import tensorflow as tf


    heights = scales_grid / ratio_sqrts * base_size[1]
    widths = scales_grid * ratio_sqrts * base_size[0]

    x_centers = tf.cast(tf.range(features_width), tf.float32)
    x_centers = x_centers * stride[1]
    y_centers = tf.cast(tf.range(features_height), tf.float32)
    y_centers = y_centers * stride[0]
    # x_centers = x_centers + offset[1]
    # y_centers = y_centers + offset[0]

    x_centers, y_centers = tf.meshgrid(x_centers, y_centers)
