Thermography Camera A device that captures thermal distribution and displays it as a 2D image. There are two main methods for configuration 2D images: scanning with a single (or a few) elements using a movable (rotation or vibration) mirror, and electronic scanning with an image sensor (FPA: Focal Plane Array (digital cameras also use this). Since the beginning of the 21st century, FPA has become mainstream. It captures infrared energy and converts it into temperature.
Infrared Light has wave properties and is also called electromagnetic waves. The length of one period of a wave is called the wavelength. UV rays have a shorter wavelength than the violet of visible light (approximately 0.35 to 0.75 μm (1000 μm = 1 mm)) that can be seen by the naked eye, and infrared rays have a longer wavelength than red. Depending on the wavelength range (wavelength band), it is classified as near infrared (approximately 0.7 to 2.5 μm), mid infrared (approximately 2.5 to 5 μm), and far infrared (approximately 5 to 1000 μm). Thermography cameras generally refer to them as near infrared (approximately 0.7 to 5 μm), short wavelength (approximately 3 to 5 μm), and long wavelength (approximately 7 to 14 μm).
Number of elements and pixel (horizontal× vertical) An element (pixel) is the smallest unit of an image, also known as a pixel. The number of elements refers to the number of elements lined up in the image sensor. The more elements you have, the clearer the image with higher resolution.
Wavelength This refers to the wavelength range to be measured. Infrared thermography measures the infrared energy emitted from an object and converts it into temperature. In principle, the wavelength range of infrared light emitted from an object differs depending on the temperature, so short wavelengths are suitable for measuring high temperatures and long wavelengths for measuring low temperatures. Also, if laser light or other light contained in the measurement wavelength is seen, there is a risk of damage to the element, whether directly or indirectly (reflected). For example, in the case of a camera with a long wavelength band (8 to 14 μm), CO 2 Lasers (10.6 μm) are a big enemy.
Field field of view (FOV) This refers to the range of the field of field of view to be measured. It is expressed as a horizontal and vertical angle. In infrared thermography, a wide-angle lens is generally equivalent to a standard lens of a general camera (35 mm film camera).
radius resolution (IFOV) (Instantaneous field of view angle) This is the size that one element is looking at. It is expressed in terms of the angle that one element is looking at. unit is "mrad" (milliradian). (Arc degree method: 1π (rad) = 180°, reading: rad = radian) Multiply this number by the measurement distance (m) to get the approximate measurement size (mm) of one element at that distance. (In practice, it is recommended to measure at least 3*3 times that size due to blurring.)
Temperature resolution This is the smallest temperature difference that can be detected by a measuring device (infrared thermography). The smaller this value, the better resolution of the temperature measurement by the infrared thermography. It is generally expressed as the Noise Equivalent Temperature Difference (NETD), but since the calculation method differs depending on the manufacturer, it is not possible to compare between manufacturers.
accuracy ratings (temperature accuracy) This refers to the deviation of the measurement value from a standard thermometer (calibration system); the smaller this value, the better the performance. Accuracy is stated only for blackbody furnaces and is not guaranteed for the actual object being measured.
Frame rate (frame time) This indicates how many times the screen is updated per second, and is also called the screen update cycle. The larger the value, the faster the temperature change can be accommodated. The temperature tracking ability of a microbolometer element is said to be limited to about 30Hz.
focus It means to focus. There are two types of focusing: autofocus and manual focus. If the focus is not aligned, accurate measurements cannot be taken.
Minimum measuring distance (shortest imaging distance) This refers to the minimum (shortest) distance at which the camera can be focused. The closer you can get, the larger the object will display and the finer resolution you can measure.
The Narcissus Phenomenon This is a phenomenon where the element itself is reflected on the object being measured. It is noticeable when facing an object with low emissivity at close range, such as when measuring an electronic circuit board. It can be avoided by keeping the distance and adjusting the angle so that the reflection of the element does not come directly in front of you.
Viewfinder This refers to a viewing window that allows you to visually check the image captured by the camera. Use it to compose and focus before taking a picture. It is often used when shooting outdoors and the image is difficult to see on the LCD screen.
Temperature range The temperature range that the camera can measure. If the measured value (the point you want to measure) is within the temperature range, the temperature data is saved even if the image is not within display temperature range (the Max to Min range of the color bar), so you can display by changing display temperature range during analyzing. However, please note that if the area is outside the display temperature range on the screen, you cannot manually focus on that area.
