Day 05: Santa Parcel Tracking

Description

To handle the huge load of parcels Santa introduced this year a parcel tracking system. He didn’t like the black and white barcode, so he invented a more solemn barcode. Unfortunately the common barcode readers can’t read it anymore, it only works with the pimped models santa owns. Can you read the barcode?

Solution

Going pixel by pixel from left to right across a single stripe, we extracted the RGB value of every stripe. They were all in ascii range so we converted them to ascii.

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from PIL import Image
import sys

img = Image.open("157de28f-2190-4c6d-a1dc-02ce9e385b5c-line.png")
pixels = img.load()
(w, h) = img.size

c = None
for i in range(w):
    q = pixels[i, 0]
    if q != c:
        if q != (255, 255, 255):
            # sys.stdout.write(chr(q[0]))
            # sys.stdout.write(chr(q[1]))
            sys.stdout.write(chr(q[2]))
    c = q

and wrote out only the blue channel since visual inspection showed that the blue channel had some {}s

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$ python3 tmp.py
X8YIOF0ZP4S8HV19{D1fficult_to_g3t_a_SPT_R3ader}S1090OMZE0E3NFP6E%

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