how can Ifind if an Image contains another Image ?

Question

3.50/5 (4 votes)

See more:

VB

Is there a way to find if a small Image is part of a larger one using vb.net code ?

thanks in advance !

Posted 29-May-11 3:52am

tasoskiller

Add a Solution

Comments

Sergey Alexandrovich Kryukov 29-May-11 13:53pm

Good question, my 5, but I don't think there is an easy and effective solution.
Important question: is it ***exact*** copy of the small image?

If so, the solution can be pretty simple, but it's hard to make if fast.
--SA

[no name] 31-May-11 12:51pm

yes ! the small image is copied from within the big one .
however, I still have a problem ( look at my reply to Dave Kreskowiak)

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Dave Kreskowiak · Answer 1 · 2011-05-29T08:08:00

Solution 1

If you're looking for an exact pixel-by-pixel copy of the smaller image in the alrger one, then it's not that hard. It's just a matter of looking for the first pixel to search for in the image, then, when/if found, looking at the adject pixels.

If you're looking for any kind of scaling or rotation of the image to search for in the larger image, now you've got an extremely difficult problem in "machine vision". Happy researching!

Posted 29-May-11 8:08am

Dave Kreskowiak

Comments

[no name] 30-May-11 1:51am

Thanks You !
You help me so much !

[no name] 31-May-11 10:15am

well... I tried it and I have some problems !
when I try this code:
[code]
Dim smallpix As Color = small.GetPixel(1, 1)
Dim i_heigh As Integer = 0, i_width As Integer = 0

For i_width = 0 To big.Width - 1

For i_height = 0 To big.Height - 1
Dim bigpix As Color = big.GetPixel(i_width, i_heigh)

If smallpix = bigpix Then
MsgBox("THE SAME !")

End If
Next
Next

[/code]
I get about of 70 similar pixels !

but when I do this :
[code]
Dim smallpix As Color = small.GetPixel(1, 1)
Dim i_heigh As Integer = 0, i_width As Integer = 0

For i_width = 0 To big.Width - 1

For i_height = 0 To big.Height - 1
Dim bigpix As Color = big.GetPixel(i_width, i_heigh)

If smallpix = bigpix Then
MsgBox("THE SAME !")
If small.GetPixel(2, 1) = big.GetPixel(i_width + 1, i_heigh) Then
MsgBox("THE SAME !!!!!!!")

End If

End If
Next
Next
[/code]

" MsgBox("THE SAME !!!!!!!") " command is never reached !
why is that ?
I am sure that the small image is part of the large one because I cropped it from there !
so I guess the problem will be somewhere in my code !!

Can you help please ???

Dave Kreskowiak 31-May-11 18:51pm

It doesn't work because you never get anything from the small image other than the first and second pixels. You need an index into the image in order to match the same pixels.

Your inner and outer loops are also too big. Think about it. You're not going to look for the pixel in the top left corner in the bottom right corner of the big image, are you? You make the loops smaller than the biggest dimensions of the large image by an amount equal to the size of the smaller image.

Now, when you do find the first pixel from the small image, you can switch to a smaller set of loops that are the size of the smaller image. Then you can use those offsets as offsets into the larger image to get the pixels.