Head-mounted display device, control method of head-mounted display device, and display system

1. A head-mounted display device that enables a user to visually recognize a virtual image and an external scene, comprising:

an image display unit that displays the virtual image, the image display unit including a right optical image display unit and a left optical image display unit; and

an augmented reality processing unit configured to:

determine a target distance at which the user is caused to visually recognize the virtual image in the external scene;

set two virtual cameras for acquiring a 2D projection image in a 3D model space based on the target distance;

obtain a first convergence angle of the virtual image displayed on the basis of first right-eye image data and first left-eye image data which are identical to each other;

calculate a target convergence angle, which is a convergence angle at the target distance with respect to two eyes of the user;

calculate a target parallactic angle, which is a parallactic angle at the target distance, according to the target convergence angle and the first convergence angle;

generate right-eye image data and left-eye image data based on the 2D projection image according to the target parallactic angle respectively;

cause the right optical image display unit to display the virtual image based on the right-eye image data; and

cause the left optical image display unit to display the virtual image based on the left-eye image data.

2. The head-mounted display device according to claim 1 , wherein:

the head-mounted display device further comprises a pixel parallactic angle storage unit that stores a difference between the first convergence angle of the virtual image displayed on the basis of the first right-eye image data and the first left-eye image data which are identical to each other and a second convergence angle of the virtual image displayed on the basis of second right-eye image data and second left-eye image data which are laterally deviated from each other; and

the augmented reality processing unit generates the right-eye image data and the left-eye image data for fitting the virtual object to the external scene using the difference stored in the pixel parallactic angle storage unit.

3. The head-mounted display device according to claim 2 , wherein the augmented reality processing unit

generates the right-eye image data and the left-eye image data from single image data indicating the virtual image using the target parallactic angle and the difference stored in the pixel parallactic angle storage unit.

4. The head-mounted display device according to claim 2 , wherein the augmented reality processing unit

generates the right-eye image data by scaling the 2D projection image captured by one virtual camera and generates the left-eye image data by scaling the 2D projection image captured by the other virtual camera using the target parallactic angle and the difference stored in the pixel parallactic angle storage unit.

5. The head-mounted display device according to claim 4 , further comprising an interocular distance storage unit that stores the user's interocular distance,

wherein the augmented reality processing unit further arranges a virtual viewpoint which is a virtual point of view in the 3D model space on the basis of the determined target distance at the time of setting the two virtual cameras, arranges one virtual camera at a position separated by the interocular distance/2 from the arranged virtual viewpoint, and arranges the other virtual camera at a position separated by the interocular distance/2 from the arranged virtual viewpoint.

6. The head-mounted display device according to claim 5 , further comprising an interpupillary distance measuring unit that measures the user's interpupillary distance,

wherein the measurement result by the interpupillary distance measuring unit is stored as the interocular distance in the interocular distance storage unit.

7. A control method of a head-mounted display device that enables a user to visually recognize a virtual image and an external scene, the head-mounted display including an image display unit that displays the virtual image, the image display unit includes a right optical image display unit and a left optical image display unit, and an augmented reality processing unit, the control method comprising:

determining a target distance at which the user is caused to visually recognize the virtual image in the external scene;

setting two virtual cameras for acquiring a 2D projection image in a 3D model space based on the target distance;

obtaining a first convergence angle of the virtual image displayed on the basis of first right-eye image data and first left-eye image data which are identical to each other;

calculating a target convergence angle, which is a convergence angle at the target distance with respect to two eyes of the user;

calculating a target parallactic angle, which is a parallactic angle at the target distance, according to the target convergence angle and the first convergence angle;

generating right-eye image data and left-eye image data based on the 2D projection image according to the target parallactic angle respectively;

causing the right optical image display unit to display the virtual image based on the right-eye image data; and

causing the left optical image display unit to display the virtual image based on the left-eye image data.