Dead zone compensation for touch screens
A method of compensated touch data values disclosed herein includes acquiring touch data values about a dead sensing zone of a touch screen, and determining a peak value of those touch data values. Then, a new peak value is calculated as a function of an average of the peak value and another value of the touch data value, and a sharpness value for the dead sensing zone is generated if a second highest value of the touch data values is less than the new peak value. Thereafter, compensated touch data values are generated for the dead sensing zone if the second highest value is greater than the new peak value.
1. A method, comprising:
acquiring touch data values from capacitive sensing locations located about a dead sensing zone of a touch screen;
calculating a centroid of the acquiring touch data values from capacitive sensing locations located about the dead sensing zone
calculating a first compensated value as a function of the centroid and a difference between one touch data value and another touch data value, wherein said one and another touch data values have highest values of the acquired touch data values from capacitive sensing locations located about the dead sensing zone; and
calculating a second compensated value as a function of the first compensated value and the centroid.
2. The method of claim 1 , wherein calculating the first compensated value comprises multiplying the difference by the centroid and summing the result with a selected one of said one and another touch data values.
3. The method of claim 2 , wherein summing comprises subtracting and wherein the selected one of said one and another touch data values is the touch data value having a highest value.
4. The method of claim 1 , wherein calculating the second compensated value comprises multiplying the first compensated value by the centroid and adding the result to the first compensated value.
5. The method of claim 1 , wherein the touch data values comprise a first value (p1) for a first location, a second value (p2) for a second location, a third value (p3) for a third location and a fourth value (p3) for a fourth location, and the centroid is calculated in accordance with the following formula:
centroid
=
p
4
-
p
2
p
3
+
max
(
p
2
,
p
4
)
-
2
*
min
(
p
2
,
p
4
)
.
6. The method of claim 5 , wherein the first compensated value is calculated in accordance with the following formula:
first compensated value=p3−((p3−p2)*centroid).
7. The method of claim 6 , the second compensated value is calculated in accordance with the following formula:
second compensated value=first compensated value+(first compensated value*centroid).
8. The method of claim 1 , wherein the centroid represents a percentage offset of the centroid from a location of said one and another touch data values having a highest value.
9. The method of claim 8 , wherein calculating the second compensated value comprises adjusting the first compensated value with an increase specified by the percentage offset.
10. A method, comprising:
acquiring touch data values from capacitive sensing locations located about a dead sensing zone of a touch screen;
calculating a centroid of the acquiring touch data values from capacitive sensing locations located about the dead sensing zone
calculating a first compensated value as a function of the centroid and a difference between one touch data value and another touch data value, wherein said one and another touch data values have highest values of the acquired touch data values from capacitive sensing locations located about the dead sensing zone;
determining whether a sharpness value of a profile including the first compensated value at the centroid meets a threshold; and
if not, then for the centroid, calculating a second compensated value as a function of the centroid.
11. The method of claim 10 , wherein determining the sharpness value comprises calculating a difference between the first compensated value at the centroid and other values in the profile at locations offset from the centroid.
12. The method of claim 11 , wherein the locations offset from the centroid are locations between the capacitive sensing locations for the acquired touch data values.
13. The method of claim 12 , wherein the other values are a determined as a function of a difference between acquired touch data values and the centroid.
14. The method of claim 10 , wherein calculating the first compensated value comprises multiplying the difference by the centroid and subtracting from a selected one of said one and another touch data values having a highest value.
15. The method of claim 10 , wherein calculating the second compensated value comprises multiplying the first peak compensated value by the centroid and adding the result to the first compensated value.
16. The method of claim 10 , wherein the touch data values comprise a first value (p1) for a first location, a second value (p2) for a second location, a third value (p3) for a third location and a fourth value (p3) for a fourth location, and the centroid is calculated in accordance with the following formula:
centroid
=
p
4
-
p
2
p
3
+
max
(
p
2
,
p
4
)
-
2
*
min
(
p
2
,
p
4
)
.
17. The method of claim 16 , wherein the first compensated value is calculated in accordance with the following formula:
first compensated value=p3−((p3−p2)*centroid).
18. The method of claim 17 , the second compensated value is calculated in accordance with the following formula:
second compensated value=first compensated value+(first compensated value*centroid).
19. The method of claim 10 , wherein the centroid represents a percentage offset of the centroid from a location of said one and another touch data values having a highest value.
20. The method of claim 19 , wherein calculating the second compensated value comprises adjusting the first compensated value with an increase specified by the percentage offset.