Infrared thermography is one of the most widely accepted tools for monitoring and diagnosing faults in electric power distribution equipment, motors and drives, and mechanical equipment of all types. Once performed only under contract by highly-trained specialists, lower-cost, easier to use cameras are bringing the technology in-house. Many plants employ thermal analysis experts to make initial surveys and set up routes, then use in-house personnel to perform routine periodic scans.
As more plants deploy user-friendly, high-resolution imagers, maintenance practitioners are using them more often and on less routine applications, finding anomalies earlier and diagnosing problem areas such as roofing, boilers and process equipment. These applications are often unique or unfamiliar, and it can be difficult to relate the thermal image to the object being evaluated.
Infrared images of low-thermal-contrast scenes are generally difficult to interpret, sometimes even for a trained user, says Tim Schooler, senior product manager, Infrared Solutions (www.infraredsolutions.com). This is one of the frustrating aspects of IR cameras to those who are unfamiliar with the imaging technology. They are often unsure of what they are looking at in the infrared image.
Infrared Solutions has addressed this problem by incorporating a 1.3 megapixel visible light sensor with its vanadium-oxide uncooled microbolometer IR array to provide greater contrast. The resulting camera, dubbed IR-Fusion, offers several ways to merge the IR and visible images on the same 5-in. display. Users can see exactly how the IR image relates to the objects in the scene.
Its a unique implementation of image fusion technology, says Schooler. IR-Fusion combines the visible and infrared images to produce a single image of greatly enhanced detail. This combining process is done with a technique called alpha-blending, which uses a ratio of each image and adds them together. You can display an image from full IR to full visible or anywhere in between -- if a blending ratio of 50/50 is used, youll see exactly half of each image blended together to create the final image.
Five viewing modes allow users to choose the most appropriate image for the job:
- Full IR: This mode offers a conventional, high-resolution IR image.
- Picture-in-picture: An IR portal is surrounded by a visible-light frame of reference to ease identification and analysis.
- Alpha blending: Visible and IR images are combined at any ratio to produce a single image with enhanced detail, available in full screen or picture-in-picture.
- IR/visible alarm: Only temperatures that fall above, below or between defined limits are shown in full IR format; the rest of the image is visible-light.
- Full visible-light: Pixel-for-pixel reference photos capture bright, detailed control images for incident remediation documents and reports.
The technology also allows the camera operator to view a laser pointer on the LCD to help pinpoint thermal problems.
The companys new SmartView software provides simple post-image temperature analysis and report capabilities by providing a single file that includes both the visible-light and IR images from the same viewing perspective.
IR-Fusion technology has a clear advantage in regards to image quality, and the alpha-blended display greatly enhances the image, especially in low-contrast scenes where the temperature differential is minimal and the IR image tends to appear to be all one color, Schooler adds. By blending the IR and visible-light images, we greatly enhance the quality of the image by showing details in the visible spectrum that are not present in the IR.