📄 dexterhelp.html
字号:
<HTML><head><TITLE>ADS Dexter Help</TITLE></head><body bgcolor="#ffffff" text="#000000" link="#0000ff" alink="#ff0000" vlink="#4000a0"><CENTER><H1><A HREF="http://adswww.harvard.edu/">ADS</A> Dexter help</H1></H1></CENTER><P ALIGN="CENTER">Please report errors or malfunctions of Dexterto <a href="mailto:gavo@ari.uni-heidelberg.de">gavo@ari.uni-heidelberg.de</a>.If possible, please include the contents of your Browser's Java Console.</P><p>Dexter is a little tool to extract data from figures on scanned pagesfrom ADS' article service. A standalone version is available at<a href="http://vo.ari.uni-heidelberg.de/sdexter">http://vo.ari.uni-heidelberg.de/sdexter</a> To use it, you need a browser that can executeJava Applets and has that feature enabled.</p><H2>Figure Selection Page</H2><p>The site operators have usually set up Dexter such that you first have toselect the portion of an image you want to work on. On this page, please waituntil a scaled-down version of the image is entirely downloaded. To select afigure, just click on one corner of the figure, hold the (left) mouse buttonand adjust the rubber band to encompass the entire figure. If the figure islarger than the applet area, the visible portion of the page will follow yourmouse pointer. When you are done, release the mouse button, and the...</P><H2>Data Extraction Window</H2><P>will pop up. The site operators can set up Dexter such that this extraction window will pop up automatically on an entire image -- the standalone service mentioned above does this for uploaded images.</p><p>Again, you should wait until the image is fully downloaded, atwhich point the window will resize to show as much of the image as is possibleon your screen.After that, the usual action sequence in there is</P><UL><LI>click-and-drag a gauge along the horizontal axis (this will be a red line)</LI><LI>click-and-drag a gauge along the vertical axis (this will be a blue line)</LI><LI>fill in the boxes marked x0/x1 and y0/y1 with the lower and upper valuesmarked by the gauges</LI><LI>left click on the points in the diagram to set points. To remove apoint, shift-click or use the middle mouse button</LI><LI>optionally change the output file name</LI><LI>click on either the "Send Data" or the "Save Data" button to receive the file with the data points</LI></UL><p>"Send data" will display the extracted data on the figure selection page (which is present even if the extraction window popped up automatically)."Save data" will usually (depending on the setup of your browser)bring up a "Save file as..."-type dialog. On the standalone version,it will additionally store the extracted file on the server for later retrieval. You can delete these server-side files and should do so if you notice a mistake.</p><p>Instead of manually marking the gauges, you can select<strong>automatic axes</strong> from the Recognizer Window orhit Control-A. You can adjust the gauges by dragging their endpoints</p><h3>Special Features</h3><P>Under the "Zoom" pull down menu, you have entries from 75dpito 600dpi to <STRONG>change the resolution</STRONG> of theimage -- for large figures, you may want to use 100 dpi, small figures will require 300dpi. Use these buttons if your screen is toosmall for the entire image or the figure is so small that you cannotmark points with sufficient accuracy. Please note that youJava virtual machine may not have enough memory for highresolution renderings of large images.</P><p>If you uploaded an image to the standalone service, these resolutionsare of course just random numbers since the service in general does not know the original resolution of the source file. 600 dpi here correspond tothe an unscaled version of the uploaded image.</p><P>The <STRONG>coordinates</STRONG> of the mouse pointer are shown in the lastline of the data extraction window. The coordinates will be in pixels as longas you have not defined both axes, and in graph coordinates otherwise. If youchange one of the text fields, you may have to force a loss of keyboard focuson that text field for the change to become effective for the mouse tracking,e.g. by clicking into the output field, pressing the tab key, setting a datapoint, or the like. Unfortunately, this behavior is platform dependent, andyou will have to try for yourself to see what works on your machine.</P><P><EM>After</EM> you have defined the axes, you can set <STRONG>error bars</STRONG> by clickingand dragging <EM>on</EM> an existing data point. Error bars are always parallelto the axes at the point of time of their creation. On output, theerror bars are shown in up to four additional columns, with horizontalerror bars first if both vertical and horizontal ones were marked; "plus"and "minus" errors are indicated by the applicable sign.If you miss the data point, Dexter starts to draw another axis gauge.To avoid clobbering your previous gauge, drop the new gauge when its length isbelow Dexter's lower limit on gauge length (about 30 pixels).To entirelyremove (as opposed to resize) the error bars, delete the data point andset a new one.