Traffic sign detection in dual-focal active camera system

Gu, Yanlei; Yendo, Tomohiro; Tehrani, Mehrdad Panahpour; Fujii, Toshiaki; Tanimoto, Masayuki

doi:10.1109/ivs.2011.5940513

Cited by 28 publications

(34 citation statements)

References 16 publications

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“…In this system, an active telephoto camera is additionally equipped, which works as an assistant and captures a higher resolution image for traffic sign. This mentioned dual-focal active camera system was firstly applied for TSR in [28] and improved in our previous works [5], [29]. The improvement is described in Sect.…”

Section: Our Previous Workmentioning

confidence: 99%

“…In this paper, we develop TSR in the dual-focal active camera system as an improvement of our previous works [5], [29]. We also adopt the two-step processing in which classification is conducted after detection.…”

Section: Traffic Sign Recognition Systemmentioning

confidence: 99%

“…In order to recognize traffic sign as soon as it becomes visible in different lighting conditions, we mainly improve the previous works [5], [29] from two aspects: First, we apply a color transformation method in images from the system, to increase the stability of the image of traffic sign in dark condition. Second, in addition to changing the direction of the telephoto camera, we also control the exposure time of the telephoto camera to capture a high accuracy image for each detected candidate.…”

Section: Traffic Sign Recognition Systemmentioning

confidence: 99%

“…Second, in addition to changing the direction of the telephoto camera, we also control the exposure time of the telephoto camera to capture a high accuracy image for each detected candidate. Besides from the abovementioned aspects, learning-based approach is applied in detection in instead of knowledge-based approach used in [5], [29]. In classification, we adopt a hierarchical classifier to substitute template matching used in [5].…”

Section: Traffic Sign Recognition Systemmentioning

confidence: 99%

“…3. Because the weight of a mirror is much lighter than a camera, the response speed of the telephoto camera is faster than the conventional system [5], [29].…”

Section: Dual-focal Active Camera Systemmentioning

confidence: 99%

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Traffic Sign Recognition with Invariance to Lighting in Dual-Focal Active Camera System

Tehrani

Yendo

et al. 2012

IEICE Trans. Inf. & Syst.

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SUMMARYIn this paper, we present an automatic vision-based traffic sign recognition system, which can detect and classify traffic signs at long distance under different lighting conditions. To realize this purpose, the traffic sign recognition is developed in an originally proposed dual-focal active camera system. In this system, a telephoto camera is equipped as an assistant of a wide angle camera. The telephoto camera can capture a high accuracy image for an object of interest in the view field of the wide angle camera. The image from the telephoto camera provides enough information for recognition when the accuracy of traffic sign is low from the wide angle camera. In the proposed system, the traffic sign detection and classification are processed separately for different images from the wide angle camera and telephoto camera. Besides, in order to detect traffic sign from complex background in different lighting conditions, we propose a type of color transformation which is invariant to light changing. This color transformation is conducted to highlight the pattern of traffic signs by reducing the complexity of background. Based on the color transformation, a multi-resolution detector with cascade mode is trained and used to locate traffic signs at low resolution in the image from the wide angle camera. After detection, the system actively captures a high accuracy image of each detected traffic sign by controlling the direction and exposure time of the telephoto camera based on the information from the wide angle camera. Moreover, in classification, a hierarchical classifier is constructed and used to recognize the detected traffic signs in the high accuracy image from the telephoto camera. Finally, based on the proposed system, a set of experiments in the domain of traffic sign recognition is presented. The experimental results demonstrate that the proposed system can effectively recognize traffic signs at low resolution in different lighting conditions.

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Section: Our Previous Workmentioning

confidence: 99%

Section: Traffic Sign Recognition Systemmentioning

confidence: 99%

Section: Traffic Sign Recognition Systemmentioning

confidence: 99%

Section: Traffic Sign Recognition Systemmentioning

confidence: 99%

“…3. Because the weight of a mirror is much lighter than a camera, the response speed of the telephoto camera is faster than the conventional system [5], [29].…”

Section: Dual-focal Active Camera Systemmentioning

confidence: 99%

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