Abstract:
A light measurement system measures light characteristics of a plurality of light sources and includes a processing unit, a plurality of capturing modules, a plurality of signal conversion units, and a demultiplexing unit. The processing unit generates a control signal for controlling the capturing modules to capture the light characteristics of the light sources. After capturing the light characteristics, the capturing modules output captured frequency-related data corresponding to the light characteristics respectively. Then, the capture frequency-related data are converted into capture bit codes by the signal conversion units respectively. Under the control of the processing unit, the demultiplexing unit selectively sends the capture bit code of each of the signal conversion units to the processing unit. Accordingly, the light measurement system measures the light sources synchronously and allows the demultiplexing unit to send the capture bit code of any one of the light sources to the processing unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101120470 filed in Taiwan, R.O.C. on Jun. 7, 2012, the entire contents of which are hereby incorporated by reference. 
     FIELD OF TECHNOLOGY 
     The present invention relates to a measurement system, in particular to the light measurement system that measures light characteristics of a plurality of light sources by a parallel processing structure. 
     BACKGROUND 
     With reference to  FIG. 1  for a conventional light measurement system  2 , the light measurement system  2  is provided for measuring for measuring the light characteristics (such as wavelength, phase, polarization state, chrominance and lumen intensity) of a plurality of light sources  22 ,  24 ,  26 ,  28 , and the light measurement system  2  comprises a plurality of capturers  212 ,  214 ,  216 ,  218 , a demultiplexer  220 , a signal processor  222  and a processing unit  224 . Wherein, the quantity of capturers  212 ,  214 ,  216 ,  218  is equal to the quantity of light sources  22 ,  24 ,  26 ,  28 . In other words, one capturer is corresponsive to one light source. 
     In addition, the demultiplexer  220  is a component having a plurality of first terminals  2202  corresponding to a single second terminal  2204 , and the demultiplexer  220  receives an external control signal CS to control one of the first terminals  2202  to connect the second terminal  2204  in order to select a connection path CP between the first terminals  2202  and the second terminal  2204 . The first terminal  2202  has 4 pins and the second terminal  2204  has 1 pin, and the demultiplexer  220  is a 1-to-4 demultiplexer depending on the number of pins. 
     In light measurement system  2 , the processing unit  224  issues and transmits a digital detecting signal DS to the signal processor  222 , and the signal processor  222  converts the detecting signal DS into an analog detecting signal DS′ and outputs the analog detecting signal DS′ to the second terminal  2204  of the demultiplexer  220 , and the demultiplexer  220  switches the connection path CP of the control signal CS sequentially, so that the detecting signal DS′ can be transmitted from the first terminals  2202  to each of the capturers  212 ,  214 ,  216 ,  218  to drive each of the capturers  212 ,  214 ,  216 ,  218  to detect the light sources  22 ,  24 ,  26 ,  28 , so as to determine whether or not the light sources  22 ,  24 ,  26 ,  28  produce lights. For example, if the capturer  212  detects that there is a light produced by the light source  22 , the capturer  212  captures the light characteristics of the light source  22  and outputs an analog capture signal CAPS, and the capture signal CAPS is transmitted to the first terminals  2202  of the demultiplexer  220 , and the control signal CS is provided for the sequential switch, so that the capture signals CAPS captured by the capturer  212  can be outputted from the second terminal  2204 . Since only the capturer  212  captures the capture signal CAPS, therefore it is necessary to wait for the control signal CS to select the first terminal  2202  and the capturer  212  before the analog capture signal CAPS captured by the capturer  212  can be transmitted to the signal processor  22  through the demultiplexer  220 , and the analog capture signal CAPS is converted by the signal processor  222  and provided for generating the digital capture signal CAPS&#39; and allowing the processing unit  224  to analyze the light characteristics of the light source  22 . 
     Although the aforementioned measurement system can measure the light characteristics of different light sources  22 ,  24 ,  26 ,  28 , the processing unit  224  has to wait for the switching time of the demultiplexer  220  and the time for converting data types by the signal processor  222  to allow the processing unit  224  to obtain the light characteristics captured by the light sources  22 ,  24 ,  26 ,  28 . According to the total time spent, the conventional measuring method is very inefficient. 
