Determining if two pictures are identical

How can I determine if 2 pictures in pictureboxes are identical?

Identical as in what? Same file or same picture?

If you're reading in from a file or comparing what;s in the ram, a checksum would work well me thinks.

Don't ask me how to do it though, :p

If you comparing against another picture, I would say to check each pixel in both pictures against each other, and if all are the same, then the pictures are equal.

The complexity of implementing this operation depends on the programming language.

you can load it as a string using

VB Code:

Open Filename For Binary As #1
        PicString = Space(LOF(1))
        Get #1, , PicString
    Close #1

do this for both pictures, then do:

VB Code:

If PicString = PicString2 Then
        'The same
    Else
        'Not the same
    End If

this should work is the file is the same format and it should work for _any_ format.

if you want to compare a .bmp with a .tga, for example, you have to load them both in an array and check all pixels or do it the slow way: load them into a picturebox (or another dc) and check them using getpixel.

VB Code:

Dim booInvalid
 
Picture1.Picture = LoadPicture("C:/Image1.jpg")     'Load first image
Picture2.Picture = LoadPicture("C:/Image2.jpg")     'Load second image
 
Picture1.ScaleMode = 3     'Scale mode set to pixels
Picture2.ScaleMode = 3     'Scale mode set to pixels
 
'Test the image demensions first
If Picture1.ScaleWidth = Picture2.ScaleWidth and Picture1.ScaleHeight = Picture2.ScaleHeight Then
     'Loop through pixel by pixel to see if the pictures match
     For X = 0 to Picture1.ScaleWidth
          For Y = 0 to Picture1.ScaleHeight
               'Check if pixels are equal
               If Not GetPixel (Picture1.hDC, X, Y) = GetPixel (Picture2.hDC, X, Y) Then
                    booInvalid = True     'Set the Invalid flag (Pictures are not equal)
               End If
          Next
     Next
Else
     booInvalid = True     'Set the Invalid flag (Pictures are not equal)
End If
 
'Return response
If booInvalid = True Then
     MsgBox "Pictures ARE NOT identical."
Else
     MsgBox "Pictures ARE identical.
End If

This will check if two pictures are identical.

-Dylan

Check out this: http://www.vbforums.com/showthread.p...hreadid=221345
The method is extremly fast