On Sun, 1 Mar 2009 11:31:03 -0000, "nightjar" cpb@insert my surname
here.me.uk wrote:


"chili-girl" wrote in message
.. .
For a normal CCTV camera (that is linked to a PC capture card) and on
a fine sunny day.

Is there a typical distance you can read a number plate.

With one of the SafeCore CCTV 1/3" SONY Colour WDR & ICR(True
Day&Night) Camera (Hi-Res.) cameras 752x582 picture element, 520 lines
resolution, 0.1 Lux / F1.2 day, 0.001 Lux / F1.2 at night
with IR switching and with effective IR illumination.

Lens fitted is a 1/3" 3.5-8mm Vari-Focal Lens, DC drive auto iris
Apertu F1.4

1 - Is there a typical distance you can read a number plate.
2 - Would I then be able to read a number plape at say 25m.
3 - What would the picture be like at night with IR on, or are they
just too grainy
4 - Or are my problems only due to the PC capture card.

At the entrance to our industrial estate there are five CCTV cameras, set up
by a security company. Two colour cameras give short range pictures of the
gate, in opposite directions. Two colour cameras give long views of vehicles
approaching the gates. One high definition monochrome camera captures the
number plates of vehicles entering the estate - you don't need colour for
number plates and monochrome is capable of both higher definition and lower
light response. It is set about3m high and looks down at about 30 degrees.
Steel bollards guide the vehicles through the gateway, ensuring that the
number plates are in the field of view. At night, the area is lit by 2 x
150W high pressure sodium street lamps, as one did not provide enough light.

Have you considered the legal or ethical implications of this? I know
the "Big Brother" philosophy seems to have spread everywhere now and
spying is acceptable. But, I for one, don't agree.

Forgive me if I have got the wrong end of the stick here.

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