Position detection system, position detection method, program, object determination system and object determination method

• US 8,897,499 B2
• Filed: 04/01/2009
• Issued: 11/25/2014
• Est. Priority Date: 04/04/2008
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Rekimoto, Junichi
• Primary Examiner(s): Bella, Matthew
• Assistant Examiner(s): Rosario, Dennis
• Application Number:
  US12/416,266
• Publication Number:
  US 20090252375A1
• Time in Patent Office: 2,064 Days
• Field of Search: 382/291, 382/103, 382/203, 345/156, 715/863
• US Class Current: 382/115
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• 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: G06T 2207/10152 Varying illumination
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80

Abstract

There is provided a position detection system including an imaging unit to capture an image of a projection plane of an electromagnetic wave, an electromagnetic wave emission unit to emit the electromagnetic wave to the projection plane, a control unit to control emission of the electromagnetic wave by the electromagnetic wave emission unit, and a position detection unit including a projected image detection section to detect a projected image of an object existing between the electromagnetic wave emission unit and the projection plane based on a difference between an image of the projection plane captured during emission of the electromagnetic wave by the electromagnetic wave emission unit and an image of the projection plane captured during no emission of the electromagnetic wave, and a position detection section to detect a position of the object based on a position of the projected image of the object.

Claims

1. A position detection system comprising:

an imaging unit for capturing a projected image of an object;

an electromagnetic wave emission unit to emit an electromagnetic wave to the imaging unit,

wherein the electromagnetic wave emission unit comprises

a first electromagnetic wave emission unit and a second electromagnetic wave emission unit placed in a different location from the first electromagnetic wave emission unit;

a control unit to control emission of the electromagnetic wave by the electromagnetic wave emission unit; and

a position determination unit, which;

obtains a first projected image of the object based on an image captured during emission of the electromagnetic wave by the first electromagnetic wave emission unit and not by the second electromagnetic wave emission unit, and

obtains a second projected image of the object based on an image captured during emission of the electromagnetic wave by the second electromagnetic wave emission unit and not by the first electromagnetic wave emission unit,

determines a spatial position of the object based on estimating a first straight line connecting the first electromagnetic wave emission unit and a first point of the first projected image of the object,

estimating a second straight line connecting the second electromagnetic wave emission unit and a second point of the second projected image of the object, and

determining an intersection of the first straight line and the second straight line as the spatial position of the object,

wherein the second point of the second projected image corresponds to the first point of the first projected image, and

determines whether the object is a finger or a fist by determining whether a proximity between a pattern in the first projected image and a pattern in the second projected image is greater than a threshold proximity.

2. The position detection system according to claim 1, wherein

the imaging unit captures a frame image in synchronization with a prescribed synchronizing signal, and

the control unit controls emission of the electromagnetic wave by the electromagnetic wave emission unit in synchronization with the prescribed synchronizing signal.

3. The position detection system according to claim 2, wherein

the control unit periodically switches among emission of the electromagnetic wave by the first electromagnetic wave emission unit and no emission of the electromagnetic wave by the second electromagnetic wave emission unit, emission of the electromagnetic wave by the second electromagnetic wave emission unit and no emission of the electromagnetic wave by the first electromagnetic wave emission unit, and no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit, and

the position determination unit obtains the first projected image of the object based on a difference between the image captured during emission of the electromagnetic wave by the first electromagnetic wave emission unit and not by the second electromagnetic wave emission unit and an image captured during no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit, and obtains the second projected image of the object based on a difference between the image captured during emission of the electromagnetic wave by the second electromagnetic wave emission unit and not by the first electromagnetic wave emission unit and an image captured during no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit.

4. The position detection system according to one of claims 1, 2, and 3, further comprising:

a filter to transmit a wavelength component of the electromagnetic wave emitted from the electromagnetic wave emission unit, wherein

the first projected image or the second projected image is the image formed by the filtered electromagnetic wave on the imaging unit.

5. The position detection system according to one of claims 1, 2, and 3, wherein the electromagnetic wave emission unit emits infrared rays or visible rays.

