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No! Image degradation is not ok.

Thanks go to George Reis of Imaging Forensics for highlighting this matter in his blog. I was prompted to put finger to keyboard upon reading his post because just last week I was banging on about this very subject in my presentation to the Association of Security Consultants in London at their Business Club meeting. If you’ll permit me to blow my own trumpet for a moment, I was genuinely, pleasantly, astounded at how many of the audience came up to me afterwards to say how much they were glad to hear someone speak up with the truth of the situation. They tell me it is very rare.

I was calling for users (and suppliers) of digital video recording systems to deliberately set up their machines for ‘Forensic Fidelity’ if there is any chance that their footage will be used in a forensic investigation. Might their recordings be used to identify an assailant or a murderer? Or might it even exonerate an innocent person? Put yourself in the shoes of the latter. Would you want to be that person relying for your liberty on a disgracefully unclear video that comes from your CCTV system or, if you’re a supplier, the CCTV of one of your customers?

Ask a forensic investigator like George how often his efforts to glean vital details from security video are thwarted by a lack of clarity brought on by excessive image degradation owing to digital compression. More and more often, I’ll wager. Manufacturers, installers and end-users are, in the vast majority of cases, far too ready to cut corners for economic reasons. They compress data far too heavily in order to save on storage capacity which costs money. Probably no independent CCTV consultant worth his salt has been asked to check that all is up to scratch for the task in hand. Big mistake. Again, the salesman’s smoke, mirrors, and head-in-the-sand view of his product’s inadequacies will rule the day and the reputation of CCTV advances one more inch around the U-bend.

The magazine article that George refers to is touting the apparent virtues of H.264 video compression and says “In surveillance, you can compress it without [worrying about] distortion of the image. Say you store the images of a parking garage overnight. If there’s a bit of distortion in the image, it’s not a problem.”

What? What?! Look at the opening paragraphs of this post and you’ll understand my exclamation and shock. It is a problem. Often a very serious one. Don’t shrug it off so glibly.

Later in the article: “They might say, ‘I want to keep very high quality 2 megapixels per second.’ That’s low for broadcast, but good for surveillance. You don’t see the degradation.”

At risk of seeming to repeat myself… What? What?!
No, sir, it’s not good for surveillance where you will see the degradation in a great many situations. You, sir, and the rest of the CCTV industry, should stop telling people such things. It’s tosh that sets the bar so low that when I ask suppliers to give us a reasonable ‘forensic fidelity’ at 4 or 6 or even 8Mbps they look at me like I’m barmy. No, penny pinching  and a lack of appreciation of the vital realities are the only barmy elements in this common situation.

This industry needs to wake up and realise what a huge disservice it is doing the owners of CCTV, the police who hope to use it as evidence, the forensic investigators who struggle to glean the information they want, and the people in the CCTV pictures who either deserve to be locked up or set free so that justice is properly served. Image distortion is a problem.

More on H.264 and on snake oil salesmen another day.

Until next time; stay focused.

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