wrong detect occluded person

[170928]

In image_base.py, when you calculate occluded person, I think there is wrong condition.

full_kp2ds is normalized to [-1 ~ +1] before passed to detect_occluded_person() as belows:

def process_kp2ds_bboxes(self, full_kps, img_shape=None, is_pose2d=None):
        ... 

        if is_pose2d.sum()>0:
            # NOTE normalized here !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            full_kp2d = [self.process_kps(full_kps[ind], img_shape,set_minus=True) for ind in np.where(is_pose2d)[0]]
           # NOTE parse_multiperson_kp2ds calls detect_occluded_person !!
            ..... = self.parse_multiperson_kp2ds(full_kp2d)

def parse_multiperson_kp2ds(self, full_kps):
       ...        
        person_centers, full_kp2ds = np.array(person_centers), np.array(full_kp2ds)
        occluded_by_who = detect_occluded_person(person_centers,full_kp2ds) if args().collision_aware_centermap else None
        return person_centers, full_kp2ds, used_person_inds, bboxes_hw_norm, occluded_by_who, heatmap, AE_joints

Therefore, I think visible condition to be greater than '-1', not '0' as belows:

def detect_occluded_person(person_centers, full_kp2ds, thresh=2*64/512.):
    '''
        Parameters
        ----------
            person_centers : (num_people, 2)
                x, y
                normalized to [-1 ~ +1]
            full_kp2ds : (num_people, num_joints, 2)
                normalized to [-1 ~ +1]
    '''
    person_num = len(person_centers)
    # index of the person at the front of an occlusion
    occluded_by_who = np.ones(person_num) * -1
    if person_num > 1:
        for inds, (person_center, kp2d) in enumerate(zip(person_centers, full_kp2ds)):
            # dist : (num_people, ); person_centers (num_people, 2) - person_center (2, )
            dist = np.sqrt(((person_centers - person_center)**2).sum(-1)) 
            if (dist > 0).sum() > 0:
                if (dist[dist > 0] < thresh).sum() > 0:
                    # Comparing the visible keypoint number to justify whether the person is occluded by the others
                    #if (full_kp2ds[inds, :, 0] > 0).sum() >= (kp2d[:, 0] > 0).sum():
                    # NOTE here !! condition to be 'coords > -1'
                    if (full_kp2ds[inds, :, 0] > -1).sum() >= (kp2d[:, 0] > -1).sum():
                        closet_idx = np.where(dist==np.min(dist[dist > 0]))[0][0]
                        if occluded_by_who[closet_idx] < 0:
                            occluded_by_who[inds] = closet_idx
    return occluded_by_who.astype(np.int)