TWI547847B - Method for determining a touch object is touched on a touch operating area and optical touch system thereof - Google Patents

Description

Method for determining a touch object contacting a touch operation area and optical touch system thereof

The present invention relates to an optical touch system and a method thereof, and more particularly to a method for determining a touch object contacting a touch operation area and an optical touch system thereof.

In today's reflective optical touch system, after the light-emitting element emits a light source, the image capturing device captures the current ambient light source signal (also referred to as an image signal), and the system determines and touches according to the reflected light path of the touch object. Control whether there is a touch point in the operation area. However, in determining whether a touch point exists or not, a threshold value (also referred to as Tss) of image signal strength is usually set. When the image signal strength of a certain segment in the image signal is higher than Tss, the system will judge the presence of the touch point, as shown in Fig. 1.

When the touch object touches the touch operation area, due to the optical reflection principle, the touch object reflects all the light paths passing through the front end of the touch object, thereby forming an upward convex signal (ie, touch) in the image signal. The phenomenon caused by the object's reflected light source). By comparing the glitch signal with Tss, the presence or absence of the touch point can be judged. However, in practical applications, the strength of the spur signal (ie, the height of the spur signal swell) may be affected by the angle at which the touch object contacts the touch operation area, such as 2A~2B shown in the figure.

When the touch object 210 is illuminated by the light-emitting element 230 on the same touch point A of the touch operation area 220, the light path is reflected back to the image capturing device 240 due to the different tilt angles of the touch object 210. The number is also different, resulting in different spur signal strength. After the actual operation and measurement, it is found that when the angle between the touch object 210 and the touch operation area 220 is 90 degrees, there is a strong spur signal, as shown in FIG. 2A. Conversely, when the angle between the touch object 210 and the touch operation area 220 is small, the intensity of the spur signal is weaker, as shown in FIG. 2B. In FIG. 2B, the system determines that the touch point of the touch object 210 on the touch operation area 220 does not exist because the intensity of the spur signal cannot reach the threshold of the Tss. If the Tss value is set to a lower threshold, a too low Tss value can easily misidentify the noise or the slight interference of the environment as a touch signal. Therefore, in practical use, if a single fixed Tss value is used, it will cause inconvenience in the above situation.

Therefore, a method for determining a touch object contacting a touch operation area and an optical touch system thereof are needed to solve the problem caused by a single Tss value.

The present invention provides a method for determining a touch object contacting a touch operation area, the method comprising: setting a plurality of light emitting elements for emitting a light source in a touch operation area; and providing an image capture device in the touch operation area, For capturing an image caused by a touch object, at least one optical reflector is disposed in the touch operation area for reflecting light emitted by the light emitting element to the image capturing device; and processing by an image After acquiring the image by the image capturing device, the device obtains a first image capturing path and a second image capturing path according to the image. Obtaining an inclination angle of the touch object in the touch operation area according to the first oscillating signal and the second spur signal of the first image capturing path and the second image capturing path And obtaining a threshold corresponding to the tilt angle from a storage module, comparing the first spur signal and the threshold value to determine whether a touch point of the touch object exists.

In some embodiments, before the taking out the first image capturing path and the second image capturing path, the method further includes the following steps: converting the image into a plurality of image capturing paths by the image processing device. The image signal is selected, and the image capturing path with the strongest image signal is selected as the first image capturing path. In some embodiments, the second image taking path is a predetermined distance from the first image taking path. In some embodiments, after the image capturing device obtains the image, the method further includes the following steps: determining, by the image processing device, whether the touch object is close to the touch operation area according to a noise threshold The value determines whether the touch object is close to the touch operation area. In some embodiments, the method further includes: storing a threshold comparison table by using a storage module; wherein the threshold value comparison table is used to record a correspondence between different inclination angles and threshold values. In some embodiments, the image is a two-dimensional image, and the image signal is a one-dimensional image signal. In some embodiments, in the embodiment, the tilt angle is an angle between the touch object and one of the touch operation areas.

