Method and system for estimating the tendency of pressure change on a touch panel

A method and a system for estimating the tendency of pressure change on a touch panel are disclosed. The method includes: getting first left-image data and first right-image data by using a left image-capturing device and a right image-capturing device at a first time, respectively; calculating first estimation pressed-area parameter according to the first left-image data and the first right-image data; getting second left-image data and second right-image data by using the left image-capturing device and the right image-capturing device at a second time, respectively; calculating second estimation pressed-area parameter according to the second left-image data and the second right-image data; and compare the first estimation pressed-area parameter with the second estimation pressed-area parameter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for estimating the tendency of pressure change; more particularly, the present invention relates to a method for estimating the tendency of pressure change on a touch panel.

2. Description of the Related Art

With the high-speed development of technology, more and more touch control products enter our lives. Generally speaking, smart phones, digital cameras, computers and televisions sold in the market today are appealed to be equipped with touch control function as one of their features. However, when a user touches a screen, the user would always expect a specific physical reaction generated after the screen is touched, such as screen depression at the time the screen is being pressed.

In order to solve the abovementioned problem, in known prior arts, visual or audio effects are utilized as assistance. For example, at the time the screen is being pressed, a visual effect of screen depression is displayed, or an audio effect of a keyboard sound effect is generated, such that the user can experience the interaction with the screen.

However, touch control belongs to a touch action, therefore the best way for interaction is to generate different feedback effects according different pressure force levels, so as to directly satisfy the user's expectation through “haptics”, such that the user can directly feel it when manipulating the system or product. The key point of providing the haptic effect is to identify the pressure that the user applies on the touch screen. If the pressure increases, the haptic effect increases accordingly; if the pressure decreases, the haptic effect decreases accordingly.

In known prior arts, generally an additional pressure sensor is used for sensing the tendency of pressure change. However, the cost would increase because of adding the pressure sensor. Therefore, there is a need to provide a method and system for estimating the tendency of pressure change on a touch panel to mitigate and/or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method for estimating the tendency of pressure change on a touch panel.

To achieve the abovementioned object, the method for estimating the tendency of pressure change on a touch panel of the present invention is used in an optically-detected input image system. The optically-detected input image system comprises a left image-capturing device and a right image-capturing device for detecting a position touched on an image screen by a user. The method for estimating the tendency of pressure change on a touch panel comprises the following steps: at a first time, obtaining first left image data by using the left image-capturing device, and obtaining first right image data by using the right image-capturing device; calculating a first estimated pressed-area parameter according to the first left image data and the first right image data; at a second time, obtaining second left image data by using the left image-capturing device, and obtaining second right image data by using the right image-capturing device; calculating a second estimated pressed-area parameter according to the second left image data and the second right image data; and comparing the first estimated pressed-area parameter with the second estimated pressed-area parameter. According to the abovementioned steps, if the second estimated pressed-area parameter is greater than the first estimated pressed-area parameter, the method determines the user increases a touch pressure on the image screen from the first time to the second time. If the second estimated pressed-area parameter is less than the first estimated pressed-area parameter, the method determines the user decreases the touch pressure on the image screen from the first time to the second time.

It is another object of the present invention to provide a system for estimating the tendency of pressure change on a touch panel, so as to determine the change of a touch pressure applied on an image screen by a user.

To achieve the abovementioned object, the system for estimating the tendency of pressure change on a touch panel of the present invention comprises a left image-capturing device, a right image-capturing device and a processor. The left image-capturing device is used for obtaining first left image data at a first time, and for obtaining second left image data at a second time. The right image-capturing device is used for obtaining first right image data at the first time, and for obtaining second right image data at the second time. The processor is used for: calculating a first estimated pressed-area parameter according to the first left image data and the first right image data; calculating a second estimated pressed-area parameter according to the second left image data and the second right image data; and comparing the first estimated pressed-area parameter with the second estimated pressed-area parameter for performing one of the following mechanisms: if the second estimated pressed-area parameter is greater than the first estimated pressed-area parameter, the system determines the user increases the touch pressure on the image screen from the first time to the second time; and if the second estimated pressed-area parameter is less than the first estimated pressed-area parameter, the system determines the user decreases the touch pressure on the image screen from the first time to the second time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer toFIG. 1, which illustrates an application diagram of a method for estimating the tendency of pressure change on a touch panel according to the present invention. As shown inFIG. 1, in one embodiment of the present invention, an optically-detected input image system10comprises a computer90, a projector80, a left image-capturing device11, a right image-capturing device12, an image screen13and a feedback device14. The computer90comprises a memory91, a processor92and an image interface93, wherein the memory91is stored with a computer program100.

