1. An image filtering method to filter an image in a parallel manner by use of a multi-core processor, and the image filtering method comprising the following steps: determining a computing direction, wherein a plurality of computing directions for said filtering processing is determined according to a number of dimensions of an image and a predetermined neighborhood range of said filtering processing; computing respective directions filtering, wherein the following processing is performed according to each of the determined computing directions for one row of pixels in the image, by taking each pixel in the row as an object pixel, performing by each thread in a plurality of threads predetermined filtering computing between an object pixel and respective neighborhood pixels of the object pixel in the computing direction; and saving the filtering computing results as the filtering results of the object pixels and the respective neighborhood pixels in a cumulative manner, wherein the neighborhood pixels are pixels located within the neighborhood range of the object pixel; and obtaining an image filtering result, wherein the filtering results of all the determined computing directions, obtained by the respective directions filtering computing step, are accumulated according to each pixel of the image to obtain an image filtering result of the image.