Variational 3D Object Detection for Monocular Ambiguity

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Solution Overview

Problem

Conventional 3D object detection from monocular RGB images is limited by a lack of 3D information, leading to ambiguity in 2D to 3D projection and occlusions, which result in overlapping image features and difficulties in distinguishing objects.

Innovation Solution

A method involving stochastic latent variables sampled from a learned latent feature distribution to lift multiple 3D proposals for detected 2D objects, using a proposal selection algorithm to reduce overlap and estimate confidence scores for selecting the best 3D proposals, thereby addressing the ambiguity and improving 3D object perception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional 3D object detection uses one-to-one mapping from 2D to 3D, then the method is simple, but the accuracy is poor due to ambiguity in projection and lack of 3D information

Engineering Contradiction:
Improve3D object detection accuracyVSAvoidmethod complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces stochastic latent variables to transform the deterministic one-to-one mapping into a probabilistic one-to-many mapping, adding a latent dimension that resolves the ambiguity between 2D projections and 3D objects. This dimensional extension allows multiple 3D proposals to be generated from a single 2D detection, improving accuracy while managing complexity through structured probability spaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the mapping parameters from fixed geometric projection to stochastic sampling from learned latent feature distributions. By sampling multiple latent variables and generating corresponding 3D proposals, the system transforms the detection problem into a probabilistic parameter estimation task, improving measurement precision through statistical modeling of 3D uncertainties.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple 3D proposals are generated from 2D objects, then the accuracy improves, but the overlap between proposals increases making it difficult to distinguish objects

Engineering Contradiction:
Improve3D pose estimation accuracyVSAvoidobject distinction difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements feedback through confidence score estimation for each 3D proposal, allowing the system to evaluate and rank generated proposals. This feedback mechanism enables the system to distinguish between high-confidence and low-confidence proposals, resolving the overlap ambiguity by selectively accepting proposals that better explain the observed 2D image features.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent segments the 3D proposal space into distinct candidates through stochastic latent variable sampling, creating multiple discrete 3D bounding box proposals instead of a single ambiguous estimate. This segmentation allows the system to individually evaluate and select the most appropriate 3D representation, reducing the difficulty of object distinction despite the increased number of proposals.

Inventive Principle:
Principle #1Segmentation

3Productivity

If monocular RGB images are used for 3D detection, then the system is simple and energy-efficient, but the lack of 3D information causes overlapping image features and detection failures

Engineering Contradiction:
Improvedetection efficiencyVSAvoid3D information loss
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent creates multiple virtual copies of the 3D object representation through stochastic latent variable sampling. Each sampled latent variable generates a corresponding 3D proposal that serves as a copy of the possible 3D interpretations of the 2D object. This copying approach allows the system to compensate for the loss of 3D information in monocular images by exploring multiple plausible 3D interpretations.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent performs preliminary action by pre-learning the latent feature distribution from training data before actual detection. This pre-computed distribution encodes prior knowledge about 3D object structures and relationships, allowing the system to generate informed 3D proposals without requiring real-time 3D information, thus maintaining efficiency while reducing information loss.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11302028B2Variational 3D object detection
Publication Date: 2022.04.12 TOYOTA JIDOSHA KK
  • US11302028B2 patent drawing
  • US11302028B2 patent drawing
  • US11302028B2 patent drawing

AI summary

A method for monocular 3D object perception is described. The method includes sampling multiple, stochastic latent variables from a learned latent feature distribution of an RGB image for a 2D object detected in the RGB image. The method also includes lifting a 3D proposal for each stochastic latent variable sampled for the detected 2D object. The method further includes selecting a 3D proposal for the detected 2D object using a proposal selection algorithm to reduce 3D proposal lifting overlap. The method also includes planning a trajectory of an ego vehicle according to a 3D location and pose of the 2D object according to the selected 3D proposal.