Rely on DVR for Alarm Motion Detection?

[ckinninger 0]

Hello,

 

I've done a couple systems in my past. I'm more of a custom A/V designer installer.

 

I have a office building wired with 16 points for cameras and motion sensors.

 

My question is... How reliable are CCTV DVR's for detecting motion and relaying to the alarm?

 

I could put a camera AND motion detector at each location but it seems a little repetitive.

 

Thanks a lot.

 

CK

[mario 0]

This past Monday, we were asked to review footage from DVR system we installed to see if we could help authorities with identifying perp from residential burglary across the street.

The one camera that was set to record on motion, did captures several vehicles driving on the street, it even recorded the homeowner backing out of his driveway at night (0555), but failed to capture the whole sequence of perp driving into same driveway (as H.O. that left that AM), the perps walking out of the car (OK, that was small motion to detect), and 4 minutes later, car pulling out of driveway and driving away.

Another camera (very bad angle and point of view) that was set to record continually during day hours caught the whole thing (obviously) but couldn't get any detail.

We've since increased the motion sensitivity of the DVR, but won't relay on it as an alarm detection point.

 

Mario

[thewireguys 3]

Well the reliability of the camera based motion detection will only be good if you have constant light levels..... other wise you will have false alarms. If you only want the system to record when there is a person there I would use PIR's they are a lot more reliable. You could tie the PIRs into the DVR and alarm panel and have a great system.

[scorpion 0]

Motion Detection is used for $800 80GB hard drives.

 

The prices have come down on the hard drives, and the hard drive sizes have increased dramatically.

 

I would recommend recording 24/7. If the DVR can do a dual record then I would recommend motion detection as well.

 

If something happens in the night then you will not have to watch from midight to 6 am to see when it happened. The motion detection will give you a "time stamp" of when it happened. This will make your "search" a little easier (including the false positives).

 

 

As for motion detectors:

I would only use them if I wanted a specific trigger responce. Walking through a "zone", or a doorway is a good way to get a facial shot. You have a narrow space, and you have them looking towards a camera.

 

I would agree having a bunch of motion detectors would be a pain, but then you would have less "false positives" compared to using the DVR motion detection.

 

If you are connecting to an alarm system then you will want to use motion detectors, and not the DVR as the false alarm fees may be prohibitive.

 

If you have doors, then can you use contact switches?

 

What do you all think?

[Soundy 1]

Motion Detection is used for $800 80GB hard drives.

 

The prices have come down on the hard drives, and the hard drive sizes have increased dramatically.

 

I would recommend recording 24/7.

 

Good in some instances... depends on how many cameras you have and how much stuff you want to save. Drives are cheap on their own, but once you get into needing five or six 1.5TB drives, you have to start factoring in the cost of enclosures and/or controllers for them as well.

 

If the DVR can do a dual record then I would recommend motion detection as well.

 

If something happens in the night then you will not have to watch from midight to 6 am to see when it happened. The motion detection will give you a "time stamp" of when it happened. This will make your "search" a little easier (including the false positives).

 

Some can also record at a slow speed on a constant basis, then kick to higher framerate, resolution and quality settings when motion is detected.

 

If you are connecting to an alarm system then you will want to use motion detectors, and not the DVR as the false alarm fees may be prohibitive.

 

Well the reliability of the camera based motion detection will only be good if you have constant light levels.....

 

We do have software-triggered monitored alarms on one site... the alarms are triggered by video analytics software (much more advanced that just basic motion detection), and the cameras are FLIR thermal cameras, which are unaffected by varying light levels.

 

Of course, that's not a CHEAP option - I think the FLIR/VA system alone ran around $80k for the hardware... installation to a 50' tower in the middle of a two-square-block storage yard not included.

[ckinninger 0]

Hello All,

 

All your replies were helpful. I don't remember the last time I got a question answered so well on a forum. I guess my question was on the weak side (not very debatable).

 

I need alarm motion detectors. I also got out of the replies that I could wire the alarm detectors to signal the DVR to step up resolution on a particular camera(s).

 

We do have software-triggered monitored alarms on one site... the alarms are triggered by video analytics software (much more advanced that just basic motion detection), and the cameras are FLIR thermal cameras, which are unaffected by varying light levels.

