Original ~600pg/hr, very portable scanner now achieving ~900pg-1100pg/hr
Posted: 19 Mar 2017, 20:45
3 years ago I posted details and plans about my portable, easy to build, single page scanner here:
viewtopic.php?f=14&t=3007
The trigger mechanism in that original version was Daniel Reetz' brilliant idea to use a bike break. Although it worked perfectly, the big problem was all the hardware around the camera, which would have to be custom designed for each camera.
David Landin suggested using an infra-red trigger. As I mentioned I hadn't thought about it because I was trying to make the system work with simple mechanical cameras that people had, rather than having to buy a special camera that had that feature (and also the trigger). However I did note it would simplify the construction a lot.
Well I got busy so was not able to work on some ideas I had for simplifying the scanner construction, one of which was not to use a dedicated camera, but an iPhone (or similar) and a Bluetooth trigger. This would effectively provide the same benefits of the David's infra-red trigger (i.e. wireless and no construction needed) but at a fraction of the cost since a special camera would not be needed.
I have finally been able to test the idea out and it worked spectacularly. One of the problems with my old camera, was it did not have a focus lock, so you had to wait for it to focus on each shot. I had speculated in my original post that, if the focusing could be eliminated, I could probably speed up the ~600 page/hour scanning rate by about 50%. Well that is exactly what happened and I'm now getting rates of 900-1100 pages per hour.
Attached below are some screenshots showing the files for 1 min of scanning (as recorded by the time stamps, which match my measurements via a stop watch while scanning) and I'm getting 16-18 pages per min, or about 960-1080 pages per hour) and it doesn't drop as much as it used to with the regular camera as the scanner as there's less fiddling with the iPhone.
I'm using an iPhone 4s with the "Camera+ Free" app (with the 5-in-1 Superbundle purchase of $2.99):
https://itunes.apple.com/us/app/camera- ... 16489?mt=8
The reason I chose this software is:
a) It has high resolution files because without it the quality is too degraded for good OCR. It offers high quality JPEG or TIF; I use JPEG as TIF is very large and seems a cause the app to crash after a few saves.
b) It has full manual controls -- white balance, shutter and ISO. ISO is particularly important and I set it at 50 to reduce grain and keep image quality up.
c) It has focus lock.
d) It works with bluetooth triggers. Apparently not all iPhone camera software does -- the key to ensuring bluetooth works, seems to be ensuring the volume controls can be used a shutter release.
For my blue tooth trigger I bought this from Amazon ($5-$7.50 depending on the day):
https://www.amazon.com/dp/B0113W600M
And to hold the iPhone I got this smart phone tripod adapter from Amazon ($8.00). I chose it because it doesn't use springs to hold the phone, but instead has a solid thumbscrew/clamp to hold the smart phone:
https://www.amazon.com/Vastar-Universal ... 01L3B5PBI/
Below are some pics of the updated scanner set up and you can see the trigger zip-tied to the white platen handle and effortless to use with your thumb. Notice also the platen is no longer connected to the camera support by cable which makes it much easier to move out of the way and deal with it.
viewtopic.php?f=14&t=3007
The trigger mechanism in that original version was Daniel Reetz' brilliant idea to use a bike break. Although it worked perfectly, the big problem was all the hardware around the camera, which would have to be custom designed for each camera.
David Landin suggested using an infra-red trigger. As I mentioned I hadn't thought about it because I was trying to make the system work with simple mechanical cameras that people had, rather than having to buy a special camera that had that feature (and also the trigger). However I did note it would simplify the construction a lot.
Well I got busy so was not able to work on some ideas I had for simplifying the scanner construction, one of which was not to use a dedicated camera, but an iPhone (or similar) and a Bluetooth trigger. This would effectively provide the same benefits of the David's infra-red trigger (i.e. wireless and no construction needed) but at a fraction of the cost since a special camera would not be needed.
I have finally been able to test the idea out and it worked spectacularly. One of the problems with my old camera, was it did not have a focus lock, so you had to wait for it to focus on each shot. I had speculated in my original post that, if the focusing could be eliminated, I could probably speed up the ~600 page/hour scanning rate by about 50%. Well that is exactly what happened and I'm now getting rates of 900-1100 pages per hour.
Attached below are some screenshots showing the files for 1 min of scanning (as recorded by the time stamps, which match my measurements via a stop watch while scanning) and I'm getting 16-18 pages per min, or about 960-1080 pages per hour) and it doesn't drop as much as it used to with the regular camera as the scanner as there's less fiddling with the iPhone.
I'm using an iPhone 4s with the "Camera+ Free" app (with the 5-in-1 Superbundle purchase of $2.99):
https://itunes.apple.com/us/app/camera- ... 16489?mt=8
The reason I chose this software is:
a) It has high resolution files because without it the quality is too degraded for good OCR. It offers high quality JPEG or TIF; I use JPEG as TIF is very large and seems a cause the app to crash after a few saves.
b) It has full manual controls -- white balance, shutter and ISO. ISO is particularly important and I set it at 50 to reduce grain and keep image quality up.
c) It has focus lock.
d) It works with bluetooth triggers. Apparently not all iPhone camera software does -- the key to ensuring bluetooth works, seems to be ensuring the volume controls can be used a shutter release.
For my blue tooth trigger I bought this from Amazon ($5-$7.50 depending on the day):
https://www.amazon.com/dp/B0113W600M
And to hold the iPhone I got this smart phone tripod adapter from Amazon ($8.00). I chose it because it doesn't use springs to hold the phone, but instead has a solid thumbscrew/clamp to hold the smart phone:
https://www.amazon.com/Vastar-Universal ... 01L3B5PBI/
Below are some pics of the updated scanner set up and you can see the trigger zip-tied to the white platen handle and effortless to use with your thumb. Notice also the platen is no longer connected to the camera support by cable which makes it much easier to move out of the way and deal with it.