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in reply to Re^3: Can i Compare two images in perl ? (It's a myth!)
in thread Can i Compare two images in perl ?

Okay. I saved those same two pngs as bmps; deleted the 3 old zips; and then compressed the bmps per your post:

C:\test>dir ?.bmp 31/05/2011 14:33 720,054 1.bmp 31/05/2011 14:33 720,054 2.bmp 2 File(s) 1,440,108 bytes C:\test>del 1.zip 2.zip 3.zip C:\test>zip 1.zip 1.bmp adding: 1.bmp (160 bytes security) (deflated 100%) C:\test>zip 2.zip 2.bmp adding: 2.bmp (160 bytes security) (deflated 100%) C:\test>zip 3.zip 1.bmp 2.bmp adding: 1.bmp (160 bytes security) (deflated 100%) adding: 2.bmp (160 bytes security) (deflated 100%) C:\test>dir ?.zip 31/05/2011 14:34 2,376 1.zip 31/05/2011 14:35 2,376 2.zip 31/05/2011 14:35 4,730 3.zip

(2376 + 2376) / 4370 = 1.0874141876430205949656750572082.

Still nowhere near the 2.0 you would expect if this worked.


Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^5: Can i Compare two images in perl ? (Still a myth!)
by SuicideJunkie (Vicar) on May 31, 2011 at 15:34 UTC

    Concatenating the bmps doesn't help much either. I got 1.12

    Perhaps we need a theoretical perfect compression algorithm?

      Great minds :)

      C:\test>copy 1.bmp/b+2.bmp/b 3.bmp 1.bmp 2.bmp 1 file(s) copied. C:\test>del 3.zip C:\test>zip 3.zip 3.bmp adding: 3.bmp (160 bytes security) (deflated 100%) C:\test>dir ?.zip 31/05/2011 14:34 2,376 1.zip 31/05/2011 14:35 2,376 2.zip 31/05/2011 14:47 4,472 3.zip

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.