Thermography principle and use of skills

The infrared thermal imager uses an infrared detector and an optical imaging objective lens to receive the infrared radiation energy distribution pattern of the target to be reflected on the photosensitive element of the infrared detector so as to obtain an infrared thermal image, which is a heat image and the surface of the object. Distribution field corresponds. In layman's terms, an infrared camera converts the invisible infrared energy emitted by an object into a visible thermal image. The different colors above the thermal image represent the different temperatures of the measured object.

The use of infrared cameras includes several major steps:

1, adjust the focal length

The image curve can be adjusted after the infrared image is stored, but the focal length cannot be changed after the image is stored, and other cluttered heat reflections cannot be eliminated. Guaranteeing correct operation for the first time will avoid mistakes in the field. Carefully adjust the focus! If the overheating or cold reflection of the background above or around the target affects the accuracy of the target measurement, try adjusting the focal length or measuring the bearing to reduce or eliminate reflection effects.

2, select the correct temperature range

Do you know the temperature measurement range of the measured object in the field? In order to obtain the correct temperature reading, be sure to set the correct temperature measurement range. When observing the target, fine-tuning the instrument's temperature span will yield the best image quality. This will also affect the quality of the temperature curve and the temperature measurement accuracy.

3, understand the maximum measurement distance

When measuring the target temperature, be sure to know the maximum measurement distance that will give you an accurate temperature reading. For an uncooled microcalorimetric focal plane detector, the target image through the thermal imaging system must occupy 9 pixels or more in order to accurately resolve the target. If the instrument is too far from the target, the target will be very small and the temperature measurement result will not reflect the true temperature of the target object correctly because the temperature measured by the infrared camera at this time averages the temperature of the target object and the surrounding environment. To get the most accurate measurement reading, fill the target object with the instrument's field of view. Show enough scenery to be able to tell the goal. The distance to the target should not be less than the minimum focal length of the thermal system of the camera, otherwise it cannot be focused into a clear image.

4, only to generate a clear infrared thermal image, or at the same time require accurate temperature measurement

What is the difference between this? A quantized temperature curve can be used to measure the temperature in the field, and it can also be used to edit a significant temperature rise. Clear infrared images are also very important. However, if during the working process, temperature measurement is required and a comparison and trend analysis of the target temperature is required, it is necessary to record all the objectives and ambient temperature conditions that affect the precise measurement of the temperature, such as emissivity, ambient temperature, wind speed and direction, and humidity. , heat reflection sources, etc.

5, a single work background

For example, when the weather is cold, when working outdoors, you will find that most of the targets are close to the ambient temperature. When working outdoors, be sure to consider the effects of solar reflection and absorption on the image and temperature measurement. Therefore, some older models of infrared cameras can only perform measurements at night to avoid the effects of solar reflections.

6, to ensure the stability of the instrument during the measurement process

Now all long wave NEC infrared cameras can achieve 60Hz frame rate, so in the process of shooting images, due to instrument movement may cause image blur. For best results, the thermal imager should be as stable as possible when freezing and recording images. When pressing the store button, it should be as light and smooth as possible. Even slight instrument shake may result in unclear images. It is recommended to use a support under the arm to stabilize, or place the instrument on the surface of the object, or use a tripod to keep it as stable as possible.