FLIR CX series User Manual

Theory of thermography
17
Figure 17.2 Gustav Robert Kirchhoff (1824–1887)
The construction of a blackbody source is, in principle, very simple. The radiation charac-
teristics of an aperture in an isotherm cavity made of an opaque absorbing material rep-
resents almost exactly the properties of a blackbody. A practical application of the
principle to the construction of a perfect absorber of radiation consists of a box that is
light tight except for an aperture in one of the sides. Any radiation which then enters the
hole is scattered and absorbed by repeated reflections so only an infinitesimal fraction
can possibly escape. The blackness which is obtained at the aperture is nearly equal to
a blackbody and almost perfect for all wavelengths.
By providing such an isothermal cavity with a suitable heater it becomes what is termed
a cavity radiator. An isothermal cavity heated to a uniform temperature generates black-
body radiation, the characteristics of which are determined solely by the temperature of
the cavity. Such cavity radiators are commonly used as sources of radiation in tempera-
ture reference standards in the laboratory for calibrating thermographic instruments,
such as a FLIR Systems camera for example.
If the temperature of blackbody radiation increases to more than 525°C (977°F), the
source begins to be visible so that it appears to the eye no longer black. This is the incipi-
ent red heat temperature of the radiator, which then becomes orange or yellow as the
temperature increases further. In fact, the definition of the so-called color temperature of
an object is the temperature to which a blackbody would have to be heated to have the
same appearance.
Now consider three expressions that describe the radiation emitted from a blackbody.
17.3.1 Planck’s law
Figure 17.3 Max Planck (1858–1947)
Max Planck (1858–1947) was able to describe the spectral distribution of the radiation
from a blackbody by means of the following formula:
where:
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FLIR CX series Specifications

General

Temperature Range	-20°C to +120°C, 0°C to +650°C (optional)
Image Frequency	9 Hz
Focus	Focus-free
Display	3.5 in. 640 × 480 color LCD with backlight
Digital Camera	5 MP
Battery life	4 hours
Thermal Sensitivity/NETD	<70 mK
Thermal sensitivity	<70 mK

Summary

Disclaimers

Legal Disclaimer and Warranty

Details legal terms, warranty periods, and limitations of liability.

Usage Statistics and Regulations

Covers data collection, government regulations, and copyright information.

Patents and EULA Terms

Lists applicable patents and explains End User License Agreement terms.

Safety Information

Battery and Camera Safety Precautions

Crucial warnings and cautions for handling batteries and operating the camera safely.

Notice to User

User Resources and Best Practices

Information on forums, calibration, accuracy, training, and documentation.

Manual Guidance

Notes on manual scope, translations, and authoritative versions.

Customer Help

Accessing Support and Submitting Questions

Guide to contacting customer support and required information for inquiries.

Downloads and Product Resources

Links for firmware, software, documentation, and technical drawings.

Quick Start Guide

Initial Camera Setup and Operation

Step-by-step instructions for basic camera setup and image capture.

Description

Camera Components and Views

Identifies external parts from front and rear views of the camera.

Screen Elements and Navigation

Explains display interface, screen elements, and menu system navigation.

Connectivity and Orientation Features

Details USB connector purpose and auto-orientation functionality.

Operation

Battery Management

Procedures for charging the battery and turning the camera on/off.

Saving and Recalling Images

Instructions for saving, storing, and retrieving captured images from memory.

Deleting Images

Steps for removing individual or all images from the camera's internal storage.

Temperature Measurement Tools

How to use the spotmeter and hide measurement displays.

Image Display and Modes

Options for changing color palettes and selecting different image presentation modes.

Adjusting Measurement Parameters

Settings for emissivity, temperature scale, reflected temperature, and distance.

Camera Settings and Updates

Configuring device settings and performing firmware updates via FLIR Tools.

Technical Data

Data Resources and Notes

Information on field-of-view calculators and notes on technical data.

FLIR C2 Specifications

Detailed technical specifications for the FLIR C2 camera model.

Mechanical Drawings

CE Declaration of Conformity

Cleaning the Camera

Camera Housing and Cables

Procedures for cleaning the camera body, cables, and other external items.

Infrared Lens Cleaning

Specific instructions and precautions for cleaning the sensitive infrared lens.

Application Examples

Moisture and Water Damage Detection

Using the camera to identify water damage in buildings.

Electrical Fault Identification

Examples of detecting faulty sockets and oxidized electrical contacts.

Building Insulation and Draft Issues

Identifying insulation deficiencies and air drafts in structures.

About FLIR Systems

Company History and Innovations

Overview of FLIR's development, milestones, and product evolution.

Knowledge Sharing and Customer Support

Information on training, application support, and the service network.

Manufacturing and Facilities Showcase

Visual examples of FLIR's development and manufacturing processes.

Glossary

Thermographic Measurement Techniques

Introduction to Measurement Principles

Explains basic concepts of infrared measurement and emissivity.

Determining Reflected Temperature

Methods and procedures for accurately determining reflected apparent temperature.

Setting Measurement Parameters

Guidance on setting distance, relative humidity, and other environmental factors.

History of Infrared Technology

Early Discoveries and Key Figures

Chronicles the initial discovery of infrared radiation and early pioneers.

Advancements in Infrared Detection

Covers improvements in detector sensitivity and military applications.

Theory of Thermography

Electromagnetic Spectrum and Introduction

Defines the electromagnetic spectrum and introduces thermography.

Blackbody Radiation Principles

Explains blackbody radiation laws (Planck, Wien, Stefan-Boltzmann).

Non-Blackbody Emitters and Materials

Discusses how real objects deviate from blackbody behavior.

The Measurement Formula

Deriving the Measurement Formula

Step-by-step derivation of the formula for object temperature calculation.

Key Measurement Parameters

Identifies essential parameters required for accurate temperature readings.

Emissivity Tables