Object detection with color, opencv, python

Question

I am trying to detect a simple object, and then detect his color. I have created my own CUSTOM HAARCASCADE but it converts the camera's image to grayscale. Maybe I could detect the object through a mask? I have not found any articles on this online.

Here is my code if u need it:

import cv2
import numpy as np

################################################################
#path = 'haarcascades/haarcascade_eye.xml'  # PATH OF THE CASCADE
path = 'haarcascades/Azuolas.xml'  # PATH OF THE CASCADE
#path = 'haarcascades/haarcascade_frontalface_default.xml'  # PATH OF THE CASCADE
#path = 'haarcascades/haarcascade_smile.xml'  # PATH OF THE CASCAD 
objectName = 'Azuolas'       # OBJECT NAME TO DISPLAY
frameWidth= 640                     # DISPLAY WIDTH
frameHeight = 480                  # DISPLAY HEIGHT
color= (255,0,255)
#################################################################


cap = cv2.VideoCapture(0)
cap.set(3, frameWidth)
cap.set(4, frameHeight)

def empty(a):
    pass

# CREATE TRACKBAR
cv2.namedWindow("Result")
cv2.resizeWindow("Result",frameWidth,frameHeight+100)
cv2.createTrackbar("Scale","Result",400,1000,empty)
cv2.createTrackbar("Neig","Result",8,50,empty)
cv2.createTrackbar("Min Area","Result",0,100000,empty)
cv2.createTrackbar("Brightness","Result",180,255,empty)

# LOAD THE CLASSIFIERS DOWNLOADED
cascade = cv2.CascadeClassifier(path)

while True:

    # SET CAMERA BRIGHTNESS FROM TRACKBAR VALUE
    cameraBrightness = cv2.getTrackbarPos("Brightness", "Result")
    cap.set(10, cameraBrightness)
    # GET CAMERA IMAGE AND CONVERT TO GRAYSCALE
    success, img = cap.read()
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    # DETECT THE OBJECT USING THE CASCADE
    scaleVal =1 + (cv2.getTrackbarPos("Scale", "Result") /1000)
    neig=cv2.getTrackbarPos("Neig", "Result")
    objects = cascade.detectMultiScale(gray,scaleVal, neig)
    # DISPLAY THE DETECTED OBJECTS
    for (x,y,w,h) in objects:
        print(objectName ,"is in my fov")
        area = w*h
        minArea = cv2.getTrackbarPos("Min Area", "Result")
        if area >minArea:
            cv2.rectangle(img,(x,y),(x+w,y+h),color,3)
            cv2.putText(img,objectName,(x,y-5),cv2.FONT_HERSHEY_COMPLEX_SMALL,1,color,2)
            roi_color = img[y:y+h, x:x+w]

    cv2.imshow("Result", img)

    if cv2.waitKey(1) & 0xFF == ord('q'):
        break 

Thanks in advance!!!!

Answer 1

I'm familiar with cv2, but haven't used it in years, so bear with me here. What I think you're saying is that when you call cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) it's overwriting the original img to grayscale, even though you've assigned it to the variable gray .

You probably need to copy the image before converting to grayscale. Clone an image in cv2 python

gray = cv2.cvtColor( img.copy(), cv2.COLOR_BGR2GRAY )