The projector80is connected to the image interface93of the computer90, so as to project an image onto the image screen13(which is, in this embodiment, a common projection screen as seen in an ordinary meeting room), such that the left image-capturing device11and the right image-capturing device12(such as CCD/CMOS cameras) respectively installed on the upper-left corner and the upper-right corner of the image screen13can detect a position touched on the image screen13by a user.

The computer90can utilize the processor92to execute the computer program100stored in the memory91to implement the method for estimating the tendency of pressure change on a touch panel of the present invention, so as to estimate the tendency of pressure change on the image screen13, and finally to provide a feedback signal according to the pressure change to the feedback device14(which is a speaker in this embodiment) or the image screen13.

Please note that the method for estimating the tendency of pressure change on a touch panel of the present invention is not limited to be implemented in the abovementioned environment. For example, the optically-detected input image system10does not necessarily need the projector80, the image screen13is a general display monitor (such as a LCD monitor), the image screen13is directly connected to the image interface93of the computer90, and the left image-capturing device11and the right image-capturing device12are similarly installed on two upper sides of the LCD monitor.

Then, please refer toFIG. 2, which illustrates a flowchart of the method for estimating the tendency of pressure change on a touch panel according to the present invention. And please also refer toFIG. 1as well asFIGS. 3-5.

First, the method performs step201: obtaining first left image data and first right image data.

Please refer toFIG. 3, which illustrates a schematic drawing of obtaining first left image data and first right image data according to one embodiment of the present invention. At a first time, the user's finger41aat or close to a first coordinate position41is pressed on the image screen13. The optically-detected input image system10can utilize the left image-capturing device11and the right image-capturing12to obtain the first left image data21and the first right image data31. Because the finger41sshades partial area of the image screen13, the first left image data21includes a first left shaded area211, and the first right image data31includes a first right shaded area311. The mechanisms of utilizing both image-capturing devices11and12to obtain both image data21and31, and wherein the image data21and31respectively include shaded areas211and311due to the finger41aare known techniques; therefore, there is no need for further description.

Then, the method performs step202: calculating a first coordinate position.

After the method obtains the first left image data21and the first right image data31, the first left image data21and the first right image data31would be transmitted to the computer90, such that the computer90can execute the computer program100to calculate the first coordinate position41at where the finger41ais located according to the shaded areas211and311. For example, the first coordinate position41can be accurately calculated by, but not limited to, utilizing triangulation. Because triangulation is a known technique, there is no need for further description.

Next, the method performs step203: obtaining second left image data and second right image data.

Please refer toFIG. 4, which illustrates a schematic drawing of obtaining second left image data and second right image data according to one embodiment of the present invention. At a second time, the user's finger42aat or close to a second coordinate position42is pressed on the image screen13. Similarly, the optically-detected input image system10can utilize the left image-capturing device11and the right image-capturing device12to obtain the second left image data22and the second right image data32, wherein the second left image data22includes a second left shaded area221, and the second right image data32includes a second right shaded area321.

Please note that the two image-capturing devices11and12are in fact constantly transmitting the left and right image data to the computer90, and the computer90is constantly calculating whether there is an object touching the screen and its coordinate position. For example, the computer90performs a calculation every 0.1 second, which is the time difference between the first time and the second time in this embodiment. Generally speaking, a calculation can be performed within 0.01 second to 1 second; therefore the time difference between the first time and the second time can be set, but not limited to, between 0.01 second and 1 second.

Then, the method performs step204: calculating a second coordinate position.

After the method obtains the second left image data22and the second right image data32, the second left image data22and the second right image data32would be transmitted to the computer90, such that the computer90can execute the computer program100to calculate the second coordinate position42.

Then, the method performs step205: comparing whether the distance between the first coordinate position and the second coordinate position is within a predetermined allowable error distance.

