Help on Vectorizing Pictures
Important: Cause Netscape has a strict Security Management, it's not possible
to view images from other hosts with Netscape 3.01. Please try HotJava (
available for SUN and Win95, get it from here)
How can one compare his results with other works from a paper or book. Typing them in by hand is neither much fun nor very accurate. The following program may help you with it.
This program is for vectorizing graphs such as profiles or pressure distributions from an image. Images should have white background color. For automatic vectorizing the lines should have lines with one pixel size. If the results of vectorizing are not sufficent, use the Pick Points feature to pick some points on the graph by hand.
- Image Location:
- Specify either an URL starting with the substring "http://" or a local filename. Filenames can only be loaded, when the security restrictions of your browser are turned off.
- The applet will try to load the specified image. If you load it from the internet, please be patient. Due to synchronizing problems, sometimes the image size can not be set. In this case please reload the image.
- Thats where the image should appear after loading. If you have some graphs digitized, their points will be shown, too. Your image may not fit in the canvas as a total. Use the sliders to adjust the image.
- One of several events can be selected for the canvas:
- Pick Points
- Pick points by hand. This can be used, when the vectorizing algorithm will not work, or to select further points. Any time this choice is selected a new curve will be started.
- Move the mouse pointer over a graph on the image and press the button. The algorithm will try to trace the graph. Any point can only be vectorized once.
- Delete Points
- Drag a rectangle over the points that should be deleted.
- Delete Graph
- Select a graph that should be deleted. Once you deleted the graph, you can't vectorize it again.
- For scaling the digitized points two reference points are needed. By default these points lie in the upper left and lower right corner and the size is set to the imagesize.
- To specify the reference points set the mouse event to pick and select the points in the image.
- Vectorizing Epsilon:
- This value is used inside the algorithm to remove points that can be represented by a single line. Default is 0.7.
- Marker Size:
- This value specifies the size of the point markers shown on the image.
- Vectorize All
- This will find all graphs in the image.
- Deletes all points and resets the image. Resetting of the image is necessary before trying to vectorize deleted graphs.
- Print Points
- Print the x and y coordinate values in the output log. Different graphs will be separated by an ampersand '&'
- Clear Output
- Clears the output log.
- Short info on the algorithm.
- The point information can be printed here. To work with the point data, select all the content in this window and copy it into any texteditor. Points are best worked up with the PD-program xvgr/xmgr by Peter Turner.
The algorithm was written by Jens Trapp. Some ideas concerning the tracking
of pixels are from an algorithm by David Cook. Any kind of feedback is appreciated.
Have fun with the Vectorize Program ...
Back to Jens Trapp's Java Page