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rapid

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Posts posted by rapid

  3. Posted

    You might want to check-out this earlier post to answer your questions regarding continuity of evidence.

     

    http://www.cctvforum.com/viewtopic.php?t=4333&highlight=

     

    In working with police, they prefer standalone systems..and simple...that is a DVD recorder (some still use VHS)....good video and simultaneous audio. They also run seperate audiocassette recorder for transcripts. Most of the rooms have two cameras (wide shot & closeup picture in picture) plus time date generation.

     

    I can understand their reasoning....if you're 4 channel unit goes down...you've got problems.....plus how do you handle multiple interviews? What about copying?

     

    I used a Sanyo DSR-M814 for prison cells, and noted it has 4 seperate audio inputs...perhaps this will do the trick for you....it's MPEG2 and easy to operate.

     

    Some of the guys have had success with other recorders so I'll let them respond.

     

    Rapid

  5. Posted

    Welcome to the forum!

     

    Here you'll find a ton of info relating to the CCTV world.

     

    Don't be shy to ask a question, there is a lot of experience in this forum. If you're looking for an answer, you're sure to find it here and usually can get answers fairly quickly and from different experience levels.

     

    As they say, "there are many ways to skin a cat" LOL

     

    Rapid

  8. Posted

    Wireless is not a good idea, there can be lots of EMI/RFI noise such as elevator motors which will give you grief.

     

    Haven't done any elevator work, however using Unshielded Twisted Pair would work...should be a spare pair of wires (from emergency phone) and you could use a balun for the video.

     

    Might have to get the elevator service company involved if there are regulations in your area.

  9. Posted

    Don't know if this is near you, but

     

    http://www.boltandscrewsupply.com/

     

    look under "Pipe Management"

     

    Wish I had a picture of the install, but had a one foot strut channel installed vertically and fastened it with bolts to a ribbed barn. Then using the strut nuts, mounted a Pelco EM1450 wall mount for the EH3512 housing. Did the trick as the metal ribs in the shed made it difficult to mount the wall mount directly. The strut allowed a flat surface away from the ribs.

     

    mmmmmm........ribs!

     

    Do you have good ribs in Arkansas!

  10. Posted

    36498_1.pngI've used these Strut mounts on exactly similiar buildings. The Strut channel is fastened to the building. They come in 16-20 foot lengths, so cut what you need.

    strutfastener6mg.jpg

    The strut nuts are inserted in the channel and twisted 90 degrees...the spring keeps the nut from falling out. You can use these nuts to secure your camera bracket. As it is a channel you can adjust the nuts up or down to fit and will tighten nicely.

     

    If you haven't seen these before, you can purchase them from a fastener supplier....in Ontario, Canada we purchase them from company called Brafasco.

     

    Cheers.......Rapid

  11. Posted

    I'll comment on the camera suggestion......find something else for outdoors!

     

    This is a CMOS imaging device not like the CCD imagers we see in most cameras. Although there are advantages/disadvantages of these cameras uniformity (image quality) is far superior in CCD. Although the CMOS does offer a compact package and low power consumption, it will have a low image quality therefore not intended for low light applications.

     

    As well, the 3.7 mm lens indicates it's very slow (high F stop) 0.1 LUX @ F2.0.

     

    You might have a look at some of the other cameras such as

    www.specotech.com who might have a camera you're looking for.

     

    Cheers........Rapid

  13. Posted

    Yes, the video must be terminated only once.

     

    Loopthrus, nowadays, are self terminating....ie if you don't plug the other side in, then it terminates into 75 ohms. If you're using T-s...you must terminate the unused end. Not a big fan of T's as they are external to devices and could be subject to breakage.

     

    Double termination can happen resulting in a crushed picture and weak sync.

     

    Cheers.....Rapid

  14. Posted

    The Panasonic sens up will provide more IR light reaching the CCD.

     

    I would pick 10X. As you go up to 32x to get more light, it's a tradeoff as you're effectively slowing the frame rate....you'll see the camera frame rate decrease as the camera image slowly builds. Too much sens up will provide an unusable image as the IR light takes over.

     

    I do love the Sens Up feature for outdoor applications.

  16. Posted

    Heard similiar story, where the wife and friends set him up.

     

    Everyone has had a few drinks this evening. When the numbers are announced, the guy hears he has won and goes crazy and admits to his wife she isn't getting any of the winnings and demands a divorce. When friends start to calm him down, he admits sleeping with his sister-in-law!

