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bike theft news
On Wed, 21 Jun 2017 09:59:16 -0000 (UTC), Duane
wrote: You can have glass break sensors turn the lights on. Yep, that would work nicely. I had a paragraph written on alternative methods and their complications, but decided to remove it to keep my rant from becoming too complicated. In most cases, a sensor would be redundant because the regular burglar alarm would also have a glass breakage sensor that turns on some lights, so that the police don't need to grope in the dark trying to find where in the store the burglar is hiding, and so that the store with the break-in is easier to identify from the street. However, using a glass breakage sensor to turn on some lights does not do anything for the long time it takes for a DVD to switch from b&w low light, to bright store lights. Notice that I said "some" lights. The problem is that most stores do not have a centralized method of turning on *ALL* the lights. When the alarm is triggered, it usually turns on one small light, often in the wrong location. To make this idea work, all the lights would need to be centrally controlled, which is possible, but currently uncommon. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#12
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bike theft news
On 21/06/2017 7:57 AM, Jeff Liebermann wrote:
On Wed, 21 Jun 2017 09:59:16 -0000 (UTC), Duane wrote: You can have glass break sensors turn the lights on. Yep, that would work nicely. I had a paragraph written on alternative methods and their complications, but decided to remove it to keep my rant from becoming too complicated. In most cases, a sensor would be redundant because the regular burglar alarm would also have a glass breakage sensor that turns on some lights, so that the police don't need to grope in the dark trying to find where in the store the burglar is hiding, and so that the store with the break-in is easier to identify from the street. However, using a glass breakage sensor to turn on some lights does not do anything for the long time it takes for a DVD to switch from b&w low light, to bright store lights. Notice that I said "some" lights. The problem is that most stores do not have a centralized method of turning on *ALL* the lights. When the alarm is triggered, it usually turns on one small light, often in the wrong location. To make this idea work, all the lights would need to be centrally controlled, which is possible, but currently uncommon. I've done security systems where this is the case. You don't actually need all of the store lights on when that isn't practical. You can set up some strategically placed flood lights. Certainly not brain surgery to set up lighting to cover a camera's scope. |
#13
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bike theft news
On 6/21/2017 7:42 AM, Jeff Liebermann wrote:
On Wed, 21 Jun 2017 00:11:12 -0400, Frank Krygowski wrote: On 6/20/2017 10:49 PM, Jeff Liebermann wrote: On Tue, 20 Jun 2017 11:27:27 -0400, Frank Krygowski wrote: Motion-activated lights indoors would make that surveillance camera a lot more useful! Not really. The problem with aiming a motion activated surveillance camera through a window is that everyone that passes by sets off the motion detector. What I had in mind was a motion detector controlling a light, not (necessarily) controlling the camera. Ummm... if the shop is dark, how is the camera going to see the burglar so that the motion detector will work? I'll try again: My side porch light is controlled by a motion detector. If it's dark outside and we walk up to the porch, the porch light comes on automatically. I've also got a light in my basement workshop that's controlled by a motion detector. If I walk into my dark workshop carrying something heavy in both arms, I don't have to flick the light switch. The light comes on automatically. I'm proposing putting that system into the bike shop, controlling a floodlight pointed the same direction as the camera. That way, the camera should be filming an illuminated subject, not one in shadows. It costs about $20 to try it. -- - Frank Krygowski |
#14
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bike theft news
On 2017-06-21 08:15, Frank Krygowski wrote:
On 6/21/2017 7:42 AM, Jeff Liebermann wrote: On Wed, 21 Jun 2017 00:11:12 -0400, Frank Krygowski wrote: On 6/20/2017 10:49 PM, Jeff Liebermann wrote: On Tue, 20 Jun 2017 11:27:27 -0400, Frank Krygowski wrote: Motion-activated lights indoors would make that surveillance camera a lot more useful! Not really. The problem with aiming a motion activated surveillance camera through a window is that everyone that passes by sets off the motion detector. Very easily solvable. What I had in mind was a motion detector controlling a light, not (necessarily) controlling the camera. Ummm... if the shop is dark, how is the camera going to see the burglar so that the motion detector will work? - LED lighting. I'll try again: My side porch light is controlled by a motion detector. If it's dark outside and we walk up to the porch, the porch light comes on automatically. I've also got a light in my basement workshop that's controlled by a motion detector. If I walk into