I had similar environment, I revisited to ensure that my environment matches with above images and still no luck. Below is the code snippet I added to SDK,
HOGDescriptor hog;
hog.setSVMDetector(HOGDescriptor::getDefaultPeopleDetector());
vector<Rect> found, found_filtered;
hog.detectMultiScale(m_src, found, 0, Size(8,8), Size(32,32), 1.05, 2);
Thanks,
Nitin