Method for controlling a light-emitting diode (LED) display panel

Abstract

The invention relates to a method for displaying a multimedia document, the method comprising the steps of: generating an image (IM) made up of pixels from a displayable or displayed version of a multimedia document (MD); determining an average (MCL) or dominant color of the image; searching in a color table (CCT) for a color closest to the average or dominant color; determining a first power consumption indicator (CS) for displaying the multimedia document as a function of the power consumption associated in the table with the closest color found; and displaying the first power consumption indicator. Figure 2

Description

Title of the invention: Method for controlling a light-emitting diode (LED) display panel technical field

[0001] The present invention relates to LED (Light-Emitting Diode) display panels, regardless of their size, LED density, or resolution. Such panels can be installed, in particular, in public spaces to provide information to people in the vicinity. More specifically, the present invention relates to a method for processing the images displayed by such a display panel in order to reduce its electrical energy consumption. State of the art

[0002] Typically, the maximum electrical power of an LED display panel ranges from 1000 W to 6000 W depending on its resolution and size (for surfaces of 2 to 8 m²). In practice, depending on the displayed content and the emitted light output, the average electrical power consumed is around 40% of the maximum power. Since the daily usage time of such a display panel is around 18 hours, a display panel with a maximum electrical power of 3000 W has an annual electricity consumption of around 7884 kWh (= 3000 x 40% x 18 x 365). An operator owning a display panel or a network of several display panels is therefore faced with the economic and environmental aspects related to the operation of such panels.

[0003] Most display panel manufacturers offer a solution for optimizing light intensity based on ambient light. Thus, when ambient light is low, the emitted light intensity is reduced, notably to minimize glare for the user. When ambient light is high, the emitted light intensity is reduced, thereby improving the readability of the display panel.

[0004] This solution provides an initial energy reduction. There are also display technologies that consume less energy (e.g., OLED, LCD, etc.). However, these technologies remain expensive and less durable in outdoor use.

[0005] It can also be observed that such a display panel can exhibit minimal energy consumption for displaying a black image, and maximum for a white image. Furthermore, the power consumption of an LED is primarily related to the luminous intensity and color emitted. In addition, the eye Human sensitivity to color is not uniform. As a result, the brightness of red LEDs is generally greatly increased to achieve equivalent perception. Consequently, the energy consumption of a display screen is primarily linked to the composition of the image being displayed. Based on these observations, it has been proposed to display a black image during periods when the display panel is inactive, particularly at night. However, the energy savings achieved with this solution remain limited since the display panel's circuits, and especially the LEDs, are always powered.

[0006] Furthermore, it has been observed that certain colors of nighttime lighting have a negative impact on wildlife. Therefore, to further optimize electricity consumption and limit or eliminate this impact, some operators completely cut off the power supply to the display panel at night.

[0007] In the interest of consumers and the environment, it is therefore desirable to further reduce the electrical energy consumption of an LED display panel. It is also desirable to raise awareness among operators of LED display panels regarding the electrical consumption of such panels in relation to the image or sequence of images to be displayed. It may also be desirable to raise awareness among operators of such display panels regarding the impact of the light emitted by them on wildlife. Summary

[0008] Embodiments relate to a method for displaying a multimedia document, the method comprising steps of: (a) generating an image made up of pixels from a displayable or displayed version of a multimedia document; (b) determining an average or dominant color of the image; (c) searching in a color table for a color closest to the average or dominant color; (d) determining a first indicator of power consumption of the display of the multimedia document as a function of a power consumption associated in the table with the closest color found; and (e) displaying the first indicator of power consumption.

[0009] In this way, it is possible to assess the power consumption associated with displaying a multimedia document that may include information of very different types, such as text, images, and video sequences. This assessment then allows for corrective measures to be taken to reduce this power consumption.

[0010] According to one embodiment, the method comprises the steps of: selecting a filter having a uniform color and opacity, the color and opacity of the filter being selected according to the average or dominant color of the image; displaying the filter as an overlay on the multimedia document according to of the filter opacity; and perform steps (a) to (e) using the multimedia document associated with the superimposed filter.

[0011] Superimposing a colored filter on the display of a multimedia document can reduce the power consumption of the display. Combined with determining the power consumption of the display of the document associated with the filter, this measurement allows for the definition of an iterative process for defining a filter that is both efficient in terms of power consumption and only slightly degrades the visual quality of the document display.

[0012] According to one embodiment, the opacity of the selected filter can be equal to 0.3 or 0.6.

