class ViBe:
'''''
classdocs
'''
__defaultNbSamples = 20 #每个像素点的样本个数
__defaultReqMatches = 2 #min指数
__defaultRadius = 20; #Sqthere半径
__defaultSubsamplingFactor = 16#子采样概率
__BG = 0 #背景像素
__FG = 255 #前景像素
__c_xoff=[-1,0,1,-1,1,-1,0,1,0] #x的邻居点 len=9
__c_yoff=[-1,0,1,-1,1,-1,0,1,0] #y的邻居点 len=9
__samples=[] #保存每个像素点的样本值,len defaultNbSamples+1
__Height = 0
__Width = 0
def __init__(self, grayFrame):
'''''
Constructor
'''
self.__Height = grayFrame.shape[0]
self.__Width = grayFrame.shape[1]
for i in range(self.__defaultNbSamples+1):
self.__samples.insert(i,np.zeros((grayFrame.shape[0],grayFrame.shape[1]),dtype=grayFrame.dtype));
self.__init_params(grayFrame)
def __init_params(self,grayFrame):
#记录随机生成的 行(r) 和 列(c)
rand=0
r=0
c=0
#对每个像素样本进行初始化
for y in range(self.__Height):
for x in range(self.__Width):
for k in range(self.__defaultNbSamples):
#随机获取像素样本值
rand=random.randint(0,8)
r=y+self.__c_yoff[rand]
if r<0:
r=0
if r>=self.__Height:
r=self.__Height-1 #行
c=x+self.__c_xoff[rand]
if c<0:
c=0
if c>=self.__Width:
c=self.__Width-1 #列
#存储像素样本值
self.__samples[k][y,x] = grayFrame[r,c]
self.__samples[self.__defaultNbSamples][y,x] = 0
def update(self,grayFrame,frameNo):
foreground = np.zeros((self.__Height,self.__Width),dtype=np.uint8)
for y in range(self.__Height): #Height
for x in range(self.__Width): #Width
#用于判断一个点是否是背景点,index记录已比较的样本个数，count表示匹配的样本个数
count=0;index=0;
dist=0.0;
while (count<self.__defaultReqMatches) and (index<self.__defaultNbSamples):
dist= float(grayFrame[y,x]) - float(self.__samples[index][y,x]);
if dist<0: dist=-dist
if dist<self.__defaultRadius: count = count+1
index = index+1
if count>=self.__defaultReqMatches:
#判断为背景像素,只有背景点才能被用来传播和更新存储样本值
self.__samples[self.__defaultNbSamples][y,x]=0
foreground[y,x] = self.__BG
rand=random.randint(0,self.__defaultSubsamplingFactor)
if rand==0:
rand=random.randint(0,self.__defaultNbSamples)
self.__samples[rand][y,x]=grayFrame[y,x]
rand=random.randint(0,self.__defaultSubsamplingFactor)
if rand==0:
rand=random.randint(0,8)
yN=y+self.__c_yoff[rand]
if yN<0: yN=0
if yN>=self.__Height: yN=self.__Height-1
rand=random.randint(0,8)
xN=x+self.__c_xoff[rand]
if xN<0: xN=0
if xN>=self.__Width: xN=self.__Width-1
rand=random.randint(0,self.__defaultNbSamples)
self.__samples[rand][yN,xN]=grayFrame[y,x]
else:
#判断为前景像素
foreground[y,x] = self.__FG;
self.__samples[self.__defaultNbSamples][y,x] += 1
if self.__samples[self.__defaultNbSamples][y,x]>50:
rand=random.randint(0,self.__defaultNbSamples)
if rand==0:
rand=random.randint(0,self.__defaultNbSamples)
self.__samples[rand][y,x]=grayFrame[y,x]
return foreground
