Object detection for signboard recognition and semi-automatic ground truth generator
| Autor: | Chen-Ya Hong, 洪晨雅 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 Data-driven object detection techniques are widely applied to a variety of practical areas. Nowadays, many research projects have been proposed to improve the accuracy of computer vision applications. In this paper, we propose an automatic signboard detection method and a semi-automatic ground truth generation method to help visually impaired people walk on streets in Taiwan. We consider that when visually impaired people walk down the street, they may be interested in certain stores. However, there is no enough public dataset for signboards of Taiwanese stores. Therefore, we collect images of 14 kinds of the most popular stores in people’s daily lives. The collected street images number over 9 million from several major cities in Taiwan; however, only about 1% of images contain a signboard. We propose an object detection module to pre-label uncertain samples. Based on this module, we also design a process so that semi-automatic ground truth generation can be achieved. Our proposed object detection network is based on Darknet-19 and we improve it by introducing several techniques, such as the dilated block, the non-local block and channel attention. The dilated block and the non-local block are introduced to increase the receptive field for the purpose of getting more information so that the accuracy of the network will be improve. We also introduce the mechanism of channel attention to give different weights for feature maps of different channels. This method can improve the accuracy again. Our proposed object detection network can achieve the accuracy of 91 % and the speed is 21 FPS. The semi-automatic ground truth generation contain several applications, such as Google Maps tool, proposed detection network and the editing tool. Google Maps tool is used to collect street images as our raw data. The proposed detection network is used to filter the images which contains signboards. The editing tool is used to verify the correctness of filtered images. The purpose of this paper is to propose the method of ground truths data collection and reduces significant effort in terms of time and human resources. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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