detecing hough lines on holistically nested edged image

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I am trying to get hough lines for document detection with HED (holistically nested edge detection) but not getting correct hough lines for the document detection.

Code:

lines = cv2.HoughLines(out,1,np.pi/180,200,np.array([]),0,0)
for line in lines:
    rho=line[0][0]
    theta = line[0][1];
    a = np.cos(theta);
    b = np.sin(theta);
    x0 = a*rho; y0 = b*rho;
    x1 = np.round(x0 + 1000*(-b))
    y1 = np.round(y0 + 1000*(a))
    x2 = np.round(x0 - 1000*(-b))
    y2 = np.round(y0 - 1000*(a))
    cv2.line(original,(int(x1),int(y1)), (int(x2),int(y2)),(0,0,255), 3)

here out is hed image and original is the original image. out(HED image)

original image

enter code here