Why megapixel ?

More pixels mean more detail is captured from a scene. Just like human eye is better able to appreciate images and videos at higher resolution, video and image processing software has more data and hence more potentially useful information that it can extract from higher resolution images. Let’s take a simple example of a face detection analytics. Face detection algorithms require faces to be at least 24x24 pixels in the image. Now consider a 640x480 (VGA resolution) sensor. Say, there is a 6 ft tall human at a distance of 15 feet from this sensor. Assuming that the field of view of this sensor is 90 degrees, the coverage at 15 distance from the sensor will be a 30ft x 30ft plane. This means that 640 pixels will cover 30 ft in width and 480 pixels will cover 30 ft in height. 1 ft high face (hello long face!) will hence get 480/30 pixels which is equal to 16 pixels in height. Clearly detecting faces at a distance of more than 15 feet will be impossible with a VGA resolution sensor based analytics. Instead if we were to use 1 or 2 megapixel sensor, it will be possible to do face detection at larger distances. In fact I will leave this as a simple exercise for our readers.

As you can see there is a direct correlation between the distance you can cover from a sensor for the purpose of analytics and the resolution of the camera as analytics require a minimum number of pixels to compute discriminating features relevant for those analytics. In a nutshell, megapixel analytics provide better solutions to existing problems and open up more possibilities for other applications areas – some of which we will cover in line with our product roadmap.

The next questions is why do we need to do this at the edge ? We will cover that in the next post.


Vijay