Develop Reference

cv2.findcontours returning none in Motion Detector App

I followed a video online about motion detection using openCV however I came across the problem that the findContours function is not returning a value. Any help is appreceated.
Here is the code:
import cv2
import time
import datetime
import imutils
def motion_detection():
video_capture = cv2.VideoCapture(0, cv2.CAP_DSHOW)
time.sleep(2)
first_frame = None
while True:
frame = video_capture.read()[1]
text = 'Unoccupied'
greyscale_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
gaussian_frame = cv2.GaussianBlur(greyscale_frame, (21, 21), 0)
blur_frame = cv2.blur(gaussian_frame, (5, 5))
greyscale_image = blur_frame
if first_frame is None:
first_frame = greyscale_image
else:
pass
frame = imutils.resize(frame, width=500)
frame_delta = cv2.absdiff(first_frame, greyscale_image)
# edit the ** thresh ** depending on the light/dark in room,
# change the 100(anything pixel value over 100 will become 255(white)
thresh = cv2.threshold(frame_delta, 100, 255, cv2.THRESH_BINARY)[1]
dilate_image = cv2.dilate(thresh, None, iterations=2)
cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[1]
for c in cnt:
if cv2.contourArea(c) > 800:
(x, y, w, h) = cv2.boundingRect(
c)
cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)
text = 'Occupied'
# text that appears when there is motion in video feed
else:
pass
''' now draw text and timestamp on security feed '''
font = cv2.FONT_HERSHEY_SIMPLEX
cv2.putText(frame, '{+} Room Status: %s' % text, (10, 20), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255), 2)
cv2.putText(frame, datetime.datetime.now().strftime('%A %d %B %Y %I:%M:%S%p'),
(10, frame.shape[0] - 10), font, 0.35, (0, 0, 255), 1)
cv2.imshow('Security Feed', frame)
cv2.imshow('Threshold(foreground mask)', dilate_image)
cv2.imshow('Frame_delta', frame_delta)
key = cv2.waitKey(1) & 0xFF
if key == ord('q'):
cv2.destroyAllWindows()
break
if __name__ == '__main__':
motion_detection()
I have tried to debug and find the problem the code is exactly what the video said to write and I have had no luck.

How to create a meter based on model's probability in Python OpenCV

I have this simple Python code that makes predictions on the emotions of the face (refer to here in case you need to run it), whether the person is happy, sad, etc. It uses cv2 and Keras. Now, I would like to visualize and place a meter on the frame based on the probability of each frame (prob value below which is a percentage). How can I do that?
Something like this. Don't worry about the colors for now.
cap = cv2.VideoCapture(1)
canvasImage = cv2.imread("fg2.png")
x0, x1 = 330, 1290
y0, y1 = 155, 700
prediction_history = []
LOOKBACK = 5 # how far you want to look back
counter = 0
while True:
# Find haar cascade to draw bounding box around face
ret, frame = cap.read()
frame=cv2.flip(frame,3)
if not ret:
break
facecasc = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
faces = facecasc.detectMultiScale(gray,scaleFactor=1.3, minNeighbors=5)
for (x, y, w, h) in faces:
cv2.rectangle(frame, (x, y-50), (x+w, y+h+10), (255, 0, 0), 2)
roi_gray = gray[y:y + h, x:x + w]
cropped_img = np.expand_dims(np.expand_dims(cv2.resize(roi_gray, (48, 48)), -1), 0)
prediction = model.predict(cropped_img)
maxindex = int(np.argmax(prediction))
text = emotion_dict[maxindex]
prob = round(prediction[0][3]*100, 2)
prediction_history.append(maxindex)
most_common_index = max(set(prediction_history[-LOOKBACK:][::-1]), key = prediction_history.count)
text = emotion_dict[most_common_index]
#if ("Sad" in text) or ("Angry" in text) or ("Disgusted" in text):
# text = "Sad"
if ("Happy" in text) or ("Sad" in text) :
cv2.putText(frame, text+": "+str(prob), (x+20, y-60), cv2.FONT_HERSHEY_SIMPLEX, 1, (255, 255, 255), 2, cv2.LINE_AA)
dim = (800,480)
frame_shrunk = cv2.resize(frame, (x1 - x0, y1 - y0))
canvasImage[y0:y1, x0:x1] = frame_shrunk
#cv2.imshow('Video', cv2.resize(frame,dim,interpolation = cv2.INTER_CUBIC))
cv2.imshow('Demo', canvasImage)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows()

