Thermal imaging is not simply “detecting heat” — it is the measurement of infrared radiation energy emitted from an object’s surface, then converting it into a temperature map (thermogram). This is why thermal imaging is widely used for predictive maintenance, electrical inspection, and mechanical fault detection.
βοΈ Working Principle Any object above absolute zero emits infrared radiation (typically in the 7.5–14 µm wavelength range for most industrial thermal cameras). The intensity of this radiation increases as temperature increases, following radiation physics (Stefan–Boltzmann relationship).
A thermal camera captures this infrared radiation through an optical lens (often germanium-based) and focuses it onto a sensor called a microbolometer detector.
π How the sensor produces the image The microbolometer contains an array of tiny heat-sensitive pixels. Each pixel absorbs IR energy and experiences a small temperature change, which causes a measurable change in electrical resistance.
This signal is then: • converted into electrical data • processed by internal algorithms • corrected using calibration references • displayed as a thermal image with temperature values
π How temperature is calculated The camera does not directly “see temperature”. It detects radiation and estimates temperature based on key parameters such as: β emissivity of the object surface β reflected ambient radiation β atmospheric transmission (distance/humidity effect) That is why accurate emissivity settings are critical for meaningful measurements.
π§ͺ Why emissivity matters -High emissivity surfaces (rubber, painted metal, plastics) emit IR well, giving stable readings. -Low emissivity surfaces (shiny metals) reflect surrounding heat sources, often causing false hot spot readings. -To improve accuracy, operators may apply black tape/paint reference points for measurement.
π What thermal imaging helps detect Thermal imaging allows early detection of abnormal heat signatures such as: • electrical loose connection (localized hot spot) • overloaded cable or breaker (uniform heating pattern) • bearing friction or lubrication failure (heat increase at housing) • misalignment in rotating equipment (uneven heating trend) • insulation degradation or heat leakage (cold/hot contrast zones)
π Thermal inspection is effective because most faults produce heat before mechanical failure occurs.
At OBSNAP, we supply thermal imaging equipment and support customers in selecting suitable thermal solutions for inspection and reliability monitoring.
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