my dark workshop carrying something heavy in both arms, I don't have to flick the light switch. The light comes on automatically. I'm proposing putting that system into the bike shop, controlling a floodlight pointed the same direction as the camera. That way, the camera should be filming an illuminated subject, not one in shadows. It costs about $20 to try it. That can be annoying because it can trip every time someone comes walking by too close to that window. There are much better alternatives such as glass break sensors. Or an invisible IR beam like garage doors have. The solutions here are simple. It just seems that the folks in the industry serving this market aren't always the smartest ones. All most do is market same-old same-old. -- Regards, Joerg http://www.analogconsultants.com/ |
#15
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bike theft news
On Tuesday, June 20, 2017 at 7:49:12 PM UTC-7, Jeff Liebermann wrote:
On Tue, 20 Jun 2017 11:27:27 -0400, Frank Krygowski wrote: Motion-activated lights indoors would make that surveillance camera a lot more useful! Not really. The problem with aiming a motion activated surveillance camera through a window is that everyone that passes by sets off the motion detector. The better DVR (digital video recorders) have programmable zones. The viewing area is chopped into small rectangular zones, each of which can be set to detect motion or ignore motion. This helps, but is far from perfect. Something like this: http://surveillance.aver.com/Images/Shared/IMD%20revised.jpg where only the door areas detect motion. The big problem with camera placement is the field of view usually ends up many times wider than a person's head. My guess(tm) is the camera field of view at the window was probably 20 times the width of a person's head. If the camera was a better quality 1920x1080, the persons head would be only: 1920 / 20 = 96 pixels wide. Try to identify someone from a photo where the person's face is only 96 pixels across. Here's me at 660 pixels across: http://802.11junk.com/jeffl/pics/jeffl/slides/jeffl-07.html and at 96 pixels across, expanded to the same image size: http://802.11junk.com/jeffl/pics/jeffl/jeffl-07-96.jpg 96 pixels across actually looks fairly good, but only under ideal conditions. Add to that the distortion caused by positioning the camera at about 45 degrees downtilt near the ceiling, marginal night time lighting, and a possible disguise. Also, the same camera would easily produce a recognizable face photo if the field of view was reduced to perhaps 5 times the width of a person's head, but then the field of view at the front window would be too small to be useful and require multiple cameras to cover the entire window. Incidentally, my favorite mistake is to put cameras on the ceiling, which usually produce great a video of the top of the burglars head, hat, or hoodie. There's also the problem that often in order get longer recording time they will reduce the dots/inch. |
#17
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bike theft news
On Thursday, June 22, 2017 at 12:37:13 PM UTC-7, Joerg wrote:
On 2017-06-21 13:30, wrote: On Tuesday, June 20, 2017 at 7:49:12 PM UTC-7, Jeff Liebermann wrote: On Tue, 20 Jun 2017 11:27:27 -0400, Frank Krygowski wrote: Motion-activated lights indoors would make that surveillance camera a lot more useful! Not really. The problem with aiming a motion activated surveillance camera through a window is that everyone that passes by sets off the motion detector. The better DVR (digital video recorders) have programmable zones. The viewing area is chopped into small rectangular zones, each of which can be set to detect motion or ignore motion. This helps, but is far from perfect. Something like this: http://surveillance.aver.com/Images/Shared/IMD%20revised.jpg where only the door areas detect motion. The big problem with camera placement is the field of view usually ends up many times wider than a person's head. My guess(tm) is the camera field of view at the window was probably 20 times the width of a person's head. If the camera was a better quality 1920x1080, the persons head would be only: 1920 / 20 = 96 pixels wide. Try to identify someone from a photo where the person's face is only 96 pixels across. Here's me at 660 pixels across: http://802.11junk.com/jeffl/pics/jeffl/slides/jeffl-07.html and at 96 pixels across, expanded to the same image size: http://802.11junk.com/jeffl/pics/jeffl/jeffl-07-96.jpg 96 pixels across actually looks fairly good, but only under ideal conditions. Add to that the distortion caused by positioning the camera at about 45 degrees downtilt near the ceiling, marginal night time lighting, and a possible disguise. Also, the same camera would easily produce a recognizable face photo if the field of view was reduced to perhaps 5 times the width of a person's head, but then the field of view at the front window would be too small to be useful and require multiple cameras to cover the entire window. Incidentally, my favorite mistake is to put cameras on the ceiling, which usually produce great a video of the top of the burglars head, hat, or hoodie. There's also the problem that often in order get longer recording time