Ask Your Question
2

What are some good implementation of efforts to digitise an analog dial?

asked 2012-10-05 02:29:48 -0500

this post is marked as community wiki

This post is a wiki. Anyone with karma >50 is welcome to improve it.

For example,

I want to install a camera in front of the dial and from the received images, extract the information like time in watch or Force from UTM.

This data extraction has to happen in Real-time and continuously. So, for example, the program output should be "the time" read from the watch which updates say, every second.

edit retag flag offensive close merge delete

Comments

I was thinking, first to convert the video to images by reducing the frame rate to say one per sec, then extracting the dial from the image, and read the angle of the pointer (blue) from the images, then convert the angle to corresponding force value by calibration.

chintanp gravatar imagechintanp ( 2012-10-05 02:35:36 -0500 )edit

Is it possible to extract the angle without converting to images?

chintanp gravatar imagechintanp ( 2012-10-05 02:36:12 -0500 )edit

1 answer

Sort by ยป oldest newest most voted
2

answered 2012-10-05 02:40:38 -0500

elmiguelao gravatar image

updated 2012-10-05 07:51:57 -0500

You can use the Hough transform to detect straight lines in the frame. Once the main lines are found, and seems it would work pretty good according to your second picture, the angles can be postprocessed. Note that the Hough operation ("transform") will return loads of straight lines of different lenght in the picture, unwanted ones should be filtered out via line size.

There is this full tutorial in openCV with code included: http://docs.opencv.org/doc/tutorials/imgproc/imgtrans/hough_lines/hough_lines.html.

edit flag offensive delete link more

Comments

Saying that hough transform is the same as findContours is a bit confusing, what do you mean by that?

Rui Marques gravatar imageRui Marques ( 2012-10-05 06:43:46 -0500 )edit

True, now that I read that. I just meant that cvFindContours also will find loads of contours that a human eye would not find relevant. I will edit the answer.

elmiguelao gravatar imageelmiguelao ( 2012-10-05 07:51:11 -0500 )edit
Login/Signup to Answer

Question Tools

1 follower

Stats

Asked: 2012-10-05 02:29:48 -0500

Seen: 590 times

Last updated: Oct 05 '12