Real-time focusing in line scan imaging

Patent metadata

Field	Value
Publication number	US-10634894-B2
Application number	US-201615763061-A
Country	US
Kind code	B2
Filing date	Sep 23, 2016
Priority date	Sep 24, 2015
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

System for acquiring a digital image of a sample on a microscope slide. In an embodiment, the system comprises a stage configured to support a sample, an objective lens having a single optical axis that is orthogonal to the stage, an imaging sensor, and a focusing sensor. The system further comprises at least one beam splitter optically coupled to the objective lens and configured to receive a field of view corresponding to the optical axis of the objective lens, and simultaneously provide at least a first portion of the field of view to the imaging sensor and at least a second portion of the field of view to the focusing sensor. The focusing sensor may simultaneously acquire image(s) at a plurality of different focal distances and/or simultaneously acquire a pair of mirrored images, each comprising pixels acquired at a plurality of different focal distances.

First claim

What is claimed is:

1. A system for scanning a sample to acquire a digital image of the sample, the system comprising:
a stage configured to support a sample;
an objective lens having a single optical axis that is orthogonal to the stage;
an imaging sensor;
a focusing sensor, wherein one point on the focusing sensor is parfocal with the imaging sensor;
at least one first beam splitter optically coupled to the objective lens and configured to receive a field of view corresponding to the optical axis of the objective lens, and simultaneously provide at least a first portion of the field of view to the imaging sensor and at least a second portion of the field of view to the focusing sensor, wherein the first portion of the field of view is a first region of the field of view, and wherein the second portion of the field of view is a second region of the field of view that is offset from the first region of the field of view; and
at least one processor configured to, for each portion of the sample to be scanned,
acquire a focusing image of the portion of the sample from the focusing sensor,
acquire a main image of the portion of the sample from the imaging sensor,
for each of a plurality of positions on the focusing sensor, calculate a contrast measure for a region of the focusing image corresponding to that position on the focusing sensor,
for each of a plurality of positions on the imaging sensor, calculate a contrast measure for a region of the main image corresponding to that position on the imaging sensor,
determine a relationship between the focusing image and the main image,
determine a peak for the relationship,
update a target surface based upon a distance between a location on the focusing sensor corresponding to the peak and a parfocal point between the focusing sensor and the imaging sensor, and
determine a position for the objective lens that provides the peak for the relationship using a feedback loop to move the objective lens until the peak is on the updated target surface,
wherein a direction of movement of the objective lens using the feedback loop is based on a relationship between the focusing image and a mirror image of the focusing image,
wherein the focusing image comprises pixels acquired at decreasing focal distances in a direction from a first side of the focusing image to a second side of the focusing image,
wherein the mirror image of the focusing image comprises pixels acquired at decreasing focal distances in a same direction as the focusing image, and
wherein the relationship between the focusing image and the mirror image of the focusing image comprises either a ratio between a contrast measure of the focusing image and a contrast measure of the mirror image of the focusing image or a difference between a contrast measure of the focusing image and a contrast measure of the mirror image of the focusing image.

2. The system of claim 1 , wherein the focusing sensor receives the second portion of the field of view along an optical path, wherein the focusing sensor is tilted at an angle with respect to the optical path, such that the second portion of the field of view is acquired, by the focusing sensor, as an image comprising pixels representing different focal distances.

3. The system of claim 1 , wherein the focusing sensor comprises a plurality of regions, wherein each region of the focusing sensor receives the second portion of the field of view along a separate optical path, wherein the focusing sensor is tilted at an angle with respect to each of the separate optical paths, such that the second portion of the field of view is acquired, by each region of the focusing sensor, at a different focal distance than the other regions of the focusing sensor, and wherein at least one point on one of the plurality of regions is parfocal with the imaging sensor.

4. The system of claim 3 , further comprising focusing optics, wherein the focusing optics comprise a plurality of second beam splitters that are optically coupled to the at least one first beam splitter and split a beam, conveying the second portion of the field of view, into the separate optical paths, and wherein the focusing optics further comprise at least one mirror that reflects the split beam into one of the separate optical paths.

5. The system of claim 3 , wherein all regions of the focusing sensor are within a single line sensor.

6. The system of claim 1 , wherein the focusing sensor comprises a plurality of regions, wherein each region of the focusing sensor receives the second portion of the field of view along a separate optical path, wherein the focusing sensor is orthogonal with respect to each of the separate optical paths, wherein each of the separate optical paths has a different focus distance, such that the second portion of the field of view is acquired, by each region of focusing sensor, at a different focal distance than the other regions of focusing sensor, and wherein at least one point on one of the plurality of regions is parfocal with the imaging sensor.

7. The system of claim 1 , wherein the focusing sensor comprises a first portion and a second portion, wherein the first portion of the focusing sensor receives the second portion of the field of view along a first optical path and is tilted at a first angle with respect to the first optical path, wherein the second portion of the focusing sensor receives the second portion of the field of view along a second optical path, that is separate from the first optical path, and is tilted at a second angle with respect to the second optical path that is reverse to the first angle, wherein at least one point on both the first portion of the focusing sensor and the second portion of the focusing sensor is parfocal with the imaging sensor, and wherein the first portion of the focusing sensor acquires a first image, wherein the second portion of the focusing sensor acquires a second image, wherein the first image comprises pixels acquired at decreasing focal distances in a direction from a first side of the first image to a second side of the first image, and wherein the second image comprises pixels acquired at increasing focal distances in a direction from the first side of the second image to the second side of the second image.

8. The system of claim 1 , wherein the focusing sensor comprises a first region and a second region, wherein the first region receives the second portion of the field of view along a first optical path, wherein the second region receives a mirrored second portion of the field of view along a second optical path, wherein the focusing sensor is tilted at an angle with respect to each of the first optical path and the second optical path, wherein at least one point on both the first region of the focusing sensor and the second region of the focusing sensor is parfocal with the imaging sensor, wherein the second portion of the field of view is received by the first region of the focusing sensor at a focal distance, and the mirrored second portion of the field of view is received by the second region of the focusing sensor at the same focal distance, wherein the first region of the focusing sensor acquires a first image of the second portion of the field of view, wherein the second region of the focusing sensor acquires a second image of the mirrored second portion of the field of view, wherein the first image comprises pixels acquired at decreasing focal distances in a direction from a first side of the first image to a second side of the first image, and wherein the second image comprises pixels acquired at decreasing focal distances in a same direction as the first image.

9. A system for scanning a sample to acquire a digital image of the sample, the system compris

Assignees

• Leica Biosystems Imaging Inc

Inventors

• Zou Yunlu
• Olson Allen
• Saligrama Kiran
• Chen Ruby
• Najmabadi Peyman
• Crandall Greg

Classifications

• G02B21/244 Primary

  using image analysis techniques · CPC title

• G02B21/18

  Arrangements with more than one light path, e.g. for comparing two specimens · CPC title

• G02B27/40 Primary

  Optical focusing aids · CPC title

• G02B21/02

  Objectives · CPC title

• G02B7/38

  measured at different points on the optical axis {, e.g. focussing on two or more planes and comparing image data} · CPC title