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NeuroScript MovAlyzeR Help | Send comments on this topic. |
Glossary Item Box
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NeuroScript MovAlyzeR Help | Send comments on this topic. |
This is a common topic for MovAlyzeR & ScriptAlyzeR. These programs will be referred to as MovAlyzeR on this page.
Before starting the tests, choose the device to be tested (settable per user), main Tool bar > Settings > Select input device. Verify that the dimensions and mapping are correctly set.
Device Settings
1. Resolution
Resolution can be obtained from Manufacturer's specifications. This is however the hardware resolution and the driver in some tablets may not be able to provide data at such a resolution. Resolution can be verified from the following tests:
a. By making a recording
o Settings > test input device > test device free hand.
o In the Dialog window, use the default settings:
o Place a ruler on the tablet and consider two points A and B horizontally, at a distance D1 cm. In case of the mouse, place a ruler on the mouse pad instead.
o Click Go to start the recording > Place the pen at point A and move till point B.
o Go to the raw data chart after recording by trial > right click > chart raw data
o Derive the distance between the two y coordinates precisely = |x1-x2| points.
Device Resolution (in cm) = D1/|x1-x2|
For example: For a graphire3, the difference in X coordinates in the x-y raw data plot, yielded 4000 points, when a line of 5cm recording was made on the tablet. Hence, the resolution is 5/4000 = 0.00125 cm
The difference in coordinates can also be found by opening the raw data file (user root folder > folder named with experiment ID > test.hwr), and considering the first and last Y coordinates (2nd column). The user root folder is the folder where you store the data for your current experiment (file > users..> click on user ID >
o Repeat the test by drawing a line in the vertical direction and measuring the Y-coordinate distance.
o Take the average of the two results or perform more iterations, to arrive at a device resolution.
Note:
Alternatively, if you want to keep the recording stored, you can create an experiment with two conditions, one for horizontal line and one for vertical line and record the movements under a subject.
b. Obtain values from the driver
MovAlyzeR has a provision to obtain the resolution, sampling rate and pen-pressure, returned by the tablet wintab driver. In case of mouse, the default settings from Windows are displayed.
You need to go to an experiment under the current user > right click > experiment settings > input device settings > click reset defaults > the corresponding values returned by the driver are displayed.
Results (tablet)
| Tablet make | Wacom | Aiptek | GTCO Calcomp | |
| Type | Graphire 3 | Intuos 2 | 8000U | CAD Pro |
| Size (WxH") | 8x6" | 8x6" | 8x6" | 9x6" |
| Manufacturer Specified resolution | 0.00125 cm (80 L/mm) | 0.001 cm (1000 L/cm) (2540 L/in) | Max. 3048 lpi / 120 lpmm | 0.000625 cm (1600 L/cm) (4000 L/in) |
| Resolution from test a. | 0.00125 cm | 0.001 cm | 0.00508 cm | 0.00253 cm |
| Actual resolution (obtained from the tablet driver) |
0.00125 cm
|
0.001 cm |
0.00508 cm | 0.00254 cm (394 L/cm) |
2. Sampling Rate
a. By making a recording
o The test procedure can be started by Settings > Test/Record Input Device.
The following window is displayed:
o 'Test device free-hand' > GO
o In the resulting dialog window, specify the resolution obtained from previous testing, and use the defaults for sampling rate and pen-pressure.
o Make a free-hand recording (say loops) on the tablet by looking at the recording window on the screen.
o During recording, read the Timer Call and the Position Update frequencies (i.e., frequency that the PC calls for and receives points, respectively). These frequencies should be equal. If not contact NeuroScript. Use the value that occurs most frequently during the movement, as the sampling frequency.
~ The recording window properties are derived from the settings of the previous experiment run for that user. If you have not yet recorded through an experiment, in the current user, the recording window will be as default: Expanded and mapped to the entire tablet.
