WO2007072319A1

WO2007072319A1 - Coordinate schemes for addressing led based matrix displays

Info

Publication number: WO2007072319A1
Application number: PCT/IB2006/054800
Authority: WO
Inventors: Robin John Blackwell; Neil Foston
Original assignee: Koninklijke Philips Electronics N. V.
Priority date: 2005-12-23
Filing date: 2006-12-13
Publication date: 2007-06-28
Also published as: EP1966784A1; JP2009521006A; TW200733041A; CN101346752A

Abstract

A display system (300) includes controllable lighting elements (330) having a control configuration; and a controller (310) configured to query the lighting elements (330) to determine their configuration. The controllable lighting elements (330) include LEDs. The controller (310) is further configured to translate input information into output information in accordance with the control configuration for control of the lighting elements, where the LEDs display a pattern in accordance with the output information. The pattern may be displayed by masking desired ones of the LEDs, where mask-based addressing compresses and reduces the size of the output information. The input and output information includes different coordinate addressing information.

Description

COORDINATE SCHEMES FOR ADDRESSING LED BASED MATRIX DISPLAYS

The present invention relates to display devices and control thereof, particularly to addressing schemes of LED-based matrix displays.

With the advent of Solid State Lighting (SSL) it is becoming possible to realize very complex dynamic and static color lighting effects. These effects may be based on a number of elements and inputs such as controllers, sensors and even audiovisual (AV) streams. In addition to using LEDs individually in various devices, the LEDs can be used in a matrix configuration to act as a display for multimedia content, e.g. a video wall or screen display. LEDs can be arranged in a variety of configurations to create matrix displays of varying size and shape. Therefore a simple mechanism is required to both describe and control these varying matrix type devices using information in various forms and coordinate systems.

Although at first it may appear that a simple Cartesian x, y based addressing mechanism would suffice, this is not true for simple irregularly shaped displays. The reason is that using Cartesian coordinates to describe non-Cartesian based (i.e., irregular) shapes, a high resolution is required and therefore a large number of LEDs and associated coordinate points are required, where many LEDs would be redundant and unnecessary if a better scheme is devised. A Cartesian addressing to display an irregular shape on LED screen displays also requires an approximation of the irregular shape, and may produce inferior results. For example, anti-aliasing is required to improve the quality of such irregular shapes displayed using Cartesian addressing in order to smooth out the approximations in the display of such irregular shapes. This can be computationally intensive, wasting computer power and processing time. Consequently, there is a need for improvement and flexibility in addressing of displays.

Accordingly, a novel display system includes controllable lighting elements having a control configuration; and a controller configured to query the lighting elements to determine their configuration. The controllable lighting elements include light emitting diodes (LEDs), for example. The controller is further configured to translate input information into output information in accordance with the control configuration for control of the lighting elements, where the lighting elements display a pattern in accordance with the output information. The pattern may be displayed by masking desired ones of the lighting elements, where mask-based addressing compresses and reduces the size of the output information.

The input and output information includes different coordinate addressing information. The controller and lighting elements communicate with each other through a network, for example, where the network detects a new connection thereto of the lighting elements and inform the controller of their presence. Alternatively or in addition, the lighting elements provide their control configuration to the controller upon connection to the network and/or upon receiving a request from the controller.

The LEDs may be configured as an array or matrix of LEDs having any desired shape which may efficiently display images of different shapes. Different addressing schemes for differently shaped matrices are used to substantially reduce the number of (or possibly eliminate) unnecessary LED modules in an LED display device. Respective addressing coordinates are computed by the controller which maybe a device separate from the LED display or integrated into the LED display for example, thus optimizing the control of the LED display. It should be noted that any type of display may be used that is configured to have addressable pixels, where LED displays or matrices are referred to herein as exemplary display devices. As is well know, a color pixel may be a set three LEDs, namely, red, green and blue LEDs. Of course, the display may be black and white instead of color, where different grey scales are used to form images.

LED matrices or arrays arranged as a display device in a lighting network system are configured to operate efficiently, such as efficiently displaying high quality images of various shapes, despite interacting with controllers that are configured to operate under a coordinate system which is different from the coordinate system of the LED display, or despite images that have descriptions in different coordinate systems. For example, a particular shape which has a Cartesian description may be efficiently displayed on the LED display configured to better display images having polar coordinates or addresses via the controller that is configured to translate Cartesian addresses/coordinates to polar addresses/coordinates.

