Zebra crossing Python Opencv project help.. I'm getting the following error

Question

I'm trying to build a project using opencv to detect crosswalk and provide details to navigate it's a project already done and the link to it is https://www.youtube.com/watch?v=b-BnqgAI5NY

cap = cv2.VideoCapture('Friday the 13th_ The Game_20170527134320.mp4') #load a video

W = cap.get(3) #get width
H = cap.get(4) #get height

#Define a new resolution 
ratio = H/W
W = 800
H = int(W * ratio)

#setup the parameters for saving the processed file
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
out = cv2.VideoWriter('processedVideo.mp4',fourcc, 15.0, (int(W),int(H)))

Dx = []
Dy = []
after =0
DxAve =0
Dxold =0
DyAve =0
Dyold =0
i = 0
state = ""

while(cap.isOpened()):
    ret, frame = cap.read()
    img = scipy.misc.imresize(frame, (H,W))

    #np.array(Image.fromarray(frame,(H,W)).resize())
    #draw camera's POV
    cv2.circle(img,(int(W/2),int(H/2)),5,(0,0,255),8)

here in the try block I have defined processedFrame properly but in the end it says not defined

    try:
        processedFrame,dx,dy = process(img)

        if (i < 6):
            Dx.append(dx)
            Dy.append(dy)
            i=i+1

    else:
        DxAve = sum(Dx)/len(Dx)
        DyAve = sum(Dy)/len(Dy)
        del Dx[:]
        del Dy[:]
        i=0

    if (DyAve > 30) and (abs(DxAve) < 300):        
        #check if the vanishing point and the next vanishing point aren't too far from each other 
        if (((DxAve - Dxold)**2 + (DyAve - Dyold)**2) < 150**2) == True:  ##distance 150 px max 
            cv2.line(img,(int(W/2),int(H/2)),(int(W/2)+int(DxAve),int(H/2)+int(DyAve)),(0,0,255),7)
            
            #walking directions
            if abs(DxAve) < 80 and DyAve > 100 and abs(Dxold-DxAve) < 20:
                state = 'Straight'
                cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,0),2,cv2.LINE_AA)

            elif DxAve > 80 and DyAve > 100 and abs(Dxold-DxAve) < 20:
                state = 'Right'
                cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,255),2,cv2.LINE_AA)

            elif DxAve < 80 and DyAve > 100 and abs(Dxold-DxAve) < 20:
                state = 'Left'
                cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,255),2,cv2.LINE_AA)
        else:
            cv2.line(img,(int(W/2),int(H/2)),(int(W/2)+int(Dxold),int(H/2)+int(Dyold)),(0,0,255),)
        
        #walking directions 
        if state == 'Straight':
            cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,0),2,cv2.LINE_AA)
        else:
            cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,255),2,cv2.LINE_AA)           

        Dxold = DxAve
        Dyold = DyAve

except:
    print('Failed to process frame')

#show & save
img = cv2.imshow('Processed',processedFrame)
out.write(processedFrame)

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

out.release()
cap.release()
cv2.destroyAllWindows()

I'm getting the following error:

Failed to process frame
Traceback (most recent call last):
  File "C:\Users\Ragha\AppData\Local\Programs\Python\Python36\crosswalk.py", line 280, in <module>
    img = cv2.imshow('Processed',processedFrame)
NameError: name 'processedFrame' is not defined

Answer 1

put the code

img = cv2.imshow('Processed',processedFrame)
out.write(processedFrame)

inside the try block

and always take care of the indentations in python.

cap = cv2.VideoCapture('Friday the 13th_ The Game_20170527134320.mp4') #load a video
W = cap.get(3) #get width
H = cap.get(4) #get height

#Define a new resolution 
ratio = H/W
W = 800
H = int(W * ratio)

#setup the parameters for saving the processed file
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
out = cv2.VideoWriter('processedVideo.mp4',fourcc, 15.0, (int(W),int(H)))

Dx = []
Dy = []
after =0
DxAve =0
Dxold =0
DyAve =0
Dyold =0
i = 0
state = ""

while(cap.isOpened()):
    ret, frame = cap.read()
    img = scipy.misc.imresize(frame, (H,W))

    #np.array(Image.fromarray(frame,(H,W)).resize())
    #draw camera's POV
    cv2.circle(img,(int(W/2),int(H/2)),5,(0,0,255),8)
    try:
        processedFrame,dx,dy = process(img)

        if (i < 6):
            Dx.append(dx)
            Dy.append(dy)
            i=i+1
        else:
            DxAve = sum(Dx)/len(Dx)
            DyAve = sum(Dy)/len(Dy)
            del Dx[:]
            del Dy[:]
            i=0

        if (DyAve > 30) and (abs(DxAve) < 300):        
            #check if the vanishing point and the next vanishing point aren't too far from each other 
            if (((DxAve - Dxold)**2 + (DyAve - Dyold)**2) < 150**2) == True:  ##distance 150 px max 
                cv2.line(img,(int(W/2),int(H/2)),(int(W/2)+int(DxAve),int(H/2)+int(DyAve)),(0,0,255),7)
                
                #walking directions
                if abs(DxAve) < 80 and DyAve > 100 and abs(Dxold-DxAve) < 20:
                    state = 'Straight'
                    cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,0),2,cv2.LINE_AA)

                elif DxAve > 80 and DyAve > 100 and abs(Dxold-DxAve) < 20:
                    state = 'Right'
                    cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,255),2,cv2.LINE_AA)

                elif DxAve < 80 and DyAve > 100 and abs(Dxold-DxAve) < 20:
                    state = 'Left'
                    cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,255),2,cv2.LINE_AA)
                else:
                    cv2.line(img,(int(W/2),int(H/2)),(int(W/2)+int(Dxold),int(H/2)+int(Dyold)),(0,0,255),)
            
            #walking directions 
            if state == 'Straight':
                cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,0),2,cv2.LINE_AA)
            else:
                cv2.putText(img,state,(50,50), cv2.FONT_HERSHEY_PLAIN, 3,(0,0,255),2,cv2.LINE_AA)           

            Dxold = DxAve
            Dyold = DyAve

            img = cv2.imshow('Processed',processedFrame)
            out.write(processedFrame)

    except:
        print('Failed to process frame')

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

out.release()
cap.release()
cv2.destroyAllWindows()