Title:
INSTRUMENT FOR MEASURING DISTANCE BY LIGHT WAVE AND LIGHT QUANTITY CONTROL METHOD THEREFOR
Document Type and Number:
Japanese Patent JP3563817
Kind Code:
B2
Abstract:
PURPOSE: To easily set the position of a concentration distribution filter by preserving the state information about the position of the filter when the power supply is turned off and using the state information as a reference state for controlling light quantity adjustment when the power supply is turned on next.
CONSTITUTION: An instrument 100 for measuring distance by light wave preserves the state information about the last position of a filter in a nonvolatile memory 18 when the power supply is turned off and updates the state information by reading the preserved information from the memory 18 and calculating the moved position of the filter based on the read value and displacement of the filter. Therefore, the instrument 100 can immediately execute distance measurement without requiring initialization. In addition, since the reliability of the filter position control drops due to accumulated errors when the control only relies upon the relative position in such a way, the reliability of the position control of the instrument 100 is secured by eliminating errors by forcing the device 10 to perform origin position detecting processing.
Inventors:
Kiyoshi Yamamoto
Application Number:
JP9165995A
Publication Date:
September 08, 2004
Filing Date:
March 24, 1995
Export Citation:
Assignee:
Pentax Co., Ltd.
International Classes:
G01C15/00; G01S7/48; G01S17/36; (IPC1-7): G01S17/36; G01S7/48
Domestic Patent References:
| JP57082319U | ||||
| JP60110820U | ||||
| JP6117685U | ||||
| JP63174079U | ||||
| JP627224A | ||||
| JP4134089U |
Attorney, Agent or Firm:
Shuhei Matsuoka