Transparent Bin Picking Using RGB Segmentation for Unreliable Depth Maps

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Solution Overview

Problem

Existing robot systems fail to accurately identify transparent objects in a bin using depth map images due to light propagation, leading to unreliable point cloud representations and ineffective object recognition for pick and place operations.

Innovation Solution

A system and method employing a deep learning mask R-CNN (convolutional neural network) for image segmentation, which generates a segmentation image by assigning labels to pixels in RGB images, allowing the robot to identify and pick up transparent objects without relying on accurate depth map images, using a 3D camera and a robot controller that performs feature extraction, region proposal, binary segmentation, and grasp pose calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If depth map images are used to identify transparent objects, then distance measurements can be obtained, but the depth map becomes unreliable due to light propagation through transparent objects

Engineering Contradiction:
Improvedepth measurement accuracyVSAvoiddepth map reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies image segmentation to divide the RGB image into distinct regions corresponding to different objects. By segmenting the image at the pixel level and labeling regions, the system can identify transparent objects based on color and texture information from the RGB image rather than relying on unreliable depth data. This segmentation approach allows the robot to locate and identify transparent objects without being affected by light propagation issues in depth maps.

Inventive Principle:
Principle #1Segmentation

2Difficulty of detecting and measuring

If model-based point cloud analysis with CAD templates is used, then object identification can be performed, but transparent objects cannot be properly identified due to ineffective point cloud representation

Engineering Contradiction:
Improveobject identification capabilityVSAvoidtransparent object detection
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent replaces the mechanical/optical point cloud-based detection system with a deep learning-based image segmentation system. Instead of using 3D point clouds that fail to represent transparent objects, the system uses 2D RGB image segmentation with convolutional neural networks to identify transparent objects based on their visual features in the image plane. This substitution of detection methodology eliminates the fundamental limitation of point cloud analysis for transparent objects.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If traditional bin picking methods are used, then general objects can be picked up, but transparent objects cannot be properly identified for picking

Engineering Contradiction:
Improvebin picking capabilityVSAvoidtransparent object identification
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the detection parameters from 3D point cloud coordinates to 2D image pixel labels. By transforming the problem from three-dimensional point cloud analysis to two-dimensional image segmentation, the system can effectively detect transparent objects using color, texture, and spatial information from the RGB image. This parameter transformation allows the bin picking system to handle both opaque and transparent objects reliably.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12036678B2Transparent object bin picking
Publication Date: 2024.07.16 FANUC LTD
  • US12036678B2 patent drawing
  • US12036678B2 patent drawing
  • US12036678B2 patent drawing

AI summary

A system and method identifying an object, such as a transparent object, to be picked up by a robot from a bin of objects. The method includes obtaining a 2D red-green-blue (RGB) color image and a 2D depth map image of the objects using a 3D camera, where pixels in the depth map image are assigned a value identifying the distance from the camera to the objects. The method generates a segmentation image of the objects using a deep learning mask R-CNN (convolutional neural network) that performs an image segmentation process that extracts features from the RGB image and assigns a label to the pixels so that objects in the segmentation image have the same label. The method then identifies a location for picking up the object using the segmentation image and the depth map image.