The invention provides an optical touch system, comprising: a touch operation area, a plurality of light-emitting elements, an image capturing device, at least one optical reflector and an image processing device. The plurality of light-emitting elements are disposed at a periphery of the touch operation area for emitting a light source. The image capturing device is disposed at a periphery of the touch operation area for capturing an image caused by a touch object. At least the above An optical reflection system is disposed at a periphery of the touch operation area for reflecting light emitted by the light emitting element to the image capturing device. The image processing device is coupled to the image capturing device. After the image capturing device obtains the image, the first image capturing path and the second image capturing path are obtained according to the image, and the touch object is used according to the touch object. The first image capturing path and the second image capturing path form a first spur wave signal and a second spur wave signal to obtain an inclination angle of the touch object in one of the touch operation areas, and a storage mode A threshold value corresponding to the tilt angle is obtained in the group, and the first spur signal and the threshold value are compared to determine whether a touch point of the touch object exists.

In some embodiments, the image processing apparatus is configured to take out the above Before the first image capturing path and the second image capturing path, the image is converted into an image signal composed of a plurality of image capturing paths, and an image capturing path with the strongest image signal is selected as the first image capturing path. In some embodiments, the second image capturing path is spaced apart from the first image capturing path by a predetermined distance. In some embodiments, after the image capturing device obtains the image, the image processing device further determines whether the touch object is close to the touch operation area according to a noise threshold. In some embodiments, the image processing apparatus further includes: the storage module, storing a threshold comparison table; wherein the threshold comparison table is used to record a correspondence between different tilt angles and threshold values. In some embodiments, the image is a two-dimensional image, and the image signal is a one-dimensional image signal. In some embodiments, the tilt angle is an angle between the touch object and one of the touch operation areas.

The above and other objects, features and advantages of the present invention will become more <RTIgt; described as follows.

Tss‧‧‧Impact signal strength threshold

A‧‧‧ touch point

210‧‧‧ touch object

220‧‧‧Touch operation area

230‧‧‧Lighting elements

240‧‧‧Image capture device

300‧‧‧Optical touch system

310‧‧‧Touch operation area

322, 324‧‧‧Lighting elements

332, 334‧‧‧ image capture device

340‧‧‧Optical reflector

350‧‧‧Image Processing Unit

352‧‧‧Storage Module

354‧‧‧Processing module

500‧‧‧2D image

510‧‧‧first image path

520‧‧‧Second image path

A‧‧‧ first glitch signal

B‧‧‧second glitch signal

θ _ab ‧‧‧ angle

600‧‧‧ method flow chart

S605, S610, S615, S620, S625‧‧ steps

The first figure shows a schematic diagram of the principle of determining a touch point.

2A-2B shows a schematic diagram of different tilt angles of a touch object in a touch operation area.

FIG. 3 is a schematic diagram of an optical touch system according to an embodiment of the invention.

FIG. 4 is a functional block diagram showing an image processing apparatus according to an embodiment of the invention.

FIG. 5A is a schematic diagram showing a two-dimensional image according to an embodiment of the invention.

FIG. 5B is a schematic diagram showing a one-dimensional image signal according to an embodiment of the invention.

FIG. 6 is a flow chart showing a method for determining that a touch object contacts a touch operation area according to an embodiment of the invention.

In order to make the objects, features, and advantages of the present invention more comprehensible, the preferred embodiments of the invention are described in the accompanying drawings. This description provides different embodiments to illustrate the technical features of the various embodiments. The configuration of each component in the embodiments is for illustrative purposes and is not intended to limit the present invention. The overlapping portions of the drawings in the embodiments are for the purpose of simplifying the description and are not intended to be related to the different embodiments.

Please refer to FIG. 3, which is one of the embodiments of the present invention. A schematic diagram of an optical touch system 300. As shown in FIG. 3 , the optical touch system 300 includes a touch operating area 310 , light emitting elements 322 and 324 , image capturing devices 332 and 334 , at least one optical reflector 340 , and an image processing device 350 .

The touch operation area 310 is used by the user for using a touch object. Touch operation. The light-emitting elements 322 and 324 are disposed at the periphery of the touch operation area 310 for emitting a light source. As shown in FIG. 3, the positions of the light-emitting elements 322 and 324 can correspond to the image capturing devices 332 and 334, respectively. The image capturing devices 332 and 334 are disposed around the touch operating area 310 for capturing an image of a touch object (eg, a stylus, a reflective pen). As shown in FIG. 3, the image capturing devices 332 and 334 are respectively disposed at the upper left corner and the upper right corner of the touch operating area 310, and the angle of the display is based on the image of the touch operating area 310. The optical reflector 340 is disposed at the periphery of the touch operation area 310 for reflecting the light emitted by the light-emitting elements 322 and 324 to the image capturing devices 332 and 334. As shown in FIG. 3, the optical reflector 340 can be disposed on both sides and the bottom of the touch operation area 310, and the optical reflector 340 is preferably a single-spectrum light-transmitting material, a light-mixing material or a reflective material. The light-emitting elements 322 and 324 preferably emit invisible light, for example, infrared light, and the image capturing devices 332 and 334 capture a two-dimensional image, which may be an invisible light image, for example, an infrared light image.

