Traffic Light Detecting Device and Traffic Light Detecting Method

• US 20160371552A1
• Filed: 03/10/2014
• Published: 12/22/2016
• Est. Priority Date: 03/10/2014
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nishiuchi, Hidekazu, Oki, Takahiko
• Granted Patent: US 9,679,207 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06V 10/22 by selection of a specific region containing or referencing a pattern; Locating or processing of specific regions to guide the detection or recognition
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: G06V 10/62 relating to a temporal dimension, e.g. time-based feature extraction; Pattern tracking
• CPC Class Codes: G06V 20/584 of vehicle lights or traffic lights
• CPC Class Codes: G08G 1/09623 Systems involving the acquisition of information from passive traffic signs by means mounted on the vehicle G08G1/0967 takes precedence
• CPC Class Codes: H04N 23/745 Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination

Abstract

A traffic light detecting device includes an image capturing unit configured to capture an image of surroundings of a vehicle and a traffic light detecting unit configured to detect a traffic light from the image. The traffic light detecting unit extracts a synchronized pixel with a luminance which varies in synchronization with an alternating current cycle of electric power supplied to the traffic light, and sets a predetermined range including the synchronized pixel as a pixel group. The traffic light detecting unit, then, judges from the synchronized pixel whether or not the traffic light is present when the synchronized pixel is continuously extracted from the pixel group for a predetermined determination period.

Claims

1. A traffic light detecting device comprising:

a camera mounted on a vehicle and configured to capture an image of surroundings of the vehicle; and

a traffic light detecting circuit configured to detect a traffic light from the image, wherein

the traffic light detecting circuit includes;

a synchronized pixel extracting unit configured to extract from the image a synchronized pixel with a luminance which varies in synchronization with an alternating current cycle of electric power supplied to the traffic light;

a pixel group setting unit configured to set a predetermined range including the synchronized pixel and neighboring pixels of the synchronized pixel as a pixel group; and

a traffic light judging unit configured to judge from the synchronized pixel whether or not the traffic light is present when the synchronized pixel is continuously extracted from the pixel group for a predetermined determination period.

2. The traffic light detecting device according to claim 1, wherein

the pixel group includes the synchronized pixel and one or more neighboring pixels adjacent to and around the synchronized pixel.

3. The traffic light detecting device according to claim 2, wherein

a width of neighboring pixels vertically adjacent to the synchronized pixel is larger than a width of the neighboring pixels horizontally adjacent to the synchronized pixel.

4. The traffic light detecting device according to claim 2, wherein

when the number of the synchronized pixels in the pixel group is larger, the pixel group setting unit sets the width of the neighboring pixels in the pixel group larger.

5. The traffic light detecting device according to claim 1, wherein

the traffic light judging unit includes a hue judging unit configured to judge whether or not a hue of the synchronized pixel is similar to a hue of a signal color, and

the traffic light judging unit judges that the traffic light is present at a position of the synchronized pixel when the synchronized pixel is continuously extracted from the pixel group for a predetermined period, and the hue of the synchronized pixel is similar to a hue of the signal color.

6. The traffic light detecting device according to claim 1, wherein

the traffic light judging unit changes the predetermined determination period in accordance with a range of a luminance variation of the synchronized pixel.

7. The traffic light detecting device according to claim 5, wherein

the hue judging unit judges whether or not a hue synthesized from the hues of all the synchronized pixels in the pixel group is similar to the hue of the signal color.

8. The traffic light detecting device according to claim 2, wherein

the pixel group setting unit superposes a luminance value of the synchronized pixel on those of the neighboring pixels.

9. A traffic light detecting method, comprising:

capturing an image of surroundings of a vehicle;

extracting from the image a synchronized pixel with a luminance which varies in synchronization with an alternating current cycle of electric power supplied to a traffic light;

setting a predetermined range including the synchronized pixel and neighboring pixels of the synchronized pixel as a pixel group; and

judging from the synchronized pixel whether or not the traffic light is present when the synchronized pixel is continuously extracted from the pixel group for a predetermined determination period.