I am still new to OpenCV(Python) and am trying out cv2.adaptiveThreshold()
to draw proper contours with a webcam running when lighting is changing. The main problem is the insane amount of noise I am getting when drawing contours so I tried to set a cv2.countourArea()
threshold but this seems not like the best solution.
Later on I deciced to try and manipulate the values of cv2.adaptiveThreshold
with a simple trackbar.
Specifically the blockSize
and CValue
. Everything works fine on the CValue but I do really struggle on the blockSize
since it needs to be an odd number. I tried something along the line of checking if the value of the empty
callback function is even and adding +1. But this does not seem to work properly. Later on I will most likely use machine-learning to change these values but for now I'd like the trackbars to work for debugging purposes.
What is the best solution here to manipulate the blockSize
with a trackbar?
Thank you in advance! :)
import cv2
import numpy as np
#####################################
winWidth = 640
winHeight = 840
brightness = 100
cap = cv2.VideoCapture(0)
cap.set(3, winWidth)
cap.set(4, winHeight)
cap.set(10, brightness)
kernel = (5, 5)
bSize_default = 1
#######################################################################
def empty(a):
pass
cv2.namedWindow("TrackBars")
cv2.resizeWindow("TrackBars", 640, 240)
cv2.createTrackbar("cVal", "TrackBars", 2, 20, empty)
def preprocessing(frame, cVal):
imgGray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# mask = cv2.inRange(imgHsv, lower, upper)
imgBlurred = cv2.GaussianBlur(imgGray, kernel, 3)
gaussC = cv2.adaptiveThreshold(imgBlurred, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY_INV, 11, cVal)
imgDial = cv2.dilate(gaussC, kernel, iterations=3)
imgErode = cv2.erode(imgDial, kernel, iterations=1)
return imgDial
def getContours(imPrePro):
contours, hierarchy = cv2.findContours(imPrePro, cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)
for cnt in contours:
area = cv2.contourArea(cnt)
if area > 60:
cv2.drawContours(imgCon, cnt, -1, (255, 0, 0), 3)
#######################################################################################################
while (cap.isOpened()):
success, frame = cap.read()
cVal = cv2.getTrackbarPos("cVal", "TrackBars")
if success == True:
frame = cv2.flip(frame, 1)
imgCon = frame.copy()
imPrePro = preprocessing(frame, cVal)
getContours(imPrePro)
cv2.imshow("Preprocessed", imPrePro)
cv2.imshow("Original", imgCon)
if cv2.waitKey(1) & 0xFF == ord("q"):
cv2.destroyAllWindows()
break
The minimum value of blocksize must be 3 and also blocksize must be odd therefore:
value_BSize= cv2.getTrackbarPos("bSize", "TrackBars")
value_BSize = max(3,value_BSize)
if (value_BSize % 2 == 0):
value_BSize += 1