1.What is meant by Field of View, and why is it important?
?????????????? The field of view is the angle of vision at which the instrument operates, and is determined by the optics of the unit. To obtain an accurate temperature reading, the target being measured should completely fill the field of view of the instrument. Since the infrared device determines the average temperature of all surfaces within the field of view, if the background temperature is different from the object temperature, a measurement error can occur. OMEGA offers a unique solution to this problem. Many OMEGA? infrared pygrometers feature patented laser switchable from circle to dot. In the circle mode a built-in laser sighting creates a 12-point circle which clearly indicates the target area being measured. In the dot mode a single laser dot marks the center of the measurement area.

2.What is emissivity, and how is it related to infrared temperature measurements?
??????????? Emissivity is defined as the ratio of the energy radiated by an object at a given temperature to the energy emitted by a perfect radiator, or blackbody, at the same temperature. The emissivity of a blackbody is 1.0. All values of emissivity fall between 0.0 and 1.0. Most infrared thermometers have the ability to compensate for different emissivity values, for different materials. In general, the higher the emissivity of an object, the easier it is to obtain an accurate?temperature measurement??using infrared. Objects with very low emissivities (below 0.2) can be difficult applications. Some polished, shiny metallic surfaces, such as aluminum, are so reflective in the infrared that accurate temperature measurements are not always possible.