Target-object distance measuring device and vehicle mounted with the device
In a target-object distance measuring device and a vehicle on which the device is mounted, a human body detection device is utilized for calculating a distance between an image capturing device and a human body candidate in an actual space based on the size of the human body candidate in the image. The head width is approximately 15-16 cm. A body height in the actual space of the human candidate in the image is estimated based on the ratio between the head-width in the extracted image and at least one size of the human body feature, such as total height, in the extracted human body candidate region, and the distance from the image capturing device to the human body candidate in the actual space is calculated based on the estimated body height in the actual space and the body height of the human body candidate in the image.
1. A target object distance measuring apparatus including a human body detector for detecting a human body based on an image acquired by an image capturing device, the target object distance measuring apparatus comprising:
a human body candidate area extractor for extracting a human body candidate area from the image;
a reference feature extractor for extracting, as a reference feature from the extracted human body candidate area, a predetermined one of human features including a total height, a torso, an arm, a leg, and a head;
a comparison feature extractor for extracting, as a comparison feature from the extracted human body candidate area, one of the human features including the total height, the torso, the arm, the leg, and the head, except for the reference feature;
a size-in-real-space estimator for estimating the size in real space of a human body candidate in the image, based on a ratio of the size of the reference feature and the size of the comparison feature; and
a distance calculator for calculating the distance from the image capturing device to the human body candidate in the real space, based on the estimated size in the real space of the human body candidate and the size of the human body candidate in the image.
2. The target object distance measuring apparatus according to claim 1 , wherein the reference feature is the head and the comparison feature is the total height.
3. A vehicle incorporating the target object distance measuring apparatus according to claim 1 , wherein the vehicle includes a notifying unit for notifying a driver of the vehicle when the human body detector detects a human body.