1. Brief Introduction Infrared cameras and infrared thermal imagers are two completely different devices. The core difference between the two types of cameras mainly lies in the different wavelengths of light captured by their sensors. An ordinary camera can capture infrared images by installing an optical filter. This is because the wavelength range covered by the optical sensor of an ordinary camera itself includes near-infrared and near-ultraviolet wavelengths. During regular photography or videography, if no filter is added, invisible near-infrared and near-ultraviolet light will also trigger the photoelectric effect on the sensor, resulting in color cast. The conventional solution is to add a filter coating on the chip surface or install a filter in the lens to block light invisible to the human eye and restore natural colors. Thermal imaging often refers to images produced by unfiltered cameras assisted by near-infrared light sources, which are widely used in security cameras and most civilian night vision devices. Cameras for infrared temperature measurement are generally called thermal imagers. They usually filter and reflect most light rays by selecting specific lens materials, allowing only a narrow band of far-infrared light to reach the sensor surface. The temperature of the target corresponding to each pixel is calculated based on the photoelectric effect generated by these weak far-infrared rays. The difference between thermal imaging and infrared imaging is as follows: infrared imaging is active infrared, while thermal imaging is passive infrared. Active infrared achieves night vision by emitting an infrared source to increase the ambient brightness by tens of thousands of times. In contrast, passive infrared detects objects through their own infrared characteristics; generally, all objects with temperatures above ambient temperature have infrared characteristics. A thermal imager is a non-contact detection device that detects infrared energy (heat), converts it into electrical signals, generates thermal images and temperature values on a display, and can perform calculations on these temperature values. Infrared image: an image formed by capturing the intensity of infrared light emitted/reflected by an object Grayscale image: an image formed by capturing the intensity of visible light of an object Color image: an image in which each pixel consists of R, G, and B components Infrared images share the same data format as grayscale images — both are single-channel images, whereas color images are three-channel images. Infrared color image

Infrared grayscale image

II. Principle of Infrared Detection Why can infrared detectors detect objects invisible to the human eye? This is because the visible spectrum of the human eye is narrow, covering light at approximately 0.4–0.8 μm. In other words, the human eye cannot perceive light in nature that falls outside this range. For example, boiling water at 100°C appears no different from cool boiled water under natural light. However, an infrared detector can distinguish between them, as high-temperature objects emit higher radiation intensity than objects at room temperature.

All objects above 0°Fahrenheit(which is -18°C) emit electromagnetic waves to the surroundings. Even if you stand still, you are constantly radiating electromagnetic waves outward. When an infrared detector is pointed at you, it can detect that your body temperature is higher than the surrounding air temperature, thus identifying your presence. Person in the woods:

A moving car. This is very useful in heavy fog. It is recommended that all vehicles be equipped with this type of sensor as a way to ensure safety.