Improving accuracy OpenCV HOG people detector [closed]

edit

Hello, I'm working in a project. A part of project consist to integrate the HOG people detector of OpenCV with a camera streaming .

Currently It's working the camera and the basic HOG detector (CPP detectMultiScale -> http://docs.opencv.org/modules/gpu/doc/object_detection.html). But don't work very well... The detections are very noising and the algorithm isn't very accuracy...

Why?

My camera image is 640 x 480 pixels.

The snippet code I'm using is:

std::vector<cv::Rect> found, found_filtered;
cv::HOGDescriptor hog;
hog.setSVMDetector(cv::HOGDescriptor::getDefaultPeopleDetector());
hog.detectMultiScale(image, found, 0, cv::Size(8,8), cv::Size(32,32), 1.05, 2);

Why don't work properly? What need for improve the accuracy? Is necessary some image size particular?

THANKS YOU VERY MUCH!!

PS: Do you know some precise people detection algorithm, faster and developed in cpp ??