Patent ID: 7697780

Claim:
A computer-based system for filtering image noise, the system comprising: an image sensor for capturing an image; a database for storing data; an image acquiring module for acquiring the image from the image sensor; a gray-scale converter for converting gray-scale values of the image, and for sharpening the image; an intersecting point selecting module for defining axes perpendicular to image borders, for determining gray-scale values of axis points by using an average value filtering method, for selecting intersecting points between the image borders and the axes, for creating an object points set, and for inputting the intersecting points into the object points set, the average value filtering method comprising selecting an axis point of one of the axes, and determining coordinates and a gray-scale value of the axis point, calculating an average value of gray-scale values of a plurality of nearby points that around the axis point, determining absolute differences between the average value and each gray-scale value of the plurality of nearby points, defining a threshold value, using the average value to replace corresponding gray-scale value if the threshold value is larger than the absolute difference, or keeping current gray-scale value if the threshold value is not larger than the absolute difference; a noise filtering module for fitting a geometric character according to the object points set and defining a tolerance threshold value, for calculating a distance from each intersecting point in the object points set to the geometric character, for determining whether the distance is larger than the defined tolerance threshold value, and for marking the intersecting point as a noise and deleting the intersecting point if the distance is larger than the defined tolerance threshold value, for creating a new object points set after deleting the intersecting points known as noises from the object points set, for fitting a new geometric character according to the new object points set; and a storing module for outputting and storing the new geometric character into the database.