# US 2018/0322639 A1 · Method for tracking a clinical target in medical images

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- Number: US 2018/0322639 A1
- Document ID: US20180322639A1
- Status: Published application
- Kind: A1
- Application number: 15/773,403
- Filed: 2016-10-28
- Published: 2018-11-08
- Earliest claimed: 2015-11-03
- Applicants: B<>Com; Inria; Institut National Sciences Appliquees
- Inventors: Lucas Royer; Alexandre Krupa; Maud Marchal
- Web page: https://patentgrep.com/patent/US20180322639A1

## CPC

- G06T 7/20: Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51)
- G06T 7/12: Edge-based segmentation
- G06T 7/143: involving probabilistic approaches, e.g. Markov random field [MRF] modelling
- G06T 2207/10016: Video; Image sequence
- G06T 2207/10068: Endoscopic image
- G06T 2207/10132: Ultrasound image
- G06T 2207/20116: Active contour; Active surface; Snakes
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

A method of tracking a clinical target in a current image of a sequence of digital medical images, with respect to a reference image of the sequence. The method includes: obtaining a segmentation of a contour of the target from the reference image; determining a region delimiting the interior of the segmented contour of the target in the reference image; obtaining a confidence measurement per image element in the determined region for the reference and current images; deforming the contour by minimising a cost function based on an intensity difference between the current and reference images in the determined region, the cost function being weighted by the confidence measurements; and adapting the reference image at least from the intensities of the current image and the current image confidence measurements in the target region, the cost function taking into account the intensities of the adapted reference image.

## Claims

### Claim 1

A method for tracking a clinical target in a current image of a sequence of digital medical images, obtained by an ultrasound or endoscopic imaging technique, with respect to a reference image of said sequence, a digital image of the sequence comprising image elements, said method comprising the following acts performed by an image processing device:
receiving the sequence of digital medical images;
obtaining a segmentation of a contour of said target from said reference image;
determining a zone delimiting the an interior of the segmented contour of the target in said reference image;
obtaining a confidence measurement per image element in said determined zone for said reference image and for said current image;
deforming said contour obtained by minimising a cost function based on an intensity difference between the current image and the reference image in the determined region, said cost function being weighted by the confidence measurements obtained for the image elements of the region; and
adapting the reference image at least from the intensities of the current image and the current image confidence measurements in the target region, and wherein the cost function takes into account the intensities of the adapted reference image.

### Claim 2 (depends on 1)

The method for tracking a clinical target according to claim 1, wherein said cost function takes into account a weighting of the combined probability density of the intensities of the current image and the reference image by said confidence measures.

### Claim 3 (depends on 1)

The method for tracking a clinical target according to claim 1, further comprising detecting at least one aberration portion in said reference image and in said current frame and wherein said aberration portion detected is taken into account in said obtaining a confidence measurement in said specific region to said reference image and said current image.

### Claim 4 (depends on 1)

The method of tracking a clinical target according to claim 1, wherein the contour deformation further takes into account a mechanical model of internal deformation of the target for correcting said deformation resulting from the minimisation of a cost function and the deformation of the contour resulting from the minimisation of a cost function with respect to the deformation resulting from the mechanical model of internal deformation of the target in the said determined region is weighted.

### Claim 5

A device for tracking a clinical target in a current image of a sequence of digital medical images, obtained by an ultrasound or endoscopic imaging technique, with respect to a reference image of said sequence, a digital image comprising image elements, the device comprising:
a processor; and
a non-transitory computer-readable medium comprising instructions stored thereon, which when executed by the processor configure the device to perform acts comprising:
receiving the sequence of digital medical images;
obtaining a segmentation of a contour of said target from said reference image;
determining a region delimiting an interior of the segmented contour of the target in said reference image;
obtaining a confidence measurement per image element in said determined region for said reference image and for said current image;
deforming said contour by minimizing a cost function based on an intensity difference between the current image and the reference image in the determined region, said cost function being weighted by the confidence measurements obtained for the image elements of the region; and
adapting the reference image at least from the intensities of the current image and the current image confidence measurements in the target region and wherein the cost function takes into account the intensities of the adapted reference image.

### Claim 6

(canceled)

### Claim 7

A non-transitory processor-readable recording medium on which is recorded a computer program comprising program code instructions for performing a method, when executed by a processor of an image processing device, for tracking a clinical target in a current image of a sequence of digital medical images, obtained by an ultrasound or endoscopic imaging technique, with respect to a reference image of said sequence, a digital image of the sequence comprising image elements, said instructions configuring the image processing device to perform acts comprising:
receiving the sequence of digital medical images;
obtaining a segmentation of a contour of said target from said reference image;
determining a zone delimiting an interior of the segmented contour of the target in said reference image;
obtaining a confidence measurement per image element in said determined zone for said reference image and for said current image;
deforming said contour obtained by minimising a cost function based on an intensity difference between the current image and the reference image in the determined region, said cost function being weighted by the confidence measurements obtained for the image elements of the region; and
adapting the reference image at least from the intensities of the current image and the current image confidence measurements in the target region, and wherein the cost function takes into account the intensities of the adapted reference image.