dsbowl_utils.py 文件源码

def adjust_gamma(imgs, gamma=1.0):
    assert (len(imgs.shape)==4)  #4D arrays
    assert (imgs.shape[1]==1)  #check the channel is 1
    # build a lookup table mapping the pixel values [0, 255] to
    # their adjusted gamma values
    invGamma = 1.0 / gamma
    table = np.array([((i / 255.0) ** invGamma) * 255 for i in np.arange(0, 256)]).astype("uint8")
    # apply gamma correction using the lookup table
    new_imgs = np.empty(imgs.shape)
    for i in range(imgs.shape[0]):
        new_imgs[i,0] = cv2.LUT(np.array(imgs[i,0], dtype = np.uint8), table)
    return new_imgs