model.py 文件源码

def _prepare_image(self, image):
        """Resize the image to a maximum height of `self.height` and maximum
        width of `self.width` while maintaining the aspect ratio. Pad the
        resized image to a fixed size of ``[self.height, self.width]``."""
        img = tf.image.decode_png(image, channels=self.channels)
        dims = tf.shape(img)
        self.width = self.max_width

        max_width = tf.to_int32(tf.ceil(tf.truediv(dims[1], dims[0]) * self.height_float))
        max_height = tf.to_int32(tf.ceil(tf.truediv(self.width, max_width) * self.height_float))

        resized = tf.cond(
            tf.greater_equal(self.width, max_width),
            lambda: tf.cond(
                tf.less_equal(dims[0], self.height),
                lambda: tf.to_float(img),
                lambda: tf.image.resize_images(img, [self.height, max_width],
                                               method=tf.image.ResizeMethod.BICUBIC),
            ),
            lambda: tf.image.resize_images(img, [max_height, self.width],
                                           method=tf.image.ResizeMethod.BICUBIC)
        )

        padded = tf.image.pad_to_bounding_box(resized, 0, 0, self.height, self.width)
        return padded