jpg and compress it aggresively using Irfanview or any other similar progam. On the compression scale of 100 (best quality) to 1 (lowest quality) you may choose 10 or lower quality. The resulting compressed jpg will show "clouds" or areas that are similar for the sake of compression. For our purpose, it shows areas of pixels with similar luminosiity. By forcing a very low quality, we can see "clouds" even in a photo that is otherwise almost perfect. Once we know which parts of the test photo are under- or overlighted we can: move the cradle, move the lamp, use a curtain or a black bristol paper to block the light from reaching the original at various points and angles.

The attached pictures show:
Daylight.jpg - a test photo taken in the middle of the room with two windows and various objects in the way of light (the gray line along the photo image is the feature of the original paper page).
Daylight10.jpg - same photo compressed at the level of 10, showing the clouds of non-uniform brightness
DayTungsten.jpg - like daylight.jpg but with a ceiling and overhead lamps switched on (I do not recommend this setup, but I have no way to stop sunlight during the daytime - blinds are too transparent. Usually i shoot at night.
DayTungsten10.jpg - same photo compressed at the level of 10

You wll notice that the better quality DayTungsten.jpg shows some non-uniformity. It is due first of all to the sunlight but also to the fact that upper part of v-cadle panel is closer to the overhead lamp than the lower part of the panel. That is why I recommend using a bright ceiling lamp only. At at distance of 1.5 or 2 meters (depending on how high is your ceiling), the 20 centimeters between the upper and lower part of the cradle panels make little difference. You can also put a white paper (you can experiment with its dimensions) on the panel opposing the original page, and it will act as a kind of mirror, directing more light to the lower parts of the original. One method of achievieng quite uniform light is using the camera flash directed to ceiling. The light reflected from the ceiling is more dissipated. I even experimented with double reflection, i.e. flash directed to --> a sheet of bristol paper (or a sheet of matt aluminium) --> ceiling --> v-cradle.

If you are a little ovewhelmed with all this, remember that one ceiling lamp will usually be ok. The brighter is the lamp, the easier it is to get the white balance (i.e. to make the white pages white rather than gray, yellowish or pinky, while keeping the print black) in the processing afterwards. I am not going into RAW processing, white balance/ISO/camera setting problems or commercial heavy weight and costly software to process your photos. I concentrate on fast shooting and batch processing. But if you plan to convert all your family photos to digital ones, you may want to learn about RAW image format and all the tricks of professional photographers. There is abundance of advice on that on the internet but rather little of what I give you here in terms of convenient fast practical arrangements.

Please note that the paper originals were put under the glass but the photos show no reflections thanks to my v-cradle design. Better results can be achieved with proper lighting, zoom, and processing (see Tungsten processed.jpg).

The question is: do we need to make the lighting perfectly uniform? My answer is:
yes, when we deal with color originals;
rather yes, when we deal with gray photos;
not necessarily when we convert the pictures to mono.

Unless you are a perfectionist and the original is in blue dark, my setup is very forgiving even with bad lighting.

BTW. There are some commercial programs that can process the photos and help you make the lighting more uniform, but in my opinion they require fine tuning for each and every photo individually. A proper test and light setting before taking pictures is the only way to avoid disappointment in the final stage of book processing.

[ereszet]

How it's made?
It is my wife's plastic compact powder case with mirror. I made a hole in the cover opposing the mirror to hang the deflector on the camera (I used a red hot nail to make the hole). If the light reflected by mirror and ceiling is not uniform enough even with soft flash, I cover it (the mirror) with a small piece of paper or a piece of matt aluminium, which dissipates the light even more.

Does it work?
Yes, for black and white book pages or pages with light colors (even glossy). For pages in dark colors, the camera will cast a barely visible (but annoying - if you are a perfectionist) reflection of itself on the original paper page in the v-cradle (the camera faces the original page at 90 degrees). That's why I usually obscure the camera with large black paperboard, which of course prevents the use of camera flash, and I stay with my proven overhead lamp (which is 45 degrees to the original book page and 45 degrees to the camera lens).
The advantage of compact flash is portability. You can use it anywhere together with a tripod and my "quick and dirty" portable cardboard v-cradle (see my earlier posts).

Cost: a gift to your lady, a Dior powder case perhaps?

[ereszet]

For software tools to process photoscanned images see post #177 (Software tools to convert paper documents to lrf with thanks to cacapee for pdflrf) and the following discussion in "Yet another PDF to LRF converter" thread in Reader Content forum.
To find post #177 use the linear method for browsing.