Patent ID: 8666175

Claim:
A method of detecting an object in an input image by using a multi-stage classifier, the method comprising: calculating, by way of a processor, a feature value based on features extracted from the input image using a classifier of an i th (i is a positive integer) stage, and comparing the calculated feature value with a first threshold value of the i th stage, and when the feature value is smaller than the first threshold value of the i th stage, classifying the input image into a non-object; comparing, when the feature value is greater than the first threshold value of the i th stage, the feature value with a second threshold value of the i th stage, and when the feature value is greater than the second threshold value of the i th stage, classifying the input image into an object; comparing, when the feature value is less than the second threshold value of the i th stage, the feature value with a third threshold value of the i th stage; when the feature value is greater than the third threshold value of the i th stage, jumping to a classifier of an i+2 th stage without calculating the feature value in a classifier of an i+1 th stage and when the feature value is smaller than the third threshold value of the i th stage, moving to the classifier of the i+1 th stage and calculating the feature value in the classifier of the i+1 th stage; and determining whether the object exists in the input image, based on a result of the classification performed by the object classification unit.