Re: security camera software/RPi
On 10/1/2014 10:57 AM, ken wrote:
> On 10/01/2014 09:08 AM Jerry Stuckle wrote:
>> On 10/1/2014 8:19 AM, ken wrote:
>>> On 10/01/2014 03:49 AM Scott Ferguson wrote:
>>>> On 01/10/14 17:42, Andrei POPESCU wrote:
>>>>> On Ma, 30 sep 14, 21:01:52, Jerry Stuckle wrote:
>>>>>> On 9/30/2014 7:11 PM, Andrei POPESCU wrote:
>>>>>>> On Sb, 27 sep 14, 05:23:29, ken wrote:
>>>>>>>>
>>>>>>>> What other cheap devices devices were you referring to that
>>>>>>>> would better handle the load?
>>>>>>>
>>>>>>> https://wiki.debian.org/RaspberryPi
>>>>>>
>>>>>> You've never actually tried a RPi with a camera, have you?
>>>>>>
>>>>>> As Ken said, the RaspberryPi is a very bad choice for such a
>>>>>> job.
>>>>
>>>> The plural of anecdote is not fact.
>>>> Have *you* tried it?
>>>>
>>>> The TP-Link TL-WR703N is less powerful than the Raspberry, yet it does
>>>> run 'monitor' with dual cameras.
>>>>
>>>>>
>>>>> 1. I think you're mixing up who said what 2. You haven't actually
>>>>> read that page, have you?
>>>>
>>>> Or these:-
>>>> ;http://through-the-interface.typepad.com/through_the_interface/2012/08/creating-a-motion-detecting-security-cam-with-a-raspberry-pi-part-1.html
>>>>
>>>>
>>>> ;http://programmaticponderings.wordpress.com/2013/01/01/remote-motion-activated-web-based-video-surveillance-with-raspberry-pi/
>>>>
>>>>
>>>>
>>>>>
>>>>> Kind regards, Andrei
>>>>>
>>>>
>>>>
>>>> Kind regards
>>>
>>> While it's understandable, unless one rereads the posts in a thread,
>>> that who said what can be lost, so I'll clarify: I didn't say the RPi
>>> was a bad choice for a security camera. What I did say was that I'd
>>> read that some people claimed to have done it (and were happy with the
>>> result). Here's one I just read which provides step-by-step
>>> instructions:
>>>
>>> <http://www.codeproject.com/Articles/665518/Raspberry-Pi-as-low-cost-HD-surveillance-camera>
>>>
>>>
>>>
>>> There are others.
>>>
>>> Re: the contention that "it doesn't work": That would need more
>>> clarification. E.g., perhaps full-motion video doesn't work, but this
>>> isn't necessary for a security camera. In the article I reference
>>> above, the author configured 2fps @ 1280x720. But then he also was
>>> running a webserver on the same RPi. I probably wouldn't do that, but
>>> rather offload the video to another machine and watch it from there. The
>>> point is, as is often the case, whether this works or doesn't may well
>>> be contingent on the system's configuration.
>>>
>>>
>>
>> 2fps is not considered adequate for security. Too much can get lost.
>> The minimum generally recognized is 7.5 fps. The RPi has trouble with
>> that, even if a webserver isn't running. As for offloading the video -
>> if you do it via the ethernet port (vs. pulling the SD card), you'll
>> find your RPi won't handle it. 7.5fps at 720p with 24 bit color comes
>> out to over 20 megabytes/sec. - far beyond the RPi's capabilities.
>>
>> So, is the solution to go to a lower resolution camera? Not really.
>>
>> There are three levels of detail considered for security cameras:
>>
>> 1. Observation - something happened
>> 2. Recognition - something happened and it's someone you recognize
>> 3. Identification - something happened and you don't recognize the
>> person but can match the person to a picture, lineup, etc.
>>
>> #1 doesn't help much - other than to maybe tell you the exact time it
>> happened. After all, you already KNOW something happened.
>>
>> #2 works if you know the person - i.e. you can see and recognize your
>> kid when he/she comes home. Much better, but it doesn't help much if
>> you don't know the person.
>>
>> #3 is required for usable security. To get this, you need a resolution
>> of around 5px/cm (12.5px/in) at the face. Anything less and you will be
>> *very* lucky to get any useful information.
>>
>> There are a lot of people who know nothing about what they are doing,
>> yet think they have security. But how many of these people have
>> actually used the information after a crime has been committed?
>>
>> Additionally, as I said before - the RPi doesn't run Debian - the
>> processor the RPi uses is ARM V6 - which is old and not supported by
>> Debian (or any of the standard distributions). So you are required to
>> use their version (Raspbian) and the software they supply (unless you
>> can compile for ARM V6 yourself).
>>
>> The RPi is a cheap toy, but that's about all it's good for. The ones I
>> evaluated are now in the landfill. There are much better ones out there
>> for very little more.
>>
>> You really shouldn't comment on things you know nothing about.
>>
>> Jerry
>
> Jerry,
>
> (Re: your last statement:) I don't. It's good advice, though I guess
> you meant it as an insult. Thanks for that.
>
> I wasn't claiming 2fps as a maximum rate, only that it was what one
> person used and was happy with, someone who was running a webserver on
> the same RPI which was also running the camera. I haven't yet seen any
> load averages or throughput numbers mentioned for this and that
> configuration... which would be what we should be talking about. Not
> having those, but only the case cited, we can consider 2fps a minimum
> and one which likely could be improved upon.
>
> You assert that a higher frame rate is necessary. I'd say it depends
> upon the environment. If someone is going to walk through my yard and
> steal or break something or try to break in, 2fps will be fine. There's
> not much a criminal can accomplish in a half second which would permit
> him to deny criminality. I'm not playing "CSI Miami" here, just getting
> a record of events. If some neighborhood kids come into my backyard and
> break a window (as happened last Halloween), 2fps is going to be enough.
> (And, as said, higher rates are more than likely possible.)
>
> As for Raspbian not really being Debian, if true, how would that be
> relevant to how well the RPi functions for this purpose?
>
>
Ken, 2fps will only let you know that something happened (which you
already know) and when it happened (maybe helpful, but usually not).
To get good chance at identifying the culprit, he/she must be facing
generally towards the camera - a side or back shot is not real useful.
At 2fps, there is a large time where the user can be looking past the
camera (one can easily turn his head almost 180 degrees in much less
than 1/2 second). As such, you will be able to see the kids - but
probably not be able to identify them (recognition is more likely).
As for Raspbian not being Debian - that means it doesn't get updates at
the same time Debian does and it doesn't have all the software available
to it that Debian does. Yes, it has many of the most common packages -
but before I threw them out I found too many things not available for
the RPi.
User support is also much worse than for Debian. Their "official"
support is also lacking (I think the Debian Developers do a pretty good
job, even though I disagree with some of their choices).
Jerry
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