Abstract:
Various techniques for synchronizing illumination with an audio signal are disclosed. According to one aspect of the techniques, an audio signal continuously is received and processed one phase or period at a time in an analyzing or detecting unit. From one phase of the audio signal, a set of light controlling parameters are determined from a look-up-table. These light controlling parameters are used to adjust duty cycles of square waves used to drive a plurality of light sources such that the illumination produced is in accordance with the audio signal.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to the area of illumination control, and more particularly related to apparatus and method for synchronizing illumination in accordance with music being played, wherein the illumination includes lights (e.g., LED or fluorescent lights) and displays (e.g., computer screen and TV displays). 
   2. Description of Related Art 
   In conventional consumer electronic products, such as mobile phone, MP3 or CD player etc., a plurality of Light-Emitting Diodes (LED) is employed to flash along with a piece of music being played to enhance visual effects. In these products, the LEDs are activated to turn off and on with the rhythm of the music. Many media players such as a DVD player or Microsoft media player, can play both audio and video media files or discs. However, when audio media is played, a display screen supporting such a media player displays either a static image or random patterns that have no any connection with the rhythm in the audio, resulting in boring visual effects. 
   Many audios, especially music and songs, possess rhythm including varying tones and tempos. Thus there is a need for techniques that converse the rhythm in audio being played into synchronized illumination in a display including LED lights and a display screen. 
   SUMMARY OF THE INVENTION 
   This section is for the purpose of summarizing some aspects of the present invention and to briefly introduce some preferred embodiments. Simplifications or omissions in this section as well as in the abstract or the title of this description may be made to avoid obscuring the purpose of this section, the abstract and the title. Such simplifications or omissions are not intended to limit the scope of the present invention. 
   In general, various techniques for synchronizing illumination with an audio signal are disclosed. According to one aspect of the techniques, a method for synchronizing illumination with an audio signal comprises receiving the audio signal continuously and processing one phase of the audio signal at a time, analyzing the one phase of the audio signal to determine a set of light controlling parameters, receiving the light controlling parameters from a look-up-table, and adjusting duty cycles of square waves used to drive a plurality of light sources such that the illumination produced is in accordance with the one phase of the audio signal. 
   The present invention may be implemented in software and hardware, or in combination of both. The present invention may be applied to control light sources along with music. The light sources may be in form of individual lights to flash along with a piece of music being played or a display screen to display patterns in synchronization of a piece of music to enhance visual effects. 
   According to one embodiment, the present invention is a device for synchronizing illumination along with an audio signal, the device comprises an analyzing unit receiving the audio signal continuously and processing one phase of the audio signal at a time, the analyzing unit configured to analyze the one phase of the audio signal to determine a set of light controlling parameters, a controlling unit coupled to a bus, and a memory unit having a look-up-table to provide the light controlling parameters, wherein duty cycles of square waves used to drive a plurality of light sources are adjusted in accordance with the light controlling parameters such that the illumination produced is in accordance with the one phase of the audio signal. 
   One of the features, benefits and advantages in the present invention is to provide techniques for synchronizing illumination with an audio signal. 
   Other objects, features, and advantages of the present invention will become apparent upon examining the following detailed description of an embodiment thereof, taken in conjunction with the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
       FIG. 1  is an oscillogram showing a phase of an audio signal; 
       FIG. 2  is a block diagram showing a device for synchronizing lights along with a piece of music in one embodiment of the present invention; 
       FIG. 3  shows that the light groups include a red light group, a blue light group and a green light group, each color light group includes at least one red light, one green light and one blue light; 
       FIG. 4   a  and  FIG. 4   b  show together an exemplary embodiment of a volume detecting unit; 
       FIG. 4   c  is a flowchart showing a flowchart or process of producing a set of light controlling parameters to control light sources; 
       FIG. 5   a  and  FIG. 5   b  show together another exemplary embodiment of a volume detecting unit; 
       FIG. 5   c  is a flowchart showing a flowchart or process of producing a set of light controlling parameters to control light sources; 
       FIG. 6   a  and  FIG. 6   b  show together an exemplary embodiment of a volume detecting unit; and 
       FIG. 6   c  is a flowchart showing a flowchart or process of producing a set of light controlling parameters to control light sources. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The detailed description of the present invention is presented largely in terms of procedures, steps, logic blocks, processing, or other symbolic representations that directly or indirectly resemble the operations of devices or systems contemplated in the present invention. These descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. 
   Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the order of blocks in process flowcharts or diagrams or the use of sequence numbers representing one or more embodiments of the invention do not inherently indicate any particular order nor imply any limitations in the invention. 
   To facilitate the description of the present invention, it deems necessary to introduce some fundamentals of sound and other related aspects. A sound is created when objects vibrate thus producing pressure waves that can be picked up by human ears. These pressure waves may be represented graphically by corresponding visual waveform.  FIG. 1  shows a phase of waveform to represent an audio signal, where the amplitude reflects the change in pressure from a peak of the waveform to a trough, causing the volume of the sound to change. At the same time, the frequency changes together with the amplitude in the waveform cause changes that sound musical to the human hearing system. 
   One of the aspects of the present invention is to synchronize illumination with an audio being played. The illumination, as used herein, includes various light emitting devices. Examples of such light emitting devices include Light Emitting Diodes (LEDs), fluorescent lights, LCD. When these light emitting devices are properly arranged, a display screen is formed. Therefore, the illumination as used herein also includes various displays such as LCD or LED-based displayed. 
   As far as a single light is concerned, it has two statuses, ON and OFF. When the light is ON, the light shines. When the light is OFF, the light goes out. Thus, if the light is driven by a square wave with a predetermined duty ratio, the light will alternate between bright and dark. Namely, the light shines in high levels of the square waves and goes out in low levels of the square wave. 
   If the duty cycle T of the square waves is short enough, it is hard for human eyes to see the lighting alternation between bright and dark, instead only continuous average brightness of the light can be sensed. The average brightness value is relative to the duty cycle of the square waves. Thus, by adjusting the duty cycle of the square waves, the brightness of the lights can be controlled. 
   It is well known that almost any visible color can be reproduced by combining three colored components, such as Red, Green, and Blue (RGB). For example, RGB=(0,0,0) represents black while RGB=(255,255,255) represents white. Respective value changes in RGB will create other colors. According to one embodiment, the lights employed include a plurality of red, blue, green lights, for example, an equal number of red, green and blue LEDs. When these lights are grouped as individual groups or sets, each set including a red light, a green light and a blue light. Essentially all visible colors may be reproduced by the sets of LEDs through the control of power applied thereto, thus creating colorfully visual effect. 
   Referring now to  FIG. 2 , there shows a block diagram for controlling colorful illumination along with music being played, according to one embodiment of the present invention.  FIG. 2  includes a volume detecting unit  100 , a parameter generator  200 , a color light driver  300  and a plurality of light groups  400 . 
     FIG. 3  shows that the light groups  400  includes a red light group, a blue light group and a green light group, each color light group includes at least one red light, one green light and one blue light. The color light driver  300  includes a red light driver, a green light driver, and a blue light driver, each is configured to produce square waves to drive a corresponding color light group. By adjusting the duty cycle of the square waves, most visible color light can be reproduced. 
   Referring back to  FIG. 2 , the parameter generator  200  is for generating light controlling parameters according to which the duty cycle of the square waves can be adjusted. In one embodiment, a lookup table is provided in a register, a RAM or a ROM in the parameter generator  200 . When an index number is inputted into the look up table, the light controlling parameters corresponding to the index number will be outputted by looking up the lookup table. 
   The volume detecting unit  100  is provided to capture the audio signal and analyze the volume thereof. According to the volume of the audio signal and variation of the volume, a corresponding index number is produced and coupled to the lookup table in the parameter generator  200 . As a result, the color light groups can be controlled to illuminate along with the audio signal. 
   Depending on implementation, the volume detecting unit  100  may be implemented in many forms in the present invention. In one embodiment as shown in  FIG. 4   a , there are a controlling unit  102 , a maximum (MAX) volume statistical unit  104  and a volume level determining unit  106 . The MAX volume statistical unit  104  is provided to capture a phase of an audio signal and compute the MAX volume of the audio signal. The controlling unit  102  is to provide a timing clock and volume level parameters according to which the volume levels can be partitioned. 
