credit to https://www.pyimagesearch.com/2018/12/17/image-stitching-with-opencv-and-python, https://www.geeksforgeeks.org/python-program-extract-frames-using-opencv/ and lots of other people who've done all the real work preceeding this

stitch the floor

Note that the original video file isn't included in this repository.

Take one minute chunk of video starting after 1:08

oName=day2a
ffmpeg -ss 00:01:08 -i ~/rov_videos_day2/2019-07-13_09.59.05.mkv -t 00:01:00 -vcodec copy videos/${oName}.mkv

Extract image every 0.5 seconds. crop 128 pixels from left and bottom (probably)

# frames per second... (images per second)
FPS=1
mkdir images/${oName}
ffmpeg -i videos/${oName}.mkv -qscale:v 2 -vf "crop=in_w-128:in_h-128:128:0,fps=${FPS}" images/${oName}/%05d.jpg

Move images into groups of no more than 10..

groups=$(( $(ls images/${oName} | wc -l) / 10))
for i in $(seq -w 0000 $groups)
do 
 mkdir images/${oName}_${i} 
 mv images/${oName}/${i}*.jpg images/${oName}_${i} 
done

Try to stitch each group

for i in $(seq -w 0000 $groups)
do 
 oLog=stitched_output/${oName}_${i}.md
 which tee >/dev/null && TEE=true
 if [ $TEE ]; then
     echo writing script output to $oLog
     echo '```bash' > $oLog
     time python3 stitch.py --nodisplay --images images/${oName}_${i} --output stitched_output/${oName}_${i}.png | tee -a $oLog
     echo '```' >> $oLog
 else
     echo > $oLog
     time python3 stitch.py --nodisplay --images images/${oName}_${i} --output stitched_output/${oName}_${i}.png 
 fi

 if [[ $(ls images/${oName}_${i} 2>/dev/null | wc -l) -gt 0 ]] ; then
    for img in $(ls images/${oName}_${i}/)
    do
        echo "<img src='../images/${oName}_${i}/${img}' width='64px' align='left' />" 
    done > $oLog

    echo "<img src='${oName}_${i}.png' alt='stitched output for ${oName}' title='stitched' />" >> $oLog
 fi
done

cleanup (delete all/most of the mess we just made)

rm -Rf images/DIRNAME* videos/DIRNAME* stitched_output/DIRNAME*

other random notes

• added --nodisplay option to squelch the image popup

  • useful when running in a loop or inside a script

• added -cthresh option to use a lower confidence level

  • after my initial image stitching test failed, setting confidence from 1.0 to 0.8 succeeded

this cropping results in a super narrow panorama..

python3 stitch.py --images images/rug   --output rug-cropped.png --crop 1

to be fair, the author said it was a hack! so we just don't use it..

python3 stitch.py --images images/rug  --output rug.png

https://stackoverflow.com/questions/40088222/ffmpeg-convert-video-to-images/40090033

test script to split videos

>python3 vproc.py videos/day2a.mkv 30

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