Use matplotlib colormap in OpenCV

mpl_cm_opencv.py

def make_colormap_from_mpl(cm):
    """Create look-up table to convert grayscale to BGR-image.

    The returned colormap can be used like 
    bgr_img = colormap[gray_img]

    Args:
        cm: Matplotlib colormap name, e.g. "autumn" or 
            colormap instance e.g. mpl.cm.autumn

    Returns:
        numpy array of shape (256, 3) with BGR ints
    """
    if isinstance(cm, str):
        import matplotlib as mpl
        cm = mpl.colormaps[cm]
    lut = cm(np.linspace(0, 1, 256))[...,:-1]
    return (lut[..., [2,1,0]] * 255).astype(np.uint8)