'Faster R-CNN with Inception Resnet v2 preprocessing.
Maps pixel values to the range [-1, 1].
Args:
resized_inputs: A [batch, height_in, width_in, channels] float32 tensor
representing a batch of images with values between 0 and 255.0.
Returns:
preprocessed_inputs: A [batch, height_out, width_out, channels] float32
tensor representing a batch of images.'

def preprocess(self, resized_inputs):

    return (((2.0 / 255.0) * resized_inputs) - 1.0)