     Therefore, finding a way to quickly measure related light characteristics of a plurality of light sources demands immediate attentions and feasible solutions. 
     SUMMARY 
     It is a primary objective of the present invention to provide a light measurement system with a parallel processing structure for measuring light characteristics (such as wavelength, phase, polarization state, chrominance and lumen intensity) of a plurality of light sources quickly. 
     Another objective of the present invention is to provide a light measurement system that uses a field programmable gate array (FPGA) to measure a plurality of light sources freely, simultaneously and quickly. 
     To achieve the aforementioned and other objectives, the present invention provides a light measurement system for measuring light characteristics of a plurality of light sources, and the light measurement system comprises a processing unit, a plurality of capturing modules, a plurality of signal conversion units and a demultiplexing unit. Wherein, the processing unit includes a plurality of pins, and the processing unit sends out a control signal through the pins; the capturing modules are coupled to the processing unit, and each of the capturing modules is provided for capturing the light characteristics of each of the light sources, and each of the capturing modules includes a control unit and a sampling unit, and the control unit controls the sampling unit to capture the light characteristics of the corresponding light source according to the control signal. In addition, the sampling unit outputs captured frequency-related data according to the light characteristics; each of the signal conversion units is coupled to the sampling unit of each of the capturing modules for converting the captured data into a capture bit code; and the demultiplexing unit is coupled to the signal conversion units and the processing unit, and the demultiplexing unit switches a connection path between each of the signal conversion units and the processing unit according to the control signal of the processing unit for outputting the capture bit code to the processing unit from each of the signal conversion units. 
     Compared with the prior art, the present invention provides a light measurement system with a parallel processing structure for measuring the light characteristics of a plurality of light sources, and the system simultaneously obtains related light characteristics of the light sources in advance from the plurality of connected capturing modules and converts a plurality of captured frequency-related data, and then the plurality of signal conversion units converts the captured data into a capture bit code, and the capture bit code is kept in the signal conversion units, and the demultiplexing unit outputs the capture bit code of the signal conversion unit to the processing unit based on the switch of the control signal to analyze the light characteristics. 
     Therefore, the present invention can shorten the measurement time and measures the light sources more effectively and efficiently than the prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of a conventional light measurement system; 
         FIG. 2  is a schematic block diagram of a light measurement system in accordance with a first preferred embodiment of the present invention; and 
         FIG. 3  is a schematic block diagram of a light measurement system in accordance with a second preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The objects, characteristics and effects of the present invention will become apparent with the detailed description of the preferred embodiments and the illustration of related drawings as follows. 
     With reference to  FIG. 2  for a schematic block diagram of a light measurement system in accordance with the first preferred embodiment of the present invention, the light measurement system  10  is provided for measuring a plurality of light characteristics of a light source  12 . For example, the light characteristics include a wavelength, a phase, a polarization state, a chrominance and a lumen intensity of the light source, wherein the light characteristics of this embodiment include the chrominance and the lumen intensity of the light source  12  having a wavelength within a range (such as the wavelength proximate to the frequency bands of red light, green light and blue light). 
     In addition, the wavelength of the light source  12  is a wavelength of red light that falls within a range from 622 nm to 780 nm, a wavelength of green light that falls within a range from 492 nm to 577 nm, or a wavelength of blue light that falls within a range from 455 nm to 492 nm. Further, chrominance is defined as the color saturation of each wavelength; and lumen intensity is defined as the physical quantity of the light intensity of the light source  12 . 
     Further, the light source  12  of this preferred embodiment is a light emitting diode. 
     The light measurement system  10  comprises a processing unit  14 , a capturing module  16 , a signal conversion unit  18  and a demultiplexing unit  20 . 
     The processing unit  14  includes a plurality of pins S 0 , S 1 , S 2 , S 3 , S 4  for issuing plural kinds of control signals from the pins S 0 , S 1 , S 2 , S 3 , and the pin S 4  is provided for receiving measurement results of the light characteristics from the demultiplexing unit  20 . Wherein, the pins S 0 , S 1 , S 2 , S 3  are divided into a trigger pin S 0 , a function pin S 1 , S 2  and a switching pin S 3  according to the desired function of the control signal. 
