Why are the levels of most thermal imaging cameras related to pixels?
1. Pixels
First of all, it is necessary to determine the pixel level of the infrared thermal imager purchased, and the level of most infrared thermal imagers is related to the pixel. The relatively high-end products in civilian thermal imaging cameras have pixels of 640*480=307,200. The infrared pictures taken by this high-end thermal imaging camera are clear and delicate, and the minimum size measured at 12 meters is 0.5*0.5cm; The pixel of the thermal imager is 320*240=76,800, and the minimum size measured at 12 meters is 1*1cm; the pixel of the low-end infrared thermal imager is 160*120=19,200, measured at 12 meters The minimum size is 2*2cm. The higher the visible pixels, the smaller the minimum size of the target that can be photographed:
2. Temperature measurement range and measured object
Determine the temperature measurement range according to the temperature range of the measured object to select an infrared thermal imaging camera with a suitable temperature range. Most of the thermal imaging cameras currently on the market are divided into several temperature ranges, such as -40-120°C and 0-500°C. It is not that the larger the span of the temperature range, the better. The smaller the span of the temperature range, the more accurate the temperature measurement will be. In addition, when the general infrared thermal imager needs to measure objects above 500°C, it needs to be equipped with a corresponding high-temperature lens.
3. Temperature resolution
The temperature resolution reflects the temperature sensitivity of an infrared thermal imager. The smaller the temperature resolution, the more obvious the infrared thermal imager perceives the temperature change. When choosing, try to choose a product with a small value of this parameter. The main purpose of the infrared thermal imager to test the measured object is to find out the temperature fault point through the temperature difference. It is not very meaningful to measure the temperature value of a single point. The main purpose is to find the relative hot spot through the temperature difference and play the role of pre-maintenance. .
4. Spatial resolution
To put it simply, the smaller the spatial resolution value is, the higher the spatial resolution is, the more accurate the temperature measurement is, and the smaller the spatial resolution value is, the smallest target to be tested can cover the pixels of the thermal imager, and the temperature of the test is the temperature of the measured target. real temperature. If the spatial resolution value is larger, the spatial resolution is lower, and the smallest target to be tested cannot completely cover the pixels of the infrared thermal imager, and the test target will be affected by its environmental radiation. The test temperature is the temperature of the measured target and its surroundings. The average temperature of , the value is not accurate enough. See the comparison below:
For high spatial resolution, the temperature of the measured point is more accurate; the spatial resolution of the right picture is low, the test temperature is the average temperature of the measured point and its surrounding environment, and the temperature measurement is not accurate.
5. Temperature stability
The core component of the infrared thermal imaging camera is the infrared detector. At present, there are mainly two kinds of detectors, namely vanadium oxide crystal and polysilicon detector. The main advantage of the vanadium oxide detector is that the MFOV (Measurement Field of View) of temperature measurement is 1, and the temperature measurement is accurate to 1 pixel. For the Amorphous Silicon sensor, the MFOV is 9, that is, the temperature of each point is obtained based on the average of 3×3=9 pixels. The vanadium oxide detector has good temperature stability, long life and small temperature drift.
6. Combination function of infrared and visible light images
If the infrared image and the visible light image are combined and displayed, a lot of work will be reduced. The unknown hotspots in the infrared image can be judged based on the visible light image, and the automatic report generation will also greatly reduce the operation time.
Seven, after-sales service support and regular calibration
Infrared thermal imaging cameras need to use blackbody radiation calibration sources for temperature calibration every few years to ensure the accuracy of temperature detection, which requires suppliers to have strong after-sales capabilities and calibration service conditions. FLIR has opened branches in Shanghai, Beijing, Guangzhou, and Chengdu in China, and has an after-sales service center in Shanghai to provide after-sales service and calibration services for Chinese customers.
