Method for palm touch identification in multi-touch digitizing systems

1 . A method for classifying input to a multi-touch sensitive digitizer that is obtained from a body part as inputs invalid for user interaction and inputs valid for user interaction, the method comprising:

identifying a plurality of discrete regions of input to a digitizer sensor;

determining spatial relation between at least two of the regions; and

classifying one of the at least two regions as either valid input region or invalid input region based on the spatial relation determined between the at least two regions.

2 . The method according to claim 1 comprising determining at least one spatial characteristic of the region to be classified and classifying the one of the at least two regions as either the valid input region or the invalid input region based on the characteristic determined.

3 . The method according to claim 1 , wherein the spatial characteristic is selected from a group including: size, shape, and aspect ratio.

4 . The method according to claim 1 , wherein the spatial relation is the distance between the at least two regions.

5 . The method according to claim 1 , comprising determining sizes of each of the plurality of discrete regions.

6 . The method according to claim 1 , wherein the at least two regions includes at least one small area region having an area below a pre-defined area threshold and at least one large area region having an area above the pre-defined area threshold.

7 . The method according to claim 1 , comprising determining a centroid of the at least one small area region and using it to determine a spatial relation between that at least two regions.

8 . The method according to claim 6 wherein the spatial relationship determined includes proximity between at least one small area region and the at least one large area region.

9 . The method according to claim 8 , wherein the proximity is determined within an area defined around the at least one small area region.

10 . The method according to claim 6 , wherein the at least one small area region is classified as either valid input or invalid input.

11 . The method according to claim 1 , wherein the invalid input region is obtained from a palm or hand touching or hovering over the digitizer sensor.

12 . The method according to claim 1 , wherein the valid input region is obtained from a fingertip touching or hovering over the digitizer sensor.

13 . The method according to claim 1 comprising using only the valid input region for user interaction with the digitizer.

14 . The method according to claim 1 , wherein the digitizer sensor includes two orthogonal sets of parallel conductive lines forming a plurality of junctions there between from which the input is received.

15 . The method according to claim 14 , wherein input to the digitizer sensor is detected by a capacitive touch detection method.

16 . The method according claim 14 , comprising detecting a pattern of signal amplitudes from the conductive lines of the digitizer sensor.

17 . The method according to claim 16 , comprising forming a two-dimensional image of signal amplitudes from the pattern of signal amplitudes.

18 . The method according claim 17 , wherein pixels of the image correspond to the signal amplitude at each of the junctions.

19 . The method according to claim 17 comprising: performing image segmentation on the image to identify the plurality of discrete regions.

20 . The method according to claim 14 , wherein sizes of the regions are defined by the number junctions included in the regions.

21 . The method according to claim 14 , wherein sizes of the regions are defined by a rectangular areas surrounding the regions, the rectangular areas having dimensions defined by a number of conductive lines on each of the orthogonal axes from which user input is detected.

22 . The method according to claim 18 , comprising classifying the one of the at least two regions as either the valid input region or the invalid input region based on amplitude level within the regions.

23 . The method according to claim 22 , wherein the amplitude level is compared to a base-line amplitude of the junctions with the regions, wherein the base-line amplitude of a junction is an amplitude at that junction in the absence of user input.

24 . The method according to claim 23 , comprising classifying the one of the at least two regions as an invalid input region in response to the region including amplitudes above their base-line amplitudes.

25 . A method for classifying input to a multi-touch sensitive digitizer that is obtained from a body part as inputs invalid for user interaction, the method comprising:

detecting a pattern of signal amplitudes from the conductive lines of the digitizer sensor, wherein the digitizer sensor includes two orthogonal sets of parallel conductive lines forming a plurality of junctions there between from which the input is received;

identifying at least one region of input to a digitizer sensor based on the pattern of signal amplitudes; and

classifying the at least one region as an invalid input region in response to the at least one region including amplitudes at junctions above a base-line amplitude junction.

26 . The method according to claim 25 , wherein the base-line amplitude of a junction is an amplitude at that junction in the absence of user input.

27 . The method according to claim 25 , comprising forming a two-dimensional image of signal amplitudes from the pattern of signal amplitudes.

28 . The method according claim 27 , wherein pixels of the image correspond to the signal amplitude at each of the junctions.

29 . The method according to claim 25 , wherein input to the digitizer sensor is detected by a capacitive touch detection method.