     In addition, the pins S 0 , S 1 , S 2 , S 3  output a high potential or a low potential for outputting a control signal matched with “1” and “0” of a logic system. Wherein, the trigger pin S 0  can output two logic states of “1” and “0” to define “Trigger” and “Not Trigger” respectively; the function pins S 1 , S 2  can output four logic states of “00”, “01”, “10” and “11” to define “Measure the wavelength of red light”, “Measure the wavelength of green light”, “Measure the wavelength of blue light”, and “Measure the lumen intensity of the light source” respectively; and the switching pin S 3  also outputs two logic states which will be described further below. 
     Wherein, the trigger signal TS and the function signal FS can be transmitted between the processing unit  14  and the capturing module  16  through a first bus  30 . Since the first bus  30  is coupled to the trigger pin S 0  and the function pins S 1 , S 2 , therefore the first bus  30  can be comprised of three first transmission lines  302 ,  304 ,  306  for transmitting the trigger signal TS and the function signal FS; and the switch signal SS can be transmitted between the processing unit  14  and the capturing module  16  through a second bus  32 . Wherein, the second bus  32  further comprises two second transmission lines  322 ,  324  coupled to the switching pins S 3  and S 4  respectively, and the second transmission line  322  is provided for transmitting the switch signal SWS and the second transmission line  324  is provided for transmitting a capture bit code CBC as described below. 
     The capturing module  16  is coupled to the processing unit  14 , and each of the capturing modules  16  further comprises a control unit  162  and a sampling unit  164 . 
     Wherein, the capturing module  16  receives the trigger signals TR and the function signals FS through the control unit  162 . When the capturing module  16  receives the trigger signal TR, the trigger signal TR is provided for driving the sampling unit  164  to capture the light characteristics of the light source  12 . For example, if the processing unit  14  outputs “1” from the trigger pin S 0 , it shows that the control unit  162  drives the sampling unit  162  and captures the light characteristics of the light source  12 . On the other hand, if the trigger pin S 0  outputs “0”, it shows that the control unit  162  turns off the sampling unit  164 , so that the light characteristics of the light source  12  will not be captured. 
     In addition, the control unit  162  determines and controls which type of light characteristics of the light source  12  to be captured by the sampling unit  164  according to the function signal FS. Assumed that the function pin S 1 , S 2  outputs a control signal “00”, the function signal FS controls the capturing module  16  to capture the light characteristics of the light source  12  with regard to the wavelength proximate to the frequency band of red light. In other words, the sampling unit  164  captures the portion of the wavelength proximate to the frequency band of red light from the light source  12  according to the control of the control unit  162 , and the sampling unit  164  outputs the captured frequency-related data CD of red light. For example, the frequency in the captured data CD is equal to 482 THz (In other words, the measured wavelength of the red light source is equal to 622 nm). The relation of the frequency and the wavelength in the captured data CD is f=c/λ, wherein f is the frequency of the detection in unit of hertz (Hz); c is the speed of light equal to 3×10 8  m/s; and λ is the wavelength in unit of meter (m). 
     For example, the control unit  162  receives the function signal FS transmitted from the processing unit  14  to control the sampling unit  164  to measure either the chrominance or the brightness of the light sources  12  with the wavelength of red light. Wherein, the function signal FS is defined as a signal for selectively measuring the wavelength of red light, the wavelength of green light, the wavelength of blue light and the lumen intensity through the function pins S 1 , S 2 . 
     The signal conversion unit  18  is coupled to the sampling unit  164  and provided for receiving the captured data CD and converting the captured data CD into a capture bit code CBC. Wherein, the capture bit code CBC is expressed in a binary number system (which is a number in terms of 2 to the power 0 to 9) and has 9 bits, so that the converted capture bit code CBC falls within a range from 000000000 to 111111111. In other words, the capture bit code CBC corresponds to a range from 0 to 1512 in the decimal number system. 
     In this preferred embodiment, the frequency of the captured data CD captured by the capturing module  16  falls within a range from 384 THz to 659 THz (In other words, the wavelength ranges from 455 nm to 780 nm) which is the optical spectrum range of visible lights. Therefore, the captured data CD can be converted easily by the signal conversion unit  18 . For example, the frequency in the captured data CD is added with a correction value (such as −482 THz), so that after the captured data CD are processed by the signal conversion unit  18 , the original captured data CD are corrected and expressed in form of the aforementioned 9 bits. 