Temperature scale The temperature range scale display on the screen (color bar) (often only the upper and lower limit limits and color bar are display, with no intermediate scale). It can be changed on the camera body or on a computer. By adjusting the display temperature range to match the area you want to measure, you can display minute temperature variations. (This is also called "thermal focus" as it "focuses" on the temperature range you want to see.)
Color Palette Color information refers to the combination of colors display on display. It can be changed later, and rainbow/iron/gray are commonly used, with rainbow colors used to clearly display temperature distribution, iron for hot spots, and gray for thermal gradients. Rainbow can also be used to show red, yellow, and blue, so it is easy to understand equipment diagnosis reports by showing dangerous areas that are hot with red, areas requiring caution with higher temperatures with yellow, and normal areas with green to blue.
Isotherm function (color alarm) This refers to specially color-coding temperature ranges that you want to pay attention to. Areas with temperatures higher than the reference value are display in red, making it convenient for screening at quarantine stations such as airports, and for instantly finding areas above a certain temperature in equipment diagnosis, as it allows you to make an instant judgment by color rather than having to look at the temperature value each time.
parameter Basic information when taking a photo with a camera. These include emissivity, temperature of the reflected light source, measurement distance, temperature of the external optics, and transmission rate of the external optics. parameter that affect the measurement accuracy can be corrected based on Kirchhoff's law. They can be changed with the software even after measurement. However, although transmission rate of window materials along the path can be corrected, if the object being measured itself is transparent, the transmission rate cannot be corrected. The correction algorithm assumes that transmission rate of the object is 0.
Kirchhoff's Laws The ratios of these three energy components - the energy radiated from the surface of the object to be measured, the energy radiated from an object in front of the surface and reflected by the surface, and the energy radiated from an constituent on the other side of the surface and transmitted through the surface - are emissivity, reflectivity, and transmission rate, where emissivity + reflectivity + transmission rate = 1.
emissivity The infrared radiation energy of blackbody, which is an ideal radiator, is set to 1, and thermal radiation (infrared energy) from an actual object is expressed as a value between 0 and 1 and is called emissivity. Even with the same material, when the surface is rough, emissivity is high, and the radiated energy is stronger, making it possible to measure with high accuracy. When emissivity is low, the radiated energy is low and the reflected energy is high, making measurement difficult.
Reflectivity If emissivity of an object is not 1, the fraction of energy that is reflected. The ratio of reflected infrared energy to the energy incident on an object is called reflectance. Assuming an object does not transmit light, 1 -emissivity = reflectance.
Reflection source temperature The apparent temperature of a nearby object (such as a wall) reflected by the object (the temperature that can be measured with emissivity of 1)
transmission rate There are measurement targets that transmit the measurement wavelength depending on the object, in which case the energy of the object's emissivity + reflectance + transmission rate enters the camera, making measurement very difficult. There is no algorithm that can correct this. Resin films and special glass materials transmit the light.
External optics transmission rate If there is a window in the path, the radiation from the object to be measured is absorption and attenuation by the window, and the radiation from the window is added. If transmission rate and temperature of the window material are known, the external optics temperature can be set and absorption by the window material (1 - external optics transmission rate) can be corrected along with the radiation.
MSX (FLIR Systems patented feature) This technology display the contours extracted from the visible image onto the thermal image in real time, making the image easier to distinguish. display /non-display setting can be made using the software.
Picture-in-Picture A type of display method for thermal imaging data. A display method in which only a part of an infrared image is display within a visible image. display /non-display setting can be made using the software.
UltraMax This function is only effective for still images saved in the camera. It achieves image quality equivalent to about four times the normal pixel count through image processing.
blackbody (furnace) It is an ideal radiator with emissivity of 1. blackbody furnace is one that approaches emissivity 1 and can be used as a standard heat source. There are cavity and flat (surface blackbody) types.
Data extension
JPG (JPEG) Still image files saved by the camera and software. In the case of FLIR cameras, the infrared thermal image file contains images based on the thermal data of each element and visible image data from the camera's built-in digital camera, which can be analyzing and adjusted using software, etc.
SEQ These are video files of thermal images recorded using research software, which can be analyzing and adjusted.
CSQ (Camera Sequence) This is a video file of the thermal image when recording with the camera body. It can be analyzing and adjusted. It is compressed compared to SEQ, so the data size is smaller.
MP4 (MPEG4) This is a video file made from the video image (no data) when recording with the camera body. It is an image video as it display on the screen. analyzing and adjustment are not possible.
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