openalpr

車牌辨識 Kurento 的車牌辨識只是個學生的測試，而且只適合歐洲車牌。 目前比較能用的是 openALPR https://github.com/openalpr

在 ubuntu 14.04 中安裝: wget -O - http://deb.openalpr.com/openalpr.gpg.key | sudo apt-key add - echo "deb http://deb.openalpr.com/master/ openalpr main" | sudo tee /etc/apt/sources.list.d/openalpr.list sudo apt-get update sudo apt-get install openalpr openalpr-daemon openalpr-utils libopenalpr-dev

$ cat alpr.js var tmp_path = '/tmp/alpr'; var counter = 7; // alpr will be triggered after every counter.

const cp = require("child_process");

cp.exec("rm -Rfv " + tmp_path + "; mkdir -pv " + tmp_path);

var ffmpeg = cp.spawn("ffmpeg",['-y','-loglevel', 'debug','-i', "rtsp://192.168.0.103/live2.sdp", '-r', '1', '-f', 'image2', '-strftime', '1', '/tmp/alpr/alpr_%Y%m%d-%H%M%S.jpg']);

ffmpeg.stderr.on('data', function (data) { });

ffmpeg.on('close', function (code) { console.log('ffmpeg child process exited with code ' + code); });

var iw = cp.spawn("inotifywait",['--monitor', tmp_path, '--event', 'CLOSE_WRITE,CLOSE', '--format', '%f']);

iw.stdout.on('data', function (data) { //console.log('stdout: ' + data); if (counter <= 0) { alpr(tmp_path + '/' + data, function (plates) { console.log(plates); }); counter = 7; } else { counter--; } });

iw.stderr.on('data', function (data) { console.log('stderr: ' + data); });

iw.on('close', function (code) { console.log('inotifywait child process exited with code ' + code); });

var alpr = function (filename) { cp.exec("alpr --json " + filename, function (error, stdout, stderr) { var j = JSON.parse(stdout); for (var i in j.results) console.log(j.results[i]); cp.exec("xloadimage -delay 1 -zoom 30 " + filename);

    if (error !== null) {
	  console.log('exec error: ' + error);
		process.exit(99);
    }

}); }

openalpr 目前沒有台灣車牌，但可以用既有國家偵測台灣車牌，若要提高識別率，則要重新訓練。訓練程式如下:

https://github.com/openalpr/train-ocr https://github.com/openalpr/train-detector

You need a few thousand cropped plate images (at the same aspect ratio) to do the detector training. OCR training can be completed with 100 or so cropped images.

已經有人訓練出新加坡車牌 https://groups.google.com/forum/#!topic/openalpr/oWU2CvTR7yU