 

I fully respect the quality and reliability level of a system like this. thewireguys touched on the constant light levels and since the thermal cameras don't use light you're both saying the same thing. I guess if an installer put in artificial light and wrote more than one alogarithm for the software detection of the camera it might work in a simliar way as a thermal system. But nowhere near as well.

 

Thanks a lot for all your help.

 

CK

[Soundy 1]

Hello All,

 

All your replies were helpful. I don't remember the last time I got a question answered so well on a forum. I guess my question was on the weak side (not very debatable).

 

I need alarm motion detectors. I also got out of the replies that I could wire the alarm detectors to signal the DVR to step up resolution on a particular camera(s).

 

We do have software-triggered monitored alarms on one site... the alarms are triggered by video analytics software (much more advanced that just basic motion detection), and the cameras are FLIR thermal cameras, which are unaffected by varying light levels.

 

I fully respect the quality and reliability level of a system like this. thewireguys touched on the constant light levels and since the thermal cameras don't use light you're both saying the same thing. I guess if an installer put in artificial light and wrote more than one alogarithm for the software detection of the camera it might work in a simliar way as a thermal system. But nowhere near as well.

 

Thanks a lot for all your help.

 

CK

 

Actually, the main factor in our system's reliability is the video analytics. Standard motion detection just looks for short-term (within a couple seconds) changes in the image - shadows moving with the sun and lighting changes from day to night won't trigger it, it's just sampling and comparing pixels for variations within a span of maybe 10-100ms.

 

What the analytics does, is look for SPECIFIC movements. For example, "tripwire" is a common, very basic detection type for most kinds of analytics: watch for an object crossing a line that the user defines. This is often refined by watching for movement in a specific direction, or crossing one line and then another. The system can also be programmed to recognize types of objects based on their size - say, to differentiate between a person, a car, or an animal. You can then combine these to, for example, trigger an alarm if a person or car crosses a fenceline, but not if an animal does it. Or you could have to trigger if a car enters a fenced area, but not if it's leaving the area, and not if a person enters or exits.

 

A lot of that ability has to be defined by the user: for example, you'll draw boxes on an image to show the system what size a person is, what size a car is, etc. Doing this at the "front" and "back" of the scene will let it know the perspective it's dealing with, so it can interpolate the sizes of those objects at points in between. It can take a good deal of time to fully set up the system for a detailed level of "intelligence".

[thewireguys 3]

Hello All,

 

All your replies were helpful. I don't remember the last time I got a question answered so well on a forum. I guess my question was on the weak side (not very debatable).

 

I need alarm motion detectors. I also got out of the replies that I could wire the alarm detectors to signal the DVR to step up resolution on a particular camera(s).

 

We do have software-triggered monitored alarms on one site... the alarms are triggered by video analytics software (much more advanced that just basic motion detection), and the cameras are FLIR thermal cameras, which are unaffected by varying light levels.

 

I fully respect the quality and reliability level of a system like this. thewireguys touched on the constant light levels and since the thermal cameras don't use light you're both saying the same thing. I guess if an installer put in artificial light and wrote more than one alogarithm for the software detection of the camera it might work in a simliar way as a thermal system. But nowhere near as well.

 

Thanks a lot for all your help.

 

CK

 

Actually, the main factor in our system's reliability is the video analytics. Standard motion detection just looks for short-term (within a couple seconds) changes in the image - shadows moving with the sun and lighting changes from day to night won't trigger it, it's just sampling and comparing pixels for variations within a span of maybe 10-100ms.

 

What the analytics does, is look for SPECIFIC movements. For example, "tripwire" is a common, very basic detection type for most kinds of analytics: watch for an object crossing a line that the user defines. This is often refined by watching for movement in a specific direction, or crossing one line and then another. The system can also be programmed to recognize types of objects based on their size - say, to differentiate between a person, a car, or an animal. You can then combine these to, for example, trigger an alarm if a person or car crosses a fenceline, but not if an animal does it. Or you could have to trigger if a car enters a fenced area, but not if it's leaving the area, and not if a person enters or exits.

