Coordinate position of moving light source by using separated groups of detectors each group having an iris

• US 6,014,129 A
• Filed: 09/20/1996
• Issued: 01/11/2000
• Est. Priority Date: 11/25/1993
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Morishita, Ichiro, Nakayama, Masaru, Umeda, Yuichi, Katagiri, Kazuhiro, Sato, Arao, Saito, Junichi
• Primary Examiner(s): Brier, Jeffery
• Assistant Examiner(s): Bell, Paul A.
• Application Number:
  US08/716,977
• Time in Patent Office: 1,208 Days
• Field of Search: 345/156, 345/157, 345/158, 356/139.03, 356/139.07, 356/139.1, 356/141.1, 356/152.2, 356/141.3, 356/141.5, 250/206.1, 250/206.2, 250/206.3
• US Class Current: 345/158
• CPC Class Codes: G01S 3/784 using a mosaic of detectors
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06F 3/0325 using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/03542 Light pens for emitting or receiving light

Abstract

A pair of detecting stations A_i and A_-i on a plane H extends along an axis X. Each of the detecting stations is provided with an iris member and a divided light receiving section. Received light outputs at each of the light receiving elements are defined as R_i, L_i, R_-i, and L_-i, and the following equation is calculated to enable a coordinate (x₀, z₀) of the moving light source to be attained by a simple calculation: S_i =(R_i -L_i)/(R_i +L_i)+(R_-i -L_-i)/(R_-i +L_-i); T_i =(R_i -L_i)/(R_i +L_i)-(R_-i -L_-i)/(R_-i +L_-i).

Claims

1. A position detecting apparatus, comprising:

a moving light source, and

n sets, n an integer not less than 2, of paired detecting sections which are spaced from each other in the direction of the x-axis of a plane perpendicular to an x-z coordinate plane at a constant distance p from the next set in the n sets, the first set in the n sets spaced at the constant distance p from the line x=0, each detecting section comprising;

an iris portion making a part of light from the moving light source pass, the iris portion having an opening, the opening having a center, and

a divided light receiving portion divided into two light receiving elements toward an alignment-direction of the detecting section, the divided portion having a center,

wherein;

the divided light receiving portions of all the detecting sections are disposed on a same x-z coordinate plane;

the center of the opening of the iris portion and the center of the divided light receiving portion are aligned in the direction of the z axis in each of the detecting sections;

received light outputs R_i and L_i are output from the two light receiving elements, respectively, of one of the divided light receiving portions of each of the detecting sections in response to an amount of light from the light source, i=2 to n;

received light outputs R_-i and L_-i are output from the two light receiving elements, respectively, of another of the divided light receiving portions of each of the detecting sections in response to an amount of light from the light source, i=2 to n, and

from the received light outputs from each of the divided light receiving portions, a position of said moving light source is determined.

2. A method of detecting the position of a moving light source, the method comprising the steps of:

receiving R_i, L_i, R_-i, and L_-i, i=2 to n, as defined in claim 1, using the apparatus recited in claim 1;

calculating S_i =(R_i -L_i)/(R_i +L_i)+(R_-i -L_-i)/(R_-i +L_-i) for all i, i=2 to n;

calculating T_i =(R_i -L_i)/(R_i +L_i)-(R_-i -L_-i)/(R_-i +L_-i) for all i, i=2 to n;

##EQU3## calculating a coordinate position (x₀, z₀) of the moving light source from S and T.

3. The method of claim 2 wherein the coordinate position (x₀, z₀) is calculated according to the formulae:

x₀ =(z₀)(a)(S)/(4d)(n) and z₀ =-(2d)(n)(n+1)(p)/(a)(T), wherein a=the size of the opening of the iris member in the x-axis direction and d=the distance between the iris member and the divided light receiving portion in the z-axis direction.

4. The position detecting apparatus of claim 1 wherein the n sets of paired detec ng sections are coaxial.

5. A method of detecting the position of a moving light source, the method comprising the steps of:

(a) providing the moving light source;

(b) providing n sets, n an integer not less than 2, of paired detecting sections which are spaced from each other in the direction of the x-axis of a plane perpendicular to an x-z coordinate plane at a constant distance p from the next set in the n sets, the first set in the n sets spaced at the constant distance p from the line x=0, each detecting section comprising;

an iris portion making a part of light from the moving light source pass, the iris portion having an opening, the opening having a center, and

a divided light receiving portion divided into two light receiving elements toward an alignment direction of the detecting section,

wherein;

the divided light receiving portions of all the detecting sections are disposed on a same plane;

the center of the opening of the iris portion and the center of the divided light receiving portion are aligned in the direction of the z axis in each of the detecting sections;

received light outputs R_i and L_i are output from the two light receiving elements, respectively, of one of the divided light receiving portions of each of the detecting sections in response to an amount of light from the light source, i=2 to n, and

received light outputs R_-i and L_-i are output from the two light receiving elements, respectively, of another of the divided light receiving portions of each of the detecting sections in response to an amount of light from the light source, i=2 to n;

(c) calculating S_i =(R_i -L_i)/(R_i +L_i)+(R_-i -L_-i)/(R_-i +L_-i) for all i, i=2 to n;

(d) calculating T_i =(R_i -L_i)/(R_i +L_i)-(R_-i -L_-i)/(R_-i +L_-i) for all i, i=2 to n;

##EQU4## (g) calculating a coordinate position (x₀, z₀) of the moving light source from S and T.

6. The method of claim 5 wherein the n sets of paired detecting sections are coaxial.

7. The method of claim 5 wherein the coordinate position (x₀, z₀) is calculated according to the formulae:

x₀ =(z₀)(a)(S)/(4d)(n) and z₀ =-(2d)(n)(n+1)(p)/(a)(T), wherein a=the size of the opening of the iris member in the x-axis direction and d=the distance between the iris member and the divided light receiving portion in the z-axis direction.