Next, please refer to FIG. 4, which is the image processing device of FIG. Functional block diagram of 350. The image processing device 350 is disposed on the touch operation area 310 and coupled to the image capturing devices 332 and 334. As shown in FIG. 4, the image processing device 350 includes a storage module 352 and a processing module 354. The image processing device 350 can be a hardware, a software, or a firmware. Image calculation processing. The storage module 352 is configured to store a threshold comparison table for recording the correspondence between different tilt angles and threshold values of the touch objects in the touch operation area 310.

First, the processing module 354 is taken by the image capturing devices 332 and 334. An image is obtained, wherein the image is a two-dimensional image. The processing module 354 first determines whether the touch object is close to the touch operation area 310 according to a noise threshold value. If the processing module 354 determines that the touch object is not in the touch operation area 310, it is determined that the image is caused by noise, and thus the image is not subsequently processed. If the processing module 354 determines that the touch object approaches the touch operation area 310, the two-dimensional image is converted into an image signal composed of a plurality of image capturing paths by using a conversion technique, and the image with the strongest image signal is selected. The path acts as a first image capture path. The processing module 354 then sets the image capturing path at a predetermined distance from the first image capturing path as a second image capturing path. Then, the processing module 354 obtains the tilt angle of the touch object in the touch operation area 310 according to the first glitch signal and the second glitch signal of the touch object in the first image capturing path and the second image capturing path. The tilt angle is an angle between the touch object and the touch operation area 310. The processing module 354 then obtains a threshold corresponding to the tilt angle according to the threshold value comparison table stored in the storage module 352. Finally, the processing module 354 compares the first spur signal and the threshold corresponding to the tilt angle to determine whether a touch point of the touch object exists.

As an example, FIG. 5A is an image capturing device 332 and The 334 picks up a touch object and touches the two-dimensional image of the touch operation area. The processing module 354 converts the two-dimensional image into a one-dimensional image signal composed of a plurality of image capturing paths by using a conversion technique as shown in FIG. 5B. The image capturing path with the strongest image signal is selected as a first image capturing path 510. Processing module 354 then The image capturing path at a predetermined distance from the first image capturing path is set as a second image capturing path 520.

The processing module 354 obtains the first spurt signal A and the second spur signal B of the touch object in the first image capturing path 510 and the second image capturing path 520 by processing the one-dimensional image signal, and calculates and obtains a first A spur signal coordinate (Xa, Ya) and a second spur signal coordinate (Xb, Yb). The processing module 354 can calculate the angle θ _ab between the first spur signal A and the second spur signal B and the touch operation area 310 by using the following formula (ie, the tilt angle of the touch object in the touch operation area): However, the operation of processing the angle θ _ab wastes a lot of performance. Based on the principle of linear proportional, the slope of the first spur signal A and the second spur signal B can be used instead of the angle θ _ab to avoid excessive operation. The sub is |(Xa-Xb)/(Ya-Yb)|.

In addition, the processing module 354 can pre-calculate the appropriate threshold value Tss corresponding to the angle θ _ab at each preset angle, and record it in the threshold value comparison table in the storage module 352. For example, the processing module 354 can preliminarily extract the set of reference bursts for each tilt angle by tilting the intensity of the weakest signal at each angle of a touch point in the touch operation area via a software-sensing touch object. The wave signal strength value (S00~S90), and defines half of its intensity as the signal strength threshold Tss. The threshold value comparison table is shown in Table 1:

Table 1 shows the intensity of the spurt signal at various angles of 0 ≦ θ _ab ≦ 90 at a touch point (for example, a touch point A) of the touch object. In this example, the angles of only 10 degrees are taken as an example, and the threshold value Tss of each angle is half of the intensity of the spur signal. It should be noted that the above threshold value Tss may vary depending on the requirements of the system, and is not limited to the contents of the present specification. It can be understood that Table 1 only lists the partial table of a single touch point. If the tilt angle is 1 degree as the minimum unit, the table of each touch point will have 90 columns and 3 columns, and each touch point There are also corresponding tables, and the values in the table are not the same for each touch point.

