Operation control map, display unit, and white line detection apparatus

• US 8,433,096 B2
• Filed: 01/26/2009
• Issued: 04/30/2013
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kageyama, Shioya, Mochida, Kentaro, Nishii, Takahito, Terui, Takekazu
• Primary Examiner(s): Mehmood, Jennifer
• Assistant Examiner(s): Mahase, Pameshanand
• Application Number:
  US12/865,824
• Publication Number:
  US 20110001640A1
• Time in Patent Office: 1,555 Days
• Field of Search: None
• US Class Current: 382/103
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• CPC Class Codes: H04N 23/76 by influencing the image signals
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation

Abstract

An operation control map of a white line detection apparatus, including a white line detection portion that detects a white line on a road based on a captured image of the road surface, that references the operation control map to determine whether to allow operation of the white line detection portion. The operation control map includes a region in which operation of the white line detection is allowed, and a region in which operation is not allowed, based on the gain of a road surface image signal and the temperature of a road surface imaging portion. The allowed region is set if the reduced accuracy of white line detection, due to the thermal noise generated in the solid-state imaging sensor, falls within an acceptable range, and the disallowed region is set if the reduced accuracy of white line detection falls outside of the acceptable range.

Claims

1. An operation control map which, in a white line detection apparatus including a road surface imaging portion, includes a solid-state imaging sensor, a white line detection portion that detects white line on a road based on a captured image of the road surface, and a determining portion that determines whether to allow operation of the white line detection portion, is referenced as a determination reference for determining whether to allow operation of the white line detection portion, comprising:

an allowed region, in which operation of the white line detection portion is allowed, that is set based on values of a gain of a road surface image signal generated by the road surface imaging portion and a detected temperature of the road surface imaging portion, which are variables in the operation control map;

a first disallowed region, in which operation of the white line detection portion is not allowed, that is also set based on the values of the variables; and

a second disallowed region, in which operation of the white line detection portion is not allowed, that is set for the temperature of the imaging portion exceeding a temperature at which operation of the imaging portion is guaranteed,

wherein the allowed region is a region that is set when reduced accuracy of white line detection, due to the thermal noise generated in the solid-state imaging sensor, falls within an acceptable range, and the first disallowed region is a region that is set when the reduced accuracy of white line detection falls outside of the acceptable range.

2. The operation control map according to claim 1, further comprising:

a buffer region interposed between the allowed region and the first disallowed region,

wherein the buffer region functions like the first disallowed region if coordinates determined by the gain and the temperature enter the buffer region from the first disallowed region due to a change in the gain, and the buffer region functions like the allowed region if the coordinates enter the buffer region from the allowed region due to a change in the gain.

3. A white line detection apparatus that detects a white line on a road, comprising:

a road surface imaging portion that includes a solid-state image sensor which captures an image of the road surface;

a gain controlling portion that controls the gain when amplifying a road surface image signal generated by the road surface imaging portion, based on the brightness around a vehicle;

a white line detection portion that compares the difference between brightness values of the road and a white line in the amplified road surface image signal with a threshold value, and detects the white line based on the comparison results;

a temperature measuring portion that measures the temperature of the road surface imaging portion;

a determining portion that determines whether to allow operation of the white line detection portion based on the gain controlled by the gain controlling portion and the temperature measured by the temperature measuring portion; and

an operation controlling portion that controls the operation of the white line detection portion based on the determination results of the determining portion,

wherein the determining portion includes an operation control map in which the gain and the temperature are variables and which has an allowed region, in which operation of the white line detection portion is allowed, and a first disallowed region, in which operation of the white line detection portion is not allowed, that are set based on the values of the variables, and a second disallowed region, in which operation of the white line detection portion is not allowed, that is set for the temperature of the imaging portion exceeding a temperature at which operation of the imaging portion is guaranteed,

and the determining portion determines whether to allow the operation based on the operation control map, and

wherein the allowed region is a region that is set when reduced accuracy of white line detection, due to the thermal noise generated in the solid-state imaging sensor, falls within an acceptable range, and the first disallowed region is a region that is set when the reduced accuracy of white line detection falls outside of the acceptable range.

4. The white line detection apparatus according to claim 3, wherein a buffer region is interposed between the allowed region and the first disallowed region, and the buffer region functions like the first disallowed region if coordinates determined by the gain and the temperature enter the buffer region from the first disallowed region due to a change in the gain, and the buffer region functions like the allowed region if the coordinates enter the buffer region from the allowed region due to a change in the gain.

5. The white line detection apparatus according to claim 3, further comprising:

a display portion that informs a user of the operating state of the white line detection portion,

wherein the display portion indicates that the white line detection portion is i) operating or ii) not operating.

6. The white line detection apparatus according to claim 4, further comprising:

a display portion that informs a user of the operating state of the white line detection portion,

wherein the operation control map further includes a region where the temperature exceeds an operation guaranteed temperature of the white line detection apparatus as an operation disallowed region, and the display portion indicates that the white line detection portion is i) operating, ii) not operating due to thermal noise, or iii) not operating due to the operation guaranteed temperature being exceeded.

7. A display unit configured to be cooperative with a white line detection apparatus, and which informs a user of the operating state of the white line detection portion,

said white line detection apparatus including a road surface imaging portion, a white line detection portion that detects white line on a road based on a captured image of the road surface, a determining portion that determines whether to allow operation of the white line detection portion based on an operation control map in which the temperature of the road surface imaging portion and the gain when amplifying a road surface image signal generated by the road surface imaging portion are variables, and an operation controlling portion that controls the operation of the white line detection portion based on the determination results of the determining portion, and

said operation control map comprising an allowed region, in which operation of the white line detection portion is allowed, and a first disallowed region, in which operation of the white line detection portion is not allowed, that are set based on the values of variables, and a second disallowed region, in which operation of the white line detection portion is not allowed, that is set for the temperature of the imaging portion exceeding a temperature at which operation of the imaging portion is guaranteed, wherein the allowed region is a region that is set when reduced accuracy of white line detection, due to the thermal noise generated in the solid-state imaging sensor, falls within an acceptable range, and the first disallowed region is a region that is set when the reduced accuracy of white line detection falls outside of the acceptable range,

the display unit indicating that the white line detection portion is i) operating when coordinates of the variables fall within the allowed region of the operation control map, ii) being controlled not to operate due to thermal noise generated in the road surface imaging portion when coordinates of the variables fall within the first disallowed region of the operation control map, or iii) being controlled not to operate due to an operation guaranteed temperature of the white line detection apparatus being exceeded when coordinates of the variables fall within the second disallowed region of the operation control map.

8. The display unit according to claim 7, wherein, in a case the white line detection portion is operating, the display unit displays a white line detected by the white line detection portion using a white line thicker than in case the white line detection portion is being controlled not to operate due to thermal noise generated in the road surface imaging portion.

9. The display unit according to claim 7, wherein if the white line detection portion is being controlled not to operate due to the operation guaranteed temperature of the white line detection apparatus being exceeded, the display unit indicates that a lane keeping assist system is currently unavailable.

10. The display unit according to claim 8, wherein if the white line detection portion is being controlled not to operate due to the operation guaranteed temperature of the white line detection apparatus being exceeded, the display unit indicates that a lane keeping assist system is currently unavailable.