dp.py

#!/usr/bin/env python
import cv2
import sys
sys.path.append('internals')
import numpy as np
import video
import distance as dis
from distance import VELOCITY

def dp(frames):
    # parameters
    GAP = 20
    WDN = 5
    START = VELOCITY - (WDN/2)
    T = len(frames)

    # dp array
    D = np.zeros((T))
    P = np.zeros((T),dtype='int')
    for i in range(GAP, T):
        D[i] = dis.getCostWoAcc(frames, i, i-1) + D[i-1]
        P[i] = i-1
        for w in range(0, WDN):
            j = i - START - w
            if(j < GAP):
                break
            cur = dis.getCostWoAcc(frames, i, j)+ D[j]
            if D[i] > cur:
                D[i] = cur
                P[i] = j

    min_end = T-1
    min_cost = D[min_end]

    for i in range(T - GAP,T):
        if D[i] < min_cost:
            min_cost = D[i]
            min_end = i

    path = [min_end]
    cur = min_end

    while cur > GAP:
        cur = P[cur]
        path = [cur] + path

    return path

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print "Usage: " + sys.argv[0] + " [input_video] [output_video]"
        exit(-1)

    frames  = video.readVideo(sys.argv[1]);
    outFile = sys.argv[2];
    idxList = dp(frames)
    video.writeVideo(outFile, frames, idxList)