[0013] Choosing a limited number of opacity values ​​reduces the task of minimizing the power consumption of a multimedia document display. It also turns out that intermediate opacity values ​​have only a slight impact on this power consumption.

[0014] According to one embodiment, the color closest to the average or dominant color is determined by a distance calculation between color components of the average or dominant color and each color in the table.

[0015] In this way, using a table of electrical consumption by color, it is possible to evaluate the electrical consumption of a particular color with a low margin of error. The margin of error is all the smaller the greater the number of colors referenced in the table.

[0016] According to one embodiment, the method includes steps consisting of determining and displaying a second indicator of electrical consumption as a function of the size of the multimedia document.

[0017] Thus, another source of electrical consumption is taken into account to obtain greater accuracy.

[0018] According to one embodiment, the method includes steps consisting of determining and displaying a third indicator of the impact on wildlife of the display of the multimedia document, based on the average or dominant color of the multimedia document.

[0019] The evaluation of this wildlife impact indicator offers the possibility, by the process defined above, of obtaining a multimedia document display with such a minimized impact.

[0020] According to one embodiment, several filters are selected and associated with the multimedia document MD, one of the filters being selected according to the ambient light to be displayed in a layer superimposed on the multimedia document.

[0021] Taking ambient light into account makes it possible to finely adjust the power consumption of the display of a multimedia document while preserving the visual quality of the display regardless of the intensity of the ambient light.

[0022] According to one embodiment, the multimedia document includes at least one of the following elements: text, one or more images, and one or more video sequences.

[0023] According to one embodiment, the multimedia document comprises one or more video sequences, several images formed of pixels being generated at successive times, the average or dominant color of the image being determined from the generated images.

[0024] Thus, it is possible to evaluate with greater precision the electrical consumption of the display of a video sequence, in particular when the video sequence has large variations in light intensity.

[0025] According to one embodiment, each electrical consumption associated with a color in the table is determined as a function of the electrical consumption of a light-emitting diode emitting the associated color.

[0026] In this way, the electrical consumption assessed for a multimedia document takes into account the display system ultimately used.

[0027] Embodiments may also relate to a multimedia document display system, the system comprising: a processor configured to implement the process as previously defined, a display screen, and multimedia document transmission circuits.

[0028] According to one embodiment, the display system comprises: a light-emitting diode display panel, multimedia document reception circuits, and a display panel control unit, configured to control the display by the display panel of a multimedia document in one or more superimposed image layers, and a uniform color filter associated with an opacity, in an image layer superimposed on the image layers displaying the multimedia document, taking into account the opacity.

[0029] Embodiments may also relate to a computer program product comprising instructions which, when the program is executed by a computer, lead the computer to implement the process as previously defined. Brief description of the figures

[0030] The present invention will be better understood with the aid of the following description of exemplary embodiments with reference to the accompanying figures, in which Identical reference signs correspond to structurally and / or functionally identical or similar elements.

[0031] [Fig. 1] Figure 1 schematically represents an image display system on a display panel, according to one embodiment,

[0032] [Fig.2] Figure 2 schematically represents the steps in calculating an indicator of electrical consumption of a display panel as a function of the images displayed, according to one embodiment,

[0033] [Fig. 3] Figure 3 schematically represents steps in determining a A filter to be applied to an image to reduce the power consumption of a display panel showing the image, according to one embodiment, detailed description

[0034] Figure 1 shows a display panel system comprising an LDSP display panel and display panel control circuits, according to one embodiment. The control circuits include a PWU power supply circuit, a CU control unit, and a DVU control circuit for the LDSP display panel. The PWU power supply circuit provides the necessary supply voltages to the CU control unit, the DVU control circuit, and the LDSP display panel.

[0035] The control unit (CU) is configured to transform a multimedia document into an image for display. The multimedia document may include text, and / or one or more images, and / or one or more video sequences. Thus, the multimedia document may contain only text, or it may be an image or a video sequence to be displayed full screen, or it may contain text and one or more overlaid images, and / or one or more overlaid video sequences. The multimedia document may also include several layers to be displayed superimposed, each layer being a separate multimedia document, and each layer to be superimposed on another layer being associated with a transparency or opacity indicator.

[0036] The DVU control circuit is configured to transform an image to be displayed, provided by the CU control unit, into control signals to control the pixels of the LDSP display panel according to the image to be displayed. The CU control unit is connected to an SRV server via an NT network, the server providing multimedia documents to be displayed by the LDSP display panel.

