# US 2019/0172223 A1 · Optimizations for Dynamic Object Instance Detection, Segmentation, and Structure Mapping

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- Number: US 2019/0172223 A1
- Document ID: US20190172223A1
- Status: Published application
- Kind: A1
- Application number: 15/972,035
- Filed: 2018-05-04
- Published: 2019-06-06
- Earliest claimed: 2017-12-03
- Assignees: Facebook, Inc.
- Applicants: Facebook, Inc.
- Inventors: Peter Vajda; Peizhao Zhang; Fei Yang; Yanghan Wang
- Web page: https://patentgrep.com/patent/US20190172223A1

## CPC

- G06T 7/73: using feature-based methods
- G06F 18/2113: by ranking or filtering the set of features, e.g. using a measure of variance or of feature cross-correlation
- G06F 18/2137: based on criteria of topology preservation, e.g. multidimensional scaling or self-organising maps
- G06F 18/214: Generating training patterns; Bootstrap methods, e.g. bagging or boosting
- G06N 3/045: Combinations of networks
- G06N 3/0464: Convolutional networks [CNN, ConvNet]
- G06N 3/0495: Quantised networks; Sparse networks; Compressed networks
- G06N 3/084: Backpropagation, e.g. using gradient descent
- G06N 3/09: Supervised learning
- G06T 7/11: Region-based segmentation
- G06T 7/75: {involving models}
- G06V 10/764: using classification, e.g. of video objects
- G06V 40/103: {Static body considered as a whole, e.g. static pedestrian or occupant recognition}
- G06N 5/022: Knowledge engineering; Knowledge acquisition
- G06T 2207/20076: Probabilistic image processing
- G06T 2207/20081: Training; Learning
- G06T 2207/20084: Artificial neural networks [ANN]
- G06T 2207/20104: Interactive definition of region of interest [ROI]
- G06T 2207/30196: Human being; Person
- G06T 2210/12: Bounding box
- G06V 20/20: in augmented reality scenes
- G06V 20/40: in video content (extracting overlay text G06V20/62; video retrieval G06F16/70; processing of video elementary streams in video servers H04N21/234; processing of video elementary streams in video clients H04N21/44)
- G06V 2201/07: Target detection
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

In one embodiment, a system accesses pose probability models for predetermined parts of a body depicted in an image. Each of the pose probability models is configured for determining a probability of the associated predetermined body part being at a location in the image. The system determines a candidate pose that is defined by a set of coordinates representing candidate locations of the predetermined body parts. The system further determines a first probability score for the candidate pose based on the pose probability models and the set of coordinates of the candidate pose. A pose representation is generated for the candidate pose using a transformation model and the candidate pose. The system determines a second probability score for the pose representation based on a pose-representation probability model. The system selects the candidate pose to represent a pose of the body based on at least the first and second probability scores.

## Claims

### Claim 1

A method comprising, by a computing system:
accessing a plurality of pose probability models for a plurality of predetermined parts of a body that is depicted in an image, respectively, wherein each of the plurality of pose probability models is configured for determining a probability of the associated predetermined part of the body being at a location in the image, wherein the plurality of pose probability models is generated by a machine-learning model;
determining a candidate pose that is defined by a set of coordinates representing candidate locations of the predetermined parts of the body in the image;
determining a first probability score for the candidate pose based on the plurality of pose probability models and the set of coordinates of the candidate pose;
generating a pose representation for the candidate pose using a transformation model and the candidate pose;
determining a second probability score for the pose representation based on a pose-representation probability model; and
selecting the candidate pose to represent a pose of the body depicted in the image based on at least the first probability score and the second probability score.

### Claim 2 (depends on 1)

The method of claim 1,
wherein each coordinate in the set of coordinates of the candidate pose is defined in a first coordinate system of the image;
wherein the pose representation is defined in a first spatial dimension and is generated by applying the transformation model to a set of normalized coordinates that correspond to the set of coordinates of the candidate pose, respectively; and
wherein each coordinate in the set of normalized coordinates is defined in a second coordinate system that is different from the first coordinate system.

### Claim 3 (depends on 2)

The method of claim 2, further comprising:
reprojecting the pose representation from the first spatial dimension into a second spatial dimension associated with the second coordinate system; and
computing a reprojection error based on the reprojected pose representation and the normalized coordinates;
wherein the selection of the candidate pose is further based on the reprojection error.

### Claim 4 (depends on 2)

The method of claim 2, wherein the pose representation is generated based on differences between the set of normalized coordinates and an aggregate representation of a plurality of sets of normalized coordinates that are associated with a plurality of poses, respectively.

### Claim 5 (depends on 2)

The method of claim 2, wherein the second coordinate system is defined relative to one or more of the predetermined parts of the body.

