util.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import print_function, division
import numba
import numpy as np

__author__ = 'Fisher Yu'
__copyright__ = 'Copyright (c) 2016, Fisher Yu'
__email__ = 'i@yf.io'
__license__ = 'MIT'

@numba.jit(nopython=True)
def interp_map(prob, zoom, width, height):
    zoom_prob = np.zeros((prob.shape[0], height, width), dtype=np.float32)
    for c in range(prob.shape[0]):
        for h in range(height):
            for w in range(width):
                r0 = h // zoom
                r1 = r0 + 1
                c0 = w // zoom
                c1 = c0 + 1
                rt = float(h) / zoom - r0
                ct = float(w) / zoom - c0
                v0 = rt * prob[c, r1, c0] + (1 - rt) * prob[c, r0, c0]
                v1 = rt * prob[c, r1, c1] + (1 - rt) * prob[c, r0, c1]
                zoom_prob[c, h, w] = (1 - ct) * v0 + ct * v1
    return zoom_prob