Convert Lux to V/lux-sec ?

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ucanthide
Posts: 66
Joined: 16 May 2015, 22:36
Location: London

Convert Lux to V/lux-sec ?

Postby ucanthide » 20 May 2015, 10:30

Does anybody know how to convert Lux to volts/lux-second, and vice versa?

Thanks

Daniel

phoenix
BRUCE ALMIGHTY
Posts: 4550
Joined: 09 May 2012, 14:40
Location: Aberdeen

Re: Convert Lux to V/lux-sec ?

Postby phoenix » 20 May 2015, 11:43

Daniel,
There's no way to convert lux to volts/lux-second
Lux is measure of visible light INTENSITY
Volts per lux-second is the VOLTAGE produced by a sensor when exposed to light of a given intensity for 1 second.
Sony specify the sensitivity of their ccd and CMOS sensors in millivolts when exposed to a halogen light source of a given intensity.
However they don't specify how much of that light actually falls on the sensor and they also have an IR filter and a f5.6 lens between the light source and the sensor.
Brigates specify the "responsivity" of their sensor in volts/lux-second (Which IMHO is a better way of doing it) but don't provide details of how they actually make the measurement.
Without a lot more detail from the manufacturers (and I doubt they will supply it) then, at present, I don't think there is a way to make comparisons of sensor sensitivity using published data
Only side by side comparison of real cameras gives a true impression of which camera is more sensitive.

Cheers

Bruce
LAND ROVER - THE WORLD'S WORST 4X4 BY FAR

ucanthide
Posts: 66
Joined: 16 May 2015, 22:36
Location: London

Re: Convert Lux to V/lux-sec ?

Postby ucanthide » 20 May 2015, 12:50

Bruce

yes this makes sense, makes a mockery of the 'information' they publish on their products really. As you say, the only was is a comparison for real, and this forum, youtube etc.

but based on the information, you think that the higher the V/lux-sec the more sensitive the chip?

Daniel

phoenix
BRUCE ALMIGHTY
Posts: 4550
Joined: 09 May 2012, 14:40
Location: Aberdeen

Re: Convert Lux to V/lux-sec ?

Postby phoenix » 20 May 2015, 13:24

Daniel,
The higher the volts per lux-second value, the more sensitive the sensor.
The only other way to compare cameras/sensors MIGHT be to compare their signal to noise ratios.
The Brigates sensor may be producing a big signal for the amount of light hitting it, but if the signal is noisy, then it won't be much good for NV purposes.
The BG0601 and BG0301 both claim signal to noise ratios of 48dB
The E700/EJ230 CAMERA claims a signal to noise ratio of greater than 50dB
The Watec 910HX (which is about the best camera out there) claims a signal to noise ratio of greater than 52dB
Even although the dB scale is logarithmic, 2dB is not much

Cheers

Bruce
LAND ROVER - THE WORLD'S WORST 4X4 BY FAR

ucanthide
Posts: 66
Joined: 16 May 2015, 22:36
Location: London

Re: Convert Lux to V/lux-sec ?

Postby ucanthide » 20 May 2015, 13:52

Bruce,

If we can buy the 13v/lux-sec 1/2'' CMOS sensor with a lux rating of 0.00008 and the S/N ratio is better than the Watec, plus it only costs £32 from the US or £55 in the UK, maybe it sounds a bit too good to be true? But there are about 7 videos on youtube that show it at night time, with both lenses, so we can get some idea of the performance.

https://www.youtube.com/watch?v=qfeg-9U8wLo
https://www.youtube.com/watch?v=9MVMVtRfhbY
https://www.youtube.com/watch?v=00MIMFxkXf4
https://www.youtube.com/watch?v=MPADiBXEA8Q
https://www.youtube.com/watch?v=jyOLOIll0Mc
https://www.youtube.com/watch?v=yUBHiYbfX_E

Plus, the images from the FPV drone footage wont be as good as for a static CCTV application, so Im optimistic it will be excellent for that purpose.

Daniel

ucanthide
Posts: 66
Joined: 16 May 2015, 22:36
Location: London

Re: Convert Lux to V/lux-sec ?

Postby ucanthide » 20 May 2015, 13:58


ucanthide
Posts: 66
Joined: 16 May 2015, 22:36
Location: London

Re: Convert Lux to V/lux-sec ?

Postby ucanthide » 20 May 2015, 20:35

Bruce,

Tell me what you think about the way this chap explains how camera sensitivity is/should be worked out:

http://www.mintron.com/htm/q&a/htm/mini ... %20lux.htm


Cheers,

Daniel

nealh
Posts: 279
Joined: 15 Oct 2013, 23:50
Location: Monroe, Louisiana

Re: Convert Lux to V/lux-sec ?

Postby nealh » 20 May 2015, 22:25

ucanthide wrote:Bruce,

If we can buy the 13v/lux-sec 1/2'' CMOS sensor with a lux rating of 0.00008 and the S/N ratio is better than the Watec, plus it only costs £32 from the US or £55 in the UK, maybe it sounds a bit too good to be true? But there are about 7 videos on youtube that show it at night time, with both lenses, so we can get some idea of the performance.

https://www.youtube.com/watch?v=qfeg-9U8wLo
https://www.youtube.com/watch?v=9MVMVtRfhbY
https://www.youtube.com/watch?v=00MIMFxkXf4
https://www.youtube.com/watch?v=MPADiBXEA8Q
https://www.youtube.com/watch?v=jyOLOIll0Mc
https://www.youtube.com/watch?v=yUBHiYbfX_E

Plus, the images from the FPV drone footage wont be as good as for a static CCTV application, so Im optimistic it will be excellent for that purpose.

Daniel

Where in the U S . I'll have a run at it.
I love this country; it's the damn government I'm afraid of!

ucanthide
Posts: 66
Joined: 16 May 2015, 22:36
Location: London

Re: Convert Lux to V/lux-sec ?

Postby ucanthide » 20 May 2015, 22:38

This is the US company, SurveilZone:

http://www.surveilzone.com/0.00008lux-s ... era-cc1564

it works out at £32, but I don't know what postage is or if you might have to pay import duties, VAT etc.

The UK company selling the same camera is tecnic:

http://www.tecnic.co.uk/Ultra-Low-Light ... 00tvl.html

works out at £55.

If you get one I'd be really interested in seeing some videos etc, because when I have the spare cash Im going to buy one.

Daniel

Tommynho
Posts: 1
Joined: 13 Feb 2018, 14:38
Location: Czech Republic

Re: Convert Lux to V/lux-sec ?

Postby Tommynho » 13 Feb 2018, 14:51

Hello,

Does anybody know, if is it possible recalculate responsivity of image sensor from V/lux*s to e-/lux*s and vice versa?

I would like to know is it better sensor with responsibility 5.48 V/lux−sec or 59 ke−/lux·s

Best Regards, Tomas.


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