Re: store system w 4-8 cameras ?

[J. <jsloud2001<removeme>@netscape.net>]

On Wed, 27 Sep 2006 15:35:40 GMT, "Roland Moore" <roland@xxxxxxxxxxxx>
wrote:

>I think you need to educate yourself a little more. Here are a few basics.
>Some of the information you're getting here on this newsgroup is probably
>confusing. Video uses the term CIF.  1 CIF, 2 CIF and 4 CIF are common
>recording quality settings (1 lower and 4 higher).

CIF stands for common image format and is one way that video
resolution can be stated.  Some manufacturers use other descriptors
such as D1.  To compare different units, it's simpler to just look at
the resolution expressed in pixels.  There's a catch with resolution
vs. frame rate.  Many units only offer the best resolution at lower
frames per second settings.  Image quality is many times more
important than the numbers of images recorded in a second.


>The FPS issue is also
>confusing. The human eye (and brain) will see 7.5 FPS as real time (don't
>argue, go actually try it and suprise yourself).

7.5 IPS does not look like real time.  Most people see 15 to 20 IPS as
fluid.  Generally, 30 IPS is accepted in the industry as "real time"
video and compares to watching television.  However, 7.5 has become
the standard for many high security applications and will almost
always yield usable images in general security applications.

> Higher frame rates are only
>required to detect slight of hand motions (like in a casino).

The requirements for higher frame rates are also a funtion of field of
view vs. the targets speed.  Fast moving objects in a relatively
narrow field of view can create the need for higher frame rates.

>Total frame
>rates are a function of the robustness of a video capture card and the
>system it is on. How you parse those FPS out to the individual channels can
>be something to pay attention to.

High quality units can display 30 IPS per channel.  Most people do not
need this, but with the cost of HDD storage being relatively cheap,
it's nice to be able to offer "real time" video for those who want it.

You need to know what you need to see, in
>what detail, and for how long the images need to be stored. If there is a
>cash register involved you need to understand what POS systems is being used
>and if you want the data inserted as text only overlay, or made part of the
>searchable events database. Once you answer those questions properly a
>better recommendation can be made. There are many more video features for
>image analytics that might not apply to your situation and budget.
>
>"- Bobb -" <bobb@xxxxxxxxxxx> wrote in message
>news:NIGdnXAD6oUpuoTYnZ2dnUVZ_qydnZ2d@xxxxxxxxxxxxxx
>> Have a friend looking to buy a convenience store and would like
>> info/recommendations on a pc-based system that would have 4/6/8 ? cameras
>> recording to the PC -  in case of  pettty theft/ hold up etc .
>>
>> Any online pointers to " the benefits of x cameras  over the
>> alternatives". for instance, with a DVR system, would it be best to go
>> with 2- 4 input cards vs 1 8 input card ?  How many fps ? how many cameras
>> per aisle ? overwrite the aisles every ... 5 minutes , 30 minutes ? How
>> much disk space per minutes etc etc.? I see wireless systems as an option,
>> but wouldn't they be subject to jamming by a prospective robber etc ?
>>
>> He asked me my opinion since I know computers , but other than the yellow
>> pages/ google etc I don't know how to research this. Since he brought it
>> up I realized that I didn't know anything about this and looking to learn.
>> A lot of what I read here is over my head and specific  ( Napco firmware ,
>> surguard mrl2 etc). Thanks for pointers/ info as to what he should
>> consider when buying a system.
>>
>> Bobb
>>
>>
>>
>>
>