Range-finding device

• US 8,072,583 B2
• Filed: 07/30/2010
• Issued: 12/06/2011
• 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
• Primary Examiner(s): ALSOMIRI, ISAM A
• Application Number:
  US12/847,507
• Publication Number:
  US 20100290029A1
• Time in Patent Office: 494 Days
• Field of Search: 356/5.01, 356/4.01, 356/501
• 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 first 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 first calculation unit;

a second calculation unit that calculates a distance change between a first distance and a second distance, the first distance being calculated most recently by the first calculation unit and the second distance having been calculated previously by the first calculation unit;

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

a display update control unit that prohibits the update to the first distance on display at the display unit when the distance change exceeds the threshold value and sustains the display of the second distance at the display unit for a duration of a predetermined holding time.

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

after the holding time elapses, the first calculation unit calculates a new distance, and the display update control unit displays the new distance at the display unit.

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

the second calculation unit calculates a difference, as the distance change, between the first distance and the second distance, and

the display update control unit prohibits the update to the first distance on display at the display unit based upon the difference.

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

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

when the decision-making unit determines that the difference exceeds the threshold value, the display update control unit prohibits the update to the first distance on display at the display unit and sustains the second distance on display at the display unit.

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

the second calculation unit calculates the difference by subtracting the second distance from the first distance and also calculates the difference by subtracting the first distance from the second distance.

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

further comprising:

a first operation member operated to select between a first mode and a second mode, wherein;

when the first mode is selected, the second calculation unit calculates a first difference by subtracting the second distance from the first distance, the decision-making unit makes a decision as to whether or not the first difference exceeds a first threshold value, and the display update control unit displays the second distance at the display unit when the first difference exceeds the first threshold value, and

when the second mode is selected, the second calculation unit calculates a second difference by subtracting the first distance from the second distance, the decision-making unit makes a decision as to whether or not the second difference exceeds a second threshold value, and the display update control unit displays the second distance at the display unit when the second difference exceeds the second threshold value.

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

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

8. 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.