To suppress an unnatural movement of a moving object at a connection point when a plurality of pieces of video data are connected to each other. A frame acquisition unit 22 acquires pieces of frame data captured at the same time, from the pieces of video data input from cameras C1 and C2. A prohibited-region setting unit 24 sets a prohibited region that is not set as a calculation target when a seam is calculated, based on a position of an object detected in an overlap region between adjacent pieces of frame data and a movement direction of the object. A seam calculation unit 25 calculates a seam between pieces of frame data adjacent to each other, without setting a pixel included in the prohibited region as the calculation target of seam calculation. A connection-frame output unit 26 connects pieces of frame data in accordance with the seam and outputs connection frame data 15.