{"id":2640,"date":"2016-12-05T00:00:11","date_gmt":"2016-12-05T08:00:11","guid":{"rendered":"http:\/\/192.168.3.4\/?p=2640"},"modified":"2018-01-09T06:51:13","modified_gmt":"2018-01-09T14:51:13","slug":"fov-field-of-view","status":"publish","type":"post","link":"https:\/\/www.cloudacm.com\/?p=2640","title":{"rendered":"FOV – Field of View"},"content":{"rendered":"

How can measurements be made when you can’t directly measure them?\u00a0 Measuring the height of a building could be done by someone hanging a string from the rooftop and then measuring the string.\u00a0 What if you can’t get access to the rooftop?\u00a0 What if you needed to measure the span of a lake or height of a mountain?\u00a0 Good luck using that string.\u00a0 Here is how FOV can be used as a measurement tool for objects in pictures, videos, etc.\u00a0 First lets define FOV.<\/p>\n

“The field of view is the extent of the observable world that is seen at any given moment. In case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation.”<\/em>
\n-Wikipedia, https:\/\/en.wikipedia.org\/wiki\/Field_of_view<\/a><\/p>\n

I want to take time to cover this topic and some measurements I’ve made of FOV.\u00a0 Image sensors have a viewable work area that they can detect.\u00a0 This is the FOV.\u00a0 There are other sensors as well that have definable FOV ranges.\u00a0 Here are examples of sensors with working FOV ranges.<\/p>\n

Image – https:\/\/www.sparkfun.com\/products\/14028<\/a> or https:\/\/www.adafruit.com\/products\/3099<\/a>
\nNear IR – https:\/\/www.sparkfun.com\/products\/11610<\/a> or https:\/\/www.adafruit.com\/products\/3100<\/a>
\nFar IR (heat) – https:\/\/www.sparkfun.com\/products\/13233<\/a>\u00a0 or http:\/\/www.digikey.com\/en\/product-highlight\/m\/melexis\/mlx90621-16-x-4-pixel-thermal-imager<\/a>
\nUltrasonic – https:\/\/www.sparkfun.com\/products\/11724<\/a> or https:\/\/www.adafruit.com\/products\/1137<\/a>
\nLIDAR – https:\/\/www.sparkfun.com\/products\/14032<\/a>
\nDistance IR – https:\/\/www.adafruit.com\/products\/1568<\/a><\/p>\n

There are at least 3 classes of FOV.\u00a0 These are Horizontal, Vertical, and Diagonal.\u00a0 I’ll reference them as hFOV, vFOV, and dFOV respectively.\u00a0 The sensors I listed above have definable FOV specs.\u00a0 The spec can also define the operational range, how far away an object can be detected.\u00a0 Here are some visual examples to better describe the concept of operational range.<\/p>\n

\"range\"<\/a><\/p>\n

This image has 4 objects in a black background.\u00a0 The objects vary in brightness due to their distance from the sensor.\u00a0 You may say you only see 3 objects.\u00a0 That is because the 4th object is outside the operational range, it blends in with the background.\u00a0 The sensor can not see it and as a result, neither can you.<\/p>\n