Information presentation apparatus and information display apparatus

An information display apparatus comprising:

• a display device having a display screen;
• image pickup means for picking up said display screen;
• means for generating display information on a mark of visible ray to be displayed at a specified position in an area of said display screen and for outputting said display information to said display device;
• means for determining, when an image of said mark is displayed in said area, a position of said image of the mark in said area picked up with said image pickup means and for determining, when a point in said area is pointed to with a pointing signal of infrared ray outputted from a pointing means, a position of an image of said pointing signal in said area picked up with said image pickup means;
• means for generating position calibration information using said specified positions of a plurality of the marks and corresponding position information on respective positions of images of the plurality of the marks;
• and
• means for correcting the position of the image of said pointing signal using said position calibration information to determine the position of the point pointed to in said area,
• wherein said image pickup means has an imaging sensitivity which is changeable between when picking up said visible ray and when picking up said infrared ray.