Although the following description is with regard to such polar displays, it should be understand that the reverse is also possible, where the display is better suited for Cartesian display of images and has a Cartesian addressing unit, while the controller is configured to control the Cartesian display to display images with shapes described in polar coordinates, for example.

Illustratively, each coordinate point of an LED matrix is mapped to a single LED module placed at the exact physical position. For example, Cartesian and polar matrices, or other coordinate addressing schemes, may be used to address individual LEDs, including transformation between the different coordinate schemes. It should be understood that the usage of particular systems, schemes, techniques, and methods disclosed herein is not however limited to only LED-matrix devices, but could also be appropriately applied, for example, to TV screens, signage, and other types of displays that will be recognized by those skilled in the art.

An LED matrix may be configured, for example, to use polar coordinates. The supporting matrix controller, for instance, understands only Cartesian coordinates. A central controller in the system (which may also be integrated with the LED matrix) may be enabled to understand the use of polar coordinates, and to transform Cartesian coordinates into polar coordinates

The display system uses multiple coordinate addressing schemes, and mask-based and geometric descriptions of addressing schemes, to describe LED-based matrix displays, including transformation between different coordinate addressing schemes. Although the system is discussed in terms of two-dimensional coordinate schemes, one skilled in the art should understand three-dimensional schemes are also equally applicable, e.g. spherical, cylindrical, and so on.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings where:

FIG 1 is a diagram of a regular square shaped 4x4 LED matrix;

FIG 2 is a diagram of a LED matrix using polar coordinates;

FIG 3 is a sample diagram of mask based pattern description;

FIG 4 is a schema of transformation from Cartesian to polar coordinates, wherein the X coordinate is transformed into Radius (1st polar coordinate), and the Y coordinate is transformed into Angle (2nd polar coordinate); FIG 5 is a schema of transformation from Cartesian to triangular coordinates, wherein the Y coordinate is transformed into the corresponding coordinate for the axis having an angle less than 90 degrees with the horizontal axis; FIG 6 is a partial schema of a lighting network including a lighting controller device and a lighting matrix device; FIG 7 is an exemplary LED matrix device description code written in

XML; FIG 8 is an exemplary coded command to the LED matrix device written in XML; and FIG 9 is a diagram displaying a monochromatic (e.g. red) circle-like shape in polar coordinates.

The following description of certain exemplary embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. FIG 1 illustrates a rectangular two-dimensional 4x4 matrix or array of LEDs 100, each element of which is represented by an LED module or RGB pixel 105. The array 100 may be combined with other arrays or may be any desired size or shape and have any desired number of pixels or LEDs to form an LED display. A standard Cartesian coordinate scheme may be used to describe such a matrix and address its LEDs. In the Cartesian coordinate scheme, the matrix is described with a conventional assumption that its origin (zero coordinate point where x=0 and y=0) is located in the top left corner of the matrix 100, for example. Thus, for instance, the LED module in the top right corner 115 would be addressed as (x=3, y=0).

However, drawing some shapes, such as circles, ovals, irregular shapes (e.g. in the form of a heart, etc.) on a matrix described using Cartesian coordinates, may require high resolution and computationally intensive techniques such as anti-aliasing. To more efficiently draw or display such shapes on the LED displays, a different coordinate addressing scheme is used. FIG 2 depicts a LED matrix 150 described in polar coordinates. The matrix' shape is formed by two concentrically and circumferentially positioned sets of LED modules (with radius=l and radius=2) and one central LED module 155 in the center of the two circumferences, shown as three overlapping circles representing an RGB triplet. It should be noted that such three overlapping circles in the figures represent an RGB triplet. The matrix 150 can be described as a polar matrix with a maximum radius=2 and angular step of 45 degrees. Individual LEDs of the matrix can be addressed using different radiuses and angle coordinates. For example, the LED module 160 to the immediate right of the central LED module 155 has the coordinates 1, 0° indicating its distance from the center is one, and it is positioned at angle zero. Similarly, the LED module 165 on the outer circle in the first quadrant has the coordinates 2, 45°, while the LED module 170 again on the outer circle below the center has the coordinates 2, 270°.

