Infrared Camera Buying Guide

Infrared thermal imaging cameras are widely used in security monitoring, vehicle night vision, temperature measurement and detection, quality management, equipment maintenance, and national defense security. In the face of the reality that there are many models and brands of thermal imaging cameras and huge price differences, many people feel a little helpless when purchasing thermal imaging cameras.

Detector resolution selection for thermal imaging cameras

The detector resolution of the infrared thermal imager is now the mainstream of 160*120 (192,000 pixels), and the mainstream models are basically this pixel. There are also lower resolutions such as 60*60 (36,000 pixels), 80*60 (48,000 pixels), and 100*100 (100,000 pixels). There are also 384*288 (1.1 million pixels) and 640*480 (3 million pixels).

For handheld infrared cameras, 160*120 is the highest resolution, and has a very good price/performance ratio. Infrared cameras with a resolution lower than this cannot be used in many occasions. The price of infrared thermal imagers with more than 1 million pixels has risen sharply, unless the resolution requirements are very high, you can choose infrared thermal imagers with more than 1 million pixels.

Lens focal length selection for thermal imaging cameras

The Infrared lenses of general infrared cameras can be replaced. A telephoto lens will improve the recognition rate at long distances, but will greatly reduce the field of view. On the contrary, the short-focus lens greatly improves the field of view, but it will reduce the recognition rate.

Image spacing, spatial resolution, field of view, and identification distance of thermal imaging cameras

The indicators like spacing, spatial resolution, field of view, and recognition distance are determined by the detector resolution and the lens focal length. These four indicators, many brands are promoting. In fact, the detector resolution and lens focal length of the infrared thermal imager are fixed, and these four indicators are fixed, and these four indicators are calculated. So don't pay too much attention when purchasing.

Image spacing: 160*120 image spacing is 51um, 320*240 image spacing is 25.4um, and so on, the higher the resolution, the smaller the image spacing.

Spatial resolution: Spatial resolution = image spacing / lens focal length. Therefore, the smaller the spatial resolution, the farther the distance can be identified. If using a 22mm standard lens. The spatial resolution of 160*120 is about 2.3mrad. If a telephoto lens is used, the spatial resolution will be smaller.

Field of view: Field of view = spatial resolution * line pixel / 17.45, such as 160*120, using a 22MM standard lens, the field of view is 21 degrees.

Recognition distance: Generally, 4 pixels are the default recognition distance, so recognition distance=target height/(spatial resolution*4). For example, 160*120, 22MM standard lens, the recognition distance is about 185 meters. If the focal length of the lens becomes 115MM, the recognition distance becomes nearly 1000 meters, and of course the field of view is greatly reduced.

Therefore, the most important indicator of thermal imaging camera Z is the resolution of the detector. In addition, the indicators mentioned above can be changed by changing the lens.

Frame rate selection for thermal imaging cameras

Frame rate is an important indicator in the purchase of infrared thermal imaging cameras. The frame rate refers to the number of images that the thermal imaging camera can complete in 1 second to capture, process, and perform. The faster the response, the higher the processing rate of the internal circuit, the higher the achievable frame rate. A thermal imager with a high frame rate is suitable for capturing the temperature movement of high-speed objects and objects with high-speed temperature changes. The general TV frame rate is 25Hz.

According to the frame rate of the thermal imager, it can be divided into two categories: fast scan and slow scan. The equipment used in the system, YL, construction and other fields generally adopts fast scanning thermal imager, otherwise it will bring some work inconvenience. Generally speaking, the frame rate of the infrared thermal imager should reach 30HZ, and the best can reach 50HZ, otherwise, in many working situations, the infrared thermal imager will not be able to work well. The level of the frame rate directly indicates the performance and response speed of the thermal imaging camera, and also directly affects the thermal imaging camera.

Lens focal length selection for thermal imaging cameras

The lenses of general infrared cameras can be replaced. A telephoto lens will improve the recognition rate at long distances, but will greatly reduce the field of view. On the contrary, the short-focus lens greatly improves the field of view, but it will reduce the recognition rate.

Image spacing, spatial resolution, field of view, and identification distance of thermal imaging cameras

The indicators like spacing, spatial resolution, field of view, and recognition distance are determined by the detector resolution and the lens focal length. These four indicators, many brands are promoting. In fact, the detector resolution and lens focal length of the infrared thermal imager are fixed, and these four indicators are fixed, and these four indicators are calculated. So don't pay too much attention when purchasing.

Image spacing: 160*120 image spacing is 51um, 320*240 image spacing is 25.4um, and so on, the higher the resolution, the smaller the image spacing.

Spatial resolution: Spatial resolution = image spacing / lens focal length. Therefore, the smaller the spatial resolution, the farther the distance can be identified. If using a 22mm standard lens. The spatial resolution of 160*120 is about 2.3mrad. If a telephoto lens is used, the spatial resolution will be smaller.

Field of view: Field of view = spatial resolution * line pixel / 17.45, such as 160*120, using a 22MM standard lens, the field of view is 21 degrees.

Recognition distance: Generally, 4 pixels are the default recognition distance, so recognition distance=target height/(spatial resolution*4). For example, 160*120, 22MM standard lens, the recognition distance is about 185 meters. If the focal length of the lens becomes 115MM, the recognition distance becomes nearly 1000 meters, and of course the field of view is greatly reduced.

Therefore, the most important indicator of thermal imaging camera Z is the resolution of the detector. In addition, the indicators mentioned above can be changed by changing the lens.

Frame rate selection for thermal imaging cameras

Frame rate is an important indicator in the purchase of infrared thermal imaging cameras. The frame rate refers to the number of images that the thermal imaging camera can complete in 1 second to capture, process, and perform. The faster the response, the higher the processing rate of the internal circuit, the higher the achievable frame rate. A thermal imager with a high frame rate is suitable for capturing the temperature movement of high-speed objects and objects with high-speed temperature changes. The general TV frame rate is 25Hz.

According to the frame rate of the thermal imager, it can be divided into two categories: fast scan and slow scan. The equipment used in the system, YL, construction and other fields generally adopts fast scanning thermal imager, otherwise it will bring some work inconvenience. Generally speaking, the frame rate of the infrared thermal imager should reach 30HZ, and the best can reach 50HZ, otherwise, in many working situations, the infrared thermal imager will not be able to work well. The level of the frame rate directly indicates the performance and response speed of the thermal imaging camera, and also directly affects the thermal imaging camera.