Imaging system and imaging method

Patent metadata

Field	Value
Publication number	US-2017285318-A1
Application number	US-201715455934-A
Country	US
Kind code	A1
Filing date	Mar 10, 2017
Priority date	Apr 1, 2016
Publication date	Oct 5, 2017
Grant date	—

Abstract

An imaging system includes: an image forming device that obtains image information of an object with the focal length to the object being changed by a variable focal length lens in an optical system, so as to form an all-focused image of the object; a sensor device that detects variations in the surface level of the object in a focus direction; and a position adjustment device that adjusts the position of the object in the focus direction in accordance with the surface level variations of the object detected by the sensor device. The position adjustment device adjusts the position of the object in the focus direction in such a manner that the surface level of the object becomes closer to the center of a variable focal length range of the variable focal length lens.

First claim

1 . An imaging system comprising:
an image forming device comprising an optical system having a variable focal length lens capable of changing a focal length to an object within a predetermined range, the image forming device obtaining image information of the object with the focal length being changed by the variable focal length lens, and forming an all-focused image of the object; a sensor device that detects variations in a surface level of the object in a direction of focus; and a position adjustment device that adjusts a position of the object in the direction of focus in accordance with the surface level variations of the object detected by the sensor device, wherein the position adjustment device adjusts the position of the object in the direction of focus in a manner such that the surface level of the object becomes closer to the center of a variable focal length range of the variable focal length lens.

2 . The imaging system according to claim 1 , wherein the sensor device detects that the surface level of the object has moved within the variable focal length range by a predetermined threshold from the center of the variable focal length range, and wherein the position adjustment device adjusts the position of the object in the direction of focus when the sensor device detects that the surface level of the object has moved by the predetermined threshold.

3 . The imaging system according to claim 2 , wherein the predetermined threshold is set as distances away in opposite directions from the center of the variable focal length range.

4 . The imaging system according to claim 1 , wherein the position adjustment device adjusts the position of the object in the direction of focus in a manner such that the surface level of the object agrees with the center of the variable focal length range.

5 . The imaging system according to claim 1 , wherein the sensor device includes a laser light source that applies laser light to the object and a photodiode that receives the laser light reflected from the object.

6 . The imaging system according to claim 1 , wherein the position adjustment device includes a moving device that moves the position of the object in the direction of focus, and a position controller that controls the moving device so as to adjust the position of the object in the direction of focus.

7 . An imaging method comprising the steps of:
obtaining image information of an object with a focal length to the object being changed by using a variable focal length lens provided in an optical system, so as to form an all-focused image of the object; detecting variations in a surface level of the object in a direction of focus; and in response to the variations in the surface level of the object, adjusting a position of the object in the direction of focus in a manner such that the surface level of the object becomes closer to the center of a variable focal length range of the variable focal length lens.

8 . The imaging method according to claim 7 , wherein the position of the object in the direction of focus is adjusted when the surface level of the object moves within the variable focal length range by a predetermined threshold from the center of the variable focal length range.

9 . The imaging method according to claim 8 , wherein the predetermined threshold is set as distances away in opposite directions from the center of the variable focal length range.

10 . The imaging method according to claim 7 , wherein the position of the object in the direction of focus is adjusted in a manner such that the surface level of the object agrees with the center of the variable focal length range.

11 . The imaging system according to claim 2 , wherein the position adjustment device adjusts the position of the object in the direction of focus in a manner such that the surface level of the object agrees with the center of the variable focal length range.

12 . The imaging system according to claim 3 , wherein the position adjustment device adjusts the position of the object in the direction of focus in a manner such that the surface level of the object agrees with the center of the variable focal length range.

13 . The imaging system according to claim 2 , wherein the sensor device includes a laser light source that applies laser light to the object and a photodiode that receives the laser light reflected from the object.

14 . The imaging system according to claim 3 , wherein the sensor device includes a laser light source that applies laser light to the object and a photodiode that receives the laser light reflected from the object.

15 . The imaging system according to claim 2 , wherein the position adjustment device includes a moving device that moves the position of the object in the direction of focus, and a position controller that controls the moving device so as to adjust the position of the object in the direction of focus.

16 . The imaging system according to claim 3 , wherein the position adjustment device includes a moving device that moves the position of the object in the direction of focus, and a position controller that controls the moving device so as to adjust the position of the object in the direction of focus.

17 . The imaging method according to claim 8 , wherein the position of the object in the direction of focus is adjusted in a manner such that the surface level of the object agrees with the center of the variable focal length range.

18 . The imaging method according to claim 9 , wherein the position of the object in the direction of focus is adjusted in a manner such that the surface level of the object agrees with the center of the variable focal length range.

Assignees

• Mitutoyo Corp

Inventors

• Cho Gyokubu
• Nagahama Tatsuya
• Ootake Takahisa
• Kitagawa Kazuki

Classifications

• G02B21/245 Primary

  using auxiliary sources, detectors · CPC title

• G02B21/025 Primary

  with variable magnification (variable magnification G02B15/00) · CPC title

• G02B27/0075 Primary

  with means for altering, e.g. increasing, the depth of field or depth of focus · CPC title

• G02B21/361

  Optical details, e.g. image relay to the camera or image sensor (G02B21/364 takes precedence; illumination details G02B21/06 and subgroups) · CPC title

• G02B21/365

  Control or image processing arrangements for digital or video microscopes (G02B21/361, G02B21/362 take precedence) · CPC title