preprocessing image for VGG16, BGR or RGB ?

[coldstarnju]

VGG16 were trained using Caffe, and Caffe uses OpenCV to load images which uses BGR by default, so VGG models are expecting BGR images. In the example, RGB images are used, but I'm not sure whether is it right because I couldn't find the op of swapping the first-layer filters of the CNN when convert caffe model to tensorflow model.

[machrisaa]

This part convert the RGB to BGR:

        # Convert RGB to BGR
        red, green, blue = tf.split(axis=3, num_or_size_splits=3, value=rgb_scaled)
        assert red.get_shape().as_list()[1:] == [224, 224, 1]
        assert green.get_shape().as_list()[1:] == [224, 224, 1]
        assert blue.get_shape().as_list()[1:] == [224, 224, 1]
        bgr = tf.concat(axis=3, values=[
            blue - VGG_MEAN[0],
            green - VGG_MEAN[1],
            red - VGG_MEAN[2],
        ])