OpenCV's RGB2YUV & YUV2RGB conversions for Numpy, for values between [0, 1] or [0, 255]

rgb2yuv_yuv2rgb.py

# The coefficients were taken from OpenCV https://github.com/opencv/opencv
# I'm not sure if the values should be clipped, in my (limited) testing it looks alright
#   but don't hesitate to add rgb.clip(0, 1, rgb) & yuv.clip(0, 1, yuv)
#
# Input for these functions is a numpy array with shape (height, width, 3)
# Change '+= 0.5' to '+= 127.5' & '-= 0.5' to '-= 127.5' for values in range [0, 255]

def rgb2yuv(rgb):
    m = np.array([
        [0.29900, -0.147108,  0.614777],
        [0.58700, -0.288804, -0.514799],
        [0.11400,  0.435912, -0.099978]
    ])
    yuv = np.dot(rgb, m)
    yuv[:,:,1:] += 0.5
    return yuv

def yuv2rgb(yuv):
    m = np.array([
        [1.000,  1.000, 1.000],
        [0.000, -0.394, 2.032],
        [1.140, -0.581, 0.000],
    ])
    yuv[:, :, 1:] -= 0.5
    rgb = np.dot(yuv, m)
    return rgb