1. A method of modeling a target object from an image captured by an image sensor, the method comprising: obtaining, by a processor, depth information from the image in which the target object is represented in a form of particles; obtaining, by the processor, distance information indicating a distance between adjacent particles in the image; detecting, by a processor, a silhouette of the target object based on the depth information without using the distance information, in response to a determination that the distance information is less than a threshold; detecting, by the processor, the silhouette of the target object based on the depth information and the distance information, in response to a determination that the distance information is greater than or equal to the threshold; and performing, by the processor, smoothing on an adjacent area comprising the silhouette of the target object in the image, in response to the determination that the distance information is greater than or equal to the threshold.