From owner-freebsd-questions@FreeBSD.ORG Sat Sep 5 16:33:05 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4C176106566B for ; Sat, 5 Sep 2009 16:33:05 +0000 (UTC) (envelope-from modulok@gmail.com) Received: from mail-ew0-f208.google.com (mail-ew0-f208.google.com [209.85.219.208]) by mx1.freebsd.org (Postfix) with ESMTP id D60E08FC0C for ; Sat, 5 Sep 2009 16:33:04 +0000 (UTC) Received: by ewy4 with SMTP id 4so1679202ewy.36 for ; Sat, 05 Sep 2009 09:33:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=RSati+RuguCuiylUFwxQ+ClTV1UZX1qK7RvsF3Hy1Lo=; b=FTa9TvSl6GBjfa2dslq6tVcZ7M1VuWryN5c+mg9h4Pz8xzz01Ra1fQeNz13QQeTXSA Rz1//vas2uScChBTomY5f7p67mYGtvLDlkCUS+/5VWY5DAPiSRZeqQTurAjMBh6STXkj aLNA+dLczDzLGwkeDVMxvkj9Ts2KvLJ2YI9SU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=tqF6bC7lhdTkAP8GoIIl8lWxS3FyehiEc1dDZOB/7DHDd3FxA0Y43bZgsGKMMbCh/o +mjgTGGex64SAq02Rt9GIYSRejCHUvzCKQf8XqE8twDoUnzzb2SOoF+7ZoV1nRIcLdWP oVDLM4MGDcVchIMQA6whFTOwVJ6YgmipOdvZw= MIME-Version: 1.0 Received: by 10.211.130.15 with SMTP id h15mr1911541ebn.82.1252168383539; Sat, 05 Sep 2009 09:33:03 -0700 (PDT) Date: Sat, 5 Sep 2009 10:33:03 -0600 Message-ID: <64c038660909050933h25a91edcw56688993f5557ad2@mail.gmail.com> From: Modulok To: FreeBSD Questions Content-Type: text/plain; charset=ISO-8859-1 Subject: Is there such thing as a 'soft checksum' tool? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 05 Sep 2009 16:33:05 -0000 List, I'm not even sure such a tool exists, but it's worth asking: I'm looking for a pseudo-checksum tool for use with catalogging images. For example, a strict checksum algorithm, like the sha family, will produce a dramatically different checksum for two files which differ by only a single bit. I'm looking for something where two images images, which are similar, get a proportionally similar checksum. When I speak of similarities I'm referring to their image patterns. i.e two images of differing sizes, which are otherwise identical, would produce very similar checksums. So the closer the checksums are, the more similar two given images are. Does anyone know of anything like this? -Modulok-