Signal processing unit of thermal imaging camera

In the operational system of a thermal imaging camera, the signal processing unit acts as the brain, playing central role. It is primarily responsible for a series of intricate processes on the raw signals received from the infrared sensor, converting them into thermal image data that intuitively reflects temperature distribution of objects. This provides a solid foundation for subsequent image display, analysis, and application.

After the infrared radiation emitted by objects, the infrared sensor generates weak electrical signals. These signals are usually very faint and mixed with a lot of noise, making it difficult to them directly. The signal processing unit first collects these raw signals and amplifies them through an amplifier to bring the signal strength to a level that can be processed. This is like adding a loudspeaker to a faint sound, allowing the subsequent "listeners" to "hear" the signal content more clearly.

to the influence of the sensor and the transmission process, various noises, such as thermal noise and electromagnetic interference noise, inevitably mix into the raw signals. These noises can with the accurate interpretation of the real signal and affect the quality of thermal imaging. The signal processing unit will use various filtering techniques, such as low-pass filtering and band filtering, to remove noise signals and retain the real and effective signals. Low-pass filtering can remove high-frequency noise, making the signal smoother; band-pass filtering can screen signals within a specific frequency range, excluding other frequency interferences, just like using a filter to remove impurities, making the signal more pure.

After amplification and filtering, the analog signals need to be converted into digital signals for processing by computers and subsequent digital processing circuits. The analog-to-d converter (ADC) in the signal processing unit undertakes this critical task. It converts the continuously varying analog signal into a discrete digital signal, representing the signal strength in form of binary code. This conversion allows the signal to be processed more precisely and efficiently in the digital system, laying the foundation for subsequent complex algorithms and analysis.

To improve the quality and accuracy of thermal imaging images, the signal processing unit will perform image enhancement and correction operations. By using contrast enhancement algorithms, the between different temperature regions in the image is increased, making the temperature differences more obvious and easier to observe and analyze. At the same time, the image is corrected for-uniformity, compensating for the brightness differences in the image caused by the inconsistent response of the sensor's pixels, ensuring that the temperature measurement of each pixel in image is accurate and consistent. These operations are like "beautifying" and "calibrating" the thermal imaging image, making the image more clearly and accurately the temperature distribution of the object.

In some thermal imaging applications, it is necessary to obtain the specific temperature value of the object. The processing unit will convert the processed signal into an actual temperature value according to the characteristics of the sensor and the calibration data, and annotate it on the image. Through the-in temperature calculation model, combined with the known environmental parameters and the sensor's response curve, the temperature corresponding to each pixel point is accurately calculated, providing users with quantitative information to meet the strict temperature measurement requirements of industrial inspection, medical diagnosis, and other applications.