CN108304760B

CN108304760B - Method and electronic device for detecting finger on-hand and off-hand

Info

Publication number: CN108304760B
Application number: CN201710859123.4A
Authority: CN
Inventors: 江元麟; 曾俊钦; 吕俊超
Original assignee: Egis Technology Inc
Current assignee: Egis Technology Inc
Priority date: 2017-01-11
Filing date: 2017-09-21
Publication date: 2021-10-29
Anticipated expiration: 2037-09-21
Also published as: CN108304760A

Abstract

A method of detecting finger-up and finger-down, comprising: detecting whether a sensing capacitance average value of an input sensing signal is larger than a high threshold value or smaller than a low threshold value; when the average value of the sensing capacitance of the input sensing signal is larger than the high threshold value, judging that a finger is placed on the fingerprint sensing device, and adjusting the high threshold value and the low threshold value according to the average value of the sensing capacitance and a compensation value; and when the average value of the sensing capacitance of the input sensing signal is smaller than the lower threshold value, judging that the finger leaves the fingerprint sensing device, and adjusting the upper threshold value and the lower threshold value according to the average value of the sensing capacitance and the compensation value.

Description

Method and electronic device for detecting finger on-hand and off-hand

Technical Field

The present invention relates generally to techniques for detecting finger-on or finger-off, and more particularly to techniques for dynamically adjusting high and low threshold values for detecting finger-on or finger-off.

Background

Mobile devices with fingerprint sensing devices have become a market trend. Before the mobile device leaves the factory or when the mobile device is started for the first time, the fingerprint sensing device is calibrated to obtain a high threshold value and a low threshold value, and the high threshold value and the low threshold value are used for detecting the condition of the upper hand (namely, the finger is detected to be placed on the fingerprint sensing device) or the separation of the upper hand (namely, the finger is detected to be separated from the fingerprint sensing device). However, when the initial calibration is incorrect, for example: during initial calibration, the false placement of a hand or other object on the fingerprint sensing device may cause the high and low threshold values to be too high or too low. Therefore, erroneous judgment occurs when the finger is detected to be on or off the hand later.

Disclosure of Invention

In view of the above-mentioned problems of the prior art, the present invention provides a finger detecting method and an electronic device that can dynamically adjust the high threshold value and the low threshold value for detecting the upper hand or the lower hand of a finger.

A method of detecting on-finger and off-finger is provided according to an embodiment of the invention. The method for detecting the finger-on and finger-off can be applied to an electronic device comprising a fingerprint sensing device. The method for detecting the finger on and off the hand comprises the following steps: detecting whether a sensing capacitance average value of an input sensing signal is larger than a high threshold value or smaller than a low threshold value; when the average value of the sensing capacitance of the input sensing signal is larger than the high threshold value, judging that a finger is placed on the fingerprint sensing device, and adjusting the high threshold value and the low threshold value according to the average value of the sensing capacitance and a compensation value; and when the average value of the sensing capacitance of the input sensing signal is smaller than the lower threshold value, judging that the finger leaves the fingerprint sensing device, and adjusting the upper threshold value and the lower threshold value according to the average value of the sensing capacitance and the compensation value.

An electronic device is provided according to an embodiment of the invention. The electronic device comprises a fingerprint sensing device and a processor. The processor is coupled to the fingerprint sensing device. The processor detects whether a sensing capacitance average value of an input sensing signal is larger than a high threshold value or smaller than a low threshold value. When the average value of the sensing capacitance of the input sensing signal is larger than the high threshold value, the processor judges that a finger is placed on the fingerprint sensing device, and adjusts the high threshold value and the low threshold value according to the average value of the sensing capacitance and a compensation value. When the average value of the sensing capacitance of the input sensing signal is smaller than the lower threshold value, the processor judges that the finger leaves the fingerprint sensing device, and adjusts the upper threshold value and the lower threshold value according to the average value of the sensing capacitance and the compensation value.

Other additional features and advantages of the present invention will be set forth in part in the description which follows, and in part will be apparent to those having ordinary skill in the art from the description, or may be learned from practice of the invention.

Drawings

Fig. 1 is a block diagram of an electronic device 100 according to an embodiment of the invention.

Fig. 2A-2C are schematic diagrams of dynamically adjusting the high threshold value and the low threshold value according to an embodiment of the invention.