</P><P>If the diagram has <STRONG>logarithmic axes</STRONG>, check the "log" check button.Note that you should not check this button if the logarithm of aquantity is plotted on a linear scale.</P><p>Dexter has a <strong>magnifying glass</strong> that is by defaultturned off because some (faulty) Java run-time libraries causethe applet to slow to a crawl when it is turned on or causeother funny effects. To turn it on, just click on the sketchedmagnifying glass on the left side of the applet. Clicking onthe area of the magnifying glass once more deactivates it again.</p><p>The magnifying glass currently does not show "temporary"features (axes and error bars during their creation), and youmay have to move the mouse to update the display after you seta point. We are looking to change this without slowing downDexter.</p><h3>Recognizers</h3><p>You can ask Dexter to do some of the marking of data pointsautomatically. Currently, three operations are supported: axisfinding, line tracing, and point marking. In general, teachinga computer to recognize features is a highly nontrivial task,so you should not expect miracles. For many plots, though,Dexter's recognizers might save you some time.</p><p>All recognizersrun in separate threads, so that you can continue workingwith Dexter. While they are running, certain operations arenot allowed (e.g., changing resolution, sending data), and the respective buttons or menu entries aregreyed out. As long as a recognizer is running, there will bea notice "Recog. running" in Dexter's status line.</p><p>Some parameters used by the recognizers can be changed usingthe Recognizer/Settings dialog. The settings become effectiveas you change them.</p><p>Because the recognizers may set a large number of points,there is a menu entry Delete all Points in the Recognizerpull-down menu. Selecting this really deletes all points set,not only those set by a recognizer. You may want to use thatfeature while experimenting with various parameters for therecognizers.</p><p>To stop a running recognizer, select "Stop Recognizer" inthe Recognizer pull-down menu.<p><p>The run time of recognizers with current Javaimplementations is mainly a function of the image size, sincethey spend most of their time transforming the image intosomething that is accessible by the program. Also, thisconversion requires significant amounts of memory. If arecognizer runs out of memory, it may just stop working (thoughin general we try to catch these cases and warn the user). Reducing the resolution might help.</p><h4>Axis Finding</h4><p>To make Dexter identify the gauges on the axes, selectRecognize/Automatic Axes or type Control-A. Note that no gaugewill be set if Dexter cannot find any ticks on an axis.</p><h4>Line Tracing</h4><p>This recognizer follows a line and leaves points along itwhere it thinks something "interesting" happens or at invervalsconfigurable in the Settings dialog. When you start the linetracer either by selecting Recognizer/Trace a line or hittingControl-T, the mouse pointer will change to a pointing finger. Click on the line you want Dexter to trace, and after a littletime you should see points marked along the line. At junctionsof lines, the tracer may become confused and take the wrongway, or it may lose the line at certain extreme points. Inthese cases is may help to give the line tracer a differentstart point or to let it run more than once.</p><h4>Point Finding</h4><p>This recognizer tries to register points similar to auser-defined template within a graph. After you start it byeither selecting Recognizer/Find Points or Control-B, it asksyou to click on a template point. When there are error bars inthe graph, either select a template without error bars or onewith large error bars (i.e., error bars larger than the markeritself), or Dexter will add the error bars into thetemplate and will have a hard time finding anything similar tothe template.</p><p>The distance measure used by the point finder is the numberof matching points normalized by the total number of points inthe template area, where two points match if they are bothblack or both white after thresholding.<p><p>You can change the maximal acceptable difference between atemplate and an acceptable data point in thesettings dialog. For bad scans, it may be necessary to raisethis value.</p><p>The point finder will not accept templates smaller than 4x4pixels. If you run into this limitation (Dexter will complainthat it could not find the start object), try increasing theresolution.</p><a name="Browsers"><H2>Browsers</H2></a><p>The apple JVM on classic MacOS disallows Dexter to open its childwindow by default. If Dexter complains that it is not allowed to opena window, go to Preferences, select the Java tab and check "Don't check"in the combo box for code checking. We recommend to undo this selection after using Dexter.</p><HR><p>A source distribution of Dexter is available at <a href="http://Dexter.sourceforge.net">sourceforge</a> underthe GNU General Public Licence.</p><HR><address><a href="mailto:gavo@ari.uni-heidelberg.de">gavo@ari.uni-heidelberg.de</a></address></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -