[This post is taking part in our Designing Hardware for HD series. Be sure to check it out!]
Now that we’re past the camera glossary part, it’s time to take a look at what is required from a good camera for visual communications.
I’ll start by saying that, as a rule of thumb, desktop video conferencing cameras are usually USB webcams and professional video conferencing systems have professional HD cameras. These are two separate types of cameras, using two different technologies.
Let’s start by looking at the different characteristics of these cameras:
| USB webcam | Professional HD camera | |
|---|---|---|
| CCD / CMOS sensor | Low cost | Good sensor, which usually costs more |
| Optical lens group | Small number of lenses | Big number of lenses |
| Field of view | Small horizontal field of view | Large horizontal field of view |
| Focus | Fixed | Usually with an automatic focus algorithm |
| White balance | Standard automatic white balance performance | Optimized for video conferencing rooms providing good illumination |
| Latency | USB will add an element of latency as images will need to be encoded using MJPEG and then decoded before being re-encoded yet again (due to the bandwidth offered by USB) | Will usually have low latency in mind |
So where will be the real differences?
- Optics – they need to take into account issues like field of view a lot more, as you want to provide a wide enough angle. They also need to provide better results in different illumination settings.
- Algorithms – white balancing and focusing need to work better
In general, a USB camera will work relatively well in normal office low illumination conditions and will not need any additional light. I’d say that while this is true, even here in RADVISION, there are changing illumination conditions in different rooms, so this might not hold true at all times.
There’s another aspect that needs to be dealt with, especially considering the segment of personal conferencing systems:
| Personal system | Room system | |
|---|---|---|
| Focus | Fixed should be fine | Auto focus is mandatory |
| Camera movements | Fixed should be fine | PTZ camera with good resolution and good depth of field |
| Conditions | “webcam” grade at the very least | More attention to illumination conditions need to be taken into account |
So you see, when you “shop around” for a camera, you need to take all of these into consideration.
My suggestion? Start from the use case: in which settings do you see the end product being used? What will be the lighting conditions? What’s the distance between the camera and the people? etc. Once you have these written down, look for a vendor that can provide the solution you need.
And don’t forget to test the end results – I’ll deal with this one in a future post, where I’ll outline a few simple tests to perform, to see if your camera is of reasonable quality at all.