Fig. 3A-3B are flow diagrams 300 illustrating a method for detecting on-finger and off-finger according to an embodiment of the invention.

Description of reference numerals:

100 electronic device

110 fingerprint sensing device

120 processor

130 storage device

300 flow chart

M1, M2, M3, M4, M5, M6, M7, M8, M9 sense capacitance average

THH1, THH2, THH3, THH4, THH5, THH6, THH7, THH8, THH9 high threshold value

THL1, THL2, THL3, THL4, THL5, THL6, THL7, THL8, THL9 low threshold value

H high flag value

L Low flag value

HI high threshold interrupt signal

LI low threshold interrupt signal

Detailed Description

The best mode for carrying out the invention is set forth in this section for the purpose of illustrating the concepts of the invention and not for the purpose of limiting the scope of the invention as defined by the appended claims.

Fig. 1 is a block diagram of an electronic device 100 according to an embodiment of the invention. According to an embodiment of the present invention, the electronic device 100 may refer to an electronic device with fingerprint recognition function, such as: an electronic device such as a mobile phone, a smart phone, a tablet computer or a notebook computer. As shown in fig. 1, the electronic device 100 may include a fingerprint sensing device 110, a processor 120, and a storage device 130. The block diagram in fig. 1 is merely for convenience of illustrating the embodiments of the present invention, but the present invention is not limited thereto.

According to an embodiment of the present invention, the fingerprint sensing device 110 may comprise a sensing chip, but the present invention is not limited thereto. The sensing chip may include a sensing array. The sensing array may be formed by a plurality of sensing units arranged in a two-dimensional manner, and each sensing unit corresponds to a pixel (pixel). The storage device 130 is used for storing a high threshold and a low threshold.

Fig. 2A-2C are schematic diagrams of dynamically adjusting the high threshold value and the low threshold value according to an embodiment of the invention. As shown in fig. 2A-2C, according to the embodiment of the invention, before the electronic device 100 is shipped or at the first start-up, the processor 120 performs an initial calibration on the fingerprint sensing device 110 to obtain a sensed capacitance average value M1. Then, the processor 120 generates a high threshold THH1 and a low threshold THL1 according to the sensed capacitor average M1, wherein the high threshold THH1 is greater than the low threshold THL 1. In addition, according to the embodiment of the present invention, before the electronic device 100 leaves the factory or at the first time of booting, a high flag value H and a low flag value L are set to a first bit value (e.g., 0 or OFF). According to the embodiment of the present invention, when the high flag value H is set to the first bit value OFF, it indicates that no finger is placed ON the fingerprint sensing device 110, and when the high flag value H is set to a second bit value (e.g., 1 or ON), it indicates that the upper hand is detected, i.e., a finger is placed ON the fingerprint sensing device 110. When the low flag value L is set to the first bit value OFF, it indicates that the finger is not detected to leave the fingerprint sensing device 110, and when the low flag value L is set to a second bit value ON, it indicates that the finger is detected to leave the fingerprint sensing device 110.

According to the embodiment of the present invention, the high threshold THH1 is a high threshold for determining upper hand (finger-on), and the low threshold THL1 is a low threshold for determining away hand (finger-off). A high threshold may be used to determine that a finger is placed on the fingerprint sensing device 110 (i.e., upper hand), and a low threshold may be used to determine that a finger placed on the fingerprint sensing device 110 is off the fingerprint sensing device 110 (i.e., off hand).

According to an embodiment of the invention, the high threshold THH1 is generated by adding a compensation value Δ to the average value M1 of the sensing capacitance, and the low threshold THL1 is generated by subtracting a compensation value Δ from the average value M1 of the sensing capacitance. According to an embodiment of the invention, the compensation value Δ is a constant. The offset Δ is a fixed value that is preset before the electronic device 100 leaves the factory, and is greater than the noise value. For example, the noise value may refer to the fluctuation of the capacitance of the fingerprint sensing device 110 when the electronic device 100 is plugged or a radio frequency signal enters the electronic device 100, and thus the compensation value Δ may be the amplitude of the fluctuation of the capacitance of the fingerprint sensing device 110.

According to the embodiment of the invention, after the initial calibration, when the fingerprint sensing device 110 generates an input sensing signal (not shown), the processor 120 detects whether a sensing capacitance average value of the input sensing signal is greater than the high threshold THH1 or less than the low threshold THL1, so as to determine that the user is in the hand or out of the hand.