Images or different shapes may be displayed on an LED display, configured in any coordinate system whether Cartesian, polar or three-dimensional, using a mask-based addressing scheme, e.g. to describe read-green-blue (RGB) triplets constituting each pixel of a matrix. FIG 3 illustrates the use of a mask-based pattern description 200 and the resultant matrix pattern 210 of nine activated monochromatic (e.g. red) LEDs 220. The mask-based scheme for addressing can also be used to describe irregularly shaped matrices. For example, an irregular shape could be defined as a masked square or in a Cartesian coordinate scheme, such that LEDs are only present in specific areas of the mask. Similarly, for the polar coordinate example, illustrated on FIG 2, a mask can be used to describe any shape, or for regular shapes, such as arcs or circles. The shapes can be alternatively geometrically described as Circle(Radius), Arc(Radius, StartAngle, EndAngle), for example. The geometric description scheme can also be used for addressing of certain matrix shapes or patterns within Cartesian coordinates, e.g. DrawSquare (OriginX=0, Origin Y=O, Size=3), or within another type of coordinates. Various masks may be used, such as geometric masks and/or fully descriptive masks. Further, it should be noted that masks may also be used for device discovery.

The use of different addressing schemes for different controlling devices necessitates a transformation procedure and respective structure for translating coordinates from one scheme to another. Each type of network may have its own discovery and description techniques, as well as use different protocols for data transmission. Transformation procedure may be used in cases where devices in a system use different coordinate schemes. For example, an LED matrix may be configured, e.g. using polar coordinates, but the supporting matrix controller, for instance, understands only Cartesian coordinates.

As shown in FIG 6, a central controller 310 in a display system 300 may be enabled to understand polar coordinates, and to transform Cartesian coordinates into polar coordinates, and vice versa. That is, the central controller 310 is configured to map the polar coordinates to the Cartesian coordinates, to be understood by a matrix controller or driver 320 of a lighting matrix display device 330, and displayed by the matrix display 340. Similar transformation of coordinates can be used where an LED matrix uses a coordinate addressing scheme that is not understood by the central controller in the lighting system. In such a case, the matrix controller can be configured to enable transforming of the coordinate addressing scheme understood by the central controller to the coordinate addressing scheme understood by the matrix controller.

FIG 4 shows a transformation from Cartesian to polar coordinates for each of the pixel 1-10, wherein the X coordinate, on the left graph of FIG 4, is transformed into the Radius (1st polar coordinate on the right graph of FIG 4) specified by the X coordinate, and the Y coordinate, on the left graph of FIG 4, is transformed into the Angle (2nd polar coordinate on the right graph of FIG 4) specified by the Y coordinate.

FIG 5 shows a y-axis transformation from Cartesian to triangular coordinates for each pixel, wherein the Y coordinate, on the left graph of FIG 5, is transformed into the corresponding coordinate on the right graph of FIG 5, by tilting the y-axis by any desired angle, such as less than 90 degrees in the positive x-direction, for example.

FIG 6 shows a display system 300 including a lighting network 350, comprising a lighting controller device 310 and a lighting matrix device 330. The lighting controller device 310 comprises a lighting network driver 360 communicating with the network 350, and a user interface 365 communicating to the lighting network driver 360, and allowing configuration of the lighting controller device 310. The lighting matrix device 330 comprises a lighting network driver 370 communicating with the network 350, an LED driver 320 communicating with the lighting network driver 370, and a LED matrix 340 controlled by the LED driver 320. A user through the user interface 365 of the lighting controller device, also referred to as a central controller 310, may configure it to enable the addressing scheme transformation procedure, particularly with the lighting matrix 330 that could have a different coordinate addressing scheme. The LED matrix 340, for example, may be configured using polar coordinates, where each LED pixel of the matrix is capable of displaying 8- bit Red, Green, and Blue color.

In general, other embodiments may have different transformation means to enable the addressing scheme transformation procedure, for example by means of a transformation device configured to recognize and understand the description of the display device's addressing scheme and translate it into the control device's addressing scheme. The same or different transformation device may be able to translate back the commands, generated by the control device, from the control device's addressing scheme into the display device's addressing scheme. This will enable the display device to execute the commands and display images accordingly. Such transformation device may be incorporated either into the control device or into the display device, or be installed separate. It also may be embodied as a piece of hardware, firmware, software on any suitable medium, or a combination thereof.

