An apparatus, method, and medium for detecting a face in an image using classifiers generated by a boost
algorithm are provided. The apparatus may include an image dividing unit dividing a black and white image into sub-windows; a sub-
window detection unit detecting a sub-window corresponding to a face image in the divided sub-windows using the front part of the
cascade of the classifiers and storing the sub-window detected as the face image; and a post-
processing unit verifying whether each of sub-windows included in a group among a plurality of groups into which stored sub-windows are grouped is the face image using the number of child detections in each group and the latter part of the
cascade of classifiers, integrating the sub-windows in the group according to the result of the
verification, and outputting the result of the integration as the face image included in the black and white image, wherein the number of child detections is the number of sub-windows included in a group. Accordingly, a
false detection rate can be decreased while a
detection rate is increased. As a result, the accuracy of
face detection can be increased.