Since the invention of the first analog video camera, it was natural to compare these devices to the human eye. Focus, light sensitivity, iris, lens, focal length and aperture are terms used to describe both. Cameras in surveillance were created to see what we as humans couldn’t. Yet in the analog CCTV world, the comparisons stopped at seeing.
In the world of IP video, cameras are computers that can see. When we talk of computers, we talk of artificial intelligence. We talk of memory. Today we can compare an IP video system to the human eye and the brain.
There are some areas today where the IP camera bests even our own human abilities, but also qualities where a surveillance system will never replace human intelligence or intuition. How do we stack up today with our IP video devices, and where will we fall behind in the future?
Seeing is believing
Let’s start with the obvious comparison: the IP camera and the human eye. While there’s no perfect calculation, the whole eye is said to have a total resolution of more than 100 megapixels, but this is hardly usable for surveillance and it’s not the actual resolution that our brain (the VMS) computes.
While the eye wins outright for overall resolution, one can argue that the usable resolution of the cornea or what the brain computes at a given time can vary greatly, but be roughly estimated between five to 10 megapixels depending on the person’s eyesight. Still, given that lens technology is not on par with the higher resolutions in security cameras—maxing out around five megapixels for professional surveillance—and that most 10 to 20MP cameras lack frame rate and image quality around the edges of the scene, it is a clear win for the human eye.
There’s one main reason that lenses are not keeping pace with IP camera and sensor development and therefore the human eye: Moore’s Law. Unlike the IT components inside a camera, optical components like the lens do not follow Moore’s Law. So while lenses are taking longer to evolve, IP camera developers are using the ever-growing processing power in the cameras to look beyond pure resolution and improve overall image clarity with better light sensitivity.
Many of us suffer with poor night vision. But unlike our eyes, cameras have the ability to leverage IR wavelengths and produce a black and white image at night. Analog held one final advantage over IP regarding light sensitivity, yet neither analog nor IP could produce color images in the dark. Both of these cornerstones were passed during the last year with the introduction of color-at-night Lightfinder technology. Here, Moore’s Law is really kicking in with sensor development and we can expect a lot of progress in low light video. Also, as CMOS sensor technologies evolve we now have the ability to be almost as light sensitive in five megapixel cameras as the human eye, and much more light sensitive than the eye in HDTV and VGA resolutions.
And then of course there is the ability to see with absolutely no light at all—which no human can do. For this we now have professional-grade, all-digital thermal network cameras that can be integrated into an IP-based surveillance system. Thermal cameras can detect humans and objects in complete darkness as well as poor visibility conditions and are no longer just for military use.
Wide dynamic range is another hot issue related to the sensor and image processing. The human eye is said to have a contrast range to 120 dB. If compared to the best wide dynamic range network cameras on the market, it’s a dead heat tie. However, when humans try to see during constant contrast change, the eyes will get very tired and a headache is likely. So in the long run, and especially when fighting direct sunlight, the camera is better than the human eye without even the need to wear sunglasses.