Remove sparse parts from binary

#!/bin/bash
LANG='C'

BLOCK_SIZE=512
SPARE_SIZE=16
IN_FILE=file.in
OUT_FILE=file.out

rm -f $OUT_FILE
# Read per block+spare and write block, skipping spare part
i=0
while [ -z "`dd if=$IN_FILE of=block.file bs=$((BLOCK_SIZE + SPARE_SIZE)) count=1 skip=$i 2> \
        >(grep 'cannot skip to specified offset')`" ]; do
    echo "Processing $i block at $(((BLOCK_SIZE + SPARE_SIZE) * i)) offset..."
    dd if=block.file bs=$BLOCK_SIZE count=1 status=none >> $OUT_FILE
    ((i++))
done
rm block.file