http://wiki.ros.org/cv_bridge/Tutorials/ConvertingBetweenROSImagesAndOpenCVImagesPython
https://answers.ros.org/question/248496/node-not-inizialized-critical-but-ignorable-error/
https://suho0515.tistory.com/34
https://ichi.pro/ko/tesseract-opencv-mich-python-eul-sayonghan-ocr-231743215466598