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Six Elements of Selecting Infrared Thermal Imager

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Six Elements of Selecting Infrared Thermal Imager

May 27,2022
The thermal imager is widely used in many industries. A thermal imager can be used to quickly detect the temperature of machined parts, so as to master the necessary information. Because the failure of electronic devices such as motors and transistors is often accompanied by an abnormal rise in temperature, thermal imagers can also quickly diagnose the failure. The following are the six elements of choosing an infrared thermal imager.

1. Pixel

First, we should determine the pixel level of the infrared thermal imager. The level of most infrared thermal imagers is related to the pixel. The relatively high-end product pixel of a civil infrared thermal imager is 640 * 480 = 307200. The infrared picture taken by this kind of high-end infrared thermal imager is clear and detailed, and the minimum size measured at 12m is 0.5 * 0.5cm; the pixel of a mid-end infrared thermal imager is 320 * 240 = 76800, and the minimum size measured at 12m is 1 * 1cm; the pixel of a low-end infrared thermal imager is 160 * 120 = 19200, and the minimum size measured at 12m is 2 * 2cm. The higher the pixel, the smaller the minimum target size of picturing.

2. Temperature measurement range and the measured object

Determined the temperature measurement range according to the temperature range of the measured object, and then select the infrared thermal imager with the appropriate temperature range. At present, most infrared thermal imagers on the market are divided into several temperature ranges, such as - 40~120℃ and 0~500℃. The larger the span of the temperature range does not mean better performance. A smaller temperature range has more accurate temperature measurements. In addition, when the general infrared thermal imager needs to measure objects above 500℃, it needs to be equipped with corresponding high-temperature lenses.

3. Temperature resolution
This indicates the temperature sensitivity of an infrared thermal imager. The smaller the temperature resolution, the more sensitive is the infrared thermal imager to the temperature change. So, choose the product with a temperature resolution as small as possible. The main purpose of using an infrared thermal imager is to find out if the spot has any temperature fault by detecting the temperature difference. Measuring the temperature of a single point is of little use. It is mainly about finding the spot having a relatively high temperature to realize pre-maintenance.

4. Spatial resolution

To put it simply, the smaller the spatial resolution value is, the higher the spatial resolution is, and the more accurate the temperature measurement is. When the spatial resolution value is smaller, the smallest target to be measured can cover the pixels of the infrared thermal imager, and the test temperature will be the real temperature of the measured target.

If the spatial resolution value is larger, the spatial resolution is lower. The smallest target to be measured 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 average temperature of the measured target and its surrounding temperature, which is inaccurate.

5. Temperature stability

The central component of an infrared thermal imager is the infrared detector. At present, there are mainly two kinds of detectors, namely vanadium oxide crystal detectors and polysilicon detectors. The main advantage of a vanadium oxide crystal detector is that its temperature measurement field of view (MFOV) is 1, which means that its temperature measurement is accurate to 1 pixel.

An amorphous silicon detector’s MFOV is 9, that is, the temperature per point was obtained based on the average of 3*3=9 pixels. It has better temperature stability, longer service life, and smaller thermal drift.

6. Combination function of infrared and visible images

A lot of work will be saved by juxtaposing the infrared image and visible image. The thermal spots in the infrared image can be positioned according to the visible image. Meanwhile, the automatic generation of the report will greatly reduce the operation time.

Quanhom is a professional custom optical lens manufacturer. We develop, manufacture, and provide customized services for various Opto-mechatronic components. Our team bridges the gap between superior performance and limited budget, especially when we are involved in projects integrating high precision. Products include infrared optical assemblies for VIS/SWIR/MWIR/LWIR, eyepieces, infrared lens elements (from monoscopic to Quickly switching between multi-field and continuous zoom infrared lenses), etc.