For large matrices or higher resolution displays, data compression techniques may be used, such as run length encoding, to reduce the data traffic, processing power, and processing time. Many different methods and techniques for data compression may be used such as those disclosed in U.S. Patent Application Publication No. US 2003/0076288 Al, which is incorporated by reference in its entirely, and describes a matrix display driver receiving compressed data input, decoding in parallel the compressed data by individual decode modules for each column line with the use of a two-stage decoding: the decoding of Huffman-coded data, encoded based on the frequency of particular signals, and the decoding of run length encoded data, wherein the compression algorithms use data redundancy to reduce bandwidth requirements.

According to the exemplary embodiment shown in FIG 6, in order to discover and control the display device 300, the lighting or central controller 310 is configured to carry out the following:

(a) The lighting matrix device or controllable lighting elements 330 (having, e.g. a polar coordinate addressing scheme) and the lighting controller 310 (having, e.g. a Cartesian coordinate addressing scheme) are connected to the same network 350.

(b) The network 350 indicates to the controller 310 that a new device (matrix device 330) is present in the network 350;

(c) The controller 310 queries the matrix device 330 for its device description;

(d) The matrix device 330 returns the description of the matrix device's coordinate scheme (in this exemplary case, it's of the polar type, having three attributes: MaxRadius, RadiusStep, AngleStep) being a first part of the addressing scheme of the matrix device, and a geometric description (in this case, specified on FIG 7 between the tags <ServiceDescription> and </ ServiceDescription> using a pre-programmed function DrawFilledCircle implementing an algorithm of executing the function with four state variables or parameters: Radius, RedValue, GreenValue, BlueValue) being a second part of the addressing scheme of the matrix device, which both parts are encoded using XML, for example, as shown in FIG 7. It should be noted that device discovery is not absolutely essential. Some networks e.g. XlO, DMX do not support it but the system could still work. Devices could be dedicated to coordinate schemes and be matched by an installer. Alternatively devices may be configured by an installer (software download, DIP switch settings) to work with certain coordinate schemes. However a device discovery network, if available, facilitate and improve the implementation.

(e) The controller 310 further controls the matrix device 330 by sending an XML coded command for example, on FIG 8, indicating to use said DrawFilledCircle with the specific values assigned to the parameters (Radius=3, RedValue=255, GreenValue=O, BlueValue=O). Multiple Commands can of course be aggregated into a single control message for efficiency. The same command could also be multi-casted to multiple displays at once.

(f) When the command is executed by the matrix device 330, the LED matrix 340 displays a resultant image, created according to the matrix' description, in the form of a plurality of circumferentially positioned activated monochromatic pixels 400 of the matrix, depicted on FIG 9.

As is understood by those skilled in the art, the instruction and description codes shown in FIGs 7-8 are snippets/fragments, rather than fully formed formal XML codes, where for clarity e.g. namespaces and headers are included. Those skilled in the art would also understand that there are other possible ways to structure such instructions or commands in XML or any other type of code or software. That is, in the given examples shown in FIGs 7-8, the descriptions and the commands are XML type, but generally it can be encoded in other suitable formats as well. It also may include a mask-based part of the addressing scheme of the matrix device, similar to that illustrated on FIG 3. This part, outlined on FIG 7 by the code line: "<DeviceMask>False</DeviceMask>", is not however used for addressing in the given example. The geometric descriptions may be written in C++, Java, or any other programming language suitable for such type of functions.

The display system 300 allows the use by a number of controllers, or pieces of computer hardware, firmware, software, other devices or media, or a combination thereof, of different coordinate addressing schemes, including the polar coordinate scheme or any other, for addressing of discrete lighting elements (pixels) or certain areas of the display, for example, to reduce the necessary number of such elements, to optimize the data processing, to efficiently utilize a particular shape or other properties of the display devices. Such use encompasses the ability to control the display devices, e.g., connected to a network, and the ability of the devices to interoperate with each other, even though they operate in different coordinate addressing schemes.

The controller may be any type of controller or processor, such as those described in U.S. 2003/0057887, that are capable of receiving and providing VO signals, executing instruction stored in a memory, which may be any type of memory, RAM, ROM, removable memory, CD-ROM, and the like, also as described in U.S. 2003/0057887. It should be understood the various control and driver functions may be implemented by hardware, software, firmware and the like, alone or combinations. Further, the controllers/drivers may be physical devices that are may be separate units alone or in combination with other units, or integrated and part of other units, such as being part of or integrated with the lighting matrix device 330. Of course, instead of separate controller units even if integrated with the lighting matrix device 330, preexisting circuitry of the lighting matrix device 330 for example may be modified, via software, firmware and/or hardware modifications and/or additions, to provide the desired functionality of the controllers and/or drivers. Of course, other processors, memories storing instructions to be executed by the processor, and other elements may be included in the display system as needed.