There is no built in function in OpenCV for drawing meters, here is a helper function that you can use to draw a meter over an image:
def draw_indicator(img, percentage):
def percentage_to_color(p):
return 0, 255 * p, 255 - (255 * p)
# config
levels = 10
indicator_width = 80
indicator_height = 220
level_width = indicator_width - 20
level_height = int((indicator_height - 20) / levels - 5)
# draw
img_levels = int(percentage * levels)
cv2.rectangle(img, (10, img.shape[0] - (indicator_height + 10)), (10 + indicator_width, img.shape[0] - 10), (0, 0, 0), cv2.FILLED)
for i in range(img_levels):
level_y_b = int(img.shape[0] - (20 + i * (level_height + 5)))
cv2.rectangle(img, (20, level_y_b - level_height), (20 + level_width, level_y_b), percentage_to_color(i / levels), cv2.FILLED)
# test code
img = cv2.imread('a.jpg')
draw_indicator(img, 0.7)
cv2.imshow("test", img)
cv2.waitKey(10000)

I have an eye blink detector that sends a keyboard press in python. Whenever I load games, the game dosen't detect the keyboard press but notepad does

This code SHOULD BE detecting when my eyes blink, then press space. In certain games (Like SCP:CB) It does not press space, but in notepad and chrome it does.
import cv2
import pyautogui
face_cascade = cv2.CascadeClassifier(cv2.data.haarcascades +
"haarcascade_frontalface_default.xml")
eyes_cascade = cv2.CascadeClassifier(cv2.data.haarcascades +
"haarcascade_eye_tree_eyeglasses.xml")
first_read = True
cap = cv2.VideoCapture(0)
ret, image = cap.read()
while ret:
ret, image = cap.read()
gray_scale = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray_scale = cv2.bilateralFilter(gray_scale, 5, 1, 1)
faces = face_cascade.detectMultiScale(gray_scale, 1.3, 5, minSize=(200, 200))
if len(faces) > 0:
for (x, y, w, h) in faces:
image = cv2.rectangle(image, (x, y), (x + w, y + h), (0, 255, 0), 2)
eye_face = gray_scale[y:y + h, x:x + w]# image
eye_face_clr = image[y:y + h, x:x + w]# get the eyes
eyes = eyes_cascade.detectMultiScale(eye_face, 1.3, 5, minSize=(50, 50))
if len(eyes) >= 2:
if first_read:
cv2.putText(image, "Eye's detected, press s to check blink", (70, 70), cv2.FONT_HERSHEY_SIMPLEX,
1, (0, 255, 0), 2)
else:
cv2.putText(image, "Eye's Open", (70, 70), cv2.FONT_HERSHEY_SIMPLEX,
1, (255, 255, 255), 2)
else:
if first_read:
cv2.putText(image, "No Eye's detected", (70, 70),
cv2.FONT_HERSHEY_SIMPLEX,
1, (255, 255, 255), 2)
else:
cv2.putText(image, "Blink Detected.....!!!!", (70, 70),
cv2.FONT_HERSHEY_SIMPLEX,
1, (0, 255, 0), 2)
pyautogui.press("space")
cv2.imshow('image',image)
cv2.waitKey(1)
print("Blink Detected.....!!!!")
else:
cv2.putText(image, "No Face Detected.", (70, 70), cv2.FONT_HERSHEY_SIMPLEX,
1, (0, 255, 0), 2)
cv2.imshow('image', image)
a = cv2.waitKey(1)
if a == ord('q'):
break
elif a == ord('s'):
first_read = False
# release the web-cam
cap.release()
cv2.destroyAllWindows()
This is the code and what it SHOULD do is make a game detect when I blink, then press space. Kinda like "Before Your Eyes"

