Article Outline
Python pil example 'QRCode'
Modules used in program:
import timeimport numpy as npimport cv2import zbarimport sympyimport os
python QRCode
Python pil example: QRCode
import os
import sympy
from sympy import *
import zbar
from PIL import Image
import cv2
#import cv2.cv as cv
import numpy as np
import time
class QRCode:
def __init__(self,tvec,rvec,value, top_right):
self.tvec = tvec
self.rvec = rvec
self.value = value
self.tr = top_right
class Camera:
def __init__(self):
# Image processing
self.cam = cv2.VideoCapture(1)
# Camera dimensions had to be set manually
#self.cam.set(3,1280)
#self.cam.set(4,720)
# QR scanning tools.
self.scanner = zbar.ImageScanner()
self.scanner.parse_config('enable')
# Figure out what camera is being used
#cam_model = arm_config["camera_model"]
# Constants based on calibration for image processing
self.cam_matrix = np.float32(
[[4.2267683970564178e+02, 0.0, 3.1950000000000000e+02],
[0.0, 4.2267683970564178e+02, 2.3950000000000000e+02],
[0.0, 0.0, 1.0]])
self.dist_coeffs = np.float32([
8.5064298756821945e-03
, 4.5102325220501040e-04
, 0.0
, 0.0
, -4.0826402839032952e-02])
self.cam.set(3,1280)
self.cam.set(4,720)
"""
self.cam_matrix = np.float32(
[[4.6005493419302496e+02, 0., 3.1950000000000000e+02],
[0.0, 4.6005493419302496e+02, 2.3950000000000000e+02],
[0.0, 0.0, 1.0]])
self.dist_coeffs = np.float32([
2.2888445335485098e-02
, 2.3578180642677610e-02
, 0.0
, 0.0
, -2.2172306449254131e-01])
"""
# initialize vertices of QR code
l = 1.5
self.qr_verts = np.float32([[-l/2, -l/2, 0],
[-l/2, l/2, 0],
[ l/2, -l/2, 0],
[ l/2, l/2, 0]])
def readQR(self):
while(True):
QRList = []
self.cam.grab()
self.cam.grab()
self.cam.grab()
self.cam.grab()
ret, frame = self.cam.read()
# Direct conversion cv -> zbar images did not work.
# Buffer file used to have native data structures.
# PIL -> zbar
"""
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
cv2.imwrite('buffer.png', gray)
pil_im = Image.open('buffer.png').convert('L')
bw = pil_im.point(lambda x: 0 if x<75 else 255, '1')
bw.save("gray.png")
pil_im = Image.open('gray.png').convert('L')
"""
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
frame = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_MEAN_C, cv2.THRESH_BINARY, 11, 2)
frame = cv2.bilateralFilter(frame, 9, 75, 75)
cv2.imwrite('buffer.png', frame)
pil_im = Image.open('buffer.png').convert('L')
width, height = pil_im.size
raw = pil_im.tobytes()
z_im = zbar.Image(width, height, 'Y800', raw)
# Find codes in image
self.scanner.scan(z_im)
count = 0
for symbol in z_im:
tl, bl, br, tr = [item for item in symbol.location]
points = np.float32([[tl[0], tl[1]],
[tr[0], tr[1]],
[bl[0], bl[1]],
[br[0], br[1]]])
ret, rvec, tvec = cv2.solvePnP(self.qr_verts, points
, self.cam_matrix
, self.dist_coeffs)
cv2.line(frame, tl, bl, (100,0,255), 8, 8)
cv2.line(frame, bl, br, (100,0,255), 8, 8)
cv2.line(frame, br, tr, (100,0,255), 8, 8)
cv2.line(frame, tr, tl, (100,0,255), 8, 8)
QRList.append(QRCode(tvec, rvec, symbol.data, tr))
count += 1
if count == 0:
#print("NO QR FOUND")
cv2.imshow('test', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
continue
# find the best QRCode to grab (closest x then highest y)
QRList.sort(key=lambda qr: qr.tvec[0], reverse=False) # sort the list of qr codes by x, smallest to largest
x_min = 100
min_qr = 0
count = 0
for qr in QRList:
#find smallest x
if abs(qr.tvec[0]) < abs(x_min):
x_min = qr.tvec[0]
min_qr = count
count += 1
targetQR = None
#check upper and lower qrs in list for height
if (min_qr > 0):
if (abs(QRList[min_qr -1].tvec[0] - x_min) < .1):
if QRList[min_qr -1].tvec[1] < QRList[min_qr].tvec[1]:
targetQR = QRList[min_qr-1]
else:
targetQR = QRList[min_qr]
if ((min_qr < (len(QRList) - 1)) and (targetQR == None)):
if (abs(QRList[min_qr +1].tvec[0] - x_min) < .1):
if QRList[min_qr +1].tvec[1] < QRList[min_qr].tvec[1]:
targetQR = QRList[min_qr+1]
else:
targetQR = QRList[min_qr]
if targetQR == None:
targetQR = QRList[min_qr]
print("value: ", targetQR.value)
print("X: ", targetQR.tvec[0])
print("Y: ", targetQR.tvec[1])
print("=====================================")
cv2.circle(frame,targetQR.tr, 10, (0,255,0), -1)
cv2.imshow('test', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
self.cam.release()
cv2.destroyAllWindows()
def QRSweep(self):
while(True):
QRList = []
self.cam.grab()
self.cam.grab()
self.cam.grab()
self.cam.grab()
ret, frame = self.cam.read()
