Infrared Thermography

Abstract

Infrared (IR) thermographic systems, or IR imagers, provide images that represent surface temperatures, or thermograms , by measuring the magnitude of infrared radiation emanating from the surface of an object. Because IR imagers see the radiation naturally emitted by objects, imaging may be performed in the absence of any additional light source. Modern IR imagers resolve surface temperature differences of 0.1 °C or less. At this high sensitivity, they can evaluate subtle thermal phenomena that are revealed only as slight temperature gradients. Some applications that employ IR thermography include inspections for predictive maintenance, nondestructive evaluation of thermal and mechanical properties, building science, military reconnaissance and weapons guidance, and medical imaging. Infrared thermography can be used both as a qualitative and a quantitative tool. Some applications do not require exact surface temperatures. In such cases, it is sufficient to acquire thermal signatures , characteristic patterns of relative temperatures of phenomena or objects. This method of qualitative visual inspection is expedient for collecting a large number of detailed data and conveying them, so that they can be easily interpreted. In contrast, accurate quantitative thermography demands a more rigorous procedure to extract valid temperature maps from raw thermal images. However, the extra effort can produce large arrays of high‐resolution temperature data that are unrivaled by contact thermal measurement techniques, such as using thermocouple wires. A skilled operator of an IR thermographic system, or thermographer , must be conscious of the possibility that reflected or transmitted, rather than emitted, IR radiation may be emanating from an object. These additional sources manifest themselves as signals that appear to be, but are not actually, based exclusively on the temperature of the spot being imaged. To understand the challenges and possibilities of IR thermography, it is necessary to review the principles of physics on which it relies. Types of imaging systems, guidance and good practice in operation are covered.

Validation of Anatomical Sites for the Measurement of Infrared Body Surface Temperature Variation in Response to Handling and Transport

“…Thermal imaging using infrared (IR) technology is a non-invasive method for measuring skin surface temperature by converting the infrared radiation emitted by a heat source into pixel intensity [12]. Based on its rapid variation in response to acute stress [13,14], IR technology represents an alternative to invasive body temperature recording.…”

Active Thermal Extraction and Temperature Sensing of Near-field Thermal Radiation

“…Such non-contact temperature sensing is important for a wide range of applications from medical to industrial domains. Current techniques often employ semiconductor based infrared photon detectors or bolometer based detectors 54 55 . The limited detection range of various semiconductor materials and the slow response of bolometers restricts the application of these techniques 54 55 .…”

“…Current techniques often employ semiconductor based infrared photon detectors or bolometer based detectors 54 55 . The limited detection range of various semiconductor materials and the slow response of bolometers restricts the application of these techniques 54 55 . Temperature sensing using ATX allows the use of visible to near infrared photo detectors to detect the upconverted fluorescence which are fast and widely available.…”

Lucid infrared thermography of thermally-constrained processors

“…The actual temperature, however, is much closer to the right coated half of the chip. To compensate for this shortcoming, a masking tape (with an emissivity of 0.92 [8]) is applied to the material's surface increasing its emissivity in the IR spectrum of the thermal camera. The masking tape was chosen due to its relatively high emissivity and it can easily be removed.…”