本文實例為大家分享了python+opencv實現移動偵測的具體代碼，供大家參考，具體內容如下
1.幀差法原理
移動偵測即是根據視頻每幀或者幾幀之間像素的差異，對差異值設置閾值，篩選大于閾值的像素點，做掩模圖即可選出視頻中存在變化的楨。幀差法較為簡單的視頻中物體移動偵測，幀差法分為：單幀差、兩楨差、和三楨差。隨著幀數的增加是防止檢測結果的重影。
2.算法思路
文章以截取視頻為例進行單幀差法移動偵測
3.python實現代碼
def threh(video,save_video,thres1,area_threh):
cam = cv2.VideoCapture(video)#打開一個視頻
input_fps = cam.get(cv2.CAP_PROP_FPS)
ret_val, input_image = cam.read()
index=[]
images=[]
images.append(input_image)
video_length = int(cam.get(cv2.CAP_PROP_FRAME_COUNT))
input_image=cv2.resize(input_image,(512,512))
ending_frame = video_length
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter(save_video,fourcc, input_fps, (512, 512))
gray_lwpCV = cv2.cvtColor(input_image, cv2.COLOR_BGR2GRAY)
gray_lwpCV = cv2.GaussianBlur(gray_lwpCV, (21, 21), 0)
background=gray_lwpCV
# es = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (9, 4))
i = 0 # default is 0
outt=[]
while(cam.isOpened()) and ret_val == True and i <2999:
## if i % 2==1:
ret_val, input_image = cam.read()
input_image=cv2.resize(input_image,(512,512))
gray_lwpCV = cv2.cvtColor(input_image, cv2.COLOR_BGR2GRAY)
gray_lwpCV = cv2.GaussianBlur(gray_lwpCV, (21, 21), 0)
diff = cv2.absdiff(background, gray_lwpCV)
outt.append(diff)
#跟著圖像變換背景
tem_diff=diff.flatten()
tem_ds=pd.Series(tem_diff)
tem_per=1-len(tem_ds[tem_ds==0])/len(tem_ds)
if (tem_per <0.2 )| (tem_per>0.75):
background=gray_lwpCV
else:
diff = cv2.threshold(diff, thres1, 255, cv2.THRESH_BINARY)[1]
ret,thresh = cv2.threshold(diff.copy(),150,255,0)
contours, hierarchy = cv2.findContours(thresh,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
# contours, hierarchy = cv2.findContours(diff.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
for c in contours:
if (cv2.contourArea(c) < area_threh) | (cv2.contourArea(c) >int(512*512*0.3) ) : # 對于矩形區域，只顯示大于給定閾值的輪廓（去除微小的變化等噪點）
continue
(x, y, w, h) = cv2.boundingRect(c) # 該函數計算矩形的邊界框
cv2.rectangle(input_image, (x, y), (x+w, y+h), (0, 255, 0), 2)
index.append(i)
# cv2.imshow('contours', input_image)
# cv2.imshow('dis', diff)
out.write(input_image)
images.append(input_image)
i = i+1
out.release()
cam.release()
return outt,index,images```
##調取函數
outt=threh('new_video.mp4','test6.mp4',25,3000)
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持億速云。
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