An installer needs a camera to monitor a hallway in an office complex. The hallway is 2.5 m (8 ft 2 in) wide. The customer wants to be able to identify people (80 pixels per face). What is the minimum resolution needed to meet this requirement?
A) 1024x768
B) 1280x720
C) 1920x1024
D) 800 x 600

Question

Quizplus · Accepted Answer

To find the minimum resolution needed, we need to calculate the number of pixels needed to cover the hallway width. 
2.5 m = 8.2 ft
Assuming a person's face occupies half the width of the hallway, the face would occupy 4.1 ft or 49.2 inches. 
To get 80 pixels per inch, we need a resolution of 80 x 49.2 = 3936 pixels
This resolution can be achieved with a resolution of 1280 x 720 (921,600 pixels) or higher, so the best answer is B, 1280 x720.

An Installer Needs a Camera to Monitor a Hallway in an Office