The utility model content
At problems of the prior art, the utility model provides a kind of anti-light interference strong touch system, described touch system comprises optical sensor, programmable logic device (PLD), light source and computing machine, described light source is connected with described programmable logic device (PLD), be in series with power driving circuit between described programmable logic device (PLD) and the described light source, described power driving circuit is used to change the luminous intensity of described light source by programmable logic device (PLD) control.
Further, include image processing program in the described computing machine.
Further, described programmable logic device (PLD) is field programmable gate array (FPGA) or CPLD (CPLD).
Further, described power driving circuit is power amplifier or field effect transistor.
Further, be integrated with SOC (system on a chip) on the described programmable logic device (PLD).
Further, described touch system also includes microprocessor, and described microprocessor is connected with described programmable logic device (PLD).
Further, described power driving circuit is power amplifier or field effect transistor.
This touch system that the utility model proposed compared with prior art is in series with power driving circuit between programmable logic device (PLD) and light source, be used to regulate the luminous intensity of light source.Optical sensor will be sampled on touch panel, parse the light intensity of bias light and this light intensity and the etalon optical power of presetting are compared the modified value that calculates light distribution, power driving circuit is adjusted the luminous intensity of light source according to the modified value of light distribution, make optical sensor be in optimum illumination condition, reduced the light interference.Simultaneously, further gather the image of touch objects on the interactive whiteboard, the image of the touch objects that collects is transferred in the computing machine, image processing program is arranged in the computing machine, image processing program draws the contrast of image by the parsing to image information, this contrast and the standard contrast of presetting are compared the modified value that calculates a contrast, simultaneously this modified value is turned back to power driving circuit, power driving circuit is adjusted luminous intensity according to this revision directive control light source, make optical sensor can photograph optimal image, further overcome the light interference problem of existing different light environment touch system.This anti-light disturbs touch system compared with prior art, and the production cost increasing degree is lower, and performance but can be improved significantly, and is applicable to various photoenvironments.
Embodiment
The utility model will be further described below in conjunction with specification drawings and specific embodiments.
Relate in the existing touch system connected mode between the part critical elements and part critical elements in the following descriptive text and no longer do specific descriptions.
Accompanying drawing 1 is according to first embodiment of the present utility model, and brief description is formed the circuit structure diagram of the main element of touch system.
With reference to accompanying drawing 1, this system comprises optical sensor 101, programmable logic device (PLD) 102, light source 103 and computing machine 104, light source 103 is connected with programmable logic device (PLD) 102, be in series with power driving circuit 105 between programmable logic device (PLD) 102 and the light source 103, power driving circuit 105 is used to control the luminous intensity of light source 103.This touch system compared with prior art, between programmable logic device (PLD) 102 and light source 103, be in series with the power driving circuit 105 of the luminous intensity that is used to regulate light source 103, the image of the touch objects that optical sensor 101 will collect on touch panel is transferred to computing machine 104, in the computing machine 104 image processing program is installed, image processing program draws the contrast of image by the parsing to image information, this contrast and the standard contrast of presetting (optical sensor can collect the picture of optimum efficiency in the case) are compared the modified value that calculates a contrast, simultaneously this modified value is turned back to power driving circuit 105, power driving circuit 105 is adjusted luminous intensity according to this revision directive control light source 103, make optical sensor 101 constantly be in optimum illumination condition, overcome the light interference problem of existing different light environment touch system.Wherein, power driving circuit 105 can be power amplifier or field effect transistor; Optical sensor 101 can be camera, CCD or CMOS; Programmable logic device (PLD) 102 can be field programmable gate array (FPGA) or CPLD (CPLD), CPLD has the time delay that can estimate and the logical block advantage to the linkage unit height ratio, FPGA can edit more flexibly, and contain high-level built-in module (such as totalizer and multiplier) and built-in memory body, support completely or the system of part reconfigures.CPLD and FPGA have advantage separately, use according to concrete condition.
Simultaneously, can also the programmable logic device (PLD) 102 in Fig. 1 on integrated SOC (system on a chip), expand the functions of use of this touch system, as can on SOC (system on a chip), loading automatic diagnosis, automatically updating function etc.
Accompanying drawing 2 is according to second embodiment of the present utility model, brief description form the circuit structure diagram of the main element of touch system.
With reference to accompanying drawing 2, this system comprises optical sensor 101, programmable logic device (PLD) 102, microprocessor 201, light source 103 and computing machine 104, microprocessor 201 is connected with programmable logic device (PLD) 102, light source 103 is connected with programmable logic device (PLD) 102, be in series with power driving circuit 105 between programmable logic device (PLD) 102 and the light source 103, power driving circuit 105 is used to control the luminous intensity of light source 103.This touch system is compared with touch system shown in Figure 1, between programmable logic device (PLD) 102 and computing machine 104, microprocessor 201 has been installed, microprocessor 201 can be expanded the function of touch system, as can on microprocessor, loading automatic diagnosis, automatically updating function etc., have more use value, and promoted extending space.Wherein, power driving circuit 105 can be power amplifier or field effect transistor; Optical sensor 101 can be camera, CCD or CMOS; Little processing 301 can be MCU or ARM; Programmable logic device (PLD) 102 can be field programmable gate array (FPGA) or CPLD (CPLD), CPLD has the time delay that can estimate and the logical block advantage to the linkage unit height ratio, FPGA can edit more flexibly, and contain high-level built-in module (such as totalizer and multiplier) and built-in memory body, support completely or the system of part reconfigures.CPLD and FPGA have advantage separately, use according to concrete condition.