# Direct conversion cv -> zbar images did not work.
# Buffer file used to have native data structures.
# PIL -> zbar
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
ret, frame = cv2.threshold(gray,85,255,cv2.THRESH_BINARY)
cv2.imwrite('buffer.png', frame)
pil_im = Image.open('buffer.png').convert('L')
width, height = pil_im.size
raw = pil_im.tobytes()
z_im = zbar.Image(width, height, 'Y800', raw)
# Find codes in image
self.scanner.scan(z_im)
count = 0
for symbol in z_im:
tl, bl, br, tr = [item for item in symbol.location]
points = np.float32([[tl[0], tl[1]],
[tr[0], tr[1]],
[bl[0], bl[1]],
[br[0], br[1]]])
tvec = self.solveQR(tl, tr, bl, br)
print("X_Displacement = ", tvec[0])
print("Y_Displacement = ", tvec[1])
print("Z_Displacement = ", tvec[2])
print("=========================================")
#ret, rvec, tvec = cv2.solvePnP(self.qr_verts, points
# , self.cam_matrix
# , self.dist_coeffs)
cv2.line(frame, tl, bl, (100,0,255), 8, 8)
cv2.line(frame, bl, br, (100,0,255), 8, 8)
cv2.line(frame, br, tr, (100,0,255), 8, 8)
cv2.line(frame, tr, tl, (100,0,255), 8, 8)
#QRList.append(QRCode(tvec, rvec, symbol.data, tr))
cv2.imshow('test', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
self.cam.release()
cv2.destroyAllWindows()
#new solvepnp
def solveQR(self, tl, tr, bl, br):
QRSize = 1.5 # units = inches
resX = 1280
resY = 720
center = [resX/2, resY/2]
#find the center of the QRCode
QRCenter = [int((tl[0] + tr[0] + bl[0] + br[0])/4), int((tl[1] + tr[1] + bl[1] + br[1])/4)]
#find pixel displacement
pixel_displacement = [(QRCenter[0] - center[0]),(QRCenter[1] - center[1])]
#find Z distance to QRCode
north = int(sqrt(pow(abs(tl[0] - tr[0]), 2) + pow(abs(tl[1] - tr[1]), 2)))
south = int(sqrt(pow(abs(bl[0] - br[0]), 2) + pow(abs(bl[1] - br[1]), 2)))
east = int(sqrt(pow(abs(tr[0] - br[0]), 2) + pow(abs(tr[1] - br[1]), 2)))
west = int(sqrt(pow(abs(tl[0] - bl[0]), 2) + pow(abs(tl[1] - bl[1]), 2)))
if (north >= south and north >= east and north >= west):
largest_edge = north
elif (south >= east and south >= west):
largest_edge = south
elif (east >= west):
largest_edge = east
else:
largest_edge = west
z_units = self.getDistance(largest_edge)
#find x and y based on distance
x_units = (QRSize)*(pixel_displacement[0]/float(largest_edge))
y_units = -1 * (QRSize)*(pixel_displacement[1]/float(largest_edge))
return [x_units, y_units, z_units]
def getDistance(self, length):
a = 2453.3
n = -1.0235
return a*math.pow(length, n)
Python links
- Learn Python: https://pythonbasics.org/
- Python Tutorial: https://pythonprogramminglanguage.com