Touch detection apparatus, touch detection method, and non-transitory computer-readable recording medium

• US 9,746,966 B2
• Filed: 02/22/2016
• Issued: 08/29/2017
• Est. Priority Date: 03/26/2015
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Suzuki, Genta
• Primary Examiner(s): Chow, Van
• Application Number:
  US15/049,729
• Publication Number:
  US 20160283040A1
• Time in Patent Office: 554 Days
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 3/042 by opto-electronic means
• 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

Abstract

A touch detection apparatus including a first camera configured to capture a plurality of first images, a second camera configured to capture a plurality of second images, a memory, and a processor configured to detect a plurality of first positions corresponding to a tip of the finger in the plurality of first images, obtain a plurality of second positions in the plurality of second images corresponding to the plurality of first positions, calculate a plurality of third positions based on the plurality of first positions and the plurality of second positions, the plurality of third positions being positions in real space of the tip of the finger, determine whether or not a calculated feature value calculated based on the plurality of third positions satisfies a condition, and determine that an action of touching an object has been performed when the calculated feature value satisfies the condition.

Claims

1. A touch detection apparatus comprising:

a first camera configured to capture each of a plurality of first images in each given period;

a second camera arranged apart from the first camera by a given interval and configured to capture each of a plurality of second images in each given period;

a memory; and

a processor coupled to the memory, and configured to;

detect a plurality of first positions corresponding to a tip of the finger in the plurality of first images;

obtain a plurality of second positions in the plurality of second images corresponding to the detected plurality of first positions;

calculate a plurality of third positions based on the detected plurality of first positions and the detected plurality of second positions, the plurality of third positions being positions in real space of the tip of the finger;

determine whether or not a calculated feature value calculated based on the plurality of third positions satisfies a condition, the condition being a feature value that represents an action of touching an object with the finger; and

determine that an action of touching the object has been performed when the calculated feature value satisfies the condition.

2. The touch detection apparatus according to claim 1, wherein the processor configured to:

when the calculated feature value satisfies the condition, cause a projector device to project a mark onto a given position; and

when at least one of the plurality of third positions is included within a given range determined based on a projected position of the mark after a projection of the mark, determine that the action of touching the object has been performed.

3. The touch detection apparatus according to claim 1, wherein the processor configured to:

calculate, as the calculated feature value, a count of times that a distance from one of the plurality of third position during a given period of time to a farthest position is less than or equal to a given value, the farthest position being a position that is the farthest from the first camera among the plurality of third positions during the given period of time; and

determine that the calculated feature value satisfies the condition when a proportion of the count of times relative to a total count of the plurality of third positions during the given period of time is greater than or equal to a given proportion.

4. The touch detection apparatus according to claim 1, wherein the processor configured to:

calculate, as the calculated feature value, a degree of variation of the plurality of third positions during a given period of time; and

determine that the calculated feature value satisfies the condition when the degree of variation of the plurality of third positions is less than or equal to a given value.

5. The touch detection apparatus according to claim 1, wherein the processor configured to:

calculate, as the calculated feature value, a degree of variation of one or more local maximum positions among the plurality of third positions during the given period of time, a distance from the one or more local maximum position to the first camera having a local maximum; and

determine that the calculated feature value satisfies the condition when the degree of variation of the one or more local maximum positions is less than or equal to a given value.

6. The touch detection apparatus according to claim 2, wherein the processor configured to:

set a projected position of the mark in accordance with one of the third positions that is farthest from the first camera during the given period of time.

7. The touch detection apparatus according to claim 2, wherein the processor configured to:

store, in the memory, a height of a furthest position from a reference plane, as a height of the object at the position, when at least one of the plurality of third positions is included within the given range by the given timing after a projection of the mark, the farthest position being a position that is the farthest from the first camera among the plurality of third positions during the given period of time; and

determine that the action of touching the object has been performed when a difference between one of the plurality of third positions from the reference plane and the height of the object at the position stored in the memory is within a given permissible range.

8. A touch detection method executed by a computer, the touch detection method comprising:

acquiring a plurality of first images captured by a first camera;

acquiring a plurality of second images captured by a second camera arranged apart from the first camera by a given interval;

detecting a plurality of first positions corresponding to a tip of the finger in the plurality of first images;

obtaining a plurality of second positions in the plurality of second images corresponding to the detected plurality of first positions;

calculating a plurality of third positions based on the detected plurality of first positions and the detected plurality of second positions, the plurality of third positions being positions in real space of the tip of the finger;

determining whether or not a calculated feature value calculated based on the plurality of third positions satisfies a condition, the condition being a feature value that represents an action of touching an object with the finger; and

determining that an action of touching the object has been performed when the calculated feature value satisfies the condition.

9. A non-transitory computer-readable recording medium storing an touch detection program that causes a computer to execute:

acquiring a plurality of first images captured by a first camera;

acquiring a plurality of second images captured by a second camera arranged apart from the first camera by a given interval;

detecting a plurality of first positions corresponding to a tip of the finger in the plurality of first images;

obtaining a plurality of second positions in the plurality of second images corresponding to the detected plurality of first positions;

calculating a plurality of third positions based on the detected plurality of first positions and the detected plurality of second positions, the plurality of third positions being positions in real space of the tip of the finger;

determining whether or not a calculated feature value calculated based on the plurality of third positions satisfies a condition, the condition being a feature value that represents an action of touching an object with the finger; and

determining that an action of touching the object has been performed when the calculated feature value satisfies the condition.