Method and apparatus for reducing noise in a scanned image while minimizing loss of detail in the scanned image

摘要

Methods of filtering random noise and salt and pepper noise that minimize a loss of detail in an image are described. Sample values of an image that are within a tolerance within a sliding window are used to normalize a sample centered in the sliding window to filter random noise and minimize a loss of detail in an image. Sample values of an image in a sliding window are sorted into a sorted array, and mapped to values based on pre-defined regions of the sorted array to filter salt and pepper noise and minimize a loss of detail in an image.

主权项

1. A method of filtering noise in an image in order to minimize a loss of detail in the image, the method comprising:
determining a plurality of samples of the image that fall within a sliding window, wherein the plurality of samples of the image in the sliding window include a first sample that is centered within the sliding window; determining values of each of the plurality of samples, wherein the first sample has a first value; sorting the values of each of the plurality of samples into a sorted array of the values of the plurality of samples; applying a first clamp level to a first end of the sorted array; applying a second clamp level to a second end of the sorted array, wherein the second end of the sorted array is opposite to the first end of the sorted array; and assigning a second value to the first sample, wherein in response to the location of the first value of the first sample in the sorted array being between (i) the first clamp level in the sorted array and (ii) the second clamp level in the sorted array, the second value is equal to the first value, wherein in response to the location of the first value of the first sample being within the first clamp level in the sorted array, the second value is equal to a value of a sample at the first clamp level in the sorted array, and wherein in response to the location of the first value of the first sample being within the second clamp level in the sorted array, the second value is equal to a value of a sample at the second clamp level in the sorted array.