Finally, the above-discussion is intended to be merely illustrative of the present invention and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, while the present invention has been described in particular detail with reference to specific exemplary embodiments thereof, it should also be appreciated that numerous modifications and changes may be made thereto without departing from the broader and intended spirit and scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

In interpreting the appended claims, it should be understood that: a) the word "comprising" does not exclude the presence of other elements or acts than those listed in a given claim; b) the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements; c) any reference signs in the claims do not limit their scope; d) several "means" may be represented by the same item or hardware or software implemented structure or function; and e) each of the disclosed elements may be comprised of hardware portions (e.g., discrete electronic circuitry), software portions (e.g., computer programming), or any combination thereof.

Claims

CLAIMS:

1. A display system (300) comprising: a plurality of controllable lighting elements (330) having a control configuration; and a controller (310) configured to query said plurality of controllable lighting elements (330) to determine said configuration; said controller being further configured to translate input information into output information in accordance with said control configuration for control of said plurality of controllable lighting elements (330).

2. The display system (300) of claim 1, wherein said input information includes one of a first coordinate address and a second coordinate address, and said output information includes another of said first coordinate address and said second coordinate address.

3. The display system (300) of claim 2, wherein said first coordinate address includes a Cartesian coordinate address and said second coordinate address includes a polar coordinate address.

4. The display system (300) of claim 1, further comprising a network (350), wherein said plurality of controllable lighting elements (330) and said controller (310) communicate with each other through said network (330).

5. The display system (300) of claim 4, wherein said network (330) is configured to detect said plurality of controllable lighting elements (330) and inform said controller (310) of a presence of said plurality of controllable lighting elements

(330).

6. The display system (300) of claim 1, wherein said plurality of controllable lighting elements (330) is configured to provide said control configuration to said controller (310) upon one of a connection to a network (350) having said controller and a request signal from said controller (310).

7. The display system (300) of claim 1, wherein said plurality of controllable lighting elements (330) displays a pattern in accordance with said output information.

8. The display system (300) of claim 7, wherein said pattern is displayed by masking desired ones of said plurality of controllable lighting elements (330).

9. The display system (300) of claim 7, wherein said output information includes mask-based addressing configured to reduce a size of said output information.

10. The display system (300) of claim 7, wherein said plurality of controllable lighting elements (330) include light emitting diodes.

11. A method of controlling a display system (300) comprising the acts of: providing control configuration of a plurality of controllable lighting elements; translating input information into output information in accordance with said control configuration; and controlling said plurality of controllable lighting elements with said output information.

12. The method of claim 11, wherein said input information includes one of a Cartesian coordinate address and a polar coordinate address, and said output information includes another of said Cartesian coordinate address and said polar coordinate address.

13. The method of claim 11, wherein said providing act includes communicating at least one of said input information and said output information through a network.

14. The method of claim 11, further comprising the acts of: detecting said plurality of controllable lighting elements (330); and informing a source (310) of said output information of a presence of said plurality of controllable lighting elements (330).

15. The method of claim 11, wherein said providing act is in response to one of a connection to a network (350) and a request signal from a source of said output information.

16. The method of claim 11, further comprising the act of displaying by said plurality of controllable lighting elements (330) a pattern in accordance with said output information.

17. The method of claim 11, further comprising the act of masking desired ones of said plurality of controllable lighting elements (330) to display a pattern in accordance with said output information.

18. The method of claim 11, further comprising the act of mask-based addressing of said plurality of controllable lighting elements (330) to display a pattern in accordance with said output information.

19. The method of claim 11, wherein said plurality of controllable lighting elements (330) include light emitting diodes.

20. A display system (300) comprising: means for providing control configuration of a plurality of controllable lighting elements (330); means for translating input information into output information in accordance with said control configuration; and means for controlling said plurality of controllable lighting elements (300) with said output information.

21. The display system (300) of claim 20, further comprising the acts of: means for detecting said plurality of controllable lighting elements; and means for informing a source of said output information of a presence of said plurality of controllable lighting elements.