# US 10,503,978 B2 · Spatio-temporal interaction network for learning object interactions

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- Number: US 10,503,978 B2
- Document ID: US10503978B2
- Status: Granted
- Kind: B2
- Application number: 15/978,738
- Filed: 2018-05-14
- Published: 2019-01-17
- Granted: 2019-12-10
- Earliest claimed: 2017-07-14
- Assignees: NEC Corporation
- Applicants: NEC Laboratories America, Inc.
- Inventors: Asim Kadav; Chih-Yao Ma; Iain Melvin; Hans Peter Graf
- Web page: https://patentgrep.com/patent/US10503978B2

## CPC

- G06V 20/46: {Extracting features or characteristics from the video content, e.g. video fingerprints, representative shots or key frames}
- G06F 18/217: {Validation; Performance evaluation; Active pattern learning techniques}
- G06V 10/82: using neural networks
- G06V 20/41: {Higher-level, semantic clustering, classification or understanding of video scenes, e.g. detection, labelling or Markovian modelling of sport events or news items (segmenting video sequences G06V20/49)}
- G06V 30/2504: {Coarse or fine approaches, e.g. resolution of ambiguities or multiscale approaches}
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

Systems and methods for improving video understanding tasks based on higher-order object interactions (HOIs) between object features are provided. A plurality of frames of a video are obtained. A coarse-grained feature representation is generated by generating an image feature for each of for each of a plurality of timesteps respectively corresponding to each of the frames and performing attention based on the image features. A fine-grained feature representation is generated by generating an object feature for each of the plurality of timesteps and generating the HOIs between the object features. The coarse-grained and the fine-grained feature representations are concatenated to generate a concatenated feature representation.

## Claims

### Claim 1

A computer-implemented method for improving video understanding tasks based on higher-order object interactions (HOIs) between object features, comprising:
obtaining a plurality of frames of a video;
generating a coarse-grained feature representation, including generating an image feature for each of a plurality of timesteps respectively corresponding to each of the frames, and performing attention based on the image features;
generating a fine-grained feature representation, including generating an object feature for each of the plurality of timesteps, and generating the HOIs between the object features; and
concatenating the coarse-grained and the fine-grained feature representations to generate a concatenated feature representation.

### Claim 2 (depends on 1)

The method of claim 1, further comprising making a prediction based on the concatenated feature representation to perform one or more operations.

### Claim 3 (depends on 2)

The method of claim 2, wherein the one or more operations include at least one of action recognition and video captioning.

### Claim 4 (depends on 1)

The method of claim 1, wherein the image features are generated using a convolutional neural network (CNN).

### Claim 5 (depends on 1)

The method of claim 1, wherein performing attention based on the image features further includes performing Scaled Dot Product (SDP) attention.

### Claim 6 (depends on 1)

The method of claim 1, wherein the coarse-grained feature representation includes attended context information.

### Claim 7 (depends on 6)

The method of claim 6, wherein generating the coarse-grained feature representation further comprises generating the attended context information by mean-pooling weighted image representations.

### Claim 8 (depends on 1)

The method of claim 1, wherein the object features are generated using a region proposal network (RPN).

### Claim 9 (depends on 1)

The method of claim 1, wherein generating the HOIs further includes:
generating projected object features respectively corresponding to the object features;
computing attention weights based at least in part on the projected object features;
performing attentive selection using a plurality of attentive selection components to generate attended object features each corresponding to a respective one of the attentive selection components;
concatenating the attended object features to generate an attended object feature representation; and
determining an HOI representation based on the attended object feature representation.

### Claim 10 (depends on 9)

The method of claim 9, wherein the projected object features are generated using a plurality of multilayer perceptrons (MLPs).

### Claim 11 (depends on 9)

The method of claim 9, wherein the attentive selection components implement dot product attention.

### Claim 12 (depends on 9)

The method of claim 9, wherein determining the HOI representation further includes implementing a long short term memory (LSTM) cell, and wherein a last hidden state of the LSTM cell is selected as the HOI representation.

### Claim 13

A computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method for improving video understanding tasks based on higher-order object interactions (HOIs) between object features comprising:
obtaining a plurality of frames of a video;
generating a coarse-grained feature representation, including generating an image feature for each of a plurality of timesteps respectively corresponding to each of the frames, and performing attention based on the image features;
generating a fine-grained feature representation, including generating an object feature for each of the plurality of timesteps, and generating the HOIs between the object features; and
concatenating the coarse-grained and the fine-grained feature representations to generate a concatenated feature representation.

### Claim 14 (depends on 13)

The computer program product of claim 13, wherein the method further comprises making a prediction based on the concatenated feature representation to perform one or more operations, and wherein the one or more operations include at least one of action recognition and video captioning.

### Claim 15 (depends on 13)

The computer program product of claim 13, wherein the image features are generated using a convolutional neural network (CNN).

### Claim 16 (depends on 13)

The computer program product of claim 13, wherein performing attention based on the image features further includes performing Scaled Dot Product (SDP) attention.

### Claim 17 (depends on 13)

The computer program product of claim 13, wherein the coarse-grained feature representation includes attended context information, and wherein generating the coarse-grained feature representation further comprises generating the attended context information by mean-pooling weighted image representations.

### Claim 18 (depends on 13)

The computer program product of claim 13, wherein generating the HOIs further includes:
generating projected object features respectively corresponding to the object features;
computing attention weights based at least in part on the projected object features;
performing attentive selection using a plurality of attentive selection components to generate attended object features each corresponding to a respective one of the attentive selection components;
concatenating the attended object features to generate an attended object feature representation; and
determining an HOI representation based on the attended object feature representation.

### Claim 19 (depends on 18)

The computer program product of claim 18, wherein determining the HOI representation further includes implementing a long short term memory (LSTM) cell, and wherein a last hidden state of the LSTM cell is selected as the HOI representation.

### Claim 20

A system for improving video understanding tasks based on higher-order object interactions (HOIs) between object features, comprising:
at least one processor operatively coupled to a memory, wherein the at least one processor is configured to:
obtain a plurality of frames of a video;
generate a coarse-grained feature representation by generating an image feature for each of a plurality of timesteps respectively corresponding to each of the frames, and performing attention based on the image features;
generate a fine-grained feature representation by generating an object feature for each of the plurality of timesteps, and generating the HOIs between the object features; and
concatenate the coarse-grained and the fine-grained feature representations to generate a concatenated feature representation.