FIG. 6 is a flow chart 600 showing a method for determining a touch object contacting a touch operation area according to an embodiment of the invention, the method being used for an optical touch system. In step S605, an image capturing device captures an image caused by a touch object in a touch operation area. In step S610, an image processing device determines whether the touch object is close to the touch operation area according to a noise threshold. If the image processing device determines that the touch object is not in the touch operation area (NO in step S610), the flow returns to S605, and the image capture device retrieves the new image.

If the image processing device determines that the touch object is close to the touch operation When the area is in the process (Yes in step S610), in step S615, the image processing apparatus obtains a first image capturing path and a second image capturing path according to the image, and the first object is based on the touch object. And taking a first spur signal and a second spur signal of the image capturing path and the second image capturing path to obtain an inclination angle of the touch object in one of the touch operation areas. Next, in step S620, the image processing device obtains a threshold corresponding to the tilt angle from a storage module. Finally, in step S625, the image processing device compares the first spur signal and the threshold to determine whether a touch point of the touch object exists.

In summary, the present invention determines that a touch object contacts a touch operation. The method of the area and the optical touch system can take two image capturing paths to discriminate whether the touch object is tilted, and use different threshold values according to different tilt angles of the touch object. Therefore, the problem of judging the touch points brought by the touch object at different tilt angles can be solved.

The above embodiments are described using a variety of angles. Obviously the teaching here It can be presented in a variety of ways, and any particular architecture or function disclosed in the examples is only a representative one. In light of the teachings herein, anyone skilled in the art will appreciate that the content presented herein can be independently rendered in various different types or in a variety of different forms. By way of example, it may be implemented by some means or by some means in any manner as mentioned in the foregoing. The implementation of one device or the execution of one mode may be implemented in any one or more of the types discussed above with any other architecture, or functionality, or architecture and functionality.

Those skilled in the art will appreciate that various illustrative logic blocks, modules, processors, devices, circuits, and calculation steps are described herein. Electronic hardware that can be used in various situations (such as digital implementations using source coding or other techniques, analog implementations, or a combination of both), various forms of programming, or design codes linked to instructions (in the text) For convenience, it is called "software" or "software module", or a combination of the two. To clearly illustrate the interchangeability of the hardware and software, a variety of descriptive elements, blocks, modules, circuits, and steps are generally described above in terms of functionality. Whether this feature is presented in hardware or software, it will depend on the specific application and design constraints imposed on the overall system. The person skilled in the art can implement the described functions in a variety of different ways for each particular application, but the implementation of this decision should not be interpreted as deviating from the scope disclosed herein.

In addition, a variety of illustrative logic blocks, modules, and power The roads and the various aspects disclosed herein may be implemented in an integrated circuit (IC), an access terminal, an access point, or by an integrated circuit, an access terminal, or an access point. The integrated circuit can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or the like. Programmable logic device, discrete gate or transistor logic, discrete hardware components, electronic components, optical components, mechanical components, or any combination of the above to perform the functions described herein And may execute an execution code or instruction that exists in the integrated circuit, outside the integrated circuit, or both. A general purpose processor may be a microprocessor, but could be any conventional processor, controller, microcontroller, or state machine. The processor may be composed of a combination of computer devices, such as a combination of a digital signal processor (DSP) and a microcomputer, a plurality of sets of microcomputers, a group of at most groups Microcomputer and a digital signal processor core, or any other similar configuration.

Any specific sequence or layering step of the procedure disclosed herein is pure For an example way. Based on design preferences, it must be understood that any specific order or hierarchy of steps in the program may be rearranged within the scope of the disclosure. The accompanying claims are therefore to be construed in a contin

The "first" and "first" used to modify components in the scope of patent application The use of ordinal numbers, etc., does not imply any prioritization, prioritization, ordering between the various elements, or the order of the steps to be performed by the method, but only as an identifier to distinguish between different elements having the same name (with different ordinal numbers) .

Although the disclosure has been described above by way of example, it is not intended to limit the scope of the present invention, and the scope of protection of the present invention can be made without departing from the spirit and scope of the disclosure. This is subject to the definition of the scope of the patent application.

