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My new "Tower" Scanner

Posted: 08 Dec 2017, 15:19
by BillGill
I just built a new one. I call it the Tower because it is higher than it is wide.
Tower (7).JPG
Tower (7).JPG (323.77 KiB) Viewed 4748 times
It is a sort of an inverted platen scanner. It is a single camera scanner. The platen is a flat plexiglass plate on top of the frame. The width of the platen (front to back) is about 5.5 inches (about 14 cm). This width was chosen because the sides of the tower are made of 1" by 6" boards. They are really .75 inch by 5.5 inch. That's about 2 cm by 14 cm. I chose that dimension because almost all of the books I plan to scan have pages that are less than 5.5 inches wide. I know that because my bookshelves are made of 1X6s, and the hardback books generally just fit on the shelf. Paperbacks of course are narrower. The camera is mounted so that the field of view just covers the entire width of the platen, with no zoom. Not using the zoom on the camera means that the distance from the camera to the platen is as short as it can be. That means the scanner can be much smaller. In fact this scanner is much smaller than either of my previous scanners. The overall height is 17 inches (about 43 cm). The width, including the lights, is about 25 inches (about 64 cm). Not counting the lights the width is 12 inches (30.48 cm).

The mirror at the bottom allows me to see the display on the camera to be sure that the book is properly positioned on the platen. It is a makeup mirror with a 3 X magnification.

The lights are 2 inexpensive clamp lights with the clamps removed. They are fastened to the tower with screws through the rims of the reflectors. They have small LED flood lamps installed in them. The lamps are daylight bulbs giving 400 lumens each. This mounting, which was driven more by necessity than by what I would have liked to have, seems to give a very even light across the page on the platen. Finding a workable lighting scheme was the biggest problem in the design of the Tower scanner.

The camera I am using is a Canon ElPH 160. So far I am getting good results. Anybody who wants to build their own Tower scanner will have to figure out how to mount the camera depending on what camera they are using. The camera should be mounted so that the lens is centered under the center of the platen, so the dimensions of the mount will vary depending on the size and shape of the camera. I have a more complicated mount than is really necessary, because there are 2 very different cameras I might use. One time when I was scanning a paperback book with my previous scanner I got all the way through and found all of the scans were fuzzy. So I mounted my 'good' camera, a Sony RX10 m2, on the scanner and repeated the scan. That time it worked. So if I run into that case again I wanted to be able to switch to the Sony. That means that the mount has to be moveable to accommodate the different mounting positions. This of course is not necessary if you never expect to change cameras.

So far the results have been quite good. Here is a sample page.
As you can see it is a pretty good scan. Running it through ABBYY Fine Reader produces quite a good output. It isn't perfect, but the I haven't ever had a page that come through the OCR process perfect. As the scanner is now I wind up with either my fingers or my wrist in the image. I am considering adding a cover that will pull down and clamp the page down. That would eliminate the extraneous stuff. I am considering ways to implement such a cover.

To use the scanner I place the first page face down on the platen with the facing page hanging over the edge. This allows me to push the platen all the way into the gutter so I can get a full scan on books with a narrow gutter margin. I snap the picture, the slide the book across to the other side with the second page on the platen and the first page hanging over the edge. After snapping that picture I pick the book up and turn the page, then repeat. On my first full book trial I wound up scanning a little over 300 pages per hour.

The biggest problem I am having right now is that I can't connect my Cannon camera to a Win 10 computer using the USB port. That means I can't run CHDKPTP to control the camera from the PC and download the pictures directly to the PC. This seems to be a problem with Win 10. I have researched the problem on the web and found several discussions of people having similar problems with Canon cameras. I have tried the suggestions that they came up with and so far nothing has worked. That means that I have to dismount the camera and pull the memory card to transfer the pictures to the PC. I have tried it with a Win 7 computer and it works fine, it seems to be a Win 10 problem.


Re: My new "Tower" Scanner

Posted: 05 Apr 2018, 13:22
by Matteus
An interesting scanner would be interesting to see more pictures and different angles. I am jealous of you who know how to build a great scanners! :-)


Re: My new "Tower" Scanner

Posted: 06 Apr 2018, 09:46
by BillGill
Thanks you for your comments. I didn't want to get too explicit in how the scanner is built, because I don't so much design my scanners as take an idea and start building it. Then I throw what I have done out there to inspire others. This one is pretty simple. 2 pieces of 1X6 lumber for uprights. A piece of 1X8 lumber for a base. A piece of 1/4 inch plywood across the back to stabilize the sides and provide a mounting location for the camera mount. The camera mount of course has to be constructed to match your camera. Basically I use a piece of wood, normally a piece of 2X4 inch lumber that is cut to the correct width to position the camera lens directly under the center of the platen. There is a groove in the mount. This is cut so that the camera is kept from rotating. The groove doesn't have to be cut, a thin piece of wood along the back side of the camera can stabilize it. That can just be tacked on. A 3/8 inch hole through the backplate and through the mount will accommodate a 1/4 X 20 bolt to hold the camera in place. 1/4 X 20 is the standard camera mounting bolt, at least here in the USA. I use an external AC power adapter which is mounted on the back side of the backplate. A power strip is mounted on the side of the box, below the light fixture. With everything plugged into that I can turn the whole thing on and off with once switch. The platen is a sheet of plexiglass cut to just fit the tops of the sides.

The construction is really quite simple. The main thing is that you need to choose the materials and construction methods to suit what you have available. Not everybody has a bunch of power tools on hand, so they do have more of a problem.

And I realize that not everybody has the ability to come up with the designs. I am a retired engineer. I have always, ever since I was a child, been interested in making gadgets. So this is just a continuation of what I have always done. But other people don't even have any idea how to go about this sort of thing. That's ok, because, just as a wild example, I have absolutely no idea how to go about making music. But I am sure glad there are people who do.


Re: My new "Tower" Scanner

Posted: 15 Nov 2019, 23:43
by pkselva
I am selva Kumaran from South india.

Thanks for this design.

I plan the same to 15 inch x 15 inch width. we need below clarifications for our project.

1. distance between Camera and glass
2. light setup position on the side panel

Please guide me to complete this project.

Thanks & Regards


Re: My new "Tower" Scanner

Posted: 16 Nov 2019, 10:46
by BillGill
Wow, 15 X 15 is a big scanner. Good luck with it.

I determined the camera position by trial and error. I built the mount so that the center of the lens was aimed at the center of the platen. Then I slid the camera up and down until it just covered the area I wanted to scan. I did this with no zoom on the camera, since I wanted the camera to be as close as possible to the platen, and didn't want to have to fiddle with the zoom before each session. It is important of course that the camera be mounted parallel to the platen.

Lighting is another problem The lighting I am using is not particularly good. However, it is good enough for my uses. I am scanning printed books, black and white, no color. If I have a picture to include I do that with a flat bed scanner, with the problems of getting a flat scan.

I worked on the lighting a while before I finally came up with the version I have. I tried a couple of different arrangements. Basically my arrangement
is 2 bright LEDs shining straight across the scanner. The platen is illuminated by the side shine of the lights. That gave me the best lighting I could get without going to extremes. This is strictly an ad hoc arrangement, built with what I had on hand or could get easily at the store.

Going to a 15 X 15 platen may produce some problems you will have to solve. The working area of my platen is about 5 1/4 inch by 8 inches. Going to larger dimensions may call for some changes in the lighting. Maybe you could use 4 lights in place of my 2. That might take care of the extra width, but I'm not sure about the extra length. This will probably require some experimentation on your part.

Good luck.