The Truth about Helmet Camera Resolution
There are a million different helmet cameras on the market today, all claiming to have the best picture and highest resolution. All sorts of sites give you stats claiming “420 horizontal lines of resolution!”, “580 vertical lines of resolution!”, and “effective pixels - 811×508!”. All of the cameras on all of these sites look identical. What do these terms truly mean? How should i know which helmet camera is right for me? When finished reading this article, you will know exactly what resolution is, how to determine the resolution of your recorder, what to look for in the resolution of a helmet camera, and which helmet camera is right for you.
The actual measure of ‘lines of resolution’ is how many vertical lines can be resolved on a display. These lines are counted horizontally from one side of the screen to the other, thus it is called horizontal resolution.
Vertical resolution is the count of how many horizontal lines can be resolved on the display. These lines are counted from top to bottom, which is why it is called vertical resolution. The TV picture is always made up of 480 effective horizontal scanning lines which always remains the same. Ultimately, vertical resolution is fixed. Horizontal resolution is dependant upon the video source and may vary with the quality of the equipment. For this reason it is more important to judge a helmet camera based on its horizontal line resolution and not its vertical line resolution.
Now that we understand the basics of resolution, we can move on to finding the right helmet camera for your video recorder. Most video recorders make it very easy to find the resolution or the horizontal line specs. Often times they are printed on the side of the recorder or easily found in the manual. For the following example I will be using the Canon zr40 Mini DV Camcorder. The horizontal lines on this recorder are 550. I want to maximize my resolution so that I am using as many of those horizontal lines as i can. To do this, you would want to purchase a helmet camera with at least 550 horizontal lines of resolution.
The final thing you need to do is consider the recording medium. The recording medium of the zr40 is mini DV tape. The highest resolution that mini DV can record is 500 horizontal lines. In order to max out my resolution, i want to buy a helmet camera with a horizontal resolution of atleast 500. A 480 would produce a great picture, but a 520 would give me a full 500 lines of resolution on the tape. Keep in mind, when you use a 520, 20 of the lines of resolution arent being used to there full potential.
If you know the resolution of your recording device and the recording medium, you should be able to purchase the best helmet camera for your specific setup. You wont waste money on high resolution setups that will not actually give you a better picture.
CCD vs. CMOS Chip
CCD sensors have been used in cameras for more than 20 years and present many advantageous qualities; among them, better light sensitivity than CMOS sensors. This higher light sensitivity translates into better images in low light conditions. CCD sensors are, however, more expensive as they are made in a non-standard process and more complex to incorporate into a camera. In addition, when there is a very bright object in the scene (such as a lamp or direct sunlight), the CCD may bleed, causing vertical stripes below and above the object. This phenomenon is called a smear.
Recent advances in CMOS sensors bring them closer to their CCD counterparts in terms of image quality. CMOS sensors provide a lower total cost for the cameras since they contain all the logics needed to build cameras around them. They make it possible to produce smaller-sized cameras. Large-sized sensors are available, providing megapixel resolution to a variety of network cameras. A current limitation with CMOS sensors is their lower light sensitivity.
Overall CCD and CMOS chips differ quite a bit depending upon application. For good video quality a CCD chip is still preferred over a CMOS chip.