After the method calculates the first coordinate position41and the second coordinate position42, the computer90executes the computer program100to compare whether the distance between the above two positions is within a predetermined allowable error distance. If yes, the method then performs step206. The predetermined allowable error distance is preferably set as 0˜15 pixels. In this embodiment, the predetermined allowable error distance is set as 8 pixels.

In this embodiment, the distance difference between the two coordinate positions41and42is 5 pixels, which is within the predetermined allowable error distance, therefore the method would continue to perform step206. Please note that the technique of calculating the distance difference between the first coordinate position41and the second coordinate position42is a known technique, therefore there is no need for further description.

The purpose of step205is to detect whether the finger41aat the first time and the finger42aat the second time touch the same position or approximate positions on the image screen13. If yes, the method would further estimate the pressure change between the touch pressure applied on the image screen13by the finger41aat the first time and the touch pressure applied on the image screen13by the finger42aat the second time.

If the distance between the finger41aat the first time and the finger42aat the second time is beyond the predetermined allowable error distance, it means the finger moves quite a distance. At this time, the method does not estimate the pressure change between the touch pressure applied on the image screen13by the finger41aat the first time and the touch pressure applied on the image screen13by the finger42aat the second time, and the method then returns to step201.

Next, the method performs step206: calculating a first estimated pressed-area parameter.

After the method confirms that the distance difference is within the predetermined allowable error distance, the method can then calculate the image area, and determine the tendency of pressure change according to the change of the image area. Please refer toFIG. 5, the first left image data21and the first right image data31obtained at the first time respectively include the first left shaded area211and the first right shaded area311, wherein the first left shaded area211includes a first left shaded area width211w, and the first right shaded area311includes a first right shaded area width311w. In this embodiment, the first estimated pressed-area parameter is estimated by, but not limited to, multiplying the first left shaded area width211wand the first right shaded area width311w. For example, the first left shaded area width211wand the first right shaded area width311wcan also be put into other mathematic formulas for calculating the first estimated pressed-area parameter. In this embodiment, the first left shaded area width211wis 30 pixels, and the first right shaded area width311wis 25 pixels, therefore the first estimated pressed-area parameter is 750 pixels.

Then, the method performs step207: calculating a second estimated pressed-area parameter.

Similarly, the second left image data22and the second right image data32obtained at the second time respectively include the second left shaded area221and the second right shaded area321, wherein the second left shaded area221includes a second left shaded area width221w, and the second right shaded area321includes a second right shaded area width321w. In this embodiment, the second left shaded area width221wis 50 pixels, and the second right shaded area width321wis 47 pixels, therefore the second estimated pressed-area parameter is 2350 pixels.

Then, the method performs step208: comparing the first estimated pressed-area parameter with the second estimated pressed-area parameter.

After the method calculates the first estimated pressed-area parameter and the second estimated pressed-area parameter, the method then compares the values of both parameters. If the second estimated pressed-area parameter is greater than the first estimated pressed-area parameter, the method determines the user increases the touch pressure on the image screen13from the first time to the second time. If the second estimated pressed-area parameter is less than the first estimated pressed-area parameter, the method determines the user decreases the touch pressure on the image screen13from the first time to the second time. In this embodiment, the second estimated pressed-area parameter is greater than the first estimated pressed-area parameter; therefore, the method determines the user increases the touch pressure on the image screen13from the first time to the second time.

Finally, the method performs step209: generating a feedback signal.

After the method estimates the change of the touch pressure applied on the image screen13by the user, the computer90can utilize the processor92to execute the computer program100, so as to generate the feedback signal for being transmitted to the feedback device14or the image screen13as a response, wherein the feedback signal can be a visual, audio or haptic feedback signal. In this embodiment, the feedback device14can be a speaker, and because the touch pressure increases from the first time to the second time, the computer program100would generate an audio feedback signal to drive the speaker to generate a louder sound; or, the method can generate a haptic feedback signal for being transmitted to the image screen13, such that the image screen13would increase a vibration level (wherein the feedback device is installed behind the screen); moreover, the method can generate a visual feedback signal, for example, when the user presses a worm of a game software application program, the worm displayed on the image screen13would generate different shapes or expressions due to different touch pressures; of course, different sounds can be generated as well.

Please note that the method for estimating the tendency of pressure change on a touch panel of the present invention is not limited to the abovementioned specific order of execution, it is understood that the order of execution may differ from the above description as long as the object of the present invention can be accomplished.