     For example, if the frequency in the captured data CD is equal to 482 THz (In other words, the wavelength corresponding to the frequency is equal to 622 nm) in this preferred embodiment, then the capture bit code DBC will be converted to 000000000. 
     The demultiplexing unit  20  is coupled to the signal conversion unit  18  and the processing unit  14 . Wherein, the demultiplexing unit  20  selectively controls the signal conversion unit  18  according to the switch signal SWS transmitted by the select pin S 3  to control whether or not to connect the signal conversion unit  18  with the processing unit  14 . If the signal conversion unit  18  and the processing unit  14  are coupled, then the capture bit code CBC can be transmitted from the signal conversion unit  18  to the processing unit  14  through the demultiplexing unit  20 , or else the capture bit code CBC of the signal conversion unit  18  cannot be transmitted to the processing unit  14  through the demultiplexing unit  20 . For example, if the switch signal SWS is “1”, it shows that the signal conversion unit  18  and the processing unit  12  are coupled to each other. On the other hand, if the switch signal SWS is “0”, it shows that the signal conversion unit  18  and the processing unit  12  are not coupled to each other. 
     In addition, the demultiplexing unit  20  comprises a plurality of input ports, output ports and selecting ports (not shown in the figure). Wherein, the input ports are coupled to the signal conversion unit  18 , and the output ports and the selecting port are coupled to the processing unit  14 . Further, the selecting port switches the connection path between the input ports and the output port according to the switch signal SWS received by the processing unit  14 . 
     In addition, the signal conversion unit  18  and the demultiplexing unit  20  are comprised of field programmable gate arrays (FPGAs). 
     With reference to  FIG. 3  for a schematic block diagram of a light measurement system in accordance with a second preferred embodiment of the present invention, the light measurement system  10 ′ comprises a processing unit  14 ′, a plurality of capturing modules  34 ,  36 ,  38 ,  40 , and a plurality of signal conversion units  42 ,  44 ,  46 ,  48 , and the demultiplexing unit  20 ′ receives a control signal from two switching pins S 5  and S 6  used for forming a 1-to-4 connection path, In other words, the switching pins S 5 , S 6  control the signal conversion units  42 ,  44 ,  46 ,  48  to output a plurality of capture bit codes CBC 1 , CBC 2 , CBC 3 , CBC 4  to the processing unit  14 ′. 
     Wherein, the capturing modules  34 ,  36 ,  38 ,  40  are provided for simultaneously detecting four sets of light sources  12 , and the capturing modules  34 ,  36 ,  38 ,  40  capture 4 groups of captured frequency-related data CD 1 , CD 2 , CD 3 , CD 4 , and the captured data CD 1 , CD 2 , CD 3 , CD 4  are converted by the signal conversion units  34 ,  36 ,  38 ,  40  into the capture bit codes CBC 1 , CBC 2 , CBC 3 , CBC 4  respectively. In addition, the demultiplexing unit  20 ′ can selectively transmit one of the capture bit codes CBC 1 , CBC 2 , CBC 3 , CBC 4  corresponding to the signal conversion units  42 ,  44 ,  46 ,  48  to the processing unit  14 ′ by the control of the switching pins S 5  and S 6 . 
     It is noteworthy that the light measurement systems  10 ,  10 ′ of the first preferred embodiment or the second preferred embodiment further comprise a box body (not shown in the figure), and the box body has a containing space formed therein and provided for containing the capturing module  16 ,  34 ,  36 ,  38 ,  40 , and the light measurement systems  10 ,  10 ′ further comprise the light source  12  or contain the light source  12 . 
     Therefore, the light measurement system of the present invention can measure the light characteristics of a plurality of light sources by a parallel processing structure, and the system simultaneously obtains the related light characteristics of the light sources from a plurality of capturing modules coupled to the light sources in advance and converts light characteristics into a plurality of captured frequency-related data, and the captured data are converted into a plurality of capture bit codes by a plurality of signal conversion units, and the capture bit codes are kept in the signal conversion units, and the demultiplexing unit is provided for outputting the capture bit code of the signal conversion unit to the processing unit in order to analyze the light characteristics according to the switching of the control signal. 
     While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.