Here is a really cool app for those of you looking to get your pixel density down right.
Do you know what pixel density you need to capture a license plate? What about a face? Unlike a complex lens calculator, there is no need to understand complicated pixel densities to use this app. Just select your sensor size, resolution, and lens, let the app do the rest. You will be given the correct distance to recognize a face, read a license plate, ID a familiar person, and to detect an intruder as well as the width of your shot at the corresponding distances. No math required.
Here’s how it works:
Select unit of measure Imperial(feet) or Metric(meters)
Sensor: Select from four different sensor sizes. You can find the sensor size of your camera from the manufacturers web site.
Camera: Select what resolution camera you would like to use. Remember raising the resolution of a camera will primarily increase the horizontal field of view. i.e. if you can get the distance you what from a 2MP camera but the horizontal FOV is too small try going to a 3MP camera and using a slightly wider lens to capture the same detail with a wider FOV.
Lens: Select from all the most common lens sizes. Use higher mm lenses to achieve greater distances and narrower FOV’s.
Facial recog. software: Maximum distance at which facial recognition software will be able to recognize a face.
License plate number: Maximum distance you will be able to read a license plate number.
Visual Identification: Maximum distance you will be able to identify a familiar person.
Detection: Maximum distance you will be able to detect a person in the video (for use with video motion or video analytics).
Horizontal FOV: The horizontal field of view is the width of your shot at the corresponding distance listed above.
Note the distances given by the pixel density calculator app are calculated under ideal conditions. Please remember you may need to adjust the given measurements to compensate for poor focus, poor lighting, motion blur etc.
Link to the app CCTV Camera Tool.