Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!news.stack.nl!aioe.org!.POSTED!not-for-mail From: Doug Anderson Newsgroups: comp.sys.mac.system Subject: Re: Any quick, easy way to compare two images? Date: 25 Jan 2014 13:27:58 -0800 Organization: Rare Lines: 45 Message-ID: References: <2ridndio-M0kOnzPnZ2dnUVZ8kmdnZ2d@giganews.com> <2fd2jijlbb.fsf@ethel.the.log> <161tzyjibp.fsf@ethel.the.log> <5cKdnS2-vfr0cX_PnZ2dnUVZ_oSdnZ2d@giganews.com> <6jy523synp.fsf@ethel.the.log> <250120141345247892%nospam@nospam.invalid> NNTP-Posting-Host: VU74RkCEue2cZAa0sAHoDA.user.speranza.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Complaints-To: abuse@aioe.org User-Agent: Emacs Gnus X-Notice: Filtered by postfilter v. 0.8.2 Xref: csiph.com comp.sys.mac.system:55356 nospam writes: > In article <6jy523synp.fsf@ethel.the.log>, Doug Anderson > wrote: > > > > >> Since all images contain random dynamic range noise regardless of how > > > >> static the scene, the function Magic will return true ("different") > > > >> every time since the files cannot be anything but different in > > > >> content. > > > > > > > > I can't tell if you are willfully misunderstanding the poster, or if > > > > you honestly don't understand him. > > > > > > > > He has a situation where an image file gets sent regularly to his > > > > computer. Due to the algorithm that sends that file to his computer, > > > > sometimes the _same file_ is getting sent more than once. > > > > > > I'm just going by his original post where he asks about: "a stream of > > > images". > > > > > > A stream of images is NOT individual files. > > > > > > I'm very willing to say, "Yes, I misunderstood him." > > > > > > But that's because his case was badly stated so pretty impossible to > > > know that he meant a hot fudge sundae and not a steak with > > > mushrooms. > > > > If you say so. I understood him, and he had clarified the situation > > several times before your post above. > > > > Don't know if that was what you were intending, but to me it felt like > > you were more interested in arguing with me than in reading what the > > original poster had to say and offering assistance. > > he did not clearly state what he wanted. several people assumed he > meant content, not file. > > if he wants to know it's a different *file*, all that needs to be done > is compare the creation date. there's no reason to bother with > comparing pixels. That might work, but it might not. Depending on the protocal by which the file was tranmitted to his computer, the creation dates could be different even though the contents of the files are identical.