[0037] According to one embodiment, the LDSP display panel is connected to the PWU power supply circuit via a CSW1 controlled switch operated by the CU control unit. For this purpose, the CU control unit can be connected to a control input of the CSW1 switch via a circuit INTC interface circuit. The INTC interface circuit is configured to shape a control signal from the CU control unit to fit the signal shape required to control the CSW1 switch.

[0038] According to exemplary embodiments, the LDSP display panel is of the LED type, for example comprising a pixel matrix, each pixel comprising at least three LEDs emitting red, green, and blue light respectively. The control unit CU may be of the personal computer type, managed by an operating system such as Microsoft Windows™. The controlled switch CSW1 may be of the relay type, configured to control a voltage between 220 and 250 V, for example 230 V, the LDSP display panel being configured to receive and use such a supply voltage.

[0039] The DVU control circuit can be powered by the PWU power supply circuit, either directly or via switch CSW1. Indeed, in certain configurations and applications, it may be desirable to be able to quickly display a multimedia document when the LDSP display panel is powered on. In this case, it may be preferable not to switch off the DVU control circuit. The function performed by the DVU control circuit can also be fully or partially integrated into the CU control unit and / or the LDSP display panel.

[0040] According to one embodiment, the multimedia documents to be displayed are processed to determine a measurement of the power consumption of the LDSP display panel when it displays them. Figure 2 shows steps S1 to S4 of a method for measuring the power consumption resulting from the display of an MD multimedia document. The measurement method is executed by a PRC processor that can be connected to a DSP display screen.

[0041] The measurement method uses a correspondence table (CCT) to establish a list of measured power consumption values ​​for a large number of colors. The CCT table provides, for each referenced color, ranging from black (0, 0, 0) to white (255, 255, 255), a power consumption measurement, for example, in mW / image pixel, each color being expressed, for example, as three RGB color component values. An example of the contents of the CCT table is provided in Table 1 below:

[0042] [Tables 1] Color indicator (R, G, B) Power consumption (mW / Px) Power consumption code 1 (0, 0, 0) 3.0 A 2 (0, 0, 70) 3.2 A 3 (70, 0, 0) 3.3 A 4 (0, 70, 0) 3.3 A 5 (0, 0, 128) 3.4 A 6 (70, 70, 70) 3.6 A 7 (128, 0, 0) 3.7 A 8 (0, 128, 0) 3.7 A 9 (0, 128, 128) 4.0 A 10 (128, 0, 128) 4.1 A 11 (128, 128, 0) 4.3 B 12 (128, 128, 128) 4.7 B 13 (0, 0, 255) 4.8 B 14 (200, 100, 0) 5.5 B 15 (0, 255, 0) 5.9 C 16 (255, 0, 0) 6.4 C 17 (180, 180, 180) 6.9 C 18 (192, 192, 192) 7.2 D 19 (0, 255, 255) 7.5 D 20 (255, 128, 0) 7.6 D 21 (211,211,211) 8.1 E 22 (255, 0, 255) 8.1 E 23 (220, 220, 220) 8.66 E 24 (255, 255, 0) 9.5 F 25 (230, 230, 250) 9.63 F 26 (255, 250, 205) 10.32 F 27 (255, 255, 255) 10.9 F

[0043] In step SI, the PRC processor generates a displayable version, for example, displays the multimedia document MD using a rendering engine and generates an image IM made up of pixels (of bitmap type), for example, by a screen capture function. The processor then determines an average color MCL of the image IM. This operation can be performed, for example, by calculating an average value of each color component of all the pixels of the image IM.

[0044] In step S2, the PRC processor searches for the color in the CCT table that is "closest" to the average MCL color calculated in step S1. To this end, the processor can, for example, calculate a Euclidean distance between the average MCL color and each color in the CCT table, and select the color in the CCT table corresponding to the shortest distance. The Euclidean distance D to a color in the CCT table can be calculated, for example, using the following equation:

[0045] D = (RCi - RCr) + (GCi - GCr) +(BCi - BCr) (1)

[0046] in which (RCi, GCi, BCi) are the color components of the average color MCL of the IM image determined in step SI, and (RCr, GCr, BCr) are the color components of the color under consideration in the CCT table. The PRC processor begins by calculating a first distance to the first color in the CCT table and stores this distance as the shortest distance SD to the index of the first color in the CCT table, namely 1. Then, the PRC processor successively calculates the distances between the average color MCL and each of the colors stored in the CCT table. If one of the distances calculated with one of the other colors in the CCT table is less than the stored distance, the processor stores the index in the CCT table of that other color and the calculated distance D as the shortest distance SD.Once all the distances D between the average MCL color of the IM image and the colors in the table have been calculated and compared, the stored index and SD distance represent the closest CCT table color and the corresponding shortest SD distance.

