recognition_utils.py 文件源码

def im_detect_and_describe(img, mask=None, detector='dense', descriptor='SIFT', colorspace='gray',
                           step=4, levels=7, scale=np.sqrt(2)): 
    """ 
    Describe image using dense sampling / specific detector-descriptor combination. 
    """
    detector = get_detector(detector=detector, step=step, levels=levels, scale=scale)
    extractor = cv2.DescriptorExtractor_create(descriptor)

    try:     
        kpts = detector.detect(img, mask=mask)
        kpts, desc = extractor.compute(img, kpts)

        if descriptor == 'SIFT': 
            kpts, desc = root_sift(kpts, desc)

        pts = np.vstack([kp.pt for kp in kpts]).astype(np.int32)
        return pts, desc

    except Exception as e: 
        print 'im_detect_and_describe', e
        return None, None