Parking assistance device

1. A parking assistance device comprising:

a processor

periodically detects a parking-possible region in which a vehicle can be parked based on a result of detection of a status of surroundings of the vehicle by periodically detecting the status of surroundings of the vehicle based on a captured image of an external camera which is mounted on the vehicle and captures external images of the vehicle;

executes, for each periodically detected parking-possible region, a candidate selection processing including a parking candidate region selection processing to select a parking candidate region as a parking candidate for the vehicle among the detected parking-possible regions, and a recommendation selection processing to select a recommendation parking candidate space for recommending a vehicle parking from the selected parking candidate regions; and

causes a display to display an image of surroundings of the vehicle in which a parking position image illustrating a parking position is superimposed on the selected parking candidate region,

wherein in the recommendation selection processing, when the parking candidate region selection processing is executed for the second time or later, the processor determines whether a predetermined duration is elapsed since the start of parking position display,

when having determined that the predetermined duration is elapsed, the parking candidate region is selected among currently detected parking-possible regions,

when having determined that predetermined duration is not elapsed, the processor determines whether the parking candidate region currently selected in the parking candidate region selection processing is same as the parking candidate region previously selected in the parking candidate region selection processing,

when having determined that the parking candidate region currently selected in the parking candidate region selection processing is same as the parking candidate region previously selected in the parking candidate region selection processing, the processor calculates a separation distance between the parking candidate region and the vehicle through subtraction of a predetermined distance, so as to calculate to be a separation distance shorter than an actual separation distance between the parking candidate region and the vehicle, and the recommendation parking candidate spaces are selected in a predetermined number or less, and in an ascending order of the calculated separation distance.

2. The parking assistance device according to claim 1 , wherein the parking candidate region selection processing includes an overlapping selection processing to select one parking-possible region as the parking candidate region based on a predetermined priority order when a plurality of the parking-possible regions at least partially overlapping with each other are detected.

3. The parking assistance device according to claim 1 , wherein the processor calculates a traveling path from the current position of the vehicle to the detected parking-possible region,

wherein the parking candidate region selection processing includes a path selection processing to select, as the parking candidate region, the parking-possible region, the traveling path of which is calculated by the path calculation unit among the detected parking-possible regions.

4. The parking assistance device according to claim 1 , wherein

the parking candidate region selection processing detects an existence of an obstacle surrounding of the vehicle from images captured by the external camera, and

includes an obstacle selection processing to select, as the parking candidate region, the parking-possible region in which no obstacle is detected among the detected parking-possible regions.

5. The parking assistance device according to claim 1 , wherein the parking candidate region selection processing includes a display range selection processing to select, as the parking candidate region, the parking-possible region at least partially included in a display region of the display among the detected parking-possible regions.

6. The parking assistance device according to claim 1 , wherein the parking candidate region selection processing includes a tilt selection processing to select, as the parking candidate region, the parking-possible region, a tilt of which relative to a front-back direction of the vehicle is in a predetermined range among the detected parking-possible regions.

7. The parking assistance device according to claim 1 , wherein the parking candidate region selection processing includes an overlapping selection processing to select as the parking candidate region, the parking-possible region not overlapping with the vehicle among the parking-possible regions detected by the parking region detection unit.

8. The parking assistance device according to claim 1 , wherein when there are a plurality of the selected parking candidate regions, the processor selects a first parking candidate region in which parking of the vehicle is recommended and a second parking candidate region different from the first parking candidate region.

9. The parking assistance device according to claim 8 , wherein the processor displays, in manners different from each other, the parking position image superimposed on the first parking candidate region and the parking position image superimposed on the second parking candidate region.

10. The parking assistance device according to claim 1 , wherein the parking position image is a parking boundary image illustrating a parking boundary.