1. An image extraction system for extracting patterns including at least one of characters, graphics and symbols from an image having a frame formed by straight line portions said image extraction system comprising: connected pattern extracting means for extracting partial patterns having connected pixels from the image; straight line extracting means for extracting straight line portions from the partial patterns; attribute adding means for categorizing the partial patterns into a first pattern including only portions of the pattern which do not touch the frame and portions of the frame which do not touch the pattern, and a second pattern including portions of the pattern which touch the straight line portion extracted by said straight line extracting means; separating means for separating the straight line portions from the second pattern; intersection calculating means for calculating intersections of the patterns and the straight line portions from the second pattern; intersection associating means for associating the intersections which are calculated by said intersection calculating means; interpolating means for interpolating a region of the pattern within the straight line portions forming the frame based on the intersections which are associated by said intersection associated means; and connection confirming means for confirming a connection of a pattern with respect to the extracted partial patterns of the pattern, said connection confirming means extracting a confirmed connection of the pattern and feeding back the portions of the pattern which cannot be confirmed to said intersection associating means, said intersection associating means re-associating the intersections calculated by said intersection calculating means with respect to the portion of the pattern fed back by said connection confirming means, said interpolating means interpolating a region of the pattern within the straight line portions forming the frame based on the intersections which are re-associated by said intersection associating means.