### Claim 6 (depends on 1)

The method of claim 1, wherein each of the plurality of probability models is a probability heat map.

### Claim 7 (depends on 1)

The method of claim 1, wherein the transformation model is generated using principal component analysis.

### Claim 8 (depends on 1)

The method of claim 1, wherein at least one of the plurality of predetermined parts of the body corresponds to a joint of the body.

### Claim 9

A system comprising: one or more processors and one or more computer-readable non-transitory storage media coupled to one or more of the processors, the one or more computer-readable non-transitory storage media comprising instructions operable when executed by one or more of the processors to cause the system to perform operations comprising:
accessing a plurality of pose probability models for a plurality of predetermined parts of a body that is depicted in an image, respectively, wherein each of the plurality of pose probability models is configured for determining a probability of the associated predetermined part of the body being at a location in the image, wherein the plurality of pose probability models is generated by a machine-learning model;
determining a candidate pose that is defined by a set of coordinates representing candidate locations of the predetermined parts of the body in the image;
determining a first probability score for the candidate pose based on the plurality of pose probability models and the set of coordinates of the candidate pose;
generating a pose representation for the candidate pose using a transformation model and the candidate pose;
determining a second probability score for the pose representation based on a pose-representation probability model; and
selecting the candidate pose to represent a pose of the body depicted in the image based on at least the first probability score and the second probability score.

### Claim 10 (depends on 9)

The system of claim 9,
wherein each coordinate in the set of coordinates of the candidate pose is defined in a first coordinate system of the image;
wherein the pose representation is defined in a first spatial dimension and is generated by applying the transformation model to a set of normalized coordinates that correspond to the set of coordinates of the candidate pose, respectively; and
wherein each coordinate in the set of normalized coordinates is defined in a second coordinate system that is different from the first coordinate system.

### Claim 11 (depends on 10)

The system of claim 10, wherein the processors are further operable when executing the instructions to perform operations comprising:
reprojecting the pose representation from the first spatial dimension into a second spatial dimension associated with the second coordinate system; and
computing a reprojection error based on the reprojected pose representation and the normalized coordinates;
wherein the selection of the candidate pose is further based on the reprojection error.

### Claim 12 (depends on 10)

The system of claim 10, wherein the pose representation is generated based on differences between the set of normalized coordinates and an aggregate representation of a plurality of sets of normalized coordinates that are associated with a plurality of poses, respectively.

### Claim 13 (depends on 10)

The system of claim 10, wherein the second coordinate system is defined relative to one or more of the predetermined parts of the body.

### Claim 14 (depends on 9)

The system of claim 9, wherein each of the plurality of probability models is a probability heat map.

### Claim 15

One or more computer-readable non-transitory storage media embodying software that is operable when executed to cause one or more processors to perform operations comprising:
accessing a plurality of pose probability models for a plurality of predetermined parts of a body that is depicted in an image, respectively, wherein each of the plurality of pose probability models is configured for determining a probability of the associated predetermined part of the body being at a location in the image, wherein the plurality of pose probability models is generated by a machine-learning model;
determining a candidate pose that is defined by a set of coordinates representing candidate locations of the predetermined parts of the body in the image;
determining a first probability score for the candidate pose based on the plurality of pose probability models and the set of coordinates of the candidate pose;
generating a pose representation for the candidate pose using a transformation model and the candidate pose;
determining a second probability score for the pose representation based on a pose-representation probability model; and
selecting the candidate pose to represent a pose of the body depicted in the image based on at least the first probability score and the second probability score.

### Claim 16 (depends on 15)

The media of claim 15,
wherein each coordinate in the set of coordinates of the candidate pose is defined in a first coordinate system of the image;
wherein the pose representation is defined in a first spatial dimension and is generated by applying the transformation model to a set of normalized coordinates that correspond to the set of coordinates of the candidate pose, respectively; and
wherein each coordinate in the set of normalized coordinates is defined in a second coordinate system that is different from the first coordinate system.

### Claim 17 (depends on 16)

The media of claim 16, wherein the software is further operable when executed to cause the one or more processors to perform operations comprising:
reprojecting the pose representation from the first spatial dimension into a second spatial dimension associated with the second coordinate system; and
computing a reprojection error based on the reprojected pose representation and the normalized coordinates;
wherein the selection of the candidate pose is further based on the reprojection error.

### Claim 18 (depends on 16)

The media of claim 16, wherein the pose representation is generated based on differences between the set of normalized coordinates and an aggregate representation of a plurality of sets of normalized coordinates that are associated with a plurality of poses, respectively.

### Claim 19 (depends on 16)

The media of claim 16, wherein the second coordinate system is defined relative to one or more of the predetermined parts of the body.

### Claim 20 (depends on 15)

The media of claim 15, wherein each of the plurality of probability models is a probability heat map.
