Temperature Measurement Using Infrared Thermography

Infrared thermography (IRT) has been used for applications in veterinary medicine – primarily in research projects – since the 1960s. Until today, however, the use of IRT as a standard procedure has only been customary in equestrian sports and for zoo animals.

During the analysis of infrared images, the existence of symmetrical temperature patterns (comparison of left and right side) can be helpful for making relevant diagnostic observations. High-quality IR cameras without any further enhancements are usually sufficient for this purpose.

Often, however, it is desirable to monitor the temperature development of a certain object, a cow udder, for example, over a longer period of time in a chronological sequence. In order to reach a medical diagnosis, it is necessary to observe the temperature development over a course of several days. In this case, the temperature has to be measured absolutely precisely, similar to measuring the body temperature using a thermometer. However, even high-quality IR cameras are usually not capable of reaching this precision without further technical adjustments due to their sensor drift.

With the contribution of several manufacturers of infrared systems technology and the TU Dresden, solutions allowing the infrared-based measurement of surface temperatures in dairy cows with an accuracy of about ±0.4 K have been developed within a number of different research and development projects. The typical conditions of measuring campaigns in agricultural enterprises were taken into account in the course of these projects.

The basis for determining the accuracy of the temperature measurement is an analysis process that has been conducted for the first time for this use case and in compliance with the specifications of the DIN 1319. Combined with the automated evaluation of the IRT images through image processing, it is possible for the first time to conduct an IRT screening of large herds over a longer period of time and with a comparatively high accuracy.

Overview of Competencies

• Analysis of the measuring conditions (feasible measuring uncertainty, sources of interference, etc.)
• Quantification and computational compensation of interferences (surrounding temperatures, THI Index, etc.)
• Design and set-up of measuring equipment
• Combining the solution with data base interfaces and automated image processing
• Selection of robust temperature parameters as a basis for diagnosis