OpenCV python output bounding rectangle X coordinates to object

I need to create an object with the value of the bounding rectangle X coordinates that is tracking movement. Using Python in OpenCV. Does anyone know of a way I can do this?
I will use that object to calculate servo values for a laser tracker.
import cv2
cap=cv2.VideoCapture(0)
ret1,frame1= cap.read()
gray1 = cv2.cvtColor(frame1, cv2.COLOR_BGR2GRAY)
gray1 = cv2.GaussianBlur(gray1, (21, 21), 0)
cv2.imshow('window',frame1)
while(True):
ret2,frame2=cap.read()
gray2 = cv2.cvtColor(frame2, cv2.COLOR_BGR2GRAY)
gray2 = cv2.GaussianBlur(gray2, (21, 21), 0)
deltaframe=cv2.absdiff(gray1,gray2)
frame_flip2 = cv2.flip(deltaframe, -1)
#cv2.imshow('delta',frame_flip2)
threshold = cv2.threshold(deltaframe, 25, 255, cv2.THRESH_BINARY)[1]
threshold = cv2.dilate(threshold,None)
#cv2.imshow('threshold',threshold)
_,countour,heirarchy = cv2.findContours(threshold, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
for i in countour:
if cv2.contourArea(i) < 600:
continue
(x, y, w, h) = cv2.boundingRect(i)
cv2.rectangle(frame2, (x, y), (x + w, y + h), (255, 0, 0), 2)
frame_flip = cv2.flip(frame2, -1)
cv2.imshow('window',frame_flip)
if cv2.waitKey(10) == ord('q'):
break
cap.release()
cv2.destroyAllWindows()

How do I fix openCV cvtColor error in my project?

I am building handwriting recognition project but I am getting this error of cvtColor while trying to change the image from BGR2HSV.
cap = cv2.VideoCapture(0)
Lower_blue = np.array([110, 50, 50])
Upper_blue = np.array([130, 255, 255])
pred_class = 0
pts = deque(maxlen = 512)
blackboard = np.zeros((480, 640, 3), dtype = np.uint8)
digit = np.zeros((200, 200, 3), dtype = np.uint8)
while(cap.isOpened()):
ret, img = cap.read()
img = cv2.flip(img, 1)
imgHSV = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
mask = cv2.inRange(imgHSV, Lower_blue, Upper_blue)
blur = cv2.medianBlur(mask, 15)
blur = cv2.GaussianBlur(blur, (5, 5), 0)
thresh = cv2.threshold(blur, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
cnts = cv2.findContours(thresh.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)[1]
center = None
if len(cnts) >= 1:
contour = max(cnts, key = cv2.contourArea)
if cv2.contourArea(contour) > 250:
((x, y), radius) = cv2.minEnclosingCircle(contour)
cv2.circle(img, (int(x), int(y)), int(radius), (0, 255, 255), 2)
cv2.circle(img, center, 5, (0, 255, 255), -1)
M = cv2.moments(contour)
center = (int(M['m10'] / M['m00']), int(M['m01'] / M['m00']))
pts.appendleft(center)
for i in range (1, len(pts)):
if pts[i - 1] is None or pts[i] is None:
continue
cv2.line(blackboard, pts[i - 1], pts[i], (255, 255, 255), 10)
cv2.line(img, pts[i - 1], pts[i], (0, 0,255), 5)
elif len(cnts) == 0:
if len(pts) != []:
blackboard_gray = cv2.cvtColor(blackboard, cv2.COLOR_BGR2GRAY)
blur1 = cv2.medianBlur(blackboard_gray, 15)
blur1 = cv2.GaussianBlur(blur1, (5, 5), 0)
thresh1 = cv2.threshold(blur1, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
blackboard_cnts = cv2.findContours(thresh1.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)[1]
if len(blackboard_cnts) >= 1:
cnt = max(blackboard_cnts, key = cv2.contourArea)
print(cv2.contourArea(cnt))
if cv2.contourArea(cnt) > 2000:
x, y, w, h = cv2.boundingRect(cnt)
digit = blackboard_gray[y:y + h, x:x + w]
#new Image = process_letter(digit)
pred_probab, pred_class = keras_predict(model1, digit)
print(pred_class, pred_probab)
pts = deque(maxlen = 512)
blackboard = np.zeros((480, 640, 3), dtype = uint8)
cv2.putText(img, "Conv Network : " + str(letter_count [pred_class]), (10, 470),
cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 255), 2)
cv2.imshow("Frame", img)
cv2.imshow("Contours", thresh)
k = cv2.waitkey(10)
if k == 27:
break
How do I fix this issue of OpenCV error? Please help!
I am getting following error:
error: OpenCV(3.4.1) C:\Miniconda3\conda-bld\opencv-suite_1533128839831\work\modules\imgproc\src\color.cpp:11214: error: (-215) (scn == 3 || scn == 4) && (depth == 0 || depth == 5) in function cv::cvtColor