According to an embodiment of the present invention, when the average value of the sensing capacitance of the input sensing signal is greater than the high threshold THH1, the processor 120 further determines whether the high flag value H is a second bit value (e.g., 1 or ON). When the high flag value H is the second bit value ON, it indicates that a finger has been previously detected to be placed ON the fingerprint sensing device 110, and the processor 120 directly adjusts the high threshold THH1 and the low threshold THL1 according to the average value of the sensing capacitance.

When the high flag value H is the first bit value (e.g., 0 or OFF), it indicates that no finger has been previously detected as being placed on the fingerprint sensing device 110. Therefore, the processor 120 first determines whether the object placed on the fingerprint sensing device 110 is a real finger. If the finger is a real finger, as shown in FIG. 2A, the processor 120 will issue a high threshold interrupt signal HI to indicate that the upper hand is detected, i.e. that a finger is placed on the fingerprint sensing device 110. The processor 120 then sets the high flag value H to the second bit value ON (indicating a hands-ON), and maintains the low flag value L set to the first bit value OFF. The processor 120 then adjusts the upper threshold THH1 and the lower threshold THL1 according to the average value of the sensed capacitance. As shown in fig. 2A, the processor 120 adjusts the high threshold THH1 and the low threshold THL1 according to the average value M2 of the sensing capacitor to generate an adjusted high threshold THH2 and an adjusted low threshold THL 2.

In the above embodiment, for the non-finger object, taking fig. 2B as an example, the processor 120 does not send out the high threshold interrupt signal HI, but directly adjusts the high threshold THH1 and the low threshold THL1 according to the average value M4 of the sensing capacitance to generate the adjusted high threshold THH4 and the adjusted low threshold THL 4.

According to another embodiment of the present invention, when the average value of the sensing capacitance of the input sensing signal is smaller than the low threshold value THL1, the processor 120 determines whether the high flag value H is the second bit value (e.g., 1 or ON). When the high flag value H is the second bit value ON (indicating that the user has detected the previous hand), the processor 120 first issues a low threshold interrupt signal LI to indicate that the finger that detected the previous hand has left the fingerprint sensing device 110, sets the high flag value H to the first bit value (e.g., 0 or OFF), and sets the low flag value L to the second bit value ON to indicate that the user has detected the departure. The processor 120 then adjusts the upper threshold THH1 and the lower threshold THL1 according to the average value of the sensed capacitance. Taking fig. 2A as an example, when the sensed capacitance average M3 is less than the low threshold THL2, since the finger ON the fingerprint sensing device 110 (i.e. the upper hand) is detected when the capacitance average M2 is detected (therefore, the high flag H is set to the second bit value ON), the processor 120 will first issue a low threshold interrupt signal LI to indicate that the finger that detected the upper hand has left the fingerprint sensing device 110 (i.e. left), and set the high flag H to the first bit value OFF, and set the low flag L to the second bit value ON to indicate that the finger has left the fingerprint sensing device 110 (i.e. left the hand). The processor 120 then adjusts the high threshold THH2 and the low threshold THL2 according to the sensed capacitance average M3 to generate a high threshold THH3 and a low threshold THL 3.

In the above embodiment, when the high flag value H is the first bit value OFF, the processor 120 directly adjusts the high threshold THH and the low threshold THL according to the average value of the sensing capacitors. Taking fig. 2B as an example, when the sensed capacitance average M7 is smaller than the low threshold THL6, since the finger is detected to be away from the fingerprint sensing device 110 (i.e. the high flag H is set to the first bit value OFF) when the capacitance average M6 is detected, the processor 120 directly adjusts the high threshold THH6 and the low threshold THL6 according to the sensed capacitance average M7 to generate the high threshold THH7 and the low threshold THL 7.

According to another embodiment of the present invention, when it is determined that the high threshold and the low threshold need to be adjusted for the hands-off situation, the processor 120 dynamically and gradually adjusts the high threshold and the low threshold to avoid the auto-unlocking (auto-unlocking) situation. As shown in fig. 2C, when the high threshold THH8 and the low threshold THL8 need to be adjusted to the high threshold THH9 and the low threshold THL9, the processor 120 may dynamically and gradually adjust the high threshold THH8 and the low threshold THL8, instead of directly adjusting the high threshold THH8 and the low threshold THL8 to the high threshold THH9 and the low threshold THL 9.

