Camera Calibration?
Discussion
I run a calibration department and was wondering how speed cameras are calibrated. I have seen a few examples of calbration certificates on the net and as far as I'm concerned they are not worth the paper they're printed on!
1. The equipment used during the calibration (standards) are not listed.
2. No traceability of the standards used back to a National Standard (UKAS etc).
3. No mention of the procedure used.
Anybody have any knowledge on this?
1. The equipment used during the calibration (standards) are not listed.
2. No traceability of the standards used back to a National Standard (UKAS etc).
3. No mention of the procedure used.
Anybody have any knowledge on this?
The most important calibration must be the timing between flashes! And I believe that this has been called into question as they appear to be unreliable!?!?!?! If the timimg is off by about a 1/10th second it can mean a (deliberate) error of many mph!!! More cash for the cashcow Scumera Pratnershits!!!
exkoose moi spllelling.....
>> Edited by JMGS4 on Thursday 2nd March 08:30
exkoose moi spllelling.....
>> Edited by JMGS4 on Thursday 2nd March 08:30
dickymint said:
I run a calibration department and was wondering how speed cameras are calibrated. I have seen a few examples of calbration certificates on the net and as far as I'm concerned they are not worth the paper they're printed on!
1. The equipment used during the calibration (standards) are not listed.
2. No traceability of the standards used back to a National Standard (UKAS etc).
3. No mention of the procedure used.
Anybody have any knowledge on this?
If you are talking about the laser speedguns as well as cameras, I did a bit of research on this to see if the annual calibration for the LTI2020 was actually worth something in court to prove the device was working.
As far as I can see from the certificate I was shown it is checked annually by aiming the device at static objects 20,40,60,80 and 100 metres I believe on a tripod. The readings taken are the result of the gun reading the distance.
If it passes this, then there are obviously no problems using it handheld on moving objects at up to 1000 metres away.
(You can't see my tongue in my cheek, but I assure you it is there...)
Einion Yrth said:
I think you may all be missing the point a bit. The calibration methods and certificates have, in effect, only to be good enough to convince a non specialist magistrate that everything's kosher, and I could knock one up in 'Word' that would be good enough for that.
Further to that, it is more accurate to say it only has to be good enough for the Home Office Scientific Branch to state that the equipment is usable. Then there is no convincing needed in court as the CPS Solicitor merely through the police witness informs the court that the goverment say it works fine, and produce the document that says so.
Einion Yrth said:
I think you may all be missing the point a bit. The calibration methods and certificates have, in effect, only to be good enough to convince a non specialist magistrate that everything's kosher, and I could knock one up in 'Word' that would be good enough for that.
This is exactly why all equipment used in a calibration should be 10 x mores accurate than the unit under test and also not out of date themselves. These standards (including their serial numbers) should also have their own certificates.....and so on. Thus you have an unbroken chain of calibrations back to a National standard. This is traceability!
Also there should be "limits of uncertainty of measurement" calculated and shown on the results sheet.
Without this info IMHO it would be extremely easy to persuade a magistrate that things are not right.
Luckily I've never been done for speeding but would test this if/when I do.
These guys make the rules.........www.ukas.com/about_UKAS/default.asp
"The United Kingdom Accreditation Service is the sole national accreditation body recognised by government to assess, against internationally agreed standards, organisations that provide certification, testing, inspection and calibration services.
Accreditation by UKAS demonstrates the competence, impartiality and performance capability of these evaluators."
"The United Kingdom Accreditation Service is the sole national accreditation body recognised by government to assess, against internationally agreed standards, organisations that provide certification, testing, inspection and calibration services.
Accreditation by UKAS demonstrates the competence, impartiality and performance capability of these evaluators."
dickymint said:
I think you may all be missing the point a bit. The calibration methods and certificates have, in effect, only to be good enough to convince a non specialist magistrate that everything's kosher, and I could knock one up in 'Word' that would be good enough for that.
This is exactly why all equipment used in a calibration should be 10 x mores accurate than the unit under test and also not out of date themselves. These standards (including their serial numbers) should also have their own certificates.....and so on. Thus you have an unbroken chain of calibrations back to a National standard. This is traceability!
Also there should be "limits of uncertainty of measurement" calculated and shown on the results sheet.
Without this info IMHO it would be extremely easy to persuade a magistrate that things are not right.
Luckily I've never been done for speeding but would test this if/when I do.
Good luck mate, i have tried that already, and my barrister also tried this and failed.
Proving the system doesnt work is easy. Getting the magistrates/judge to see that the system is flawed is easy. However getting them to overrule the Home Office Scientific Branches opinion that the device works is nigh on impossible. You will have to find a magistrate with balls as big as beachballs to have the guts to say that in his lawful opinion the evidence he is seeing is better than the Home Offices. Further to that, the CPS would most likely not let it lie that and would appeal against the decision.
>> Edited by justinp1 on Thursday 2nd March 12:27
>> Edited by justinp1 on Thursday 2nd March 12:28
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