I think following error: error: (-215) (scn == 3 || scn == 4) && (depth == 0 || depth == 5) in function cv::cvtColor is because of camera unable to capture frame correctly. Check this by printing ret value. It camera is able to capture frame correctly, it will return True, else False. Above error is happening because None is passed to cv2.cvtColor function. You can use below code as a safety check:
if ret is True:
# your code goes here
else:
break
Moreover, please consider below points:
It's cv2.waitKey(10), not cv2.waitkey(10)[Capital 'K']
cv2.findContours function return 3 values(i.e. image, contours and hierarchy) in OpenCV 3.x but just 2 values(i.e. contours, hierarchy) in openCV 4.x
len(pts) != [] doesn't make sense. Here, you are trying to compare a number to an empty list. Change it to len(pts) != 0.
What's letter_count inside cv2.putText function. Kindly recheck it.
In place of re-initializing deque(pts = deque(maxlen = 512)) in case of len(cnts)==0 and len(pts) != 0, you can use the old pts by simply clearing it using pts.clear(). Just a thought!
Also, add below code at the end:
cap.release()
cv2.destroyAllWindows()
Try below modified code(Tested using openCV v4.0.0):
import cv2
import numpy as np
from collections import deque
cap = cv2.VideoCapture(0)
Lower_blue = np.array([110, 50, 50])
Upper_blue = np.array([130, 255, 255])
pred_class = 0
pts = deque(maxlen = 512)
blackboard = np.zeros((480, 640, 3), dtype = np.uint8)
digit = np.zeros((200, 200, 3), dtype = np.uint8)
while(cap.isOpened()):
ret, img = cap.read()
img = cv2.flip(img, 1)
imgHSV = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
mask = cv2.inRange(imgHSV, Lower_blue, Upper_blue)
blur = cv2.medianBlur(mask, 15)
blur = cv2.GaussianBlur(blur, (5, 5), 0)
thresh = cv2.threshold(blur, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
cnts = cv2.findContours(thresh.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)[0]
center = None
if len(cnts) >= 1:
contour = max(cnts, key = cv2.contourArea)
if cv2.contourArea(contour) > 250:
((x, y), radius) = cv2.minEnclosingCircle(contour)
cv2.circle(img, (int(x), int(y)), int(radius), (0, 255, 255), 2)
cv2.circle(img, center, 5, (0, 255, 255), -1)
M = cv2.moments(contour)
center = (int(M['m10'] / M['m00']), int(M['m01'] / M['m00']))
pts.appendleft(center)
# print(pts)
for i in range (1, len(pts)):
if pts[i - 1] is None or pts[i] is None:
print("Continue")
continue
cv2.line(blackboard, pts[i - 1], pts[i], (255, 255, 255), 10)
cv2.line(img, pts[i - 1], pts[i], (0, 0,255), 5)
cv2.imshow("Frame", img)
cv2.imshow("Contours", thresh)
# press q to stop
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
if len(pts) != 0:
blackboard_gray = cv2.cvtColor(blackboard, cv2.COLOR_BGR2GRAY)
blur1 = cv2.medianBlur(blackboard_gray, 15)
blur1 = cv2.GaussianBlur(blur1, (5, 5), 0)
thresh1 = cv2.threshold(blur1, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
print('Hello')
blackboard_cnts = cv2.findContours(thresh1.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)[0]
if len(blackboard_cnts) >= 1:
cnt = max(blackboard_cnts, key = cv2.contourArea)
print(cv2.contourArea(cnt))
if cv2.contourArea(cnt) > 2000:
x, y, w, h = cv2.boundingRect(cnt)
digit = blackboard_gray[y:y + h, x:x + w]
#new Image = process_letter(digit)
#pred_probab, pred_class = keras_predict(model1, digit)
print(digit.shape)
#pts = deque(maxlen = 512)
pts.clear()
blackboard = np.zeros((480, 640, 3), dtype = np.uint8)
#cv2.putText(img, "Conv Network : " + str(letter_count[pred_class]), (10, 470), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 255), 2)
cv2.putText(img, "Conv Network :", (10, 470), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 255), 2)
cv2.imshow("Frame", img)
cv2.imshow("Contours", thresh)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows()