Gesture detection device and gesture detection method

A gesture detection device that is applied to a vehicle including a vehicle body having an opening portion, a door configured to open and close the opening portion, a camera configured to image a user who faces the opening portion, and a door drive unit configured to drive the door, and that detects a gesture that triggers an operation of the door and is made by the user using a predetermined body part,

• a body part of the user different from the predetermined body part being a reference body part,
• the gesture detection device comprising:
• a position acquisition unit configured to acquire a predetermined position which is a position of the predetermined body part and a reference position which is a position of the reference body part in an image captured by the camera;
• a direction determination unit configured to determine whether the user faces the opening portion based on the reference position in the image;
• and
• a gesture determination unit configured to determine whether the user has made a gesture based on changes of the predetermined position and the reference position in a plurality of the images captured at different imaging times, when the direction determination unit determines that the user faces the opening portion, wherein
• the gesture determination unit determines that the user has made a predetermined gesture for opening at least the door, when the predetermined position is moved relative to the reference position in a predetermined direction corresponding to an opening direction of the door.