等比例缩放

def preprocess_image(image, image_size=608):
    # image, RGB
    image_height, image_width = image.shape[:2]
    if image_height > image_width:
        scale = image_size / image_height
        resized_height = image_size
        resized_width = int(image_width * scale)
    else:
        scale = image_size / image_width
        resized_height = int(image_height * scale)
        resized_width = image_size
    image = cv2.resize(image, (resized_width, resized_height))
    image = image.astype(np.float32)
    image /= 255.
    mean = [0.485, 0.456, 0.406]
    std = [0.229, 0.224, 0.225]
    image -= mean
    image /= std
    pad_h = image_size - resized_height
    pad_w = image_size - resized_width
    image = np.pad(image, [(0, pad_h), (0, pad_w), (0, 0)], mode='constant')

    return image, scale
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23