Fixed Pattern Noise
FPN can be a major issue in digital imaging, as it can detract from the quality and accuracy of images. It is especially problematic in low-light conditions.
Fixed Pattern Noise (FPN) is a common issue in digital imaging, particularly in cameras that use CMOS (Complementary Metal-Oxide-Semiconductor) or CCD (Charge-Coupled Device) sensors. FPN refers to a consistent pattern of bright or dark pixels that appear in the same location on every image captured by the camera, regardless of the subject or lighting conditions.
FPN is caused by variations in the sensitivity of individual pixels on the camera sensor. These variations can occur during the manufacturing process, or they can develop over time due to environmental factors such as temperature changes. When the camera captures an image, these variations in sensitivity can result in some pixels producing a slightly different output than others, leading to the appearance of fixed pattern noise in the image.
FPN can be a major issue in digital imaging, as it can detract from the quality and accuracy of images. It is especially problematic in low-light conditions, where the noise can become more apparent. However, there are several ways to address FPN, including:
Calibration: Some cameras come with a built-in calibration process that can help to reduce FPN. This involves capturing images of a uniform surface and using software to adjust the sensitivity of each pixel to make them more uniform.
Dark frame subtraction: Another technique for reducing FPN involves capturing a dark frame, which is an image captured with the lens covered. The camera can then subtract this dark frame from subsequent images to remove FPN.
Post-processing: Finally, FPN can be reduced in post-processing using software tools such as noise reduction filters. These filters can help to smooth out the variations in pixel sensitivity, resulting in a cleaner, more uniform image.
In summary, fixed pattern noise is a common issue in digital imaging, but it can be addressed through a variety of techniques including calibration, dark frame subtraction, and post-processing. By reducing FPN, photographers can ensure that their images are clean, accurate, and visually appealing.