Image processor and image processing method for parking frame estimation on a road surface

1. An image processor comprising:

a processor; and

a non-transitory computer-readable medium having stored thereon executable instructions that, when executed by the processor, cause the image processor to function as:

a line extraction portion that is configured to extract: (i) a first line from a first image generated from a first surrounding image of a vehicle captured by an imaging device at a first predetermined timing; and (ii) a second line from a second image generated from a second surrounding image of the vehicle captured by the imaging device at a second predetermined timing which is after the first predetermined timing;

a tracking determination portion that is configured to determine whether the second line extracted by the line extraction portion fulfills a predetermined condition or not;

a comparing portion that is configured to compare the second line that is determined as fulfilling the predetermined condition by the tracking determination portion with the first line to obtain degrees of similarity and coincidence thereof, the degrees of similarity and coincidence being based on an angle difference and a distance difference between the first line and the second line;

a parking area line determination portion that is configured to determine the second line as a parking area line when the degrees of similarity and coincidence that are obtained are equal to or more than a given value;

a parking frame setting portion that is configured to set a parking frame using the second line that is determined as the parking area line by the parking area line determination portion; and

a vehicle speed acquisition portion that is configured to acquire a speed of the vehicle,

wherein the comparing portion is configured to not obtain the degree of coincidence when the speed of the vehicle acquired by the vehicle speed acquisition portion is equal to or less than a predetermined speed.

2. The image processor according to claim 1 , wherein the executable instructions, when executed by the processor, cause the image processor to further function as an angle parking frame determination portion that is configured to determine whether the parking frame set by the parking frame setting portion is an angle parking frame or not.

3. The image processor according to claim 1 , wherein the executable instructions, when executed by the processor, cause the image processor to further function as a display control portion that is configured to control a display portion to superimpose a parking frame image on the second image generated from the second surrounding image of the vehicle to create a superimposed image and display the superimposed image, the parking frame image showing the parking frame set by the parking frame setting portion.

4. The image processor according to claim 1 , wherein the line extraction portion is further configured to:

scan the second image generated from the second surrounding image of the vehicle in a predetermined direction;

detect pixels whose luminance or color parameter in an image signal of the second image generated from the second surrounding image of the vehicle vary more than a threshold;

detect a portion where an arrangement of the pixels that have been detected is equal to or longer than a given length as an edge; and

extract the second line in accordance with the edge.

5. An image processing method comprising:

extracting a second line from a second image generated from a second surrounding image of a vehicle captured by an imaging device at a second predetermined timing;

determining whether the second line fulfills a predetermined condition or not;

comparing the second line that is determined as fulfilling the predetermined condition with a first line that is extracted from a first image generated from a first surrounding image of the vehicle captured by the imaging device at a first predetermined timing that has passed to obtain degrees of similarity and coincidence thereof, the degrees of similarity and coincidence being based on an angle difference and a distance difference between the first line and the second line;

determining the second line as a parking area line when the degrees of similarity and coincidence that are obtained are equal to or more than a given value;

setting a parking frame using the second line that is determined as the parking area line; and

acquiring a speed of the vehicle,

wherein the degree of coincidence is not obtained when the speed of the vehicle which is acquired is equal to or less than a predetermined speed.