Visualization chapter added

README.md

@@ -141,3 +141,9 @@ The interrupt caused by gamma pulses is handled in function `handleInterrupt()`.
 The webserver provides all 4096 channel counters as a JSON formatted stream. This webpage can be displayed in any webbrowser by typing http://gamma.local/json. The displayed JSON stream can be downloaded as a JSON file for further offline processing (e.g. with the Python script). The JSON file contains in the header beside the 4096 channel counters also the elapsed time of the current measurement, the total number of events (peaks) in the current measurement and the average of counts (peaks) per minute. The following screenshot shows an example:
 
 <img src="/Screenshots/screenshot01.png" alt="" width="1000" title="JSON stream">
+
+### Visualization
+
+The webserver provides also a visualization of the captured data. This webpage can be displayed in any webbrowser by typing http://gamma.local/spectrum. All channel counters are normalized by the elapsed time (unit: cpm, counts per minute) and are on the y-axis, whereas the channels [0 .. 4095] are on the x-axis. This gives you a gamma spectrum. An embedded javascript helps for visualization the spectrum in a Google line chart. The javascript produces also a second smoothed curve (red) which is generated by a kind of 2-way low pass filter. Beside this some useful information is shown in the heading of the webpage, e.g. the elapsed time of the current measurement, the total number of events (peaks) in the current measurement and the average of counts (peaks) per minute. The following screenshot shows an example:
+
+<img src="/Screenshots/screenshot02.png" alt="" width="1000" title="Spectrum">