Object Detection Using Deep CNNs Trained on Synthetic Images
This addresses the data scarcity issue in computer vision for domains like packaged food detection, though it is incremental as it builds on existing transfer learning methods.
The paper tackled the problem of needing large annotated datasets for training object detectors by showing that effective detection can be achieved using synthetic images, with a CNN trained on 4000 synthetic images achieving 24 mAP on a test set of 55 products, and adding 400 real images increased mAP by 12%.
The need for large annotated image datasets for training Convolutional Neural Networks (CNNs) has been a significant impediment for their adoption in computer vision applications. We show that with transfer learning an effective object detector can be trained almost entirely on synthetically rendered datasets. We apply this strategy for detecting pack- aged food products clustered in refrigerator scenes. Our CNN trained only with 4000 synthetic images achieves mean average precision (mAP) of 24 on a test set with 55 distinct products as objects of interest and 17 distractor objects. A further increase of 12% in the mAP is obtained by adding only 400 real images to these 4000 synthetic images in the training set. A high degree of photorealism in the synthetic images was not essential in achieving this performance. We analyze factors like training data set size and 3D model dictionary size for their influence on detection performance. Additionally, training strategies like fine-tuning with selected layers and early stopping which affect transfer learning from synthetic scenes to real scenes are explored. Training CNNs with synthetic datasets is a novel application of high-performance computing and a promising approach for object detection applications in domains where there is a dearth of large annotated image data.