   The volume level determining unit  106  coupled to the controlling unit  102  and the MAX volume statistical unit  104  is provided to determine which volume level the MAX volume of the audio signal corresponds to, according to the determined volume level, and produce a corresponding index number for the lookup table. 
   Referring to  FIG. 4   b , there shows an exemplary detailed block diagram in accordance with  FIG. 4   a . The MAX volume statistical unit  104  includes a comparator which captures a phase of the audio signal and computes the MAX volume of the audio signal and a register that the MAX volume of the phase audio signal is reserved therein. The controlling unit  102  includes a calculator producing the timing clock and a file register receiving and reserving the volume level parameters from a bus, and coupling them to the volume level determining unit  106 . 
   As shown in the figure, the volume level determining unit  106  includes a successive comparator, an encoder, a comparator, a selector, a register and a subtractor. The successive comparator is provided to receive the volume level parameter from the controlling unit  102  and the MAX volume of the audio signal from the register of the MAX volume statistical unit  104 , then determine which volume level the MAX volume of the audio signal corresponds to. The encoder encodes the determined volume level into a current index number. 
   The comparator compares the current index number with a last index number and outputs a selecting signal to the selector. One input of the selector receives the current index number, the other input of the selector is coupled to an output of the subtractor. The last index number is provided into the subtractor, where the last index number is subtracted by one. If the current index number is larger than the last index number, the current index number is selected; otherwise, the last index number is selected. The selected index number is reserved in the register as the index number to be provided to the lookup table. 
     FIG. 4   c  shows a flowchart or process  401  for controlling illumination in accordance with an audio signal. The process  401  may be implemented in hardware, software or in combination of both as a method, an apparatus or a part of a system. To facilitate the description of the process  401 ,  FIG. 4   a  and  FIG. 4   b  are referenced. 
   The process  401  begins with an initialization operation that requires or causes the lookup table  200  to contain light controlling parameters, and the whole volume range is partitioned into several volume levels according to the volume level parameters. Examples of the light controlling parameters include brightness controlling parameters and color controlling parameters according to one embodiment. 
   At  410 , the MAX volume statistical unit  104  captures a phase of an audio signal and computes the MAX volume of the audio signal. The volume level determining unit  106  determines at  412  which volume level the MAX volume of the audio signal corresponds to according to the partitioned volume levels. At  414 , the encoder encodes the determined volume level into a current index number. The comparator determines if the current index number is larger than the last one at  416 . If the current index number is larger than the last one, the selector selects the current index number to be reserved in the register at  418 , otherwise, the last index number subtracted by one is selected as the current index number at  420 . 
   At  422 , the lookup table outputs the light controlling parameters corresponding to the current index number to the color light driver  300 . As a result, the color light groups produce colorful illumination in synchronization with the audio signal by adjusting the duty cycle according to the light controlling parameters at  424 . It should be noted that the comparator, depending on implementation, the selector and the substractor may not be necessary or substituted by other proper elements. 
     FIG. 5   a  and  FIG. 5   b  show together a block diagram according to another embodiment of the present invention. The volume detecting unit  100  shown in  FIGS. 5   a  and  5   b  includes a controlling unit  102 , a MAX volume statistical unit  104  and a volume variation determining unit  108 . The MAX volume statistical unit  102  includes a comparator that receives a phase of an audio signal and computes the MAX volume of the audio signal and a register the MAX volume of the phase audio signal is to be reserved therein. The controlling unit  104  also includes a calculator that produces a timing clock and a file register to receive configuration parameters from a bus and output a slope threshold of volume variation. 
   The volume variation determining unit  108  includes a register, a volume threshold generator, a variation comparator, a volume comparator, and a calculator. The register is provided to store the MAX volume of the last phase of the audio signal from the register of the MAX volume statistical unit  102  and couple the MAX volume to an input of the volume comparator. A second input of the volume comparator receives the MAX volume of the current phase of the audio signal. The volume comparator determines if the MAX volume of the current phase of the audio signal is larger than that of the last phase of the audio signal. If yes, which represents that the audio signal rises, light controlling parameters for turning on the color light groups are outputted; otherwise, light controlling parameters for turning off the color light groups are outputted. 
