How to choose a suitable infrared thermal imager?

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How to choose a suitable infrared thermal imager? [Copy link]

Infrared thermal imagers and their working principles passively receive infrared radiation (heat) emitted by the target being measured and convert this heat energy into a visual image with temperature data (all objects above absolute zero -273°C emit infrared radiation). In layman's terms, infrared thermal imaging is a technology that can convert infrared images into thermal radiation images, which can read temperature values from the image. Therefore, each pixel in the thermal radiation image is actually a temperature measurement, which can achieve non-contact measurement of the surface temperature of an object. What indicators should be paid attention to when choosing a thermal imager?

1. Brand

There are many brands on the market, common brands include Fluke, FILI, Testo, Infotech, Uni-T, Hikvision, etc. There are certain differences in test accuracy, stability, and software. You can buy according to your budget and buy the ones that meet your requirements. If you are doing scientific research, choose imported instruments as much as possible.

2. Type

At present, it is mainly divided into three categories: portable (pocket type), handheld, and online. They can be selected according to their respective needs and applications. The pocket type is cheap, easy to operate, and easy to carry. The handheld type is generally used in industry, with better performance than the portable type, clearer photos, and indicators are generally higher than the portable type. The online type generally requires software design and is suitable for long-term detection. If used, you must carry a monitor and a notebook for online observation.

3. Temperature range

The temperature range refers to the lowest or highest temperature value of the measured object. It is necessary to predict the temperature of the object to be tested in advance and make a selection. Secondly, accuracy needs to be considered.

4. Thermal sensitivity

It is a measure of the ability of a thermal imager detector to distinguish subtle differences in thermal radiation in an image. Thermal sensitivity is generally expressed in milliKelvin (mK) or temperature. Generally speaking, the smaller the thermal sensitivity, the stronger the ability to resolve thermal signals.

5. IFOV spatial resolution

At the unit test distance, the minimum target ( area ) that each pixel of the infrared thermal imager can detect is measured in mRad . To put it simply, when the unit distance is the same, the smaller the IFO , the smaller the area that a single pixel can detect. The unit measurement area is composed of more pixels, the more details the image presents, and the clearer the presentation. Remember that the smaller the IFOV , the better. Of course, the cost needs to be considered.

6. FOV

FOV is also called field of view in optical engineering . The size of the field of view determines the field of view of the optical instrument , which generally refers to the vertical and horizontal angles. Generally speaking, the range that a thermal imager can detect can be calculated using the FOV calculator. It is worth noting that if you want to see a larger range at the same distance, choose a wide-angle lens, and if you want to see farther, choose a telephoto lens. It is the same as the camera. Some thermal imagers do not support lens installation, so you need to look at the technical indicators when purchasing. For some thermal imager indicators, if you see the D:S ratio and the ratio of distance to light spot, remember that the larger the ratio, the better.

7. Infrared image resolution

Infrared resolution refers to the pixels of the thermal imager detector. Similar to visible light, the higher the pixels, the clearer and more delicate the picture. The higher the pixels, the more temperature data can be obtained at the same time. This is simple, just like when we buy a mobile phone, the higher the resolution, the clearer the image we see.

8. Frame rate

The frame rate of a thermal imager system refers to the number of thermal images that the infrared imager can collect per second. If it is a dynamic moving target, the higher the frame rate, the better. Currently, 9Hz , 30Hz , 60Hz or higher are common in the market. Of course, if the budget is sufficient, it is better to buy a thermal imager with a high frame rate. For recording videos, it will reduce the appearance of ghosting.

9. Focal length

The focal length of a thermal imager can be fixed or adjustable. Currently, there are four main focusing methods for infrared thermal imagers: focus-free, manual focus, automatic focus, and laser automatic focus. Generally, the lower the price, the more likely it is to be focus-free. It is very convenient, but its disadvantages are that the spatial resolution is not high and it cannot shoot at close range. It would be better to choose automatic focus. In fact, the choice mainly depends on purchasing needs.

10. Emissivity

The emissivity ε represents the ability of an object to emit infrared radiation outward. The emissivity of each object is a constant less than 1. The emissivity of non-metallic and metallic materials is very different. The industry default emissivity is 0.95 . Don't worry about how to set the emissivity. The hot wire meter has a built-in reference. For example, plastic, paint, leather, iron, stainless steel, etc., you can test different objects and select different emissivities. If you don't set it, it may affect the temperature accuracy.

The above content is a simple guide shared by Antai Testing on how to choose a suitable thermal imager. I hope it can help you. Secondly, after-sales and professional training services are also very important. Choose a supplier with good training and maintenance. Secondly, there are many operating skills for using infrared thermal imagers. It is not just as simple as taking pictures and recording videos. Training is required, including software operation analysis, how to generate reports, professional learning, and reliable services to ensure that we can use it better.


This content was originally created by Antai Testing Equipment , a netizen on the EEWORLD forum. If you need to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source

led2015

I used to think that I only needed to include the parts of electronic devices that I would use, but later I thought that was naive.

qwqwqw2088

The test distance range is not specified

What does the FOV field of view include?