Apparatus for recognizing signs, method thereof, and method for recognizing image

PURPOSE: A sign recognizing device, a sign recognizing method thereof, and an image recognizing method thereof are provided to reduce the operation of DCT(Discrete Cosine Transform) conversion for sign recognition by binarizing an image. CONSTITUTION: A sign recognizing device extracts an ROI(Region Of Interest) including sign information from an image(210). The device binarizes the ROI(220). The device converts the DCT of the ROI by using a computation value table according to DCT coefficient coordinates(235,240). The device extracts a DCT coefficient as a feature value of a sign(250). The device recognizes the sign(260). [Reference numerals] (210) Extract a region of interest including the information of a sign from an image; (220) Binarize the region of interest using a preset critical value; (230) Thin the binarized region of interest; (235) Select a DCT coefficient coordinate for performing DCT conversion; (240) DCT convert the binarized region of interest according to the DCT coefficient coordinate using a preset computation value table; (250) Extract a DCT coefficient computed by the DCT conversion as a feature value; (260) Recognize a sign by calculating distances between each feature value of a plurality of classes and the extracted feature values and classifying which class among a plurality of classes the sign is belonged to; (AA) Start; (BB) End