Real-time focusing in line scan imaging

Patent metadata

Field	Value
Publication number	US-11243387-B2
Application number	US-202017105232-A
Country	US
Kind code	B2
Filing date	Nov 25, 2020
Priority date	May 2, 2012
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

Systems and methods for capturing a digital image of a slide using an imaging line sensor and a focusing line sensor. In an embodiment, a beam-splitter is optically coupled to an objective lens and configured to receive one or more images of a portion of a sample through the objective lens. The beam-splitter simultaneously provides a first portion of the one or more images to the focusing sensor and a second portion of the one or more images to the imaging sensor. A processor controls the stage and/or objective lens such that each portion of the one or more images is received by the focusing sensor prior to it being received by the imaging sensor. In this manner, a focus of the objective lens can be controlled using data received from the focusing sensor prior to capturing an image of a portion of the sample using the imaging sensor.

First claim

What is claimed is:

1. A system for capturing a digital image of a microscope slide, the system comprising:
an objective lens having an optical field of view;
at least one imaging line sensor positioned in a first optical path of the optical field of view and configured to receive light from at least a first portion of the optical field of view;
at least one focusing line sensor positioned in a second optical path of the optical field of view and configured to receive light from at least a second portion of the optical field of view, wherein the at least one focusing line sensor is tilted at an angle θ with respect to an axis that is perpendicular to the second optical path; and
at least one processor configured to determine a focus height Z at which to position the objective lens, before imaging the first portion of the optical field of view using the at least one imaging line sensor, based on the following relationship:

L
=

Z
*

M

f
⁢
o
⁢
c
⁢
u
⁢
s
⁢
i
⁢
n
⁢
g

2

sin
⁢

⁢
θ

,

wherein L is a location on the at least one focusing line sensor, and wherein M focusing is an optical magnification of the second optical path.

2. The system of claim 1 , wherein the at least one processor is further configured to control movement of the objective lens to position the objective lens, based on the determined focus height Z, when imaging the light from the first portion of the optical field of view.

3. The system of claim 2 , wherein the at least one processor is configured to, during a single scan in one direction, for each of a plurality of positions on the microscope slide:
acquire image data of the position using the at least one focusing line sensor;
determine a location L 2 on the at least one focusing line sensor that has a best focus in the image data acquired using the at least one focusing line sensor;
determine a focus height Z 2 that corresponds to the location L 2 ;
move the objective lens to the focus height Z 2 ; and
acquire image data of the position using the at least one imaging line sensor while the objective lens is at the focus height Z 2 .

4. The system of claim 3 , wherein determining the focus height Z 2 comprises calculating the focus height Z 2 as:
Z 2 =Z 1 +( L 2 −L 1 )* M focusing 2 ,

wherein L 1 is a preceding location on the at least one focusing line sensor, having a best focus in the image data acquired using the at least one focusing line sensor, for a preceding position on the microscope slide, and wherein Z 1 is a focus height calculated for L 1 .

5. The system of claim 3 , wherein the best focus comprises a highest contrast.

6. The system of claim 1 , wherein, while the at least one imaging sensor acquires an image of the light from the first portion of the optical field of view, the at least one focusing sensor simultaneously acquires an image of the light from the second portion of the optical field of view.

7. The system of claim 6 , wherein the first portion of the optical field of view follows the second portion of the optical field of view in a scanning direction.

8. The system of claim 7 , wherein the first portion of the optical field of view is in a center of the optical field of view, and wherein the second portion of the optical field of view is offset from the center of the optical field of view.

9. The system of claim 8 , wherein the second portion of the optical field of view is spaced apart from the first portion of the optical field of view by a distance that is equal to N scan lines, wherein N is greater than or equal to one.

10. The system of claim 1 , further comprising a beam splitter that splits an optical path through the objective lens into the first optical path and the second optical path.

11. The system of claim 10 , further comprising a mirror that bends light within at least one of the first optical path and the second optical path.

12. The system of claim 1 , further comprising a microlens array positioned within the second optical path, such that a plurality of micro images of the first portion of the optical field of view are formed on each location L on the at least one focusing line sensor.

13. A method for capturing a digital image of a microscope slide, comprising:
by at least one processor, calculating a focus height Z at which to position an objective lens, before imaging at least a first portion of an optical field of view of the objective lens using at least one imaging line sensor positioned in a first optical path of the optical field of view, based on the following relationship:

L
=

Z
*

M

f
⁢
o
⁢
c
⁢
u
⁢
s
⁢
i
⁢
n
⁢
g

2

sin
⁢

⁢
θ

,

wherein L is a location on the at least one focusing line sensor having a best focus value, and wherein M focusing is an optical magnification of the second optical path.

Assignees

• Leica Biosystems Imaging Inc

Inventors

• Zou Yunlu
• Crandall Gregory
• Olson Allen

Classifications

• G02B21/245

  using auxiliary sources, detectors · CPC title

• G02B21/006 Primary

  focusing arrangements; selection of the plane to be imaged · 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