600‧‧‧ method flow chart

S605, S610, S615, S620, S625‧‧ steps

Claims (16)

A method for determining a touch object contacting a touch operation area, the method comprising: setting a plurality of light-emitting elements for emitting a light source in a touch operation area; and providing an image capture device in the touch operation area for Taking an image caused by a touch object; providing at least one optical reflector in the touch operation area for reflecting light emitted by the light emitting element to the image capturing device; and by using an image processing device After the image capturing device obtains the image, the first image capturing path and the second image capturing path are obtained according to the image, and the touch object is in the first image capturing path and the second image capturing path according to the touch object. a spur wave signal and a second spur wave signal, obtaining an inclination angle of the touch object in the touch operation area, and obtaining a threshold value corresponding to the tilt angle from a storage module, comparing the first protrusion The wave signal and the threshold value determine whether the touch point of one of the touch objects exists. The method for determining a touch object contacting a touch operation area according to the first aspect of the patent application, wherein before the taking out the first image taking path and the second image taking path, the method further comprises the steps of: The image processing device converts the image into an image signal composed of a plurality of image capturing paths, and selects an image capturing path with the strongest image signal as the first image capturing path. The method for determining a touch object contacting a touch operation area according to the second aspect of the patent application, wherein the second image taking path is at a predetermined distance from the first image taking path. The method for determining a touch object to touch a touch operation area according to the first aspect of the patent application, wherein the image capture device obtains the image, further comprising the following steps: according to the image processing device, according to a noise The threshold value determines whether the touch object is close to the touch operation area. The method for determining a touch object contacting a touch operation area as described in claim 1 further includes: storing a threshold value comparison table by using a storage module; wherein the threshold value comparison table is used to record different The relationship between the tilt angle and the threshold value. A method for determining a touch object contacting a touch operation area as described in claim 2, wherein the image is a two-dimensional image, and the image signal is a one-dimensional image signal. The method of determining a touch object contacting a touch operation area according to the first aspect of the patent application, wherein the tilt angle is an angle between the touch object and one of the touch operation areas. The method for determining that a touch object contacts a touch operation area, as described in claim 6, further comprising: obtaining, by the image processing device, the first spur signal and the second spur signal a spur signal coordinate (Xa, Ya) and a second spur signal coordinate (Xb, Yb), and the above angle θ _ab is An optical touch system includes: a touch operation area; a plurality of light-emitting elements are disposed at a periphery of the touch operation area for emitting a light source; an image capture device is disposed around the touch operation area for capturing an image caused by a touch object; The at least one optical reflector is disposed at a periphery of the touch operation area for reflecting light emitted by the light emitting element to the image capturing device; and an image processing device coupled to the image capturing device, After the image capturing device obtains the image, the first image capturing path and the second image capturing path are obtained according to the image, and the touch object is in the first image capturing path and the second image capturing path according to the touch object. a first glitch signal and a second glitch signal, obtaining an inclination angle of the touch object in the touch operation area, and obtaining a threshold corresponding to the tilt angle from a storage module, comparing the first A glitch signal and the threshold value are used to determine whether a touch point of the touch object exists. The optical touch system of claim 9, wherein the image processing device converts the image into a plurality of image taking paths before taking out the first image capturing path and the second image capturing path. The image signal is composed, and the image capturing path with the strongest image signal is selected as the first image capturing path. The optical touch system of claim 10, wherein the second image taking path is at a predetermined distance from the first image capturing path. The optical touch system of claim 9, wherein the image capturing device is further configured according to the image capturing device The noise threshold value determines whether the touch object is close to the touch operation area. The optical touch system of claim 9, wherein the image processing device further comprises: the storage module, storing a threshold comparison table; wherein the threshold value comparison table is used to record different tilt angles and thresholds. The corresponding relationship of values. The optical touch system of claim 10, wherein the image is a two-dimensional image, and the image signal is a one-dimensional image signal. The optical touch system of claim 9, wherein the tilt angle is an angle between the touch object and one of the touch operation areas. The optical touch system of claim 14, wherein the image processing device calculates a first spur signal coordinate (Xa, Ya) according to the first glitch signal and the second glitch signal. a second spur signal coordinate (Xb, Yb), and the above angle θ _ab is