According to the embodiment of the invention, the high threshold THH2 is generated by adding the sensing capacitance average M2 to the compensation value Δ, and the low threshold THL2 is generated by subtracting the sensing capacitance average M2 from the compensation value Δ. In analogy, the high threshold THH3 is the sensing capacitance average value M3+ the compensation value Δ; and the lower threshold THL3 is the sensing capacitance average M3-offset Δ. The high threshold THH4 is the sensing capacitance average M4+ the compensation value Δ; and the lower threshold THL4 is the sensing capacitance average M4-offset Δ. The high threshold THH5 is the sensing capacitance average M5+ the compensation value Δ; and the lower threshold THL5 is the sensing capacitance average M5-offset Δ. The high threshold THH6 is the sensing capacitance average M6+ the compensation value Δ; and the lower threshold THL6 is the sensing capacitance average M6-offset Δ. The high threshold THH7 is the sensing capacitance average M7+ the compensation value Δ; and the lower threshold THL7 is the sensing capacitance average M7-offset Δ. The high threshold THH8 is the sensing capacitance average M8+ the compensation value Δ; and the lower threshold THL8 is the sensing capacitance average M8-offset Δ. The high threshold THH9 is the sensing capacitance average M9+ the compensation value Δ; and the lower threshold THL9 is the sensing capacitance average M9-offset Δ.

Fig. 3A-3B are a flowchart 300 of a method for detecting on-finger and off-finger according to an embodiment of the invention, which is applied to the electronic device 100. As shown in fig. 3A-3B, first, in step S310, the fingerprint sensing device 110 of the electronic device 100 is activated. In step S320, a high flag value H and a low flag value L are set as a first bit value (e.g., 0 or OFF), the fingerprint sensing device 110 is calibrated to obtain a sensed capacitance average M1, the sensed capacitance average M1 is added with a compensation value Δ to generate a high threshold THH1, and the sensed capacitance average M1 is subtracted with the compensation value Δ to generate a low threshold THL1, wherein the high threshold THH1 is greater than the low threshold THL 1. The compensation value Δ is pre-stored in the storage device 130 of the electronic device 100 before the electronic device 100 is shipped from the factory.

When the high flag value H is set to the first bit value OFF, it indicates that no finger is placed ON the fingerprint sensing device 110, and when the high flag value H is set to a second bit value (e.g., 1 or ON), it indicates that a top hand is detected, i.e., a finger is placed ON the fingerprint sensing device 110. When the low flag value L is set to the first bit value OFF, it indicates that the finger is not detected to leave the fingerprint sensing device 110, and when the low flag value L is set to a second bit value ON, it indicates that the finger is detected to leave the fingerprint sensing device 110.

In step S330, it is detected whether the average value M of the sensing capacitances of the input sensing signals is greater than the high threshold THH or less than the low threshold THL. When the average value M of the sensing capacitances of the input sensing signals is greater than the high threshold value THH, step S340 is performed. In step S340, it is determined whether the high flag value H is a second bit value (e.g., 1 or ON). When the high flag value H is the second bit value ON (indicating that the previous hand has been detected), step S350 is performed. In step S350, the high threshold THH and the low threshold THL are adjusted according to the average value M of the sensing capacitors to generate an adjusted high threshold THH and an adjusted low threshold THL. The adjusted high threshold THH is the average value M of the sensing capacitors plus a compensation value Δ, and the adjusted low threshold THL is the average value M of the sensing capacitors minus the compensation value Δ.

When the high flag value H is the first bit value OFF (indicating that the previous hand is not detected), step S360 is performed. In step S360, it is determined whether the object placed on the fingerprint sensing device 110 is a real finger. If the finger is a real finger, the process proceeds to step S370. In step S370, a high threshold interrupt signal HI is asserted to indicate that a finger is detected to be placed ON the fingerprint sensing device 110 (upper hand), and the high flag value H is set to the second bit value ON and the low flag value L is maintained to be set to the first bit value OFF. Next, step S350 is performed to adjust the high threshold THH and the low threshold THL according to the average value M of the sensing capacitors. If the object is not a finger, step S350 is performed directly, and the high threshold THH and the low threshold THL are adjusted according to the average value M of the sensing capacitance.

