Thermocameras

• Thermocameras show the eye an image of an area showcasing cooler spots with the color blue and the hotter spots with red. As the device reads the heat, it gathers hot spots beyond general surfaces. This allows you to see hotter objects behind cover such as inside buildings or behind other things. The military often uses such devices to determine where people are in buildings, forests or deserts, as humans are usually the hottest point around.
  
  

Pyrometers

• Pyrometers use a laser to take the temperature of a point. You aim the detector at whatever object you wish to determine the temperature of. The laser measures the surface temperature and gives you a reading in Fahrenheit or Celsius. The laser cannot penetrate the outer layer in order to get an internal temperature; it only reads the heat at the point of contact.
  
  

Measurements

• Thermocameras use light waves to determine the amount of energy or "heat" put off by an area. The shorter wavelengths mean greater energy. This directly determines the color the camera shows the visible eye. Pyrometers use the same theory, measuring the wavelengths or emissivity as the laser bounces off the object. This gives the meter a general temperature determination.
  
  

Effectiveness in the Dark

• Thermocameras have the added advantage of working in the dark. If you cannot see something with your eye, you will still be able to see the heat. No matter how dark it is, the thermocamera will give you a color reading of the area. A pyrometer also works in the dark. You may not be able to tell exactly what you are aiming the meter at if ambient light is lacking.