Image display apparatus and method, and storage medium

An image display method for displaying an image in a virtual space in accordance with a posture of a viewpoint of a user on an optical see-through-type display picture surface through which a real space is transparently observable with the virtual image, said method comprising:

• a switching step of performing switching between a first mode and a second mode;
• a posture-information output step of calculating, in the first mode, the posture of the viewpoint based on correction information and measured values of the posture having three degrees of freedom input from a posture sensor and outputting the calculated posture as posture information, and outputting, in the second mode, a predetermined posture as posture information relating to the viewpoint;
• an image generation step of generating the image based on the posture information output in said posture-information output step;
• an instruction-information input step of inputting instruction information instructing that the posture of the viewpoint coincides with the predetermined posture;
• a correction-information calculation step of calculating the correction information based on the measured values of the posture when and/or before and after the instruction information has been input, and the predetermined posture;
• a modification information input step of inputting modification information for modifying the correction information;
• and
• a correction-information modification step of modifying the correction information in accordance with the modification information.

An image display method for generating a superposed image obtained by superposing an image in a virtual space in accordance with a posture of a viewpoint of an image pickup apparatus on an image in a real space photographed by the image pickup apparatus, and displaying the generated superposed image on a display picture surface, said method comprising:

• a switching step of performing switching between a first mode and a second mode;
• a posture-information output step of calculating, in the first mode, the posture of the viewpoint based on correction information and measured values of the posture having three degrees of freedom input from a posture sensor and outputting the calculated posture as posture information, and outputting, in the second mode, a predetermined posture as posture information relating to the viewpoint;
• an image generation step of generating the superposed image based on the posture information output in said posture-information output step;
• an instruction-information input step of inputting instruction information instructing that the posture of the viewpoint coincides with the predetermined posture;
• a correction-information calculation step of calculating the correction information based on the measured values of the posture when and/or before and after the instruction information has been input, and the predetermined posture;
• a modification-information input step of inputting modification information for modifying the correction information;
• and
• a correction-information modification step of modifying the correction information in accordance with the modification information.