Utilities for bounding box

bbox_utils.py

def transform_predicitions(window_prediction_bbox, xs, ys):
    '''
    Transform SSD bounding boxes in a sliding window, to absolute coordinates in the original image 
    '''
    r= []
    for label, score, xmin, ymin, xmax, ymax  in window_prediction_bbox:
        label = int(label)
        xmin = math.ceil(xmin*box_width)+xs
        xmax = math.ceil(xmax*box_width)+xs
        ymin = math.floor(ymin*box_height)+ys
        ymax = math.floor(ymax*box_height)+ys
        r.append((label, score, xmin, ymin, xmax, ymax))
    return r    

def show_predictions(predictions_bbox, current_axis=None):
    '''
    Plots multiple bounding boxes with absolute coordinates
    '''
    if current_axis==None:
        current_axis = plt.gca()
    for label, score, xmin, ymin, xmax, ymax  in predictions_bbox:
        label = int(label)
#         print('label', label, 'xmin', xmin, 'ymin', ymin, 'xmax', xmax, 'ymax', ymax)
        display_txt = '{:0.2f}, {}'.format(score, label)
        coords = (xmin, ymin), xmax-xmin+1, ymax-ymin+1
        color = colors[label]
        current_axis.add_patch(plt.Rectangle(*coords, fill=False, edgecolor=color, linewidth=2))
        display_txt = '{:0.2f}, {}'.format(score, label)
        current_axis.text(xmin, ymin, display_txt, bbox={'facecolor':color, 'alpha':0.5})  
        
def overlap(xmin, ymin, xmax, ymax, xmin2, ymin2, xmax2, ymax2):
    return xmin < xmax2 and xmax > xmin2 and ymin < ymax2 and ymax > ymin2

def unify_bboxes(predictions_bbox):
    '''
        Somtimes SSD will predict multiple bounding boxes on top of each.
        This is very naive :)
    '''
    r=[]
    for label, score, xmin, ymin, xmax, ymax  in predictions_bbox:
        found = False
        for label2, score2, xmin2, ymin2, xmax2, ymax2  in predictions_bbox:
            if label2==label and score2>score and overlap(xmin, ymin, xmax, ymax, xmin2, ymin2, xmax2, ymax2):
                found=True
                break
        if not found:        
            r.append((label, score, xmin, ymin, xmax, ymax))
    return r