~ When the pen exceeds the digitizer window, recording discontinues.
~ Lifting the pen too far away from the digitizer may suspend recording.
o After completing the recording, the data recorded are shown.
o The small squares mark the individual samples. The distances between the samples (representing time intervals of 1/Sampling Rate) should vary fluently and should not show any gaps. Irregular spacing implies undesirable, non-constant sampling. The pen-ups are marked with a grey color.
o Charts of recorded data: X-Y, X-Z, Y-Z, Sample number vs. X, Y, and Sample number vs. z are available. Charts can be customized and exported, for more details, refer chart properties help page.
b. Obtain values from the driver
MovAlyzeR has a provision to obtain the resolution, sampling rate and pen-pressure, returned by the tablet wintab driver. In case of the mouse, the pen pressure is always 1.
You need to go to an experiment under the current user > right click > experiment settings > input device settings > click reset defaults (need to do this only if you have not already done so, while determining the resolution) > the corresponding values returned by the driver are displayed.
o To see how the tablet driver or mouse settings can affect the sampling rate, see this section. The mouse speed can be manipulated via My Computer >Control Panel >Mouse. Under Pointer Options > Select Pointer Speed. Also in Pointer options> Switch OFF the option 'Enhance Pointer Precision'. For maximal resolution, set mouse speed as fast.
Results (tablet)
| Tablet make | Wacom | Wacom | Aiptek | GTCO Calcomp |
| Type | Graphire 3 | Intuos 2 | 8000U | CAD Pro |
| Size (WxH") | 8x6" | 8x6" | 8x6" | 9x6" |
| Manufacturer Specified Sampling rate (Hz) | 100 | 100 (200Hz in recognition data mode) |
150 | 200 (Max data rate of 200 Coordinates per second) |
| Measured sampling rate (Hz) (from the above test) | 100 | 101 to 103 | 127 | 67 |
| Measured sampling rate (Hz) (from the tablet driver ) |
100
|
100 |
150 | 75 |
Pen Pressure
To see how the tablet driver settings can affect the pen pressure, see this section.
a. Obtain values from the driver
MovAlyzeR has a provision to obtain the resolution, sampling rate and pen-pressure, returned by the tablet wintab driver. In case of the mouse, the pen pressure is always 1.
You need to go to an experiment under the current user > right click > experiment settings > input device settings > click reset defaults (need to do this only if you have not already done so, while determining the resolution or sampling rate) > the corresponding values returned by the driver are displayed.
Results (tablet)
| Tablet make | Wacom | Wacom | Aiptek | GTCO Calcomp |
| Type | Graphire 3 | Intuos 2 | 8000U | CAD Pro |
| Size (WxH") | 8x6" | 8x6" | 8x6" | 9x6" |
| Pen-Pressure (from the driver) | 1 | 1 | 8 | 1 |
Pen Proximity
The distance from the surface of the tablet up to which pen movements are detected and recorded.
o Keep a ruler vertically on the tablet.
o In MovAlyzeR, Settings > Test/Record input device > Test device free-hand > go.
o Move the pen back and forth over the tablet and move vertically down from say 3 cm, until the point where the cursor on the display shows some movements and gray lines.
o Repeat the process to get the position more precisely moving in the area detected earlier, to find the point beyond beyond which there is no movement detected.
| Tablet make | Wacom | Wacom | Aiptek | GTCO Calcomp |
| Type | Graphire 3 | Intuos 2 | 8000U | CAD Pro |
| Size (WxH") | 8x6" | 8x6" | 8x6" | 9x6" |
| Specified by manufacturer | 0.04" (1mm) | 0.24" (6mm) | 0.32" (8 mm) | 0.4" (10.16 mm) |
| Measured from the above test | 10mm | 16 mm | 26 mm | 12-13 mm |
| See Also |
Getting Started: MovAlyzeR to Test Digitizers
NSHelp: Testing Subject (Gripper)
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