Equirectangular Image Data Detection, Segmentation and Classification of Varying Sized Traffic Signs: A Comparison of Deep Learning Methods

Abstract

There are known limitations in mobile omnidirectional camera systems with an equirectangular projection in the wild, such as momentum-caused object distortion within images, partial occlusion and the effects of environmental settings. The localization, instance segmentation and classification of traffic signs from image data is of significant importance to applications such as Traffic Sign Detection and Recognition (TSDR) and Advanced Driver Assistance Systems (ADAS). Works show the efficacy of using state-of-the-art deep pixel-wise methods for this task yet rely on the input of classical landscape image data, automatic camera focus and collection in ideal weather settings, which does not accurately represent the application of technologies in the wild. We present a new processing pipeline for extracting objects within omnidirectional images in the wild, with included demonstration in a Traffic Sign Detection and Recognition (TDSR) system. We compare Mask RCNN, Cascade RCNN, and Hybrid Task Cascade (HTC) methods, while testing RsNeXt 101, Swin-S and HRNetV2p backbones, with transfer learning for localization and instance segmentation. The results from our multinomial classification experiment show that using our proposed pipeline, given that a traffic sign is detected, there is above a 95% chance that it is classified correctly between 12 classes despite the limitations mentioned. Our results on the projected images should provide a path to use omnidirectional images with image processing to enable the full surrounding awareness from one image source.

A new method and practical recommendations for measuring geometric accuracy, linear and angular measurements of helical surfaces of end mill for HSM

“…Determining the focal planes of an image based on the criteria of brightness intensity and contrast are widely used in solving technical problems [58]. Semantic image segmentation has many applications such as road sign detection [59], climate zone classification [60,61] and vegetation [62]. For semantic segmentation, various functions are used, such as pixel color, Histogram of Oriented Gradients (HOG) [63], Scale Invariant Feature Transform (SIFT) [64 Local Binary Patterns (LBP) [65], features from accelerated segment test (FAST) [66].…”