Pedestrian detection method and system in vehicle

1. A pedestrian detection method comprising:

transmitting and receiving a radar signal to and from an object in front of a vehicle to sense the object;

capturing an exterior image of the vehicle;

calculating a distance between the vehicle and the sensed object, detecting the sensed object in the captured image, and setting a region of interest (ROI) including the sensed object;

selecting, according to the distance between the vehicle and the sensed object, one pedestrian detection method among a plurality of pedestrian detection methods including a first pedestrian detection method detecting the pedestrian in a unit of a pixel and a second pedestrian detection method detecting the pedestrian in a unit of a cell including a plurality of pixels; and

detecting a pedestrian in the ROI according to the selected one pedestrian detection method.

2. The method of claim 1 , wherein the detecting of the pedestrian in the ROI includes, when the distance between the vehicle and the sensed object is less than a preset distance, detecting the pedestrian in the unit of the cell including the plurality of pixels.

3. The method of claim 1 , wherein the detecting of the pedestrian in the ROI includes, when the distance between the vehicle and the sensed object is greater than a preset distance, detecting the pedestrian in the unit of the pixel.

4. The method of claim 1 , wherein the setting the ROI comprises setting a size of the ROI in inverse proportion to the distance between the vehicle and the sensed object.

5. A pedestrian detection system comprising:

a radar sensor configured to transmit and receive a radar signal to and from an object in front of a vehicle to sense the object;

an image capturer configured to capture an exterior image of the vehicle; and

a controller configured to calculate a distance between the vehicle and the sensed object through the radar signal, detect the sensed object in the captured image, set a region of interest (ROI) including the sensed object, select, according to the distance between the vehicle and the sensed object, one pedestrian detection method among a plurality of pedestrian detection methods including a first pedestrian detection method detecting a pedestrian in a unit of a single pixel and a second pedestrian detection method detecting the pedestrian in a unit of a cell including a plurality of pixels, and detect the pedestrian in the ROI according to the selected one pedestrian detection method.

6. The system of claim 5 , wherein the controller includes:

a first processor configured to detect the pedestrian on the basis of a histogram of oriented gradient (HOG) method when the distance between the vehicle and the sensed object is smaller than a preset distance; and

a second processor configured to detect the pedestrian in units of pixels when the distance between the vehicle and the sensed object is greater than the preset distance.

7. The system of claim 5 , wherein the controller includes:

a first processor configured to detect the pedestrian in the unit of the cell including the plurality of pixels when the distance between the vehicle and the sensed object is less than a preset distance; and

a second processor configured to detect the pedestrian in the unit of the pixel when the distance between the vehicle and the sensed object is greater than the preset distance.

8. The system of claim 5 , wherein a size of the ROI is set in inverse proportion to the distance between the vehicle and the sensed object.

9. The system of claim 5 , wherein the controller is configured to:

calculate a confidence based on information of the object sensed based on the radar signal; and

determine the sensed object as an object detectable as the pedestrian when the calculated confidence is greater than a preset threshold value.

10. A pedestrian detection method comprising:

transmitting and receiving a radar signal to and from an object in front of a vehicle to sense the object;

capturing an image of the vehicle;

calculating a distance between the vehicle and the sensed object, and calculating a confidence based on information of the object sensed based on the radar signal;

when the calculated confidence is greater than a preset threshold value, identifying the sensed object as an object detectable as the pedestrian;

detecting the object detectable as the pedestrian in the captured image, and setting a region of interest (ROI) including the object detectable as the pedestrian;

detecting the pedestrian in the ROI by selecting, according to the distance between the vehicle and the sensed object, between one method detecting the pedestrian in a unit of a pixel and another method detecting the pedestrian in a unit of a cell having a plurality of pixels.