[0047] In step S3, the PRC processor can evaluate the power consumption CS of the IM image by multiplying the power consumption corresponding to the closest color in the CCT table by a number of pixels on the target LDSP display screen. The PRC processor then displays the image's power consumption value on the DSP screen. A power consumption code, for example, ranging from A for black to F for white, can be assigned to each power consumption value indicated in the CCT table. In this case, the power consumption code can be displayed on the DSP screen.

[0048] In the case where the multimedia document MD comprises a sequence of images or a video sequence, several IM screenshots are acquired, for example, at regular intervals during the display of the sequence. The average color is then calculated for all the IM screenshots or for each screenshot. In the latter case, an average consumption can be determined from the consumptions evaluated for the different screenshots.

[0049] Based on the consumption value and / or the consumption code displayed, the user can decide to modify the multimedia document to reduce its power consumption. To this end, it activates a multimedia document IMDU modification unit.

[0050] Figure 3 illustrates steps S5 to S8 of modifying a multimedia document (MD), performed by the IMDU modification unit, which can be implemented by the PRC processor. In step S5, the user is prompted to choose a color filter level, for example, from low, medium, and high filter levels. The low filter level includes color filters designed to slightly reduce the power consumption associated with displaying the multimedia document (MD) while preserving its visual quality. The medium filter level aims to reduce the power consumption of the multimedia document (MD) more significantly. The high filter level aims to reduce the power consumption of the multimedia document (MD) even further, but at the cost of degrading the visual quality of the multimedia document display.

[0051] The filters may be in the form of a uniformly colored rectangle covering the entire surface of the LDSP display panel and having an opacity defined according to the selected filter level. The filter color may be defined according to the average MCL or dominant color of the MD document. It may also be possible to offer the user a choice among several possible filter colors.

[0052] By way of example, the low and medium filter levels correspond to opacities of 0.3 and 0.6 respectively, with an opacity of 0 specifying that the filter is completely transparent, and an opacity of 1 specifying that the filter is completely opaque. The color of a low or medium level filter can correspond to the complementary color of the average or dominant color of the MD document. The high filter level corresponds to a black filter (0, 0, 0) with an opacity of 0.6.

[0053] Step S6 is an average color calculation of the MD document, which can be identical to that performed in step S1, or a dominant color calculation. The dominant color of a multimedia document can be evaluated, as with the average color, from a bitmap version of the multimedia document by identifying the color displayed by the largest number of pixels in the bitmap version. This step is omitted if the user has selected the high filter level, since only one filter (black) belongs to this filter level.

[0054] At step S7, the MD multimedia document is displayed on the DSP screen with the filter determined in step S5 or corresponding to the average or dominant color determined in step S6. This display is achieved by superimposing a first lower layer containing the MD document and a second upper layer containing the selected filter, this second layer being displayed taking into account the opacity of the selected filter. The user is then prompted to choose whether to validate this filter as is. The user can then choose from the displayed options, or select other filters or a different filter type. If the user chooses the latter, step S5 is executed again. If the user wishes to select other filters, several FTS filters of different colors are presented. Selecting a new filter triggers the display of the MD multimedia document and the selected filter superimposed on the MD document. The user is then prompted again to confirm the filter as displayed, or to request other filters.

[0055] Step S8 is executed when the user has validated an FLT filter in step S7. This step generates a new multimedia document incorporating the initial MD document and displaying the selected FLT filter in a top layer with the opacity corresponding to the selected filter level. The modified MD multimedia document can then be processed by steps S1 to S3 to determine and display its power consumption (CS). Thus, the user can visualize the impact of the chosen filter on the power consumption of the MD multimedia document displayed with the selected filter.

[0056] According to one embodiment, the PRC processor is also configured to determine another power consumption indicator based on the size of the multimedia document MD. This indicator is determined from the size, for example in kilobytes, of all the media included in the MD. Since the multimedia document MD is transmitted, for example, over the NT network, its size can affect server storage costs and transmission costs, particularly in terms of power consumption. The power consumption indicator related to the size of the MD can thus be determined and displayed by the PRC processor, for example, in step S3.

