AutoIt - Find duplicate images by content? - image

Question

I am looking for a way to find duplicate images using AutoIt. I've looked into PixelSearch and SearchImage but neither do exactly what I need them to do.
I am trying to compare 2 images by filename and see if they are the same image (a duplicate). The best way I've thought to do it would be to:
1) Get both image sizes in pixels
2) Use a while loop to get the color of each pixel and store it in an array
3) Check to see if both arrays are equal to each other.
Does anybody have any ideas on how to achieve this?

Answer 1

I just did some more research on this subject and built a small UDF based on a few answers I read. (Mainly based off of monoceres's answer on AutoItScript.com). I figured I would post my solution here to help any future developers!
CompareImagesUDF.au3
Func _CompareImages($ciImageOne, $ciImageTwo)
_GDIPlus_Startup()
$fname1=$ciImageOne
If $fname1="" Then Exit
$fname2=$ciImageTwo
If $fname2="" Then Exit
$bm1 = _GDIPlus_ImageLoadFromFile($fname1)
$bm2 = _GDIPlus_ImageLoadFromFile($fname2)
; MsgBox(0, "bm1==bm2", CompareBitmaps($bm1, $bm2))
Return CompareBitmaps($bm1, $bm2)
_GDIPlus_ImageDispose($bm1)
_GDIPlus_ImageDispose($bm2)
_GDIPlus_Shutdown()
EndFunc
Func CompareBitmaps($bm1, $bm2)
$Bm1W = _GDIPlus_ImageGetWidth($bm1)
$Bm1H = _GDIPlus_ImageGetHeight($bm1)
$BitmapData1 = _GDIPlus_BitmapLockBits($bm1, 0, 0, $Bm1W, $Bm1H, $GDIP_ILMREAD, $GDIP_PXF32RGB)
$Stride = DllStructGetData($BitmapData1, "Stride")
$Scan0 = DllStructGetData($BitmapData1, "Scan0")
$ptr1 = $Scan0
$size1 = ($Bm1H - 1) * $Stride + ($Bm1W - 1) * 4
$Bm2W = _GDIPlus_ImageGetWidth($bm2)
$Bm2H = _GDIPlus_ImageGetHeight($bm2)
$BitmapData2 = _GDIPlus_BitmapLockBits($bm2, 0, 0, $Bm2W, $Bm2H, $GDIP_ILMREAD, $GDIP_PXF32RGB)
$Stride = DllStructGetData($BitmapData2, "Stride")
$Scan0 = DllStructGetData($BitmapData2, "Scan0")
$ptr2 = $Scan0
$size2 = ($Bm2H - 1) * $Stride + ($Bm2W - 1) * 4
$smallest = $size1
If $size2 < $smallest Then $smallest = $size2
$call = DllCall("msvcrt.dll", "int:cdecl", "memcmp", "ptr", $ptr1, "ptr", $ptr2, "int", $smallest)
_GDIPlus_BitmapUnlockBits($bm1, $BitmapData1)
_GDIPlus_BitmapUnlockBits($bm2, $BitmapData2)
Return ($call[0]=0)
EndFunc ;==>CompareBitmaps
Now to compare imagages, all you have to do is include the CompareImagesUDF.au3 file and call the function.
CompareImagesExample.au3
#Include "CompareImagesUDF.au3"
; Define the two images (They can be different file formats)
$img1 = "Image1.jpg"
$img2 = "Image2.jpg"
; Compare the two images
$duplicateCheck = _CompareImages($img1, $img2)
MsgBox(0,"Is Duplicate?", $duplicateCheck)

Answer 2

If you want to find out if both images are an exact match, regardless if names are the same or different, use the built-in Crypt function _Crypt_HashFile with MD2 or MD5 to make a hash of both files and compare that.