抽出した輪郭を間引いてみる

昨日はオブジェクトから輪郭を抽出する処理を書きました。今日は、
輪郭を等間隔に間引いたものの形状がどうなるか見てみます。前処理としてオリジナルデータのオブジェクト領域が小さかったのでscipyのzoom関数で２倍に拡大してから処理に入っています。あと、符号化もしてます。等間隔に間引くだけなら符号化する必要はないかもしれませんが、あとで何かに使えるかもしれないので、符号化してみました。

# -*- coding: utf-8 -*-
import random
import re
import numpy as np
from numpy import arange
import matplotlib.pyplot as plt
from scipy.ndimage import zoom

def rawObjectToMatrix(ro):
    ret = []
    lines = ro.splitlines()
    for line in lines:
        if line.strip()=="":
            continue
        ret.append(map(lambda x: 0 if x == " " else 1, line))
    whiteRow = [[0 for _ in xrange(len(ret[0]))]]
    return whiteRow + ret + whiteRow

def pb(lst2d):
    ret = ""
    for lst in lst2d:
        lst = map(abs, lst)
        ret += "".join(map(str, lst)) + "\n"
    print ""
    print ret

def readMyData():
    with open("a.txt", 'r') as fp:
        text = fp.read()
    objectRawDataList = re.split(r"\n\n", text)
    objectRawDataList = filter(lambda x: x != "", objectRawDataList)
    return map(lambda ro: rawObjectToMatrix(ro), objectRawDataList)

lst = readMyData()

sampleMatrix = zoom(np.array(lst[5]), 1.5)
pb(sampleMatrix)

height = sampleMatrix.shape[0]
width = sampleMatrix.shape[1]

mat = sampleMatrix.copy()
for rn, _ in enumerate(mat):
    for cn, __ in enumerate(_):
        if mat[rn, cn] == 1 and mat[rn + 1, cn] == 1:
            mat[rn, cn] = 0

out = mat
mat = sampleMatrix.copy()
for rn, _ in enumerate(mat):
    for cn, __ in enumerate(_):
        if mat[(height - 1) - rn, cn] == 1 and mat[(height - 1) - rn - 1, cn] == 1:
            mat[(height - 1) - rn, cn] = 0

out |= mat
mat = sampleMatrix.copy()
for rn, _ in enumerate(mat):
    for cn, __ in enumerate(_):
        if mat[rn, cn] == 1 and mat[rn, cn + 1] == 1:
            mat[rn, cn] = 0

out |= mat
mat = sampleMatrix.copy()
for rn, _ in enumerate(mat):
    for cn, __ in enumerate(_):
        if mat[rn, (width - 1) - cn] == 1 and mat[rn, (width - 1) - cn - 1] == 1:
            mat[rn, (width - 1) - cn] = 0

out |= mat  
pb(out)

firstPosFlat = out.flatten().argmax()
pos = firstPosFlat / width, firstPosFlat % width
startPos = pos
code = []
while True:
    if   out[pos[0] - 1, pos[1]    ] == 1:
        out[pos[0] - 1, pos[1]    ] = 2
        pos = pos[0] - 1, pos[1]
        code.append((-1, 0))
    elif out[pos[0] - 1, pos[1] + 1] == 1:
        out[pos[0] - 1, pos[1] + 1] = 2
        pos = pos[0] - 1, pos[1] + 1
        code.append((-1, 1))
    elif out[pos[0]    , pos[1] + 1] == 1:
        out[pos[0]    , pos[1] + 1] = 2
        pos = pos[0]    , pos[1] + 1
        code.append((0, 1))
    elif out[pos[0] + 1, pos[1] + 1] == 1:
        out[pos[0] + 1, pos[1] + 1] = 2
        pos = pos[0] + 1, pos[1] + 1
        code.append((1, 1))
    elif out[pos[0] + 1, pos[1]    ] == 1:
        out[pos[0] + 1, pos[1]    ] = 2
        pos = pos[0] + 1, pos[1]    
        code.append((1, 0))
    elif out[pos[0] + 1, pos[1] - 1] == 1:
        out[pos[0] + 1, pos[1] - 1] = 2
        pos = pos[0] + 1, pos[1] - 1
        code.append((1, -1))
    elif out[pos[0]    , pos[1] - 1] == 1:
        out[pos[0]    , pos[1] - 1] = 2
        pos = pos[0]    , pos[1] - 1
        code.append((0, -1))
    elif out[pos[0] - 1, pos[1] - 1] == 1:
        out[pos[0] - 1, pos[1] - 1] = 2
        pos = pos[0] - 1, pos[1] - 1
        code.append((-1, -1))
    if pos == startPos:
        break

pb(out)


mabiki = [1, 2, 4, 8, 16, 32]
for m in mabiki:
    pr = 0
    pc = 0
    p = []
    for n, c in enumerate(code):
        dr, dc = c
        pr += dr
        pc += dc
        if n % m == 0:
            p.append((pr, pc))

    x = map(lambda x: x[1], p)
    y = map(lambda x: x[0], p)
    x += [0]
    y += [0]
    fig, ax = plt.subplots(1)
    ax.plot(x, y)
    fig.savefig("/Users/kei/Desktop/mabiki%d.png"%m)

出力(上から順に、オリジナル, 2, 4, 8, 16, 32ステップごとにサンプルをとった場合の集合)：