 

A lot of that ability has to be defined by the user: for example, you'll draw boxes on an image to show the system what size a person is, what size a car is, etc. Doing this at the "front" and "back" of the scene will let it know the perspective it's dealing with, so it can interpolate the sizes of those objects at points in between. It can take a good deal of time to fully set up the system for a detailed level of "intelligence".

 

Pixel based motion detection is very basic. With most Cameras/DVRs you you set it up by selecting a part of the image and then you set the percentage of pixels that have to change to trigger the event. It doesn't care what changed the pixels so the reliability is based of the constant lighting levels. You can set it up perfectly for day time then you check it at night all the noise in the image will trigger then event. To get it setup properly at night you tweak the settings to work properly and you then miss some events during the day which can lead to unhappy customers.

 

ipConfigure does there motion detection differently they setup a tic-tac-toe grid of trip wires..... They have the best non-analytic motion detection I have seen.

 

But Analytics are where its at once the system is setup properly it is a very powerful security system. Camera's need to be installed at proper angles and locations then as Soundy described you have to setup the Analytic your running.

[thewireguys 3]

Motion Detection is used for $800 80GB hard drives.

 

The prices have come down on the hard drives, and the hard drive sizes have increased dramatically.

 

I would recommend recording 24/7. If the DVR can do a dual record then I would recommend motion detection as well.

 

If something happens in the night then you will not have to watch from midight to 6 am to see when it happened. The motion detection will give you a "time stamp" of when it happened. This will make your "search" a little easier (including the false positives).

 

 

As for motion detectors:

I would only use them if I wanted a specific trigger responce. Walking through a "zone", or a doorway is a good way to get a facial shot. You have a narrow space, and you have them looking towards a camera.

 

I would agree having a bunch of motion detectors would be a pain, but then you would have less "false positives" compared to using the DVR motion detection.

 

If you are connecting to an alarm system then you will want to use motion detectors, and not the DVR as the false alarm fees may be prohibitive.

 

If you have doors, then can you use contact switches?

 

What do you all think?

 

you could get really creative with this....

 

http://www.linearcorp.com/product_detail.php?productId=1024

[hardwired 0]

Had a dozen of these at a high end home calling presets on Pelco Spectra's through a Pelco 6700 matrix... trick stuff, at the time...

 

http://www.optexamerica.com/productpage.aspx?l1=2&l2=&id=38

 

The batteries will last 2+ years, with Lithiums....

[scorpion 0]

 

 

you could get really creative with this....

 

http://www.linearcorp.com/product_detail.php?productId=1024

 

 

I guess I will not embarass myself with Active Home Pro, and this;

http://www.x10.com/products/x10_ms14a.htm

 

LOL!

[Neutech 0]

Use Redwalls or Optex external Pir's connected to DVR

 

I wouldnt rely on just MD on a DVR

 

makes for a good system

[cglaeser 0]

Use Redwalls or Optex external Pir's connected to DVR

 

Crow PIR is another excellent choice. Optex can be wireless. Crow is typically wired, but alarm signal could be wireless.

 

Best,

Christopher

[hardwired 0]

Protech Piramid sensors http://www.protechusa.com/products.htm are a dual-tech microwave/ PIR sensor that work really well for false alarm rejection, I used about ten of them in combination with cameras for a remote guard tour/ monitoring setup at an industrial park, they had almost no false alarms with them.

 

They also have a model with a camera in the same housing, I haven't tried that one yet, though.

 

Not cheap, but you get what you pay for with them.. I've noticed them around our local National Guard base, too...

[rory 0]

I would not rely on video motion detection for a burglar alarm system. It is good to save on hard drive space and assist in locating events, for the CCTV system, but I would suggest installing motion detectors, or beams, for the alarm system. Ive used Optex for beams, and others for motions, such as Rokonet.

[Soundy 1]

I would not rely on video motion detection for a burglar alarm system.

 

That's what it really comes down to - basic motion detection 99.9% of the time is too unreliable for an alarm system, usually because false positives are way too common. A bush or tree moving in the wind can trip it, or an animal, the glare of passing headlights... lines of electrical noise... even the shifting of color artifacts when a day/night camera goes to B&W mode can cause constant tripping of the motion detection.