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I have read datamatrix from images and now am trying to read that from webcam but it is not working and I keep getting errors. I have tried barcode/qrcode detection from pyimagesearch site.

I have used Zbar library which works well but doesn't support datamatrix. Now I am trying with pylibdmtx which works well for images but lags and doesn't detect in video.

code 1

from imutils.video import VideoStream
from pyzbar import pyzbar
from pydmtx import DataMatrix
import zxing
import argparse
import datetime
import imutils
import time
import cv2

# construct the argument parser and parse the arguments
ap = argparse.ArgumentParser()
reader = zxing.BarCodeReader("/home/creator/.local/bin/zxing")
ap.add_argument("-o", "--output", type=str, default="barcodes.csv",
    help="path to output CSV file containing barcodes")
args = vars(ap.parse_args())

# initialize the video stream and allow the camera sensor to warm up
print("[INFO] starting video stream...")
vs = VideoStream(src=0).start()
# vs = VideoStream(usePiCamera=True).start()
time.sleep(2.0)

# open the output CSV file for writing and initialize the set of
# barcodes found thus far
csv = open(args["output"], "w")
found = set()


# loop over the frames from the video stream
while True:
    # grab the frame from the threaded video stream and resize it to
    # have a maximum width of 400 pixels
    frame = vs.read()
    frame = imutils.resize(frame, width=40)

    # find the barcodes in the frame and decode each of the barcodes
    barcodes = pylibdmtx.decode(frame)

        # loop over the detected barcodes
    for barcode in barcodes:
        # extract the bounding box location of the barcode and draw
        # the bounding box surrounding the barcode on the image
        (x, y, w, h) = barcode.rect
        cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 0, 255), 2)

        # the barcode data is a bytes object so if we want to draw it
        # on our output image we need to convert it to a string first
        barcodeData = barcode.data.decode("utf-8")
        barcodeType = barcode.type
        print("Data :",barcodeData,'\n')
        print("Type :",barcodeType)

        # draw the barcode data and barcode type on the image
        text = "{} ({})".format(barcodeData, barcodeType)
        cv2.putText(frame, text, (x, y - 10),
            cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255), 2)


        # if the barcode text is currently not in our CSV file, write
        # the timestamp + barcode to disk and update the set
        if barcodeData not in found:
            csv.write("{},{}\n".format(datetime.datetime.now(),
                barcodeData))
            csv.flush()
            found.add(barcodeData)

    # show the output frame
    cv2.imshow("Barcode Scanner", frame)
    key = cv2.waitKey(1) & 0xFF

    # if the `q` key was pressed, break from the loop
    if key == ord("q"):
        break

# close the output CSV file do a bit of cleanup
print("[INFO] cleaning up...")
csv.close()
cv2.destroyAllWindows()
vs.stop()

code 1 runs but it is too slow and doesn't detect anything.

Result: should a read datamatrix shown at the camera.

Connan king
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1 Answers1

0
  • change the line 3 to:

from pylibdmtx import pylibdmtx

  • as i didnt have zxing i have commented those lines(4 and 13) in the code.

  • Datamatrix decoder doesnt have a Type like bardcode decoder. So change the line 52 as below:

    barcodeType = "DMC" #barcode.type

  • Added a print statement to see the decoded output as shown below inside the loop:

for barcode in barcodes:

    print(barcode)

OUTPUT:

Type : DMC Decoded(data=b'800400547311010400109085566', rect=Rect(left=241, top=238, width=65, height=-83)) Data : 800400547311010400109085566

Type : DMC Decoded(data=b'800040547311010400102325376', rect=Rect(left=259, top=140, width=-119, height=110)) Data : 800040547311010400102325376

PLEASE SOMEONE HELP WITH SLOWNESS ISSUE AS I COULDN'T FIND A REASON FOR THAT.

deeps
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