Vanishing point correction apparatus and method

• US 10,235,579 B2
• Filed: 04/14/2016
• Issued: 03/19/2019
• Est. Priority Date: 05/26/2015
• Status: Active Grant

• Current Assignee: PLK Technologies Co., Ltd.
• Original Assignee: PLK Technologies Co., Ltd.
• Inventors: Park, Kwang Il, Lim, Sang Mook, Kim, Jin Hyuck
• Primary Examiner(s): Mistry, Oneal R
• Application Number:
  US15/560,296
• Publication Number:
  US 20180060679A1
• Time in Patent Office: 1,069 Days
• CPC Class Codes: G06T 2207/30261 Obstacle
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06T 7/62 of area, perimeter, diameter or volume
• CPC Class Codes: G06V 10/255 Detecting or recognising potential candidate objects based on visual cues, e.g. shapes
• CPC Class Codes: G06V 10/421 by analysing segments intersecting the pattern
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: G06V 10/50 by performing operations within image blocks; by using histograms, e.g. histogram of oriented gradients [HoG]; by summing image-intensity values; Projection analysis
• CPC Class Codes: G06V 10/62 relating to a temporal dimension, e.g. time-based feature extraction; Pattern tracking
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads
• 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: G08G 1/16 Anti-collision systems road vehicle drive control systems for predicting or avoiding probable or impending collision otherwise than by control of a particular sub-unit B60W30/08
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

A vanishing point correction method may include the steps of: (a) extracting a contour candidate point of an object considered as the forward vehicle from the image taken by the camera; (b) tracking a movement of the contour candidate point over time; (c) determining whether the contour candidate point belongs to the vehicle; (d) setting the contour candidate point to a vehicle contour point of the forward vehicle, when it is determined at the step (c) that the contour candidate point belongs to the vehicle; (e) calculating a variation in width between vehicle contour points at the same height among the vehicle contour points; and (f) calculating a variation of the vanishing point.

Claims

1. A vanishing point correction method that corrects the position of a vanishing point in an image taken by a camera in an image recognition system mounted in a vehicle, the vanishing point correction method comprising the steps of:

(a) extracting a contour candidate point of an object considered as the forward vehicle from the image taken by the camera;

(b) tracking a movement of the contour candidate point over time;

(c) determining whether the contour candidate point belongs to the vehicle;

(d) setting the contour candidate point to a vehicle contour point of the forward vehicle, when it is determined at the step (c) that the contour candidate point belongs to the vehicle;

(e) calculating a variation in width between vehicle contour points at the same height among the vehicle contour points; and

(f) calculating a variation of the vanishing point through Equation 13 below;

2. The vanishing point correction method of claim 1, wherein the step (a) comprises extracting a point at which a horizontal edge and a vertical edges cross each other in the image taken by the camera, as the contour candidate point.

3. The vanishing point correction method of claim 1, wherein the step (b) comprises the steps of:

(b-1) defining a first block having a plurality of pixels around the contour candidate point in a first image;

(b-2) defining a second block having the same size as the first block in a second image after a predetermined passage of time from the first image;

(b-3) determining whether a pixel value of the second block coincides with a pixel value of the first block, while moving the second block to around the contour candidate point based on the same position as the first block in the second image; and

(b-4) determining that the contour candidate point has moved in the corresponding block, when it is determined at the step (b-3) that the pixel value of the second block coincides with the pixel value of the first block.

4. The vanishing point correction method of claim 1, wherein the step (c) comprises the steps of:

(c-1) extracting the bottom of a rear wheel or the end of a lower shadow area of the forward vehicle, and recognizing the bottom of the rear wheel or the end of the lower shadow area as a distance reference point;

(c-2) subtracting a relative distance to the distance reference point from a relative distance to the contour candidate point through Equation 6 below;

(c-3) determining whether the subtraction result of the step (c-2) is constant over time within a predetermined error range; and

(c-4) determining that the corresponding contour candidate point belongs to the vehicle, when it is determined at the step (c-2) that the subtraction result of the step (c-2) is not constant over time;

5. The vanishing point correction method of claim 1, wherein the step (c) comprises the steps of:

(c-1) extracting the bottom of a rear wheel or the end of a lower shadow area of the forward vehicle, and recognizing the bottom of the rear wheel or the end of the lower shadow area as a distance reference point;

(c-2) calculating a height of the contour candidate point relative to the distance reference point through Equation 7 below;

(c-3) determining whether the calculation result of the step (c-2) is constant over time within a predetermined error range; and

(c-4) determining that the corresponding contour candidate point belongs to the vehicle, when it is determined at the step (c-3) that the calculation result of the step (c-2) is constant over time;

6. A vanishing point correction apparatus that is mounted in a vehicle and corrects the position of a vanishing point in an image taken by a camera, the vanishing point correction apparatus comprising:

a contour candidate point extraction unit configured to extract a contour candidate point of an object considered as a forward vehicle from the image taken by the camera;

a contour point determination unit configured to track a movement of the contour candidate point, determine whether the contour candidate point belongs to the vehicle, and set the contour candidate point to a vehicle contour point when the contour candidate point belongs to the vehicle;

a contour point variation calculation unit configured to calculate a variation in width between vehicle contour points at the same height among the vehicle contour points; and

a vanishing point correction unit configured to calculate a vanishing point variation from the width variation calculated through the contour point variation calculation unit, using Equation 13 below;

7. The vanishing point correction apparatus of claim 6, wherein the contour candidate point extraction unit extracts a point at which a horizontal edge and a vertical edge cross each other in the image taken by the camera, as the contour candidate point.

9. The vanishing point correction apparatus of claim 6, wherein the contour point determination unit comprises a height tracking unit configured to extract the bottom of a rear wheel or the end of a lower shadow area of the forward vehicle, recognize the bottom of the rear wheel or the end of the lower shadow area as the distance reference point, determine whether a height of the contour candidate point relative to the distance reference point through Equation 7 below is constant over time, and determine that the contour candidate point belongs to the vehicle, when the height of the contour candidate point is constant over time:

8. vanishing point correction apparatus 6, wherein the contour point determination unit comprises a relative distance tracking unit configured to extract the bottom of a rear wheel or the end of a lower shadow area of the forward vehicle, recognize the bottom of the rear wheel or the end of the lower shadow area as a distance reference point, determine whether a result obtained by subtracting a relative distance to the distance reference point from a relative distance to the contour candidate point through Equation 6 below is constant over time, and determine that the corresponding contour candidate point belongs to the vehicle, when the subtraction result is not constant over time: