TOUCH DETECTION APPARATUS, TOUCH DETECTION METHOD AND RECORDING MEDIUM

• US 20140015950A1
• Filed: 07/08/2013
• Published: 01/16/2014
• Est. Priority Date: 07/12/2012
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Kobayashi, Kiwamu
• Granted Patent: US 9,690,430 B2
• Time in Patent Office: Days
• US Class Current: 348/77
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

A touch detection method executed by a touch detection apparatus projects light that does not include a wavelength component of visible light onto a screen, has a sensitivity in a wavelength component of the light projected by the projecting, takes an image on the screen in a state where light is projected by the projecting, and performs detection pertaining to a touch, based on image data taken by the image-sensing.

Claims

1. A touch detection apparatus, comprising:

a lighting unit configured to project light including invisible wavelength components onto a screen;

an image sensing unit configured to have a sensitivity to wavelength components of the light projected from the lighting unit, and to take images of regions of the screen on which the light is being projected by the lighting unit; and

a detection unit configured to detect a touch pertaining to the screen based on images taken by the image sensing unit.

2. The touch detection apparatus according to claim 1, wherein the image sensing unit takes the images of regions of the screen on which the light is being projected by a plurality of the lighting units.

3. The touch detection apparatus according to claim 1, wherein the detection unit detects a touch based on pieces of image data respectively taken by a plurality of the image sensing units.

4. The touch detection apparatus according to claim 1, further comprising:

a shadow image data generation unit configured to generate shadow image data by performing subtraction between image data taken by the image sensing unit with the light being projected onto the screen from the lighting unit, and image data taken by the image sensing unit without the light being projected onto the screen from the lighting unit,

wherein the detection unit detects a touch based on the shadow image data.

5. The touch detection apparatus according to claim 4, further comprising:

a reference image data generation unit configured to generate reference image data by performing subtraction between image data taken by the image sensing unit without the light being projected onto the screen from the lighting unit or object blocking off the light in an area as a target of detection pertaining to a touch, and image data taken by the image sensing unit with the light being projected onto the screen from the lighting unit and without object blocking off the light in an area as a target of detection pertaining to a touch; and

a normalization unit configured to generate normalized shadow image data by normalizing the shadow image data using the reference image data,

wherein the detection unit detects a touch based on the normalized shadow image data.

6. The touch detection apparatus according to claim 5, further comprising:

a shadow region image data generation unit configured to generate shadow region image data by binarizing the normalized shadow image data,

wherein the detection unit detects a touch based on the shadow region image data.

7. The touch detection apparatus according to claim 6, further comprising:

an OR shadow region image data generation unit configured to generate OR shadow region image data by applying an OR operation to plural pieces of the shadow region image data,

wherein the detection unit detects a touch based on the OR shadow region image data.

8. The touch detection apparatus according to claim 7, further comprising:

a calculation unit configured to calculate a distance between end points of two protruding shapes from the OR shadow region image data,

wherein the detection unit detects a touch based on the distance calculated by the calculation unit.

9. The touch detection apparatus according to claim 1, wherein the detection unit detects at least any one of a touched position and a touchdown.

10. A touch detection method, comprising:

lighting that instructs a lighting unit to project light including invisible wavelength components onto a screen;

image-sensing that has a sensitivity to wavelength components of the light projected from the lighting unit, and that takes images of regions of the screen on which the light is being projected by the lighting unit; and

detecting that detects a touch pertaining to the screen based on the images taken by the image-sensing.

11. A non-transitory computer-readable recording medium having recorded therein a program for causing a computer to execute:

lighting that instructs a lighting unit to project light including invisible wavelength components onto a screen;

image-sensing that has a sensitivity to wavelength components of the light projected from the lighting unit, and that takes images of regions of the screen on which the light is being projected by the lighting unit; and

detecting that detects a touch pertaining to the screen based on the images taken by the image-sensing.