When the average value M of the sensing capacitances of the input sensing signals is less than the lower threshold value THL, step S380 is performed. In step S380, it is determined whether the high flag value H is a second bit value (e.g., 1 or ON). When the high flag value H is the second bit value ON (indicating that the upper hand has been detected), step S390 is performed. In step S390, a low threshold interrupt signal LI is issued to indicate that the finger of the previous hand has been detected to leave the fingerprint sensing device 110 (i.e. the case of the detected hand leaving), and the high flag H is set to the first bit value OFF (indicating that the hand has not been detected), and the low flag L is set to the second bit value ON (indicating that the hand has been detected). Next, step S350 is performed to adjust the high threshold THH and the low threshold THL according to the average value M of the sensing capacitors. When the high flag value H is the first bit value OFF (indicating that the previous hand is not detected and therefore there is no case of leaving the hand), step S350 is directly performed.

The method for detecting the upward and downward movement of the finger and the electronic device 100 according to the embodiment of the invention can be dynamically adjusted to determine the upper and downward threshold values of the upward and downward movement of the finger. Therefore, even if the upper threshold and the lower threshold generated by the fingerprint sensing device 110 during the initial calibration are incorrect (e.g., the hand or other object is placed on the fingerprint sensing device 110 by mistake during the initial calibration, which causes the upper threshold and the lower threshold to be too high or too low), the electronic device 100 can improve the accuracy of determining the upper and lower finger thresholds by dynamically adjusting the upper and lower threshold for determining the upper and lower finger thresholds.

The steps of the methods and algorithms disclosed in the present specification may be implemented directly in hardware, in a software module, or in a combination of the two by executing a processor. A software module (including executable instructions and associated data) and other data may be stored in a data memory such as Random Access Memory (RAM), flash memory (flash memory), Read Only Memory (ROM), Erasable Programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), registers, hard disk, portable diskette, compact disk read only memory (CD-ROM), DVD, or any other computer readable storage media format known in the art. A storage medium may be coupled to a machine, such as, for example, a computer/processor (which may be referred to herein as a processor for convenience of description), which may read information (such as program code) from, and write information to, the storage medium. A storage medium may incorporate a processor. An Application Specific Integrated Circuit (ASIC) includes a processor and a storage medium. A user equipment includes an ASIC. In other words, the processor and the storage medium are embodied in the user equipment without being directly connected to the user equipment. In addition, in some embodiments, any suitable computer program product includes a readable storage medium including program code associated with one or more of the disclosed embodiments. In some embodiments, the product of the computer program may include packaging materials.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, but does not mean that they are present in every embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment of the invention.

The above paragraphs use various levels of description. It should be apparent that the teachings herein may be implemented in a wide variety of ways and that any specific architecture or functionality disclosed in the examples is merely representative. Any person skilled in the art will appreciate, based on the teachings herein, that each of the layers disclosed herein can be implemented independently or that more than two layers can be implemented in combination.

Although the present invention has been described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for detecting finger on-hand and off-hand is applied to an electronic device, which comprises a fingerprint sensing device, and comprises the following steps:

detecting whether a sensing capacitance average value of an input sensing signal is larger than a high threshold value or smaller than a low threshold value;

when the average value of the sensing capacitance of the input sensing signal is larger than the high threshold value, judging that a finger is placed on the fingerprint sensing device, and adjusting the high threshold value and the low threshold value according to the average value of the sensing capacitance and a compensation value; and

when the average value of the sensing capacitance of the input sensing signal is smaller than the lower threshold value, determining that the finger leaves the fingerprint sensing device, and adjusting the upper threshold value and the lower threshold value according to the average value of the sensing capacitance and the compensation value,

wherein the upper threshold is the average value of the sensing capacitance plus the compensation value, and the lower threshold is the average value of the sensing capacitance minus the compensation value.

2. The method of claim 1, wherein the offset is a fixed value that is preset before the electronic device leaves factory and is greater than a noise value.

3. The method of detecting on-finger and off-finger of claim 1, further comprising:

starting the fingerprint sensing device;

calibrating the fingerprint sensing device to obtain the average value of the sensing capacitance;

generating the high threshold value and the low threshold value according to the average value of the sensing capacitors; and

setting a high flag value and a low flag value to a first bit value, wherein the setting of the high flag value to the first bit value indicates that no finger is detected to be placed on the fingerprint sensing device and the setting of the low flag value to the first bit value indicates that no finger is detected to be removed from the fingerprint sensing device.