they will reduce the dots/inch. Why? You just record round-robin and when the glass brake sensor triggers you make sure that things are no longer over-written _and_ are immediately being transferred offsite via Internet. In case the perps find the stack of DVRs and rip them out. In this day and age you could record a whole week in hi-def. Our DVR in the living room can record over 100 full-length movies in hi-def. Enough for watching Westerns all week with zero sleep. Firstly - most of these burglar alarm cameras are totally enclosed and even usually wireless. So they record internally on what would be a thumb drive I suppose. In order to get the longest period before over-writing occurs they will both reduce the frames per second and the definition of the picture. Remember that transmitting these pictures (when you may have 5 or 10 cameras) is resource limited and you want as much self containment as possible. Battery life is also a consideration. |
#18
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bike theft news
On 2017-06-22 13:41, wrote:
On Thursday, June 22, 2017 at 12:37:13 PM UTC-7, Joerg wrote: On 2017-06-21 13:30, wrote: On Tuesday, June 20, 2017 at 7:49:12 PM UTC-7, Jeff Liebermann wrote: On Tue, 20 Jun 2017 11:27:27 -0400, Frank Krygowski wrote: Motion-activated lights indoors would make that surveillance camera a lot more useful! Not really. The problem with aiming a motion activated surveillance camera through a window is that everyone that passes by sets off the motion detector. The better DVR (digital video recorders) have programmable zones. The viewing area is chopped into small rectangular zones, each of which can be set to detect motion or ignore motion. This helps, but is far from perfect. Something like this: http://surveillance.aver.com/Images/Shared/IMD%20revised.jpg where only the door areas detect motion. The big problem with camera placement is the field of view usually ends up many times wider than a person's head. My guess(tm) is the camera field of view at the window was probably 20 times the width of a person's head. If the camera was a better quality 1920x1080, the persons head would be only: 1920 / 20 = 96 pixels wide. Try to identify someone from a photo where the person's face is only 96 pixels across. Here's me at 660 pixels across: http://802.11junk.com/jeffl/pics/jeffl/slides/jeffl-07.html and at 96 pixels across, expanded to the same image size: http://802.11junk.com/jeffl/pics/jeffl/jeffl-07-96.jpg 96 pixels across actually looks fairly good, but only under ideal conditions. Add to that the distortion caused by positioning the camera at about 45 degrees downtilt near the ceiling, marginal night time lighting, and a possible disguise. Also, the same camera would easily produce a recognizable face photo if the field of view was reduced to perhaps 5 times the width of a person's head, but then the field of view at the front window would be too small to be useful and require multiple cameras to cover the entire window. Incidentally, my favorite mistake is to put cameras on the ceiling, which usually produce great a video of the top of the burglars head, hat, or hoodie. There's also the problem that often in order get longer recording time they will reduce the dots/inch. Why? You just record round-robin and when the glass brake sensor triggers you make sure that things are no longer over-written _and_ are immediately being transferred offsite via Internet. In case the perps find the stack of DVRs and rip them out. In this day and age you could record a whole week in hi-def. Our DVR in the living room can record over 100 full-length movies in hi-def. Enough for watching Westerns all week with zero sleep. Firstly - most of these burglar alarm cameras are totally enclosed and even usually wireless. So they record internally on what would be a thumb drive I suppose. That would be the first big mistake of the alarm company or store owner. All it takes is one serious whack with a basseball bat or a well aimed shot from the 22 and the evidence is toast. In order to get the longest period before over-writing occurs they will both reduce the frames per second and the definition of the picture. Remember that transmitting these pictures (when you may have 5 or 10 cameras) is resource limited and you want as much self containment as possible. Battery life is also a consideration. Wireless? Battery? That sounds like one of those $499 specials with half a dozen cameras and lots of marketing fluff. A proper system must be installed with wires and functionally tied into other sensors such as the ones for breaking glass. Self-containment is not always a good thing for surveillance. You don't want to enable the perp to destroy evidence, either by brute force or by setting the store on fire. At that point the evidence must already be stored securely offsite or at least at a safe place in the building. That sometimes even catches those that are supposed to protect us. They thought they had ripped all the surveillance and recording equipment out but missed some: http://ktla.com/2015/06/11/video-of-...attorney-says/ -- Regards, Joerg http://www.analogconsultants.com/ |
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