tf_anchors.py

from math import sqrt

min_scale = 0.2
max_scale = 0.95
num_layers = 6
aspect_ratios = [1.0, 2.0, 0.5, 3.0, 0.333]
image_width = 300
image_height = 300

scales = [min_scale + (max_scale - min_scale) * i / (num_layers - 1) for i in range(num_layers)] + [1.0]

for i in range(num_layers):
    if i == 0:
        widths = [0.1, min_scale * sqrt(2.0), min_scale * sqrt(0.5)]
        heights = [0.1, min_scale / sqrt(2.0), min_scale / sqrt(0.5)]
    else:
        widths = [scales[i] * sqrt(ar) for ar in aspect_ratios]
        heights = [scales[i] / sqrt(ar) for ar in aspect_ratios]

        widths += [sqrt(scales[i] * scales[i + 1])]
        heights += [sqrt(scales[i] * scales[i + 1])]
    widths = [w * image_width for w in widths]
    heights = [h * image_height for h in heights]

    print widths
    print heights
    print ''