webcam motion detection

[mary]

here is a link: http://www.imagemagick.org/script/compare.php

there are also COM and dll library to compare 2 jpg.

The idea is: you take 2 jpg from your webcam and compare them with imagemagick. If the difference is more than $tolerance value ==> there is motion

sorry i have no code to help you but i'll do so if i succeed

[DirtDBaK]

nice idea, try making some code! And when you do, I'd love to check it out...

[KeCe]

goddamit why did you post something without code? make us some code

[PartyPooper]

goddamit why did you post something without code? make us some code

Oh, now that's really going to get results - NOT.

[C2C]

gotta love borat

[JellyFish666]

1 year old topic, ducks for cover eeek!

Edited May 5, 2008 by JellyFish666

[PartyPooper]

More like 6 months

[Yorn]

Yes, the only way I've come close to doing motion detection is to use third party software and just monitor the size of the images folder to see if things change. When they do, I have events trigger, but it's not the best at all. In fact, it kind of sucks. I really wish there was a DLL out there that someone could use to make a *good* motion detection program.

[jpam]

prospeed.dll can.

it has a CompareBytes() function

its not in the udf, but i can put it in if you want

don't ask me to write a complete motion detection program.

i will only include it in the udf , with 1 example.

Edited May 5, 2008 by jpam

[Skrip]

Zerocool made a very nice one awhile back. I cannot seem to find it now, but it worked nicely. Although, I cannot remember if he actually used AutoIt to make it..

[james3mg]

If ImageMagickObject.dll is registered on your machine, the code should be something along these lines:

(note that the default threshold may be an inappropriate value-I'm not currently on a computer with ImageMagickObject registered, so I'm not sure what range the MAE metric could return).

#include <ImageMagickObject.dll.au3>
Func _MotionDetected($_Pic1,$_Pic2,$_Threshold=15)
    Local $oIM=ObjCreate("ImageMagickObject.MagickImage")
    Local $_ReturnVal=$oIM.Compare("-metric","MAE",$_Pic1,$_Pic2)
    If $_ReturnVal>=$_Threshold Then
        Return 1
    Else
        Return 0
    EndIf
    $oIM=0
EndFunc

You could get my ImageMagickObject.dll.au3 include file here (thanks again GeoSoft for hosting this, originally from this thread), but if I remember right, I didn't include the .Compare functions in that dll...you'd be better off installing ImageMagick yourself, and choosing to register the dll in the installation routine. If you do try my include, note that because it registers a COM dll on your system, you'll need administrative privileges the first time you run it (#requireadmin on vista). After it's registered the first time, it will run at any privilege level.

Edited May 5, 2008 by james3mg

[Yorn]

jpam, that sounds interesting. I wouldn't expect a complete motion detection program or UDF, but if there's a way to compare two images of a captured webcam image, that would be interesting. If it's comparing bytes of a file or filesize, however, I wouldn't bother. I've already tried doing that method and it's not a very useful method for motion detection.

[NELyon]

jpam, that sounds interesting. I wouldn't expect a complete motion detection program or UDF, but if there's a way to compare two images of a captured webcam image, that would be interesting. If it's comparing bytes of a file or filesize, however, I wouldn't bother. I've already tried doing that method and it's not a very useful method for motion detection.

A long time ago I used the PixelXXXX Functions to make my mouse follow a highlighter.

If you have a good enough quality camera and a viewer, you could use the pixel functions to monitor non-discreet changes (As in all likely hood, the image will change every second, but subtlety)

[jpam]

it compares 2 bitmap array data's with a user definded tolerance

the tolerance is the amount off bytes that may diiffer from the 2 pictures

something like this ; $result = CompareBytes($array1, $array2, $bytesSize, 50)

$array1 = bitmap array data

$array2 = bitmap array data

$bytesSize = byteSize of the bitmap

50 = tolerance , how many bytes may different from the 2 bitmaps

$return value = 0 if the bitmaps are the same ,else the total bytes that are different

[jpam]

I did some testing with CompareBytes()

it works

between 1 and 1.5 ms for a 400x400 pixel bitmap

[McGod]

Easy method:

Have it take a base screenshot and MD5 it

Every 5 seconds, take a screenshot and MD5 it then compare the two.

If they aren't the same MD5 then something changed.

[james3mg]

Easy method:

Have it take a base screenshot and MD5 it

Every 5 seconds, take a screenshot and MD5 it then compare the two.

If they aren't the same MD5 then something changed.

The problem is that you'll never get two pictures of something that are exactly the same. Note that the OP was looking for a tolerance of some kind, which is why the ImageMagick method is a good fit- it gives you the AMOUNT of change from one picture to another. Edited May 6, 2008 by james3mg

[spudw2k]

The compare would work great for simple motion/action, but I was wondering does Imagemagick support some sort of co-ord info for where in the motion is detected? (top right of picture, bottom left, etc..)

[Wus]

If you have access to the pixels then you could code up a simple mean-square error function (though it wouldn't really be an error, just a difference), and then threshold based on that error. I'm pretty sure it's one of the most common error measures there is. The only difficulty would probably be in determining an appropriate size for the threshold... but that is just a matter of experiment.

http://en.wikipedia.org/wiki/Mean_square_error

Edit:

And if you want information on where the motion occurred I would probably

(1) create an error map

(2) apply some smoothing (probably a blur or unsharp mask)

(3) normalize it

(4) fit a rectangle around the top x% of the error (this rect would tell you where the motion occurred)

Edited May 7, 2008 by Wus

[jpam]

here's the script i did some testing with

you need prospeed3.0.dll and the prospeed3.0 udf for it

download @ http://prospeed-jan.xprofan.com/

i cannot anwser any questions for 10 days, holiday in spain

expandcollapse popup

#include <prospeed3.0.au3>

GUICreate("Compare 2 images", 800, 400)
GUISetState()

$hdc = GetHDC()

$clock1  = LoadFileImage("clock.png")
$size = GetInfosImage($clock1,7)

$clock2 = CreateImage(400,400)
PaintImage($clock2,0,0,400,400,$clock1,0,0,0)
ColorFillImage($clock2,398,398,400,400,0xFFFFFF)

PaintImage($hdc,0,0,400,400,$clock1,0,0,0)
PaintImage($hdc,400,0,400,400,$clock2,0,0,0)

CreateBuffer(800,400)
SetBuffer($hdc)

$array1 = InitFX($clock1)
$array2 = InitFX($clock2)

$Struct1 = DllStructCreate("byte["&$size&"]")
$Struct2 = DllStructCreate("byte["&$size&"]")

$mem1 = SaveToMemoryFX($array1, DllStructGetPtr($Struct1))
$mem2 = SaveToMemoryFX($array2, DllStructGetPtr($Struct2))

$time = TimerInit()

$chk2 = CompareBytes(DllStructGetPtr($Struct1), DllStructGetPtr($Struct2), $size, 0)

$stop = TimerDiff($time)
MsgBox(0,$stop,$chk2)

While 1
    $msg = GUIGetMsg()
    If $msg = -3 Then 
        $Struct1 = ""
        $Struct2 = ""
        FreeAllImages()
        FreeFX($array1)
        FreeFX($array2)
        DestroyBuffer()
        Exit        
    EndIf
WEnd