Use you provide .pb works on CPU speed:100ms per image

[yhl2018]

[mrgloom]

For which input resolution? 640 x 480 ?

256 x 256
Inference time:  0.022 sec

512 x 512
Inference time:  0.08 sec

640 x 480
Inference time:  0.105 sec

1024 x 1024
Inference time:  0.343 sec