[0057] According to one embodiment, the PRC processor is also configured to determine the impact of displaying the MD multimedia document on wildlife, particularly when the LDSP display panel is installed outdoors or is installed inside a building but visible from the outside, for example, in front of a window or shop window. Studies have shown that the extent of disturbance caused by lighting on certain animals varies depending on the color of that light. This color varies from one animal species to another, but yellow appears to be the most tolerated by wildlife in general. According to one embodiment, a code representing the impact of displaying the MD document is determined and displayed, for example, in step S3.

[0058] Furthermore, the determination of the filter colour in step S7 can be carried out in such a way as to minimize the impact on wildlife of displaying the MD document with the filter thus determined.

[0059] The MD multimedia document is finally associated with the selected FLT filter and its opacity and transmitted by the SRV server to the CU control unit for display on the LDSP display panel. The CU unit is configured to display the MD document in one or more layers, and to display the filter, taking into account its opacity, in a layer superimposed on the layers containing the MD document.

[0060] According to one embodiment, several filters are associated with the multimedia document MD and transmitted to the control unit CU, the latter being configured to select one of these filters based on the ambient light and display it in a layer superimposed on one or more layers in which the MD document is displayed. For this purpose, the CU can be connected to a sensor providing an ambient light intensity measurement.

[0061] It will be evident to those skilled in the art that the present invention is susceptible to various embodiments and applications. In particular, the invention is not limited to the application of colored filters combined with opacity or transparency to modify the power consumption associated with displaying a document. Other methods involving adjustments to other display parameters such as brightness, white balance, or color temperature can also affect power consumption.

[0062] Other opacity values ​​can also be chosen for the filters. It is important that this number of values ​​be reduced.

[0063] Moreover, other methods than distance calculations in coordinate space (R, G, B) can be easily implemented.

Claims

Demands

1. 1. A method for displaying a multimedia document, the method comprising steps of: (a) generating an image (IM) made up of pixels from a displayable or displayed version of a multimedia document (MD); (b) determining an average (MCL) or dominant color of the image; (c) searching in a color table (CCT) for a color closest to the average or dominant color; (d) determining a first power consumption indicator (CS) of the display of the multimedia document as a function of a power consumption associated in the table with the closest color found; and (e) displaying the first power consumption indicator.

2. 2. A method according to claim 1, comprising the steps of: selecting a filter (FLT) having a uniform color and opacity, the color and opacity of the filter being selected according to the average or dominant color of the image; displaying the filter superimposed on the multimedia document (MD) according to the opacity of the filter; and performing steps (a) to (e) from the multimedia document associated with the superimposed filter.

3. 3. A method according to any one of claims 1 to 2, wherein the opacity of the selected filter can be equal to 0.3 or 0.

6.

4. 4. Method according to claim 1 or 3, wherein the color closest to the average or dominant color is determined by a distance calculation between color components of the average or dominant color and each color in the table (CCT).

5. 5. A method according to any one of claims 1 to 4, comprising steps of determining and displaying a second power consumption indicator as a function of the size of the multimedia document (MD).

6. 6. A method according to any one of claims 1 to 5, comprising steps of determining and displaying a third indicator of the wildlife impact of the multimedia document display (MD), depending on the average (MCL) or dominant color of the multimedia document.

7. 7. A method according to any one of claims 1 to 6, wherein several filters (FTS) are selected and associated with the multimedia document MD, one of the filters being selected based on the ambient light to be displayed in a layer superimposed on the multimedia document (MD).

8. 8. A method according to any one of claims 1 to 7, wherein the multimedia document (MD) comprises at least one of the following: text, one or more images, and one or more video sequences.

9. 9. A method according to any one of claims 1 to 8, wherein the multimedia document (MD) comprises one or more video sequences, several images (IM) formed of pixels being generated at successive times, the average (MCL) or dominant color of the image being determined from the generated images.

10. 10. A method according to any one of claims 1 to 9, wherein each electrical consumption associated with a color in the table (CCT) is determined as a function of the electrical consumption of a light-emitting diode emitting the associated color.

11. 11. Multimedia document display (MD) system, the system comprising: a processor (PRC) configured to implement the method according to any one of claims 1 to 10, a display screen (DSP), and multimedia document transmission circuits.

12. 12. Display system according to claim 11, comprising: a light-emitting diode (LED) display panel, multimedia document receiving circuits, and a display panel control unit (CU), configured to control the display by the display panel of a multimedia document (MD) in one or more superimposed image layers, and a uniform color filter (FLT) associated with an opacity, in an image layer superimposed on the image layers displaying the multimedia document, taking into account the opacity.

13. 13. Product computer program comprising instructions which, when the program is executed by a computer, lead this one to implement the process according to one of claims 1 to 10.

Images