Please help me find an embedded camera

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Hi all

I am new to this embedded scene and I really need some help. I am
trying to assemble a PC104 camera solution that fullfills the
following criteria:

- must use as little power as possible
- obviously the cheaper the better :)
- the camera startup time must be very quick
- the time needed for taking a picture must be very quick (fast moving
- the camera must be able to take pictures in darkness (at night)
without a flash
- the pics need to be 640x480 black and white
- once the image is captured, I would like it to eventually end up as
a JPEG so that the filesize is minimal. This is because it will be
transmitted via a GPRS module.

I might be betraying my ignorance with the above list, but any
information would be useful to a newbie such as myself. Thanks in
advance for any help.

Adam Wynne

Re: Please help me find an embedded camera
On 4 Oct, in article

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Without some sort of budget it is difficult to determine. Also it depends
on whether you want a still/video camera, how much control over the camera
you need, how much of the camera and lighting part of the system you will

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What is very quick ??? 0.5s, 1ms, 1us??

How much control over the camera you want affects this, as well as your
lighting and possibly lens control systems.

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Short exposure time in cameras is not a problem, your problem will be
lighting and lenses, which also depends on the distance of the object,
other ambient lighting and lighting effects (e.g. are you going to
have the travel of the sun to contend with).

You do not say if this is triggered by an external device or time
interval or by picture content to determine if you need a still camera
or video camera, or even camera chips.

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So you need an IR extended range CMOS camera, but how are you going
to light the object being photographed? Cameras cannot make light
happen, YOU will have to flood the area of the object at the right
distance with some form of IR source (LOTs of IR LEDs), this will
push power consumption up.

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How often are you wanting to take images?
Are you taking one image or a sequence?

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How do you want to capture the image? USB, Firewire, analog grabber
another mothod?

How often you are taking images and what you are doing to images are
mainly system dependent, JPEG compression is really the domain of your
PC104 system. Some cameras do this, but you are unlikely to get fast
setup, fast grab, and especially night vision as these are meant for
people to take snapshots.

Your choice of compression may not be the best choice as it is a lossy
compression, compression choices depend on range of image content you
need, range of image noise and resolution you need amongst many other

As you say this is using GPRS I can ONLY assume this is an external
box so will the camera be part of a weatherproof enclosure or need its
own weatherproof (possibly vandal proof) enclosure. The environment
will greatly affect what you need and cost.

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There are too many unknowns to give a sensible solution primarily as
you don't say how much building you are expecting to do.

You would be amazed how much power even the cheap security cameras
with night illumination use and you have no control over exposure time

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Paul Carpenter          |
< PC Services
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Re: Please help me find an embedded camera
Hi there, me again :)

The camera will be used for still photos only and I don't care what
interface is used to get to the camera (firewire/USB etc). The startup
time and capture time should be about 100 ms.

I don't mind how much building I have to do regarding assembling the
system, but would obviously prefer as little as possible.

If there's one constraint that can be let slip, its cost. So if I can
buy a night vision enabled single shot digital camera module, I'd
rather do that then build my own.

Thanks again

Re: Please help me find an embedded camera

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Re: Please help me find an embedded camera
On 4 Oct, in article

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So forget USB web cameras and probably firewire as the setup time is
NOT determined by the camera but the vagueries of the operating system
and everything attached to it. Some can take seconds to load their
drivers and get sorted out with USB software.

What is your budget? If less than 100 UKP/USD/EUR don't expect
anything more than random capture of an image that will randomly
be synced with what you were expecting to take a picture of.

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First you have got to get some camera fundamentals sorted IN THIS ORDER

        1/ How fast EXACTLY is the object moving
        2/ How fast an exposure time is required to get a still from
           that object without blur.
        3/ How FAR away is the object and Field of View required

These determine lenses and how much lighting is required, the further
away the object, the amount of light (lux) illuminating the object
goes up by at LEAST a SQUARE as lux is an area measurement.

        Is the object reflective/absorbent of light?
        What angle and type of lighting is required?

These will affect how you light the object, and image quality.

Then can you illuminate the object with the SAME amount of lux at NIGHT?
If not forget night time capture.

This is true of ALL types of cameras photographic/video/still using
film, analog or digital electronics. Putting electronics instead of film
does not change the laws of physics relating to optics and the like.

Now you know how much the lighting and lenses is going to cost in money
and power consumption, so you now know if the cost and power budget
are still possible.

How do I trigger the camera trigger ACCURATELY to the motion of a 'high
speed' object? This determines what you have to do for camera latency of
trigger and exposure.

THEN and ONLY THEN can you start to look for a camera that can do those
characteristics. As you may not be able to put the right lenses or lighting
or control exposure time on any old cheap module.

Once you have the camera your choices of capture method can be sorted. Along
with how you ACCURATELY trigger the camera to take the picture which if it
is high speed object will HAVE to be HARDWARE as software especially via USB
will be as accurate as a mythical 'man month'.

Doing it the WRONG way round guarantees the old adage of computers and HiFi

        Garbage In Garbage Out

To give some idea two stories for you:-

1/  A certain printing press had continuous paper being monitored at
    high speed (10m/s and above), so had short exposure time and a lot of
    light at close distance (0.5m and less), Only a measly little 7KW of
    light. They had to be careful about stopping the press BEFORE turning
    off the lights otherwise it was an expensive mistake.

    They were printing paper money! (Legally)

2/  UK Highways surface inspection research vehicle to measure cracks in
    road surface from 2mm upwards, using TDI line scan cameras synchronised
    to pulses from the wheels at speed up to 50mph (approx 22m/s), had
    special light pipes in an enclosed and skirted box close to the road.
    Light level about 3KW and line scans being done at over 11KHz rate.

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I doubt you will easily find a cheap camera module to do what you want.
You desparately need to check what your front end is doing first not
from the back end of PC104 system outwards.

Computer systems are relatively cheap and have various options more than
your camera choices are.

If you don't understand your front end issues the rest is a waste of time!

Paul Carpenter          |
< PC Services
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