From owner-freebsd-questions@FreeBSD.ORG Mon Sep 7 08:28:46 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 43A98106566B for ; Mon, 7 Sep 2009 08:28:46 +0000 (UTC) (envelope-from parv@pair.com) Received: from hrndva-omtalb.mail.rr.com (hrndva-omtalb.mail.rr.com [71.74.56.125]) by mx1.freebsd.org (Postfix) with ESMTP id B9EC08FC14 for ; Mon, 7 Sep 2009 08:28:45 +0000 (UTC) Received: from localhost.hawaii.res.rr.com ([98.150.187.245]) by hrndva-omta02.mail.rr.com with ESMTP id <20090907082844800.OSRB28062@hrndva-omta02.mail.rr.com>; Mon, 7 Sep 2009 08:28:44 +0000 Received: from holstein.holy.cow (localhost [127.0.0.1]) by localhost.hawaii.res.rr.com (Postfix) with ESMTP id 9CC473403; Sun, 6 Sep 2009 22:31:13 -1000 (HST) Received: (from parv@localhost) by holstein.holy.cow (8.13.8/8.13.8/Submit) id n878VCLD002920; Sun, 6 Sep 2009 22:31:12 -1000 (HST) (envelope-from parv@pair.com) X-Authentication-Warning: holstein.holy.cow: parv set sender to parv@pair.com using -f Date: Sun, 6 Sep 2009 22:31:12 -1000 From: parv@pair.com To: modulok@gmail.com Message-ID: <20090907083112.GA2787@holstein.holy.cow> Mail-Followup-To: modulok@gmail.com, Lowell Gilbert , freebsd-questions@freebsd.org References: <64c038660909050933h25a91edcw56688993f5557ad2@mail.gmail.com> <44skf0c6zq.fsf@lowell-desk.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <44skf0c6zq.fsf@lowell-desk.lan> Cc: Lowell Gilbert , freebsd-questions@freebsd.org Subject: Re: 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: Mon, 07 Sep 2009 08:28:46 -0000 in message <44skf0c6zq.fsf@lowell-desk.lan>, wrote Lowell Gilbert thusly... > > Modulok writes: (I am replyin to Lowell's reply for I do not have OP.) > > 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? See if this ... http://www.stonehenge.com/merlyn/LinuxMag/col50.html ... fits. - parv --