Direct pose estimation networks aim to directly regress the 6D poses of target objects in the scene image using a neural network. These direct methods offer efficiency and an optimal optimization target, presenting significant potential for practical applications. However, due to the complex and implicit mappings between input features and target pose parameters, direct methods are challenging to train and prone to overfitting on mappings seen during training, resulting in limited effectiveness and generalization capability on unseen mappings. Existing methods focus primarily on improvements of the network architecture and training strategies, with less attention given to mappings. In this work, we propose a geometric constraints learning approach, which enables networks to explicitly capture and utilize the geometric mappings between inputs and optimization targets for pose estimation. Specifically, we introduce a residual pose transformation formula that preserves pose transformation constraints within both the 2D image plane and the 3D space while decoupling the absolute pose distribution, thereby addressing the pose distribution gap issue. We further design a Geo6D mechanism based on the formula, which enables the network to explicitly utilize geometric constraints for pose estimation by reconstructing the inputs and outputs. We select two different methods as our baseline and extensive experiments show that Geo6D enhances the performance and reduces the dependence on extensive training data, remaining effective even with only 10% of the typical data volume.

As RGB-D sensors become more affordable, using RGB- D images to obtain high-accuracy 6D pose estimation results becomes a better option. State-of-the-art approaches typically use different backbones to extract features for RGB and depth images. They use a 2D CNN for RGB images and a perpixel point cloud network for depth data, as well as a fusion network for feature fusion. We find that the essential reason for using two independent backbones is the “projection breakdown” problem. In the depth image plane, the projected 3D structure of the physical world is preserved by the 1D depth value and its built-in 2D pixel coordinate (UV). Any spatial transformation that modifies UV, such as resize, flip, crop, or pooling operations in the CNN pipeline, breaks the binding between the pixel value and UV coordinate. As a consequence, the 3D structure is no longer preserved by a modified depth image or feature. To address this issue, we propose a simple yet effective method denoted as Uni6D that explicitly takes the extra UV data along with RGB-D images as input. Our method has a Unified CNN framework for 6D pose estimation with a single CNN backbone. In particular, the architecture of our method is based on Mask R-CNN with two extra heads, one named RT head for directly predicting 6D pose and the other named abc head for guiding the network to map the visible points to their coordinates in the 3D model as an auxiliary module. This end-to-end approach balances simplicity and accuracy, achieving comparable accuracy with state of the arts and 7.2x faster inference speed on the YCB-Video dataset.

Deep learning is a popular direction in computer vision and digital image processing. It is widely utilized in many fields, such as robot navigation, intelligent video surveillance, industrial inspection, and aerospace. With the extensive use of deep learning techniques, classification and object detection algorithms have been rapidly developed. In recent years, with the introduction of the concept of “unmanned retail,” object detection, and image classification play a central role in unmanned retail applications. However, open-source datasets of traditional classification and object detection have not yet been optimized for application scenarios of unmanned retail. Currently, classification and object detection datasets do not exist that focus on unmanned retail solely. Therefore, in order to promote unmanned retail applications by using deep learning-based classification and object detection, in this article we collected more than 30 000 images of unmanned retail containers using a refrigerator affixed with different cameras under both static and dynamic recognition environments. These images were categorized into ten kinds of beverages. After manual labeling, images in our constructed dataset contained 155 153 instances, each of which was annotated with a bounding box. We performed extensive experiments on this dataset using ten state-of-the-art deep learning-based models. Experimental results indicate great potential of using these deep learning-based models for real-world smart unmanned vending machines.

In recent years, deep learning techniques have been commonly used in the fields of image processing and computer vision. With the popularity of deep learning models, researchers have developed many effective object detection methods. Unmanned retail applications start to utilizing object detection algorithms for changing traditional retail modes. Until now, there is no public datasets for object detection in unmanned retail application environments. Moreover, state-of-the-art deep learning-based object detection models have not yet been examined in this application scenario. In this paper, we compiled a large-scale dataset which contains over 30,000 images captured in a refrigerator equipped with different cameras. 10 kinds of beverages were utilized for targeted objects. An empirical study on this dataset is performed by using several recent developed deep learning models. Results demonstrate the effectiveness of using deep learning techniques real-life unmanned retail environments.

In this paper, linear active disturbance rejection control (LADRC) is investigated for the load frequency control (LFC) systems with wind turbine. The wind power is considered as a stochastic load to the power grid. To compensate the stochastic disturbance with LADRC, we adopt a two-stage design method. First an LQG controller is designed to handle the stochastic nature of the load, then the intrinsic link between LQG and LADRC is analyzed and the designed LQG controller is converted to a conventional LADRC so that the LADRC maintains the same property of rejecting stochastic disturbance with the LQG controller. Simulation results show that the designed LADRC with the proposed method can damp the stochastic load disturbance very well.