Deep learning has improved many computer vision tasks by utilizing data-driven features instead of using hand-crafted features. However, geometric transformations of input images often degrade the performance of deep learning based methods. In particular, rotation-invariant features are important in computer vision tasks such as face detection, biological feature detection of microscopy images, or robot grasp detection since the input image can be fed into the network with any rotation angle. In this paper, we propose rotation ensemble module (REM) to efficiently train and utilize rotation-invariant features in a deep neural network for computer vision tasks. We evaluated our proposed REM with face detection tasks on FDDB dataset, robotic grasp detection tasks on Cornell dataset, and real robotic grasp tasks with several novel objects. REM based face detection deep neural networks yielded up to 50.8% accuracy in face detection task on FDDB dataset at false rate 20 with IOU 75%, which is about 10.7% higher than the baseline. Robotic grasp detection deep neural networks with our REM also yielded up to 97.6% accuracy in robotic grasp detection on Cornell dataset that is higher than current state-of-the-art performance. In robotic grasp task using a real 4-axis robotic arm with several novel objects, our REM based robotic grasp achieved up to 93.8%, which is significantly higher than the baseline robotic grasps (11.0-56.3%).
Robotic grasp detection for novel objects is a challenging task, but for the last few years, deep learning based approaches have achieved remarkable performance improvements, up to 96.1% accuracy, with RGB-D data. In this paper, we propose fully convolutional neural network (FCNN) based methods for robotic grasp detection. Our methods also achieved state-of-the-art detection accuracy (up to 96.6%) with state-of- the-art real-time computation time for high-resolution images (6-20ms per 360x360 image) on Cornell dataset. Due to FCNN, our proposed method can be applied to images with any size for detecting multigrasps on multiobjects. Proposed methods were evaluated using 4-axis robot arm with small parallel gripper and RGB-D camera for grasping challenging small, novel objects. With accurate vision-robot coordinate calibration through our proposed learning-based, fully automatic approach, our proposed method yielded 90% success rate.
Robotic grasp detection task is still challenging, particularly for novel objects. With the recent advance of deep learning, there have been several works on detecting robotic grasp using neural networks. Typically, regression based grasp detection methods have outperformed classification based detection methods in computation complexity with excellent accuracy. However, classification based robotic grasp detection still seems to have merits such as intermediate step observability and straightforward back propagation routine for end-to-end training. In this work, we propose a novel classification based robotic grasp detection method with multiple-stage spatial transformer networks (STN). Our proposed method was able to achieve state-of-the-art performance in accuracy with real- time computation. Additionally, unlike other regression based grasp detection methods, our proposed method allows partial observation for intermediate results such as grasp location and orientation for a number of grasp configuration candidates.