Quote:
Originally Posted by tomsem
Fountain Pen is not pressure sensitive. Marker and Pencil are.
Fountain pen is like a thin line segment at about a fixed 20 degree angle. The thinness varies over a narrow range with the stroke 'weight'. The segment length is determined by one of the five 'weights'. So minimum thickness when direction aligns with 20 degrees, maximum thickness is achieved when direction is aligned with 110 degrees. (Seems this is biased to right handers, there should be one with minus 20 degree pitch as well! Will this discrimination never end?!)
Pencil is only type with tilt.
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Thanks for the info. I am currently trying to correlate raw digitizer data (tilt and pressure) with the stroke thickness and density that appear to be generated based on them. That knowledge will be helpful in forming hypotheses.
Quote:
Originally Posted by tomsem
Attached samples:
- notebook with Pencil strokes with various weights, pressures, and tilt, and Fountain pen strokes at different angles (the 'circles' are at least 2 strokes, but hopefully capture all angles for each 'weight')
- notebook with single stroke, video recorded
- the video recording of stroke
- PDF export for each notebook
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Thanks for doing all of that work!
It will take me some time to analyze the notebook with all of the various samples. Already I have found several things that break my previous assumptions. Many of those strokes have density and thickness far beyond anything I saw previously.
Also that notebook contains two templates, vertical_rule_margin_1860x2480 and dotted_1860x2480, with only the second being active. I did not expect that and my KFX Input plugin currently does not handle it correctly. Did you possibly start with one template and then switch to another in that notebook?
Quote:
Originally Posted by tomsem
The stroke started at about 2 37/60 seconds (60fps) and ended 5 41/60 s so 3 4/60 seconds total.
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The stroke in the notebook matching the video contains 885 points. With a duration of 3.07 seconds that means the digitizer captures at least 288 points per second.
In the samples I have analyzed I have never found two subsequent points at the same location so it appears that those are eliminated to save space. That means the actual number of points originally generated by the digitizer was likely greater than found in the notebook and the actual sampling rate is likely higher. I am guessing that it is 300 samples per second but it could be even more.
If you are interested in pursuing this further then a different test could be done to get a more accurate measurement. For example a stroke could be made with the pen moving more quickly, already in motion before pressing down and lifting it, so that points are not eliminated near the ends. Another idea would be to first draw two lines and then quickly draw a new stroke that crosses them. The time at which the new stroke crosses the others could be detected on video and also within the captured data. That would mitigate against the potential loss of points near the ends of the measured stroke.
Those are just some ideas. I understand if you believe that you have already put enough effort into this.