# US 10,375,330 B2 · Systems and methods for surface topography acquisition using laser speckle

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- Number: US 10,375,330 B2
- Document ID: US10375330B2
- Status: Granted
- Kind: B2
- Application number: 15/592,622
- Filed: 2017-05-11
- Published: 2017-11-30
- Granted: 2019-08-06
- Earliest claimed: 2016-05-27
- Assignees: Verily Life Sciences LLC
- Applicants: Verily Life Sciences LLC
- Inventors: Eden Rephaeli; Daniele Paolo Piponi
- Web page: https://patentgrep.com/patent/US10375330B2

## CPC

- A61B 5/0066: {Optical coherence imaging}
- A61B 1/05: characterised by the image sensor, e.g. camera, being in the distal end portion
- A61B 1/0661: {Endoscope light sources}
- G01B 9/02094: {Speckle interferometers, i.e. for detecting changes in speckle pattern}
- G01B 11/24: for measuring contours or curvatures
- G06T 7/521: from laser ranging, e.g. using interferometry; from the projection of structured light
- G06T 7/529: from texture
- H04N 23/56: provided with illuminating means
- H04N 25/60: Noise processing, e.g. detecting, correcting, reducing or removing noise
- A61B 5/0084: {for introduction into the body, e.g. by catheters (A61B5/1459 takes precedence)}
- A61B 5/1072: {measuring distances on the body, e.g. measuring length, height or thickness (A61B5/1076 takes precedence)}
- A61B 5/1076: {for measuring dimensions inside body cavities, e.g. using catheters (A61B3/1005 takes precedence)}
- A61B 5/7246: {using correlation, e.g. template matching or determination of similarity}
- G06T 2207/20021: Dividing image into blocks, subimages or windows
- G06T 2207/20056: Discrete and fast Fourier transform, [DFT, FFT]
- H04N 23/555: {for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present disclosure relates to systems and devices configured to determine the distance to objects within a field of view. Namely, at least a portion of the field of view may be illuminated with a coherent light source. Due to interactions between the laser light, the transmission medium, and the object, characteristic laser speckle patterns may be formed. These characteristic laser speckle patterns may be imaged with a camera. Using statistical image analysis, an estimated distance to the objects within the field of view may be obtained. For example, the image frame may be partitioned into a plurality of image segments. An autocorrelation for each image segment of the plurality of image segments may be obtained. A depth map may be obtained based on the autocorrelations.

## Claims

### Claim 1

A system, comprising:
at least one laser light source;
an image sensor; and
a controller comprising a memory and at least one processor, wherein the at least one processor executes instructions stored in the memory to carry out operations, wherein the operations comprise:
causing the at least one laser light source to illuminate a field of view with coherent laser light so as to form a characteristic laser speckle pattern;
causing the image sensor to capture an image frame, wherein the image frame comprises information indicative of the characteristic laser speckle pattern;
partitioning the image frame into a plurality of image segments;
determining an autocorrelation for each image segment of the plurality of image segments; and
based on the autocorrelations, determining a depth map of the field of view.

### Claim 2 (depends on 1)

The system of claim 1, wherein determining the autocorrelation for each image segment comprises determining a power spectrum of the respective image segment, wherein the power spectrum of the respective image segment comprises a square of a Fourier transform of an image intensity of the respective image segment.

### Claim 3 (depends on 1)

The system of claim 1, wherein the image frame is one image frame from a plurality of image frames of the field of view, wherein determining the depth map of the field of view comprises averaging the autocorrelations of corresponding image segments of the plurality of image frames.

### Claim 4 (depends on 1)

The system of claim 1, wherein the at least one laser light source emits a plurality of laser wavelengths, wherein the characteristic laser speckle pattern comprises at least two laser wavelengths from the plurality of laser wavelengths.

### Claim 5 (depends on 1)

The system of claim 1, further comprising an endoscope, wherein the field of view is illuminated via the endoscope or the image frame is captured via the endoscope.

### Claim 6 (depends on 1)

The system of claim 1, further comprising a surgical laser, wherein the operations further comprise causing the surgical laser to illuminate at least a portion of the field of view based on the depth map.

### Claim 7 (depends on 1)

The system of claim 1, wherein causing the at least one laser light source to illuminate the field of view comprises scanning the at least one laser light source over the field of view.

### Claim 8 (depends on 1)

The system of claim 1, wherein the operations further comprise at least one of: moving a position of the at least one laser light source, interposing a moving diffuser between the at least one laser light source and the field of view, adjusting an optical path of light emitted by the at least one light source to illuminate the field of view, or adjusting an operating condition of the at least one laser light source.

### Claim 9 (depends on 1)

A method utilizing the system of claim 1, wherein the method comprises determining a depth map of a portion of a patient during a surgical procedure.

### Claim 10

A method, comprising:
illuminating a field of view with coherent laser light of at least one laser light source so as to form a characteristic laser speckle pattern;
capturing, with an image sensor, an image frame, wherein the image frame comprises information indicative of the characteristic laser speckle pattern;
partitioning the image frame into a plurality of image segments;
determining an autocorrelation for each image segment of the plurality of image segments; and
based on the autocorrelations, determining a depth map of the field of view.

### Claim 11 (depends on 10)

The method of claim 10, wherein determining the autocorrelation for each image segment comprises determining a power spectrum of the respective image segment, wherein the power spectrum of the respective image segment comprises a square of a Fourier transform of an image intensity of the respective image segment.

### Claim 12 (depends on 10)

The method of claim 10, wherein the image frame is one image frame from a plurality of image frames of the field of view, wherein determining the depth map of the field of view comprises averaging the autocorrelations of corresponding image segments of the plurality of image frames.

### Claim 13 (depends on 10)

The method of claim 10, wherein the at least one laser light source emits a plurality of laser wavelengths, wherein the characteristic laser speckle pattern comprises at least two laser wavelengths from the plurality of laser wavelengths.

### Claim 14 (depends on 10)

The method of claim 10, wherein the field of view is illuminated via an endoscope.

### Claim 15 (depends on 10)

The method of claim 10, wherein the image frame is captured via an endoscope.

### Claim 16 (depends on 10)

The method of claim 10, further comprising illuminating, with a surgical laser, at least a portion of the field of view based on the depth map.

### Claim 17 (depends on 10)

The method of claim 10, wherein illuminating the field of view with coherent laser light comprises scanning the at least one laser light source over the field of view.

### Claim 18 (depends on 10)

The method of claim 10, further comprising, capturing a second image frame after moving a position of the at least one laser light source.

### Claim 19 (depends on 10)

The method of claim 10, further comprising, capturing a second image frame after interposing a diffuser between the at least one laser light source and the field of view.

### Claim 20 (depends on 10)

The method of claim 10, further comprising, capturing a second image frame after adjusting an operating condition of the at least one laser light source.