6. A position detection method comprising the steps of:

obtaining

a first projected image of the object on an imaging unit, which is based on an image captured during emission of an electromagnetic wave by a first electromagnetic wave emission unit and not from a second electromagnetic wave emission unit, and

a second projected image of the object on the imaging unit, which is based on an image captured during emission of an electromagnetic wave by the second electromagnetic wave emission unit and not from the first electromagnetic wave emission unit; and

determining a spatial position of the object based on estimating a first straight line connecting the first electromagnetic wave emission unit and a first point of the first projected image of the object,

estimating a second straight line connecting the second electromagnetic wave emission unit and a second point of the second projected image of the object, and

determining an intersection of the first straight line and the second straight line as the spatial position of the object,

wherein the second point of the second projected image corresponds to the first point of the first projected image, and determining whether the object is a finger or a fist by determining whether a proximity between a pattern in the first projected image and a pattern in the second projected image is greater than a threshold proximity.

7. The method according to claim 6 further comprising:

capturing an image in synchronization with a prescribed synchronizing signal, and

controlling emission of the electromagnetic wave by at least one of the first electromagnetic wave emission unit and the second electromagnetic wave emission unit in synchronization with the prescribed synchronizing signal.

8. The method according to one of claims 6 and 7 further comprising:

filtering the electromagnetic wave emitted by at least one of the first electromagnetic wave emission unit and the second electromagnetic wave emission unit for a wavelength component, and

capturing the image formed on the imaging unit by the filtered electromagnetic wave.

9. The method according to one of claims 6 and 7, further comprising:

emitting infrared rays or visible rays by at least one of the first electromagnetic wave emission unit and the second electromagnetic wave emission unit.

10. The position detection method of claim 6, further comprising:

periodically switching among emission of the electromagnetic wave by the first electromagnetic wave emission unit and no emission of the electromagnetic wave by the second electromagnetic wave emission unit, emission of the electromagnetic wave by the second electromagnetic wave emission unit and no emission of the electromagnetic wave by the first electromagnetic wave emission unit, and no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit; and

obtaining the first projected image of the object based on a difference between the image captured during emission of the electromagnetic wave by the first electromagnetic wave emission unit and not by the second electromagnetic wave emission unit and an image captured during no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit, and obtaining the second projected image of the object based on a difference between the image captured during emission of the electromagnetic wave by the second electromagnetic wave emission unit and not by the first electromagnetic wave emission unit and an image captured during no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit.

11. A non-transitory computer readable medium storing a program that causes a computer to implement functions comprising:

a control section configured to control emission by a first electromagnetic wave emission unit and emission by a second electromagnetic wave emission unit;

a projected image determination section configured to obtain a first projected image of an object on an imaging unit, which is based on an image captured during emission of an electromagnetic wave by the first electromagnetic emission unit and not from the second electromagnetic emission unit, the object being located between the first electromagnetic wave emission unit and the imaging unit,

the projected image determination section further obtaining a second projected image of the object on the imaging unit, which is based on an image captured during emission of an electromagnetic wave by the second electromagnetic emission unit and not from the first electromagnetic emission unit, the object being located between the second electromagnetic wave emission unit and the imaging unit; and

a position determination section to;

determine a spatial position of the object based on estimating a first straight line connecting the first electromagnetic wave emission unit and a first point of the first projected image of the object,

estimating a second straight line connecting the second electromagnetic wave emission unit and a second point of the second projected image of the object, and

determining an intersection of the first straight line and the second straight line as the spatial position of the object,

wherein the second point of the second projected image corresponds to the first point of the first projected image, and

determining whether the object is a finger or a fist by determining whether a proximity between a pattern in the first projected image and a pattern in the second projected image is greater than a threshold proximity.

12. The position detection method of claim 11, wherein:

the control section periodically switches among emission of the electromagnetic wave by the first electromagnetic wave emission unit and no emission of the electromagnetic wave by the second electromagnetic wave emission unit, emission of the electromagnetic wave by the second electromagnetic wave emission unit and no emission of the electromagnetic wave by the first electromagnetic wave emission unit, and no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit; and

the projected image determination section obtains the first projected image of the object based on a difference between the image captured during emission of the electromagnetic wave by the first electromagnetic wave emission unit and not by the second electromagnetic wave emission unit and an image captured during no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit, and obtains the second projected image of the object based on a difference between the image captured during emission of the electromagnetic wave by the second electromagnetic wave emission unit and not by the first electromagnetic wave emission unit and an image captured during no emission of the electromagnetic wave by the first electromagnetic wave emission unit and the second electromagnetic wave emission unit.