capture image to slow with java

asked 2013-09-05 13:54:56 -0600

a242133
1 ●1

updated 2013-09-13 11:47:58 -0600

open webcam, read and releas takes about 600ms. Is there a way to speed-up? Using it on Windows 7 with latest java and recent opencv:

VideoCapture webcam = new VideoCapture();
boolean opened = webcam.opened();
if (opened) {
    return null;
}
try {
    webcam.open(0);
} catch (Exception e) {
    return null;
}

if (!webcam.opened()) {
    return null;
}
try {
    Mat frame = new Mat();
    webcam.read(frame);
    //do somethinig
    webcam.release();
} catch (Exception e) {
    null
}
return null;

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Comments

So many information about your system, camera etc.

Moster ( 2013-09-05 16:25:26 -0600 )edit

@Monster You're right. I did add more information

a242133 ( 2013-09-06 10:45:26 -0600 )edit

Does it speed up if you dont use try catch?

Moster ( 2013-09-08 09:39:29 -0600 )edit

No, it doesn't help.

a242133 ( 2013-09-09 14:22:57 -0600 )edit

Would it be possible for you to try the same on c++? If it takes the same time, you wont really be able to speed it up I guess

Moster ( 2013-09-12 13:23:42 -0600 )edit

Never used c++, so it gonna take a while

a242133 ( 2013-09-13 02:39:09 -0600 )edit

What might bring a little speed is to directly call new VideoCapture(0) and then only check once webcam.opened(), but maybe only a little bit.

Moster ( 2013-09-13 02:51:11 -0600 )edit

Well, camera initialization does take a while, even in pure C/C++.

Daniel Baggio ( 2014-01-18 21:56:10 -0600 )edit

(sorry, initially posted as answer, now posting as comment, I'm a little new to this site)

Can you confirm which part of the code is slow? Is it opening the camera, or reading frames?

I'm asking because I have discovered that opening a connection to an IP camera in Java is horribly slow (have to wait a whole minute), but getting frames from the camera afterwards runs at reasonable speed.

arp ( 2014-09-29 12:13:59 -0600 )edit

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VideoCapture capture = new VideoCapture(0); int WIDTH = 320; int HEIGHT = 240; if (capture.isOpened()) { // to get the actual width of the camera System.out.print("Width: " + capture.get(Highgui.CV_CAP_PROP_FRAME_WIDTH)); // to get the actual height of the camera System.out.println(", Height: " + capture.get(Highgui.CV_CAP_PROP_FRAME_HEIGHT)); boolean wset = capture.set(Highgui.CV_CAP_PROP_FRAME_WIDTH, WIDTH); boolean hset = capture.set(Highgui.CV_CAP_PROP_FRAME_HEIGHT, HEIGHT); if (!hset || !wset) { System.out.println("Width Changed: "+wset); System.out.println("Height Changed: "+hset); // to get the actual width of the camera System.out.println(capture.get(Highgui.CV_CAP_PROP_FRAME_WIDTH)); // to get the actual height of the camera System.out.println(capture.get(Highgui.CV_CAP_PROP_FRAME_HEIGHT)); } }

capture image to slow with java

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