4. The method of detecting on-finger and off-finger of claim 1, further comprising:

when the average value of the sensing capacitors of the input sensing signals is larger than the high threshold value, judging whether a high flag value is a first bit value;

when the high flag value is the first bit value, determining whether the object on the fingerprint sensing device is a real finger; and

if the finger is true, a high threshold interrupt signal is issued to indicate that a finger is detected to be placed on the fingerprint sensing device, and the high flag value is set to a second bit value and a low flag value is set to the first bit value.

5. The method of detecting on-finger and off-finger of claim 1, further comprising:

when the average value of the sensing capacitance of the input sensing signal is smaller than the lower threshold value, judging whether a high flag value is a first bit value; and

when the high flag value is not the first bit value, a low threshold interrupt signal is asserted, and the high flag value is set as the first bit value and a low flag value is set as a second bit value.

6. The method of claim 1, wherein the step of adjusting the upper threshold and the lower threshold according to the average value of the sensed capacitance and the compensation value comprises:

the upper threshold value is set to the average value of the sensing capacitance plus the compensation value and the lower threshold value is set to the average value of the sensing capacitance minus the compensation value.

7. The method of claim 1, wherein the step of adjusting the upper threshold and the lower threshold according to the average value of the sensed capacitance and the compensation value comprises:

dynamically and gradually adjusting the high threshold to the average value of the sensing capacitance plus the compensation value, an

Dynamically and gradually adjusting the lower threshold value to the average value of the sensing capacitance minus the compensation value.

8. An electronic device, comprising:

a fingerprint sensing device; and

a processor coupled to the fingerprint sensing device for detecting whether a sensed capacitance average value of an input sensing signal is greater than a high threshold value or less than a low threshold value,

wherein when the average value of the sensing capacitances of the input sensing signals is greater than the high threshold value, the processor determines that a finger is placed on the fingerprint sensing device, and adjusts the high threshold value and the low threshold value according to the average value of the sensing capacitances and a compensation value; and

wherein when the average value of the sensing capacitance of the input sensing signal is smaller than the lower threshold value, the processor determines that the finger leaves the fingerprint sensing device, and adjusts the upper threshold value and the lower threshold value according to the average value of the sensing capacitance and the compensation value,

9. The electronic device of claim 8, wherein the offset value is a fixed value that is preset before the electronic device leaves the factory and is greater than a noise value.

10. The electronic device of claim 8, wherein the processor calibrates the fingerprint sensing device to obtain the average value of the sensing capacitance when the fingerprint sensing device is activated, and the processor generates the high threshold and the low threshold based on the average value of the sensing capacitance, and the processor sets a high flag value and a low flag value to a first bit value, wherein the setting of the high flag value to the first bit value indicates that no finger is detected to be placed on the fingerprint sensing device, and the setting of the low flag value to the first bit value indicates that no finger is detected to be removed from the fingerprint sensing device.

11. The electronic device of claim 8, wherein when the average value of the sensing capacitance of the input sensing signal is greater than the high threshold, the processor further determines whether a high flag is a first bit value; when the high flag value is the first bit value, the processor further determines whether the object on the fingerprint sensing device is a real finger, and if so, the processor sends a high threshold interrupt signal to indicate that a finger is detected to be placed on the fingerprint sensing device, and sets the high flag value as a second bit value and sets a low flag value as the first bit value.

12. The electronic device of claim 8, wherein the processor further determines whether a high flag is a first bit when the average value of the sensing capacitances of the input sensing signal is less than the low threshold, and the processor issues a low threshold interrupt signal when the high flag is not the first bit, sets the high flag to the first bit, and sets a low flag to a second bit.

13. The electronic device of claim 8, wherein the processor adjusts the upper threshold and the lower threshold based on the average sensed capacitance and the offset by setting the upper threshold as the average sensed capacitance plus the offset and setting the lower threshold as the average sensed capacitance minus the offset.

14. The electronic device of claim 8, wherein the processor adjusts the high threshold and the low threshold based on the average sensed capacitance and the compensation value by dynamically and gradually adjusting the high threshold to the average sensed capacitance plus the compensation value and dynamically and gradually adjusting the low threshold to the average sensed capacitance minus the compensation value.