   The volume threshold generator receives the MAX volume of the last phase and the slope threshold of volume variation, and produces a threshold MAX volume. The variation comparator determines if the MAX volume of the current phase exceeds the threshold MAX volume. If yes, a number in the calculator increases by one as the current index number; otherwise, the number in the calculator keeps unchanged as the current index number. 
     FIG. 5   c  shows a flowchart or process  501  for controlling illumination in accordance with an audio signal. The process  501  may be implemented in hardware, software or in combination of both as a method, an apparatus or a part of a system. To facilitate the description of the process  501 ,  FIG. 5   a  and  FIG. 5   b  are referenced. 
   The process  501  begins with an initialization operation in which the lookup table  200  containing light controlling parameters is established, and the slope threshold in the file register is configured and sent to the volume threshold generator. In one embodiment, the light controlling parameters includes brightness parameters and color parameters. 
   The process  501  goes to  510 , where the MAX volume statistical unit captures a phase of an audio signal and computes the MAX volume of the audio signal. At  512 , the volume comparator determines if the MAX volume of the current phase audio signal rises by comparing it with the MAX volume of the last phase of the audio signal. If yes, the process  501  goes to  514  where the light controlling parameters for turning off the color light groups are outputted. If no, the process  501  goes to  516  where the volume threshold generator produces a threshold MAX volume. 
   At  518 , the variation comparator determines if the MAX volume of the current phase exceeds the threshold. If yes, the last index number in the calculator increases by one to work as the current index number at  520 ; otherwise, the last index number in the calculator remains the same as the current index number at  522 . 
   The lookup table at  524  outputs the controlling parameters, in accordance with the current index number, to the color light group driver. Namely, the square wave generator is configured to adjust the duty cycles of the waves according to the controlling parameters so as to obtain colorful light along with the audio signal (e.g., music). As a result, the color light groups are driven to produce colorful illumination along with the audio signal by adjusting the duty cycle according to the light controlling parameters at  526 . It can be understood that the MAX volume statistical unit  104  continuously captures the audio signal as it comes in and the above operations will be repeated until the streaming of the audio is finished. 
     FIG. 6   a  and  FIG. 6   b  show together a block diagram according to another embodiment of the present invention. The block diagram of the volume detecting unit  100  shown in  FIGS. 6   a  and  6   b  includes a controlling unit  102 , a MAX volume statistical unit  104 , a volume level determining unit  106 , a volume variation determining unit  108  and a mode selecting unit  110 . The controlling unit  102  controls the mode selecting unit  110  to select an output from either the volume level determining unit  106  or the volume variation determining unit  108 , where the output is applied to the volume detecting unit  100 . When the volume level determining unit  106  is selected, the volume detecting unit  100  of the embodiment is similar to that of the embodiment shown in  FIG. 4   a  and  FIG. 4   b . When the volume variation determining unit  108  is selected, the volume detecting unit  100  of the embodiment is similar to that of the embodiment shown in  FIG. 5   a  and  FIG. 5   b . Accordingly, the specific description of the volume detecting unit  100  of the embodiment is not to be provided. 
     FIG. 6   c  shows a flowchart or process  601  for controlling illumination in accordance with an audio signal. The process  601  may be implemented in hardware, software or in combination of both as a method, an apparatus or a part of a system. To facilitate the description of the process  501 ,  FIG. 6   a  and  FIG. 6   b  are referenced. However, as stated above, when the volume level determining unit  106  is selected, the volume detecting unit  100  of the embodiment is similar to that of the embodiment shown in  FIG. 4   a  and  FIG. 4   b , and when the volume variation determining unit  108  is selected, the volume detecting unit  100  of the embodiment is similar to that of the embodiment shown in  FIG. 5   a  and  FIG. 5   b . Thus those skilled in the art can readily understand the process  601  given the assumption. As the process  601  is substantially similar to that of  FIG. 4   c  and  FIG. 5   c , except that a mode selecting operation is now added. 
   The present invention has been described in sufficient details with a certain degree of particularity. It is understood to those skilled in the art that the present disclosure of embodiments has been made by way of examples only and that numerous changes in the arrangement and combination of parts may be resorted without departing from the spirit and scope of the invention as claimed. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description of embodiments.