Extracting data from oscilloscope bitmap screen capture
this is a follow-up of my previous post; I tested most of the suggested
graph-to-data software mentioned.
All are based on the same assumption: the image is produced by a curve
tracer, that is, some device where x or absolute displacement speed is
constant, resulting in lines with uniform vertical width.
I enclose a small excerpt of the image produced by the oscilloscope.
- each vertical graduation is produced from 25 values, the vertical
amplitude representing the max and the min of those 25 points; the vertical
resolution is quite limited
- the color seems to be linked to the points density:
when the vertical bar is bright, the average value is greater than the bar
when the vertical bar is faded, the average value is smaller than the bar
Basically the vertical point density is non-uniform and somehow translated
by the brightness level. The data extraction software that I tested produced
different coverages between bright and faded zones, but with inverted logic,
taking a lot of points on isolated spikes and less on bright zones; so the
statistics are completely modified.
So I come back with the original question: how can I digitze the graph to
extract data; taking into account the color as a density indicator ?