Method and system for adaptive stylus force or pressure sensing
An apparatus and method for adapting a conversion of a force or pressure sensed at a stylus into a converted output used for an inking process at a host device, wherein samples of the converted output are collected over a predetermined time period. Then, the collected samples are evaluated and at least one parameter of the conversion is controlled in response to a result of the evaluation. Thereby, a user-specific probability distribution of the sensed force or pressure can be matched to a desired probability distribution of the inking process.
1. An apparatus comprising:
a collector for collecting samples of inking levels over a time period, the inking levels used for an inking process at a host device; and
an evaluator for evaluating the collected samples, wherein the evaluator is adapted to control a parameter of a conversion of force or pressure data output by a sensor of a stylus into the inking levels in response to a result of the evaluation;
wherein the evaluator is adapted to control the parameter to modify a probability distribution of the samples of the inking levels to match with a desired probability distribution of the inking process.
2. The apparatus of claim 1 , further comprising a transmitter for transmitting the inking levels to a digitizer of the host device to indicate ink thickness values.
3. The apparatus of claim 1 , wherein the evaluator is adapted to decide that the parameter is to be adjusted if a deviation between a parameter of the probability distribution of the collected samples and a corresponding parameter of the desired probability distribution exceeds a threshold.
4. The apparatus of claim 1 , wherein the collector is adapted to continuously or intermittently collect the samples of the inking levels to obtain a histogram of data representing the force or pressure sensed at the stylus.
5. The apparatus of claim 4 , wherein the evaluator is adapted to perform the control based on a histogram equalization technique.
6. The apparatus of claim 5 , wherein the evaluator is adapted to accomplish the histogram equalization technique by spreading out and/or shifting an intensity of collected samples of the inking levels to adapt an intensity range of the collected samples to an available range of levels of displayed ink of the host device.
7. The apparatus of claim 1 , wherein the evaluator is adapted to detect an individual type of the stylus based on a statistically characteristic force or pressure distribution.
8. The apparatus of claim 1 , wherein the evaluator is adapted to detect a specific type of use of the stylus based on a statistically characteristic force or pressure distribution.
9. The apparatus of claim 8 , wherein the evaluator is further adapted to control the parameter of the conversion in based on the detected specific type of use of the stylus.
10. The apparatus of claim 1 , wherein the collector and evaluator are adapted to perform the collection and evaluation in different force/pressure sub-ranges with different evaluation criteria.
11. The apparatus of claim 1 , wherein the collector is adapted to collect samples of the inking levels from a plurality of different styli, and wherein the evaluator is adapted to control the parameter of the conversion based on a combination of the samples of the different styli.
12. A stylus comprising an apparatus according to claim 1 , the sensor for sensing the force or pressure, and a converter for converting the sensed force or pressure data into the ink levels used for the inking process at the host device.
13. A host device comprising an apparatus according to claim 1 .
14. The host device of claim 13 , further comprising a converter for converting the sensed force or pressure data into the ink levels used for the inking process at the host device.
15. A method comprising:
collecting information about ink levels over a time period, the ink levels used for an inking process at a host device;
evaluating the collected information; and
controlling a parameter of a conversion of force or pressure data output by a sensor of a stylus into the ink levels in response to a result of the evaluation;
wherein the parameter is controlled to modify a probability distribution of samples of the inking levels to match with a desired probability distribution of the inking process.
16. A computer program embodied on a computer-readable memory and comprising code configured so as when run on a processor to perform a method comprising:
collecting information about ink levels over a time period, the ink levels used for an inking process at a host device;
evaluating the collected information; and
in response to a result of the evaluation, controlling a parameter of a conversion of force or pressure data output by a sensor of a stylus into the ink levels,
wherein the parameter is controlled to modify a probability distribution of samples of the ink levels to match with a desired probability distribution of the inking process.
17. The computer program of claim 16 , wherein evaluating the collected information comprises deciding that the parameter is to be adjusted if a deviation between a parameter of the probability distribution of the collected information and a corresponding parameter of the probability distribution exceeds a threshold.
18. The computer program of claim 16 , wherein collecting the information about the ink levels comprises continuously or intermittently collecting the samples of the ink levels to obtain a histogram of data representing the force or pressure sensed at the stylus.
19. The computer program of claim 16 , wherein controlling the parameter comprises controlling the parameter based on a histogram equalization technique.
20. The computer program of claim 16 , wherein the method further comprises detecting at least one of an individual type or a specific use of the stylus based on a statistically characteristic force or pressure distribution.