     

    Not a good situation.

  17. Posted

    Chain of evidence would be most questioned. Seeing where the DVR is located, you might be challenged on why the DVR is secured here. Who would/could have access to this DVR? Is it password protected?

     

    I'm assuming you performed maintenance on this unit in last few weeks? months? Is the time and date correct? Anyone verify you went on-site to do this maintenance? If there was an alarm system on-site, can the alarm log be linked to the video....ie alarm back door (Cam 1) front (Cam 25)....

     

    Don't know this DVR, but they might want it (whole unit) as this is an original. Provide them a copy and log everything....who made the copy....date and time.

     

    These are some of the questions you may need to address (if you haven't already)

     

    Haven't seen the video...could you PM me.

     

    Cheers......Rapid

  20. Posted

    You've brought up an important point regarding optical aberration (distortion) as this is quite common with dome cameras. Camera view can be clear looking straight out and then distorted if adjusted at an angle.

     

    I prefer the box cameras as well, although my clients would like the discrete dome cameras. Nice thing about domes is you can't see what they are actually looking at whereas the box cameras you can. Box housings tend to displace the activity elsewhere.

     

    Other items for your list (or clarification)

     

    minimum scene illumination

    focal length

    fstop

    backlight compensation

    power consumption

    mounting to standard electrical box

    dome material - clear, smoked, again optical abberation.

     

    Cheers.....Rapid

  21. Posted

    First of all, welcome to the group!

     

    Don't know where you're from but there is good reading on interrogation/interview rooms at www.leva.org. Here you'll find Best Practices relating to video files and how they are to be processed in the event they are used in court.

     

    The Toshiba DVR's usually make use of the MJPEG compression engine. JPEG is "lossy," meaning that the decompressed image isn't quite the same as the one you started with, however you can vary the degree of lossiness by adjusting compression parameters. Key is to keep the compression file size the largest possible. As it is an interrogation room, you won't be recording 24/7 so keep the quality to a maximum. Toshiba does have a Proprietary MJPEG which may cause you some grief down the road.

     

    As far as the audio/video sync challenge, this might prove to be a problem. In working with forensics specialists, they recommended we install traditional VHS recorders (I know) and separate audiocassette recorders. We have started using DVD recorders which make use of MPEG2 compression engine which keeps audio/video in sync. Updating your AVI codecs might improve audio/video sync.

     

    Regarding digital signatures, most likely you won't be subpoenaed at some point as an expert witness. Toshiba would have to contacted as their compression is proprietary. There are forensic video analysts like Grant Fredericks who are recognized and can be called upon to verify the validity of a digital CCTV file. The law enforcement should have procedures in place regarding continuity of evidence and other aspects of interrogation, so digital signatures are not that important.

     

    AVI files would not be admissible in court as they are not the original file. They would be fine for defense or crown prosecutors to review, but there must be an original. We’re finding the police use the original recorder to playback the files. Can the Toshiba export to another medium? CD for example?

     

    Just a few things to consider.

     

    Rapid

  24. Posted

    Based on your budget and interference, I would rethink wired cameras.

     

    1. Wireless systems are expensive considering you would like three cameras thus 3 seperate video channel tx's and 3 video channel rx's. Wired cameras are more economical, easy to install and can be discrete.

     

    2. Power is always a concern for wireless systems, although you mentioned you had a plan for power. Wireless video but hardwired power?

     

    3. Video motion is not a good idea for wireless cameras. RF interference or fading in and out of video channels (no change in camera view) will trigger the video motion.

     

    4. Digital recording of wireless video can produce unusable video when you review, especially if you have RF interference.

     

    I'm not putting wireless video down, just identifying challenges you will have if you install a multiple camera wireless system.

     

    We've installed many high end wireless systems in various applications, however they can run in the $15K range. Videocomm has some 2.4 Ghz 4 channel systems you can look at.

     

    http://www.videocommtech.com/

     

    Cheers.....Rapid

  25. Posted

    Looks like you have a ground loop which generally causes these video "hum bars" where a light bar slowly drifts vertically through the picture. This is the 60Hz AC line.

     

    Somewhere you have a ground loop, possibly at the card. Try pulling all the cameras off and then one by one reattaching. You may find the culprit.

     

    You could also purchase a "hum bucker" or isolator for the troubled camera.

     

    Cheers....Rapid

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