Accompanying drawing 3 is the process flow diagrams according to the anti-light interference method of the utility model embodiment.This method comprises following step:
Step 301: energized starts touch system.
Step 302: scan whole touch panel, sampling on the touch panel image and parse the light distribution of the image on this touch panel.
In step 302, scan whole touch panel, sampling on the touch panel image and parse the light distribution of the image on this touch panel.The whole touch panel of programmable logic device (PLD) 102 control optical sensors 101 scannings is sampled to the image on the touch panel simultaneously and the image of sampling is transferred to computing machine 104.Image processing programs in the computing machine 101 can be resolved sampled images and be obtained light distribution on this interactive whiteboard.The gray-scale value that this embodiment carries out the light distribution of this step acquisition is m~n.
Step 303: whether the light distribution of judging image is in the feasible region, as is not in the feasible region, then enters step 304; As be in the feasible region, then enter step 306.
In step 303, judge whether the light distribution on the touch system is in the feasible region, feasible region is that 101 detected minimum intensity of light of energy of optical sensor are to the scope between the largest light intensity.In general the gray-scale value of feasible region is between 120~230.Be not in (m<120, n>230, m>230 or n<120) in the feasible region as light distribution, then enter step 304; Be in (m 〉=120, n≤130) in the feasible region as light distribution, then enter step 306.
Step 304: the modified value that the light distribution and the default etalon optical power distribution of image is compared and calculate light distribution.
In step 304, image processing program in the computing machine is compared the light intensity of the bias light on the interactive whiteboard and is calculated the modified value of light distribution with preset standard light distribution (can make optical sensor bring into play the light distribution of optimal performance, its mean value is about 180).Then the revision value of light distribution is 180-m and 180-n.
Step 305: the luminous intensity of adjusting light source according to the modified value of light distribution.
In step 305, programmable logic device (PLD) 102 sends revision directive according to the modified value (180-m and 180-n) of the light distribution that computing machine 104 is sended over to power driving circuit 105, power driving circuit 105 is adjusted luminous intensity according to revision directive control light source 103, and light distribution is in the feasible region.
Step 306: return step 302, restart next round scanning, the bias light on the interactive whiteboard is monitored in real time and optimized.
In actual applications, step 306 is specially following steps:
Step 3061: scan whole touch panel, judge whether to exist touch objects.
In step 3061, the whole touch panel of programmable logic device (PLD) 102 control optical sensors, 101 scannings judges whether touch objects is arranged on the touch panel.Wherein, touch objects can be user's hand, finger or blank pen etc.
Step 3062:, then return step 302 as on touch panel, not detecting touch objects; As on touch panel, detecting touch objects, then enter step 3063.
In step 3062, on touch panel, do not detect touch objects as optical sensor 101, then return step 302, rescan touch panel; On touch panel, detect touch objects as optical sensor 101, then enter step 3003.
Step 3063: calculate the positional information of touch objects and carry out the corresponding instruction that touches, return step B, restart next round scanning.
In step 3063, computing machine 104 calculates the position coordinates of touch objects according to triangulation location, and output simultaneously is corresponding to touch instruction.Return step 302, restart next round scanning.
Fig. 4 is the process flow diagram to a kind of prioritization scheme of the anti-light interference method of the utility model embodiment.
With reference to Fig. 4, this prioritization scheme is adjusted the luminous intensity of light source 103 according to the contrast of touch objects image information, makes optical sensor 101 can photograph more distinct image.This prioritization scheme improves the step 3063 among Fig. 3, and the step 3063 after the improvement may further comprise the steps:
Step 401: parse the contrast of touch objects image information and the contrast of this image information and default standard contrast are compared the modified value that calculates contrast.
In step 401, optical sensor 101 is transferred to computing machine 104 with the image information of detected touch objects, image processing program in the computing machine 104 is resolved this image information, draws the contrast of this image information, and the contrast that this embodiment carries out the acquisition of this step is P.(optical sensor can photograph the picture of optimal effectiveness in the case with default standard contrast with the contrast of this image information simultaneously, in general the mean value of standard contrast is generally about 50%) compare the modified value (p-50%) that calculates contrast, the modified value with this contrast sends to programmable logic device (PLD) 102 simultaneously.
Step 402: adjust the luminous intensity of light source according to the modified value of contrast, calculate the positional information of touch objects and carry out the corresponding instruction that touches, return step B, restart next round scanning.
In step 402, programmable logic device (PLD) 102 sends revision directive according to the modified value (p-50%) of the contrast that computing machine 104 is sended over to power driving circuit 105, power driving circuit 105 is adjusted luminous intensity according to revision directive control light source 103, makes it can create the bias light that makes optical sensor 101 give play to optimum efficiency.Computing machine 104 calculates the position coordinates of touch objects according to triangulation location then, and output simultaneously is corresponding to touch instruction.Return step 302, restart next round scanning.
Although have illustrated and described several several embodiment of the present utility model, those skilled in the art should understand under the situation that does not break away from the utility model spirit and principle and can change these embodiments that its scope definition in the claims.