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Posted on 07/10/04 01:09:07 AM |
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unspun™
Guest Reply |
Forensic Photoshop?
This might not be the best place to ask this, but I just bought the book, so I thought I'd try here. Nice book, too, btw. I've been using some of the techniques in the book myself for a long time, without knowing it. But the book looks to take me to the next level. Anyway...my question. I'm doing some investigative work for someone and I'm trying to enhance a jpg image well enough to read a really small clock in it. It occurred to me there might be people who do forensic photoshop stuff and there might be a way to learn some techniques. Pointers? Thanks. |
Posted on 07/10/04 08:25:25 AM |
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trinityofone
Guest Reply |
Re: Forensic Photoshop?
I wouldn't think it possible to enhance an image, especially a JPEG, enough to be able to make out fine detail. JPEG by its very nature has already lost its definition. _________________ It must be Thursday, I never could get the hang of Thursdays |
Posted on 07/10/04 09:22:02 AM |
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Steve Caplin
Administrator Posts: 7021 Reply  |
Re: Forensic Photoshop?
Oh, I'd say it's always possible to enhance an image, especially if what you want is to be able to decipher a clock rather than, say, make the image look more attractive. You might start out with the Unsharp Mask filter, which is the easiest way of recovering detail. And, surprisingly, the Emboss filter can be rather good for this: choose low settings and you'll find that, as you rotate the emboss angle, you might just hit on one that 'lights' the clock so it's legible. Sounds like a great challenge, by the way. Are you able to post it here so we can all have a go? |
Posted on 07/10/04 12:04:47 PM |
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maiden
Golden Gif Gagster Posts: 471 Reply  |
Re: Forensic Photoshop?
Yeah as Steve said - post it here if you can, Unspun, and lets see if we can collectively, or individually crack it. _________________ mad as a badger and twice as furry |
Posted on 11/10/04 6:35:13 PM |
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unspun™
Guest Reply |
Re: Forensic Photoshop?
The attachment I'm posting is a .psd file, because I can't post the entire photo (for reasons of confidentiality) and I assumed that if I cropped a jpg file and re-saved it, that would make things worse. I did manage, using curves and the unsharp mask to make out what appears to me to be a time of -- well, I'll tell you what, I'll not say anything to prejudice anyone until after others try. Suffice it to say that the client feels the image is too unclear to use, even though it does appear that the time I gave them reinforced what they already thought (although they had not told me in advance what time they thought was on the clock, just as I'm not saying anything right now). So they're calling in experts to tell them the time based on shadows in other photos from the same set. Thanks, in advance, for ideas. I'm also interested more generally in the issue of learning techniques of forensic digital photography and Photoshop. P.S. I'm doing some reading on channels and wondering if this would help. [Attachment: DCP_00035.psd (24.41kb)] |
Posted on 12/10/04 09:27:28 AM |
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Steve Caplin
Administrator Posts: 7021 Reply |
Re: Forensic Photoshop?
Well, what an interesting puzzle! I've spent far too long on this, trying Embossing, Lighting Effects, Trace Contour and all kinds of bizarre stuff. None of it really helped. But here's my conclusion: The green channel shows the clearest definition of the clock, so I copied this to a new document. Enlarging it in steps of 110% produces slightly crisper results than just going for a big enlargement straight off, so I did this to bring it up to the size shown here. This seems to pretty clearly show the hands at the positions marked with the red overlay. But that could be either about 20 past 1, or about 10 past 4. I found a website that translates digital time into analog, and tried matching both times. While the first is a good fit, there's no way of adjusting the time on the second to make both hands point in the right direction. So the time, as far as I can tell, is 1.23 (can't tell if it's am or pm, though!). Anyone else found a better way of enhancing the image?  |
Posted on 12/10/04 12:24:38 PM |
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maiden
Golden Gif Gagster Posts: 471 Reply |
Re: Forensic Photoshop?
I'm not that sure of my conclusions but I make it 10 minutes to 4 
It's a very tricky one to determine as there is so much gray that I wasn't sure what was shadow & highlight and what was the hands of the clock. _________________ mad as a badger and twice as furry |
Posted on 18/10/04 02:23:42 AM |
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unspun™
Guest Reply |
Re: Forensic Photoshop?
Well, hmmm.... Since my own enhancements appeared to show that it was between 2:15 and 2:20, I guess the law firm is right in hiring experts to examine the shadows on some of the outdoor photos that were done in the same sequence. 
With three of us coming up with different answers, this wouldn't be reliable enough for a courtroom. Still, it has piqued my interest in doing digital forensics using Photoshop! (And I'm still open for good resources on that, if anyone knows any.) |
Posted on 18/10/04 08:02:57 AM |
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maiden
Golden Gif Gagster Posts: 471 Reply |
Re: Forensic Photoshop?
I've not heard of a Photoshop forensic science book but a good book regarding the restoration of blurry/old/ripped photos is: Photoshop Restoration & Retouching by Katrin Eismann www.quepublishing.com ISBN 0-7897-2318-2 All in all there is very little that can determined from the photograph you posted as there just isn't enough information in the picture to determine objects like clock hands from shadow and highlights. We could all be completely wrong but I think Steve's is probably the nearest given the limited information derived from the picture. Is the photograph on film or is it digital? As film forensics can determine the amount of light exposured to each grain of silver halide using traditional forensics, giving a much more positive appraisal of the clock's time. _________________ mad as a badger and twice as furry |
Posted on 27/03/05 06:58:26 AM |
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Einstein D Kid
Teen Trickster Posts: 281 Reply  |
Re: Forensic Photoshop?
so what did they decide I downloaded and seems to me like what steve is saying is probly right _________________ Don't judge a man till youve walked a mile in his shoes, (that way, when you judge him, he'll be a mile away, and barefoot) |