Sticker Segmentation

[mwarning]

I was looking for a way to segment the stickers into separate images. This script works for https://github.com/securingdev/awesome-stickers/blob/master/raw/attrition_01.pdf

#!/bin/sh

input="$1"

# verbose
set -x

if [ ! -f "$input" ]; then
  echo "File not found: $input"
  exit 1
fi

background_color=$(convert "$input" -colors 32 -depth 8 -format "%c" histogram:info: | sort -r -n |  awk '{print($4); exit;}')

# avoid white
if [ "$background_color" = "white" ]; then
  background_color="rgb(254,254,254)"
fi

echo "background_color: $background_color"

convert "$input" +repage -alpha off \
  -fuzz 5% -fill "$background_color" -opaque "$background_color" \
  +dither -colors 32   \
  -morphology dilate octagon \
  -fuzz 0 -fill white +opaque "$background_color" -fill black +opaque white \
  -type bilevel \
  -define connected-components:exclude-header=true \
  -define connected-components:verbose=true \
  -define connected-components:area-threshold=5000 \
  -connected-components 8 -auto-level lumps.png

greys=$(convert lumps.png -colors 255 -depth 8 -format "%c" histogram:info: | awk '!/#000000/{print($3)}')
mask=0
for grey in $greys; do
  convert lumps.png -fuzz 1% -fill black +opaque "$grey" -fill white -opaque "$grey" mask_${mask}.png
  mask=$((mask + 1))
done

seg=0
rm -f segment_*png
for f in mask_*png; do
   convert "$input" "$f" -compose copy-opacity -composite -trim +repage segment_${seg}.png
   seg=$((seg + 1))
done

[mwarning]

Discussion: https://github.com/ImageMagick/ImageMagick/discussions/2537