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ipman

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Posts posted by ipman

  1. Posted

    Robert, it looks like the trick is in arecont "% Motion Detection Activity" parameter. On your arecont screenshot you have option "50% motion activity" selected. But in the IP Video Tool you have 100% recording.

     

    You can just specify "50%" recording activity and get almost the same result - BW: 33.9 MBit (32) HDD:2.5TB (2.4)

  2. Posted

    Looks nice software, downloaded, tried, looking good for lenses, but not so good for storage calculation and network bandwidth as its shows completely different numbers compared to Arecont Vision calculations.

     

    It would be an offtopic here, but I have made a test of BW calculation with Arecont and Axis calc:

     

    Bandwidth, MBit/s (2MegaPixel, 6 FPS, Parking Lot):

Compression                             | Arecont | JVSG 5.3  | AXIS
---------------------------------------------------------------------
Low Compression  (MJPG-10 HighQuality)  | 13      | 13.6      | 12
Medium Compression (MJPG-50 LowQuality) | 7       | 7.4       | 6.3
Hi Compression (MJPG-70 Poor Quality)   | 5       | 5.85      | 5.3

HDD storage space (30 days, 100% recording):

Compression                             | JVSG 5.3 | Arecont  | AXIS
---------------------------------------------------------------------
Low Compression  (MJPG-10 HighQuality)  | 4.3      | 4        | 3.6
Medium Compression (MJPG-50 LowQuality) | 2.4      | 2.4      | 1.9 
Hi Compression (MJPG-70 Poor Quality)   | 1.79     | 1.75     | 1.6

     

    I would say BW&HDD space estimations are surprisingly accurate

  3. Posted · Edited by Guest

    Well, Robert I am not agree.

    I would say the View Designer is too basic.

    It even calculates horizontal projection wrongly.

    Lets make a small test:

     

    Camera Installation Height = 6.5 m

    Sensor Size = 1/3"

    Lens focal length = 4 mm

    Distance = 10 m

    Object size = 1.8 m, like here

     

    Let's see horizontal projection in "IP Video System Design Tool 5.3", "Video Cad6" and "View Designer 1.0".

     

    Additionally imagine you put a 1.8m tall man at 4m distance from camera and 3.3m on the right (orange man - in JVSG at mouse cursor position).

     

     

    91753_1.jpg 91753_2.jpg

    91753_3.jpg

     

    As you can see man at (4m; 3.3m) is visible but View Designer shows the max right position at 4.5m/2 = 2.25 m. But it is not correct.

     

    Please download JVSG tool and compare results yourself.

  7. Posted · Edited by Guest

    The post above shows it is not easy to select lens.

     

    I recommend software utility ver. 5.3 from http://www.jvsg.com

    - you see what you get because of 3D-preview.

    - you have exact calulations of focal length, field of view, angles and other staff.

     

    It does make sense to have a look.

  10. Posted

    Tony, in my opinion you don't need vario lens, because of such short distance.

     

    For 18 ft and typical 1/4" IP camera you need lens with focal length not more than 4 mm.

     

    See picture for 3.3 mm lens bellow:

     

    85568_1.jpg

     

     

    I don't know what is the best camera height, so you can play yourself with paper calculator or lens calculation software.

     

    But, probably it is better to put camera on second floor.

  12. Posted

    required storage space=image size* frames per second * period of request

     

    my principal question is how i can calculating the image size?

    and how resolution and compression influences the image size?

    best regards

     

    Actually there is no formula for it, because the compression is not a linear process, but there are many software bandwidth calculators:

     

    http://www.google.com/search?hl=en&q=ip+camera+calculator&btnG=Google+Search

     

     

     

    Just enter your resolution, compression, FPS, number of cameras and get the result.

  14. Posted

    I was thinking since all the network traffic is local only maybe my external line has nothing to do with the system, and I just need my switch to be able to handle all this data, but not sure I'm right

     

     

    At first I would find a best FPS/compression/bandwith proportion for your cameras.

     

    You can do it with any IP camera calculator.

     

     

    Practical bandwith of 1Gbit LAN is about 500 mbits. So for 200 cameras you shold have a camera bandwith of 2.5 mbits. Than you can figure out your compression/FPS.

  18. Posted · Edited by Guest

     

    What I am trying to calculate in some semi-scientific way is the area of coverage for each of these cameras (between 60-80 when we are all done). I want to put them in the best place to catch the most "action."

     

    Is there some way based on the mounting height, etc. to determine the area of coverage for a camera.

     

    Sure you can google many different field of view calculators. Some of them go in 3D. If you have time can give a try to "CCTV Design Tool"

     

    See video tutorials

  22. Posted

    Curious, does it make much difference having a megapixel lens?

     

    Are the standard lenses that crap they cant work with a higher res ccd?

     

    Exactly. Like if you take AXIS 206M - 1 megapixel camera - the picture looks exactly the same as AXIS 206 640x480 if you just zoom in photoshop.

     

    It is not the only one example. Once I took the Mobotix M10 1MPix camera, that camera costs about 1000 EUR, and the picture was really the same as 640x480.

     

    Optical resolution of the lens is a problem for megapixel cameras. I havn't found any zoom or variofocal lens yet.

  23. Posted · Edited by Guest

    ... But you better have blazing speed on your upload because they can get rather large filesizes.

     

    Thats right!

     

    1. For example 3 mpixel camera can give a single frame from 150 to 600 Kb and with 25 FPS can use whole 100 MBit Ethernet just for one camera.

     

    Personally I think you have to play with a bandwidth calculator for a twenty minutes before to get a impression what the megapixel cameras are consuming.

     

     

    2. The second problem with a megapixel camera is a proper lens for it.

    A typical CCTV lens has optical resolution about 0.6 MPix.

     

    Initially I didn't found any proper lens, and was in panic but later I found couple of them from Tamron and Pentax.

     

    Actually there are some mpixel lens, but I found only fixed ones.

     

    So it will be nice to check the lens before!

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