1. An apparatus, the apparatus comprising: a key joint detector configured to analyze an image to detect key joint data regarding respective plural key joints of an object in the image; a database configured to store respective information of plural object poses representing potential poses of one or more objects; and a pose retriever configured to generate at least one candidate pose for the object based on the detected key joint data, to calculate a pose likelihood value of the at least one candidate pose based on the key joint data, to calculate a pose naturalness measurement value of the at least one candidate pose based on a pose database, and to retrieve a most likely pose based on the pose likelihood measurement value and the pose naturalness measurement value.