1. An ultrasonic diagnostic apparatus comprising: an image acquisition unit configured to acquire an ultrasonic image; a first calculation unit configured to calculate directions of edges in a local region in the ultrasonic image, sizes of the edges in the local region, and directional uniformity of the edges in the local region; a second calculation unit configured to calculate a composite coefficient by using the sizes of the edges and the directional uniformity of the edges; a third calculation unit configured to calculate a filtering coefficient for a region corresponding to the local region based on the composite coefficient; and a filtering unit configured to perform filtering processing for sharpening or smoothing the ultrasonic image with respect to the ultrasonic image by using the filtering coefficient.