ZoneMinder Forums

I've read the "detect speed of object" posting of Nov 29, 2006. Speeding is a significant problem on my street, where many small children live. The police told me that my personal testimony must be supported by hard evidence. I would love to install a camera or two cameras in front of my house to catch the speeding drivers. I have two small kids of my own.

My house is located a short distance before a sharp curve. Speeding motorbikes or cars come fast and slow down significantly just in front of my house to safely enter the sharp bend.

I would envision two cameras. Camera A that would start recording whenever it detects incoming motion, camera B would photograph the car's/motorbike's nameplate as it slows down. Some postprocessing software would discard all recordings with non-speeding cars. That would be 95% of all recordings. The total number of cars passing through our street is probably 300-900.

I understand that ZoneMinder cannot do it out of the box. But is it feasible? It would be such an enormously useful thing and many people could use it to make residential places safer. It would certainly save lives.

i think it would be easier to have 2 zones on a single camera rather than 2 cams, you would need a cam seperate for reg capture and one for detection. Possible im sure, i was looking at it for industrial estates. You wouldnt be able to presecute on the strength of that alone, as it wouldnt be calibrated etc. But might be enough to get the person to plead guilty. But i have been done by numerous official (gatso) cams, not so sure i like the idea of having more of them about lol

milos wrote:But is it feasible?

Yes you could do this. Off the top of my head I think i'd do this.

Set up a monitor that covers the whole street. Split the road into zones. set each zone to be modetect. Turn STATS on.

Once an alarm occurs, read the database and extract the STATS for each frame for that alarm. The Stats will give a timestamp that the zone was triggered. If you know the distance between the zones (in real life, not pixels), then you can calculate the speed of the object by dividing the distance travelled by the time taken. Anything that is over your threshold (100mph??) generate a message/email with the event id.
The script would have to be knocked together from perl/mysql/shell and would exist outside of the Zoneminder scripts. you could even run it at 3am each day and process all new events since 3am the previous day.

Number plate recognition... not a clue I'm afraid.

As already said... it won't be admissible as evidence in court, and the police won't be interested in it either... however, you might choose to post up the number plates onto telegraph poles along the road showing the speed they were clocked at (your guestimate). It might shame them into slowing down!

jamescollings wrote:
Number plate recognition... not a clue I'm afraid.

As already said... it won't be admissible as evidence in court, and the police won't be interested in it either... however, you might choose to post up the number plates onto telegraph poles along the road showing the speed they were clocked at (your guestimate). It might shame them into slowing down!

Thank you for the plan. Sounds good. Although I would much rather use Python than Perl... but in this case I will have no choice. Or could I perhaps query the database and do the rest in Python?

As for numberplate recognition - I did not ask for that. It will be enough if a human can read the number.

It may be admissible in court. I am negotiating with my friend, a judge, to find a feasible solution.

I hate the booming surveillance as much as everyone else... but having motorbikes and cars speeding over 100 kilometres per hour in a residential area is just awful in my opinion.

Slightly offtopic: cheap USB camera looks better to me than a full-blown IP or WiFi enabled camera... but a USB-via-UTP extender would have to be used, because the Linux server is about 40 metres from the measuring point... it might be better to install a simple ITX-based diskless Linux box at the measuring point, connected to the server via UTP... the reason I would prefer USB is not price but the speed... standalone IP/WiFi cameras offer 640x480 at 15 fps max... while USB cameras offer 640x480 at 30 fps... am I wrong?

Depends on the IP cam, Axis will do 30 fps at 640x480

forget webcams mate... really

and i was meaning human number plate capture not full blown anpr. YOu need to get a good capture of a large plate, at a high shutter speed, at a high frame rate, 70mph would need 20fps i think. If you use std cams then the whole thing will be blurred at 1/50th