RANGE-FINDING DEVICE

• US 20100290029A1
• Filed: 07/30/2010
• Published: 11/18/2010
• Est. Priority Date: 08/06/2008
• Status: Active Grant

• Current Assignee: Nikon Vision Co., Ltd. (Nikon Corporation)
• Original Assignee: Nikon Vision Co., Ltd. (Nikon Corporation)
• Inventors: HATA, Yukitsugu
• Granted Patent: US 8,072,583 B2
• Time in Patent Office: Days
• US Class Current: 356/5.01
• CPC Class Codes: A63B 2071/065 Visualisation of specific exercise parameters
• CPC Class Codes: A63B 2102/32 Golf
• CPC Class Codes: A63B 2220/20 Distances or displacements
• CPC Class Codes: A63B 2220/805 Optical or opto-electronic sensors
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 7/4873 by deriving and controlling a threshold value
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

A range-finding device includes: a light emitting unit that continuously emits measurement light to be used for distance measurement toward a measurement target object; a light-receiving unit that receives reflected light reflected by the measurement target object; a calculation unit that repeatedly calculates a distance to the measurement target object over predetermined time intervals by using the reflected light; a display unit at which an update of the distance is displayed each time the distance is calculated by the calculation unit; and a display update control unit that prohibits the update of the distance on display at the display unit and sustains the display of the previously calculated distance at the display unit according to a change in the most recently calculated distance calculated most recently by the calculation unit relative to the previously calculated distance having been calculated previously by the calculation unit.

Claims

1. A range-finding device, comprising:

a light emitting unit that continuously emits measurement light to be used for distance measurement toward a measurement target object;

a light-receiving unit that receives reflected light reflected by the measurement target object;

a calculation unit that repeatedly calculates a distance to the measurement target object over predetermined time intervals by using the reflected light;

a display unit at which an update of the distance is displayed each time the distance is calculated by the calculation unit; and

a display update control unit that prohibits the update of the distance on display at the display unit and sustains the display of the previously calculated distance at the display unit according to a change in the most recently calculated distance calculated most recently by the calculation unit relative to the previously calculated distance having been calculated previously by the calculation unit.

2. A range-finding device according to claim 1, wherein:

when prohibiting the update of the distance on display at the display unit, the display update control unit sustains the display of the previously calculated distance at the display unit for a duration of a predetermined holding time.

3. A range-finding device according to claim 2, wherein:

once the holding time elapses, a distance newly calculated by the calculation unit is displayed at the display unit.

4. A range-finding device according to claim 1, further comprising:

a difference calculation unit that calculates a difference between the distance most recently calculated by the calculation unit and the previously calculated distance having been calculated previously by the calculation unit, wherein;

the display update control unit prohibits the update of the distance on display at the display unit based upon the difference as the change.

5. A range-finding device according to claim 4, further comprising:

a decision-making unit that makes a decision as to whether or not the difference calculated by the difference calculation unit exceeds a threshold value, wherein;

when the decision-making unit determines that the difference exceeds the threshold value, the display update control unit prohibits the update of the distance on display at the display unit and sustains the previously calculated distance on display at the display unit.

6. A range-finding device according to claim 5, wherein:

the difference calculation unit calculates the difference by subtracting the previously calculated distance from the most recently calculated distance and also calculates the difference by subtracting the most recently calculated distance from the previously calculated distance.

7. A range-finding device according to claim 6, wherein:

the difference calculation unit includes a first difference calculation unit that calculates the difference by subtracting the previously calculated distance from the most recently calculated distance and a second difference calculation unit that calculates the difference by subtracting the most recently calculated distance from the previously calculated distance;

the decision-making unit includes a first decision-making unit that makes a decision as to whether or not the difference calculated by the first difference calculation unit exceeds a first threshold value and a second decision-making unit that makes a decision as to whether or not the difference calculated by the second difference calculation unit exceeds a second threshold value; and

the range-finding device further comprises a first operation member operated to select between a first mode and a second mode, in the first mode the display update control unit displaying the previously calculated distance at the display unit when the difference calculated by the first difference calculation unit exceeding the first threshold value, and in the second mode the display update control unit displaying the previously calculated distance at the display unit when the difference calculated by the second difference calculation unit exceeding the second threshold value.

8. A range-finding device according to claim 7, further comprising:

a second operation member operated to adjust a setting for the first threshold value, the second threshold value or the holding time.

9. A range-finding device according to claim 1, further comprising:

a viewing optical system through which the measurement target object is viewed, wherein;

a display is brought up at the display unit so that at least an index indicating a measurement position and the distance having been calculated are viewed within a visual field containing the measurement target object.