Method of reading characters and method of reading postal addresses

A method of reading a postal address comprising:

• a first step of converting image information, which includes character string information having a town name portion and a street number portion, into an electrical signal;
• a second step of locating a character string description region in the electrical signal of the image information, and extracting combinations of connected image components, which form characters in the character string description region, as tentative character patterns;
• a third step of implementing the character classification for each of the tentative character patterns by making reference to the character classification dictionary thereby to obtain recognition candidate characters and the similarity of tentative character patterns and the recognition-candidate characters;
• a fourth step of forming a lattice consisting of the recognition-candidate characters, implementing the matching for the lattice with a town name dictionary thereby to identify character strings of the town name portion in the tentative character patterns, and detecting the head position of the street number portion;
• a fifth step of extracting, based on the information of the head position obtained in said fourth step, periphery information of tentative character patterns which correspond to recognition-candidate characters of tentative character patterns in the street number portion, and applying weights to the tentative character patterns for evaluating the credibility of the periphery information of the tentative character patterns by making reference to the segmentation dictionary, which contains likelihood of the periphery information, by using the recognition-candidate character as the key;
• a sixth step of segmenting the street number portion into characters based on the weights;
• and
• a seventh step of implementing the word-wise matching with a street number dictionary for a set of character classification results produced in said sixth step thereby to identify the character string of street number.

A method of reading characters with a postal address reading apparatus having an image input means for converting image information of a written surface into an electrical signal and means of reading out of the image a character string written on the surface, said method comprising:

• a first step of extracting the signal of the character string from the electrical signal of the image;
• a second step of extracting a tentative character pattern which is deemed to form a character from the signal of the character string, or, in case a tentative character pattern cannot be determined uniquely, extracting a plurality of tentative character patterns;
• a third step of implementing the character classification for the extracted tentative character pattern;
• a fourth step of calculating the external form penalty based on the assessment of the periphery information depending on the possible types of error of character segmentation;
• and
• a fifth step of confining candidates of tentative character patterns in accordance with the character classification result of said step 3 and the external form penalty calculated in said fourth step, and implementing the matching for the character pattern candidates with character strings stored in advance in a dictionary which contains character strings that can possibly be written on written surfaces, thereby recognizing the character string written on the written surface.