IMAGING SYSTEM AND TECHNIQUES
Systems and techniques for an optical scanning microscope and/or other appropriate imaging system includes components for scanning and collecting focused images of a tissue sample and/or other object disposed on a slide. The focusing system described herein provides for determining best focus for each snapshot as a snapshot is captured, which may be referred to as “on-the-fly focusing.” The devices and techniques provided herein lead to significant reductions in the time required for forming a digital image of an area in a pathology slide and provide for the creation of high quality digital images of a specimen at high throughput.
1 . A device for obtaining a focused image of a specimen, comprising:
an objective lens disposed for examination of the specimen;
a slow focusing stage coupled to the objective lens, wherein the slow focusing stage controls movement of the objective lens;
a dither focus stage including a dither lens, wherein the dither focus stage moves the dither lens;
a focus sensor that provides focus information in accordance with light transmitted via the dither lens;
at least one electrical component that uses the focus information to determine a metric and a first focus position of the objective lens in accordance with the metric, wherein the at least one electrical component sends position information to the slow focusing stage for moving the objective lens into the first focus position; and
an image sensor that captures an image of the specimen after the objective lens is moved into the first focus position.
2 . The device according to claim 1 , further comprising:
an XY moving stage, wherein the specimen is disposed on the XY moving stage, and wherein the at least one electrical component controls movement of the XY moving stage, and wherein the movement of the XY moving stage is phase locked with the motion of the dither lens.
3 . (canceled)
4 . The device according to claim 1 , wherein the dither focus stage includes a voice-coil actuated flexured assembly that moves the dither lens in a translational motion.
5 . The device according to claim 1 , wherein the dither lens is moved at a resonant frequency that is at least 60 Hz, and wherein the at least one electrical component uses the focus information to perform at least 60 focus calculations per second.
6 . The device according to claim 1 , wherein the focus sensor and the dither focus stage are set to operate bidirectionally, wherein the focus sensor produces the focus information on both an up and down portion of a sinusoid waveform of the motion of the dither lens at the resonant frequency.
7 . The device according to claim 1 , wherein the metric includes at least one of contrast information, sharpness information, and chroma information.
8 . (canceled)
9 . The device according to claim 1 , wherein the focus information includes information for a plurality of zones of a focus window that is used during a focus scan of the specimen, and the device further comprising:
an XY moving stage, wherein the specimen is disposed on the XY moving stage, wherein the at least one electrical component controls movement of the XY moving stage, and wherein the information from at least a portion of the plurality of zones is used in determining a speed of the XY moving stage.
10 . The device according to claim 1 , wherein the focus information includes information for a plurality of zones of a focus window that is used during a focus scan of the specimen and wherein a field of view of the focus sensor is tilted in relation to a field of view of the image sensor.
11 . A method for obtaining a focused image of a specimen, comprising:
controlling movement of an objective lens disposed for examination of the specimen;
controlling motion of a dither lens;
providing focus information in accordance with light transmitted via the dither lens;
using the focus information to determine a metric and determine a first focus position of the objective lens in accordance with the metric; and
sending position information that is used to move the objective lens into the first focus position.
12 . The method according to claim 11 , wherein the first focus position is determined as a best focus position, and the method further comprising:
capturing an image of the specimen after the objective lens is moved into the best focus position.
13 . The method according to claim 11 , further comprising:
controlling movement of an XY moving stage on which the specimen is disposed.
14 . The method according to claim 11 , wherein the dither lens is moved at a resonant frequency that is at least 60 Hz, and wherein at least 60 focus calculations are performed per second.
15 . The method according to claim 11 , wherein the metric includes at least one of: sharpness information, contrast information and chroma information.
16 . (canceled)
17 . The method according to claim 11 , wherein the focus information includes information for a plurality of zones of a focus window that is used during a focus scan of the specimen, and the method further comprising:
controlling movement of an XY moving stage on which the specimen is disposed, wherein the information from at least a portion of the plurality of zones is used in determining a speed of the XY moving stage.
18 . The method according to claim 11 , wherein the focus information includes information for a plurality of zones of a focus window that is used during a focus scan of the specimen, and wherein the movement of the XY moving stage is controlled to provide forward and backward translational scanning of the specimen.
19 . A method for obtaining an image of a specimen comprising:
establishing a nominal focus plane;
positioning the specimen at a starting position having associated x and y coordinates; and
performing first processing in a single traversal over said specimen, said first processing including:
determining, for each of a plurality of points, a focus position using a dither lens; and
acquiring, for each of said plurality of points, a frame in accordance with said focus position.
20 . A computer readable medium comprising code stored thereon for obtaining a focused image of a specimen, the computer readable medium comprising code stored thereon for:
controlling movement of an objective lens disposed for examination of the specimen;
controlling motion of a dither lens;
providing focus information in accordance with light transmitted via the dither lens;
using the focus information to determine a metric and determine a first focus position of the objective lens in accordance with the metric; and
sending position information that is used to move the objective lens into the first focus position.
21 - 71 . (canceled)
72 . A computer readable medium comprising code stored thereon for obtaining an image of a specimen, the computer readable medium comprising code stored thereon that, when executed, performs a method comprising:
establishing a nominal focus plane;
positioning the specimen at a starting position having associated x and y coordinates; and
performing first processing in a single traversal over said specimen, said first processing including:
determining, for each of a plurality of points, a focus position using a dither lens; and
acquiring, for each of said plurality of points, a frame in accordance with said focus position.