How Do Infrared Cameras Work?
Infrared cameras are sophisticated instruments that take heat energy and transform it into an image that we can see with our eyes. They literally give you super heat vision. Everything in the world emits infrared energy. This energy is all around us and behaves mostly the same way that visible light behaves. The big difference is that our eyes cannot see this heat energy. The infrared cameras gather this IR energy with specialized optics and focus it onto a thermal sensor which in turn converts that data into a usable image. The image is then displayed on an LCD screen or eyepiece.
More advanced infrared cameras are actually designed to provide not only a visual representation of the heat energy in the scene but to also provide you with numeric temperature measurement. These types of infrared cameras are known as radiometric cameras. The sensor is calibrated so that we can determine the temperature of each pixel in the scene. Not only can you visualize the heat but also measure it from a distance. This is also known as non-contact temperature measurement.
You can imagine that there would be hundreds of uses for this technology in the industrial and commercial world. Every day new uses are being pioneered by people just like you and me. The most common infrared cameras are either handheld systems for in field thermal analysis (AKA thermography) or laboratory type cameras that are better suited for lab analysis or process control machine vision.
Handheld Infrared Cameras.
Handheld infrared cameras come with a wide range of features and price tags. Typically price is determined first by the resolution of the thermal sensor. This can range from 80×60 pixels all the way up to 640×480 pixels. Most common resolutions however are 160×120, 320×240 and 640×480. Next features will determine the ultimate price. Todays infrared cameras usually have a visual camera integrated into them so that they can take a thermal and regular picture side by side. This is useful for reporting purposes. Many infrared cameras also now let you combine or overlay the thermal and visual image for an interesting effect. This is sometimes called thermal fusion or sensor fusion. Another factor is the capabilities of the temperature measurement feature. Some cameras are limited to measuring only the center spot of the image while others can measure any pixel and place multiple areas of interest on the screen at the same time. Finally, infrared cameras differ in how they interface with your PC computer. Most all infrared cameras will store the image and data digitally so that you can download it to the PC for further analysis or report generation. This can vary from a simple JPEG file that only has the temperature onscreen (like a screenshot of the camera LCD) to full featured data file with temperature and visual data embedded. The more advanced cameras will also have more advanced software packages that allow for detailed offline analysis. The top of the line cameras will include a live to PC interface that lets you analyze and record information directly from the infrared camera to your PC software.
Laboratory Infrared Cameras and Infrared Microscopes.
Laboratory infrared cameras are highly sensitive instruments with features and sensors designed specifically for scientific analysis. These can be regular uncooled cameras or high end ultra sensitive cooled thermal imagers. Most Lab type cameras utilize a computer interface for data capture and to adjust camera settings. These types of cameras are very popular for medical imaging, PCB analysis, new product design and any application that requires a visual representation of heat. A very exotic type of Lab camera is the infrared camera microscope. These cameras have specialized optics that allow for very close up detailed imaging of your components. Microscope cameras need to be used on a microscope stand for proper imaging.