Realizing a book scanner with CHDK and a Canon Powershot A460 or A560

Lebeau

187

Re: Realizing a book scanner with CHDK and a Canon Powershot A460 or A560

« Reply #10 on: 03 / May / 2011, 12:32:44 »

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Is motion detection an add-on to your solution ?

To automate panoramic capture, I use motion detection within Lua script to detect "no motion", inserting a timeout delay parameter and checking if motion where detected. Then if no motion is detected, that means that I have finished to move the cam. Sounds good for you ?

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Galerie Photobucket, Canal YouTube, Galerie Panoramio

solkron

4

Re: Realizing a book scanner with CHDK and a Canon Powershot A460 or A560

« Reply #11 on: 03 / May / 2011, 18:20:14 »

Quote from: NewbieToobie on 02 / May / 2011, 18:15:44

I've used a 5megapixel camera to easily archive a book in the past. Comparing those older cameras to a webcam does them a disservice. Any of those cameras listed on the Cam4You Remote site would be more than what you need. It sounds more and more like you don't want real solutions, you just want to invent problems.

Hmm ok that's right, I had no experiences with digital cameras until now. But do you know if I can control the software via command line? I couldn't find out that yet and this is important for the automation process.

Quote from: Lebeau on 03 / May / 2011, 12:32:44

Is motion detection an add-on to your solution ?

To automate panoramic capture, I use motion detection within Lua script to detect "no motion", inserting a timeout delay parameter and checking if motion where detected. Then if no motion is detected, that means that I have finished to move the cam. Sounds good for you ?

Yes that sounds very good for me. Until now I programmed a motion detector using the web cam. I've set a movement threshold, if this threshold was passed the program waits until the movement in the image is zero and than it takes the photo. If you would share your script I could sell my web cam. Would make the construction much easier.

Today I bought a camera and I hope it will arive on saturday. Then I can try out all your hints.

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Lebeau

187

Re: Realizing a book scanner with CHDK and a Canon Powershot A460 or A560

« Reply #12 on: 03 / May / 2011, 19:48:36 »

I think my script could be too versatil for your application but here is one of my function.

Wait for cells : "0" wait for no motion, "1" wait for only one cell motion
Launch delay : msec waiting before scanning for motion
Grid resolution : "3" means 12x9, "4" means 16x12, detection matrix
Check period : msec between scan check
Cell sensitivity : motion threshold between 0 to 255; 255 means wait expiring timeout
No motion timeout : the expiring timeout, without detecting motion

Code: [Select]

-- in Lua
function motion(wait_for_cells, launch_delay, grid_resolution, check_period, cell_sensitivity, no_motion_timeout)
    c=launch_delay
    g=grid_resolution
    k=4*g
    l=3*g
    e=check_period
    f=cell_sensitivity
    d=no_motion_timeout
    r=0
    repeat
        r=md_detect_motion(k, l, 1, d, e, f, 1, m, 0, 1, 1, k, l, 16, 11-g, c)
    until r >= wait_for_cells
return r
end