Device for observing a sample and method for observing a sample

Patent metadata

Field	Value
Publication number	US-10754141-B2
Application number	US-201716337153-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Sep 30, 2016
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

There is provided a device allowing a sample to be observed in a first mode, by lensless imaging using a first sensor. The first mode allows a first image to be obtained, on the basis of which a region of interest of the sample may be identified. The device then allows, via a relative movement, the region of interest to be analyzed using a more precise second mode and in particular using an optical system coupled to a second sensor.

First claim

The invention claimed is:

1. A device for observing a sample, comprising:
a first light source configured to emit an incident light wave that propagates to the sample;
a first image sensor configured to acquire a first image of the sample illuminated by the incident light wave;
a sample holder configured to hold the sample between the first light source and the first image sensor such that no magnifying optics are disposed between the sample and the first image sensor, the first image sensor being exposed to an exposure light wave, the acquired first image defining a first field of view of the sample;
a second image sensor, optically coupled to an optical system having a magnification higher than 1, the second image sensor being configured to acquire a second image of the sample, held on the sample holder, in a second field of view of the sample that is smaller than the first field of view;
a stage configured to move the sample relative to the first image sensor and to the optical system, so as to alternate between:
a first mode, in which the sample is disposed within a field of view of the first image sensor, so as to acquire the first image, and
a second mode, in which the sample is disposed within a field of view of the second image sensor, so as to acquire the second image; and

a processor configured to use a numerical propagation operator and the acquired first image, so as to:
calculate a complex expression for the exposure light wave on a reconstruction surface lying facing the first image sensor, and
form a reconstructed image from a modulus and/or a phase of the calculated complex expression,

wherein, in the second mode, a position of the sample with respect to the optical system is defined depending on a region of interest selected in the reconstructed image.

2. The device of claim 1 , further comprising a second light source configured to illuminate the sample during the acquisition of the second image of the sample.

3. The device of claim 1 , further comprising:
a selector configured to select a region of interest in the acquired first image, and
a processor configured to determine a relative position of the sample with respect to the optical system, in which position the selected region of interest lies in the second field of view of the sample,
wherein the stage is further configured to automatically position the sample relative to the optical system in the determined relative position determined by the processor.

4. The device of claim 1 , wherein the first image sensor lies in a detection plane, and the device further comprises a processor configured to apply a digital focus to the acquired first image so as to estimate a distance between the sample and the detection plane in the selected region of interest, such that the determined relative position of the sample with respect to the optical system is determined depending on the estimated distance.

5. The device of claim 1 ,
wherein the first image sensor and the second image sensor are fixed, and
wherein the stage is further configured to move the sample:
to face the first image sensor in the first mode, and
to face the optical system in the second mode.

6. The device of claim 1 , wherein the sample is fixed and the stage is further configured to move the first image sensor to face the sample in the first mode, and/or to move the optical system to face the sample in the second mode.

7. A method for observing a sample, comprising:
a) illuminating the sample using a first light source;
b) acquiring a first image of the illuminated sample using a first image sensor, the first image sensor being exposed to an exposure light wave, the sample being held between the first light source and the first image sensor, no magnifying optics being disposed between the first image sensor and the sample;
c) selecting a region of interest of the sample in the acquired first image;
d) moving the sample relative to the first image sensor and to an optical system having a magnification higher than 1, the optical system being optically coupled to a second image sensor, the movement being carried out automatically by a stage, such that the region of interest of the sample selected in step c) is within a field of view of the second image sensor; and
e) illuminating the sample using a second light source and acquiring a second image of the region of interest of the sample, using the second image sensor,
wherein the first image sensor lies in a detection plane, and step c) further comprises:
ci) using a propagation operator and the acquired first image, so as to calculate a complex expression for the exposure light wave on a reconstruction surface lying facing the detection plane,
cii) forming a reconstructed image, based on a modulus and/or a phase of the complex expression calculated in ci), and
ciii) selecting a region of interest in the reconstructed image.

8. The method of claim 7 , wherein the relative movement of the sample results in automatically passing between:
a first mode, in which the sample is disposed within a field of view of the first image sensor, so as to acquire the first image, and
a second mode, in which the sample is disposed within the field of view of the second image sensor, so as to acquire the second image.

9. The method of claim 7 , wherein, in step c), the region of interest is selected, in the acquired first image, using a manual selector or via an analysis of the acquired first image, the analysis being based on a predefined selection criterion and being implemented by a processor.

10. The method of claim 7 ,
wherein, in step ci), the propagation operator is applied to an intermediate image, obtained from the acquired first image and comprising a number of pixels lower than a number of pixels of the acquired first image, a field of view of the intermediate image being similar to a field of view of the acquired first image, and
wherein step c) further comprises:
applying a propagation operator to the acquired first image, in the region of interest selected in step ciii), so as to calculate a complex expression for the exposure light wave on a reconstruction surface lying facing the detection plane, thereby defining a complex image of interest,
from the calculated complex image of interest, forming a reconstructed image of interest, based on the modulus and/or the phase of the complex expression, and
displaying the reconstructed image of interest.

11. The method of claim 7 , wherein, in step ciii), the region of interest is selected, in the reconstructed image, using a manual selector or via an analysis of the reconstructed image, the analysis being based on a predefined selection criterion and being implemented by a processor.

12. The method of claim 7 , wherein, in step ci), the reconstruction surface is a sample plane in which the sample lies.

13. The method of claim 7 , further comprising, prior to step c), calibrating a position of the sample with respect to the detection plane, the calibrating comprising:
selecting a plurality of calibration points in the first image acquired;
defining an elementary calibration region about each selected calibration point;
implementing, with a processor, a digital focusing algorithm, so as to estimate a calibration distance, between the sample and the detection plane, for each elementary calibration region; and
partitioning the first image acquired into various elementary images, and associating, with each elementary image, a distance between the sample and the detection plane, depending on the calibration distance estimated for each elementary calibration region, the partitioning comprising:

Assignees

• Commissariat Energie Atomique

Inventors

• Allier Cedric
• Bordy Thomas
• Cioni Olivier
• Herve Lionel
• Morel Sophie

Classifications

• G03H2223/18

  Prism · CPC title

• G03H2001/005

  in microscopy, e.g. digital holographic microscope [DHM] · CPC title

• G03H2227/03

  Means for moving one component (G03H1/0476, G03H2001/2695 take precedence) · CPC title

• G03H2001/0447

  In-line recording arrangement · CPC title

• G02B21/362

  Mechanical details, e.g. mountings for the camera or image sensor, housings (G02B21/364 takes precedence) · CPC title