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Chapter 3
Figure 2. Gray scale images of a car engine – the left view has white as the hottest temperature and
the right view shows black as the hottest.
temperatures. Therefore, images will
better illustrate smaller temperature
dierences. On the other hand, a
broader scale and/or higher maximum
temperature range may be needed to
prevent saturation of the portion of the
image at the highest temperature.
As an adjunct to the temperature range
selection, most cameras allow a user
to set up a color scale or gray scale to
optimize the camera image. Figure 2
illustrates two gray scale possibilities.
In Figure 1, a so-called “iron scale” was
used for a color rendering. In a manner
similar to the gray scale above, the
hottest temperatures can be rendered
as either lighter colors or darker colors.
Another possibility is rendering images
with what is known as a rainbow scale
(Figure 3).
While choice of color scale is often a
matter of personal preference, there may
be times when one type of scale is better
than another for illustrating the range of
temperatures in a scene.
Figure 3. Rainbow scale showing lower
temperatures towards the blue end of the
spectrum.
Application Examples
Go/No-Go. In these applications, one or
more temperatures are monitored to
make sure they meet process criteria,
and machinery is shut down or product
rejected when a measured temperature
goes above or below the setpoint. A
good example of this is a manufacturer
of automotive door panels that uses
IR cameras to monitor and measure
part temperatures prior to a molding
procedure.
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