Information processing apparatus and input control method

1. An information processing apparatus comprising:

a camera serving as an image capturing section configured to capture an image of a hand;

a memory device configured to store a program; and

a central processing unit configured to execute the program to perform operations of:

an extracting section configured to extract a hand area from the image input by the image capturing section;

a reference line determining section configured to determine a predetermined line in the image as a reference pushdown line based on the hand area;

a determining section configured to determine a pushdown move if the bottom part of the hand area comes below the reference pushdown line;

a first position determining section configured to determine a depth position based on an aspect ratio of the hand area if the pushdown move is determined by the determining section, wherein the aspect ratio of the hand area is a ratio of a height of the hand area to a width of the hand area, and a depth indicated by the determined depth position increases in response to a change in the aspect ratio when the height of the hand area increases relative to the width of the hand area;

a second position determining section configured to determine a lateral position based on a position of the bottom part of the hand area if the pushdown move is determined by the determining section; and

an input key determining section configured to determine an input key from the determined depth position and lateral position.

2. The information processing apparatus as claimed in claim 1 , wherein the extracting section calculates an aspect ratio of the hand area as a reference, and sets one or more threshold values based on the aspect ratio,

wherein the first position determining section determines the depth position by comparing the threshold values and the aspect ratio of the hand area when the pushdown move is determined by the determining section.

3. The information processing apparatus as claimed in claim 2 , wherein the determining section changes the reference pushdown line depending on the aspect ratio of the hand area.

4. The information processing apparatus as claimed in claim 1 , wherein the second position determining section determines the lateral position based on a lateral width of the hand area and the position of the bottom part of the hand area.

5. The information processing apparatus as claimed in claim 1 , wherein the second position determining section estimates which finger corresponds to the bottom part of the hand area, and based on the estimated finger, determines the lateral position.

6. The information processing apparatus as claimed in claim 1 , wherein the extracting section extracts the hand area having a palm part removed based on luminosity or brightness.

7. The information processing apparatus as claimed in claim 1 , wherein the reference line determining section determines the reference pushdown line for each of a plurality of input rows in the depth direction.

8. The information processing apparatus as claimed in claim 1 , further comprising:

a display section configured to display the image superposed with a virtual keyboard, and to highlight a key corresponding to a position determined by the first position determining section or the second position determining section.

9. An input control method executed by a computer, the method comprising:

capturing an image of a hand;

extracting a hand area from the image;

determining a predetermined line in the image as a reference pushdown line based on the hand area;

determining a pushdown move if the bottom part of the hand area comes below the reference pushdown line;

determining a depth position based on an aspect ratio of the hand area if the pushdown move is determined, wherein the aspect ratio of the hand area is a ratio of a height of the hand area to a width of the hand area, and a depth indicated by the determined depth position increases in response to a change in the aspect ratio when the height of the hand area increases relative to the width of the hand area;

determining a lateral position based on a position of the bottom part of the hand area if the pushdown move is determined; and

determining an input key from the determined depth position and lateral position.

10. A non-transitory computer-readable recording medium having a program stored therein for causing a computer to execute an input control method, the method comprising:

capturing an image of a hand;

extracting a hand area from the image;

determining a predetermined line in the image as a reference pushdown line based on the hand area;

determining a pushdown move if the bottom part of the hand area comes below the reference pushdown line;

determining a depth position based on an aspect ratio of the hand area if the pushdown move is determined, wherein the aspect ratio of the hand area is a ratio of a height of the hand area to a width of the hand area, and a depth indicated by the determined depth position increases in response to a change in the aspect ratio when the height of the hand area increases relative to the width of the hand area;

determining a lateral position based on a position of the bottom part of the hand area if the pushdown move is determined; and

determining an input key from the determined depth position and lateral position.