n06_pytorch_utils.py 文件源码

def randomDistort2(img, num_steps=10, distort_limit=0.2, u=0.5):
    if random.random() < u:
        height, width, channel = img.shape

        x_step = width // num_steps
        xx = np.zeros(width, np.float32)
        prev = 0
        for x in range(0, width, x_step):
            start = x
            end = x + x_step
            if end > width:
                end = width
                cur = width
            else:
                cur = prev + x_step * (1 + random.uniform(-distort_limit, distort_limit))

            xx[start:end] = np.linspace(prev, cur, end - start)
            prev = cur

        y_step = height // num_steps
        yy = np.zeros(height, np.float32)
        prev = 0
        for y in range(0, height, y_step):
            start = y
            end = y + y_step
            if end > width:
                end = height
                cur = height
            else:
                cur = prev + y_step * (1 + random.uniform(-distort_limit, distort_limit))

            yy[start:end] = np.linspace(prev, cur, end - start)
            prev = cur

        map_x, map_y = np.meshgrid(xx, yy)
        map_x = map_x.astype(np.float32)
        map_y = map_y.astype(np.float32)
        img = cv2.remap(img, map_x, map_y, interpolation=cv2.INTER_LINEAR, borderMode=cv2.BORDER_REFLECT_101)
    return img


## blur sharpen, etc