FR2840754A1 - Home cinema image processing installations having image processing mechanism converting digital words video format and detection element modifying digital words following image characteristics and user defined color response. - Google Patents

Abstract

The image processing mechanism (2) of digital words has a digital word input and output delivering digital video words to a display mechanism. A process transforms the digital words and a detection element (6) modifies the digital words as a function of the display mechanism color characteristics, following user defined color response.

Description

respective decoding of the two digital video signals.

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  The present invention relates to image processing and applies in particular

  to home cinema installations.

  Such installations generally comprise a video source, for example a DVD optical disc player or a demodulator connected to a cable or to a satellite or hertzian antenna, and a projection assembly comprising a projector and an associated screen. In practice, each projector has its own response, that is to say that for identical video data, the rendering of the images produced by projectors emanating from different manufacturers will not always be the same. It follows that the rendering of a film has

  the screen may not be the one the director validated.

  In addition, the ambient light conditions in which the projection takes place are not always optimal and wind likely to affect the appearance of the projected images. The headlamps are more or less powerful and a higher level of surrounding lighting can be tolerated with the brighter headlamps. It can be difficult for an individual to determine the acceptable level of ambient lighting that does not adversely affect the quality of the images. There is a need to improve or modify the rendering of the projected images, in order for example to approach the

  projection conditions validated by the director.

  In addition, treatment lines have been developed for cinema laboratories. These channels generally include a film film scanner, an imager and a projection assembly comprising a digital projector. There is a need to ensure that the images displayed on the screen of the laboratory projection set, validated by the director, correspond as faithfully as possible to what will be obtained during the projection in the rooms or at special

  "home cinema" facilities.

  The invention aims to meet all or part of the above needs.

  According to a first of its aspects, the invention relates to a device for processing video data, which can be characterized by the fact that it comprises: - at least one input for receiving incoming video data, - at least one output for deliver outgoing video data to a display device, - at least one processor to transform the incoming video data into

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  outgoing video data as a function of at least one piece of information supplied by a detection element capable of measuring at least one color characteristic of an image produced by the display device and / or as a function of at least one piece of information entered by the user regarding desired color response for different input data. The expression "video data" must be understood in a broad sense and covers data which includes at least information relating to the image. Video data can thus include, for example, additional information linked to the soundtrack. These data can be in analog or digital form. Data can for example be transmitted according to one of the following standards: PAL, RGB, YUV, SVHS, SDI, HDSDI, USB, FIREWIRE, VGA, SGA, XGA, or under other

formats again.

  The term "processor" includes any system for processing digital or possibly analog data, comprising one or more microprocessors, memories, graphics cards, analog / digital converters. The processor can optionally be integrated into a device such as a computer, a projector or television. The display device may include a projection assembly comprising

  a projector and a screen or screen with a cathode ray tube or liquid crystal.

  The term "projector" refers both to projectors intended to be associated with screens used in reflection as in transmission, for "home cinema" installations, cinemas or cinema laboratories. A projector can comprise for example a halogen lamp and a set of colored matrixes with liquid crystals or several colored light sources and a set of mirrors which can be

  each control in displacement, for example by a piezoelectric motor.

  It is possible, thanks to the invention, to process the video data before it is sent to the display device so as to take account of the specific color characteristics of the display device. The video data can thus be, for example, processed before being sent to the display device so as to obtain the

  global response sought for the processing device and the display device.

  In an exemplary implementation of the invention, the device may include a housing and, on this housing, at least two connectors that can be connected to the processor

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  for the connection of cables used respectively for the transmission of video data

  and that of the outgoing video data.

  The device may include at least one indicator to indicate if a

  predetermined condition of light environment is satisfied for the projection of a film.

  To this end, the detection element may for example include a sensor

  configure to measure the ambient light intensity.

  The detection element can be mobile or fixed relative to the processor.

  When the detection element is mobile, it can be connected to the processor by

a wireless link for example.

  The device can include a selector making it possible to make a selection between several possible treatments of the incoming video data, according to the desired rendering

by the user.

  The detection element may include a sensor configured to measure by

  example of the levels of red, green and blue on the projected image.

  The processor can be configured to send to the display device reference data making it possible to view at least one image used for carrying out measurements on the screen of the display device. The processor can be configured to determine, based at least on information transmitted by the sensing element

  when the above image is viewed, the response from the display device.

  Another subject of the invention is, according to another of its aspects, a “home cinema” installation, characterized by the fact that it comprises: - a video source comprising an optical disc player or a video data receiver, - a projection assembly comprising a projector and a screen, - a video data processing device as defined above for

  receive data from the source and transmit it, after processing, to the projector.

  The invention also has for its object and, according to another of its aspects, a cinema room, comprising: - a video source comprising a player of a medium on which wind recorded video data or a video data receiver, - at at least one projection set including a projector and a screen in the room,

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  - At least one video data processing device as defined above, for receiving data from the source and transmitting it, after processing, to the projector. Another subject of the invention is, according to another of its aspects, a video data processing method, in which incoming video data is transformed into outgoing video data by applying a correction function taking account of the colorimetric response of at minus a device such as a digital projector, which wind

for outgoing data.

  "Colorimetric response" means the color actually produced by the device when it receives a corresponding data. The colorimetric response can be the response in static regime, that is to say correspond to the response of the device when the incoming data is invariable in time, which is the case for example when

  The image remains the same during the projection.

  The invention will be better understood on reading the detailed description

  which follows, non-limiting examples of implementation, and on examining the accompanying drawing, in which: - Figure 1 is a schematic and partial view of a "home cinema" installation comprising a device of data processing carried out in accordance with the invention, - Figure 2 shows, schematically, the processor of the device of Figure 1, - Figure 3 shows, schematically and partially, the rear facade of the device of Figure 1, - Figure 4 shows an example of response curve of a display device, - Figure 5 shows partially, schematically, a laboratory processing chain, and - Figure 6 shows, schematically, an equipped cinema room

  of a digital projector operated in accordance with one aspect of the invention.

  The installation 1 of “home cinema” represented in FIG. 1 comprises a processing device 2 produced in accordance with the invention, configured to receive incoming video data coming from a video source 3, for example a disc player

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  DVD optics or a demodulator or decoder, and supplying outgoing video data to a display device comprising a projection assembly comprising a projector 4 and

an associated screen, not shown.

  In the example considered, the processing device 2 comprises a housing 5 and a detection element 6, movable relative to the housing 5, comprising at least one sensor

optics 7.

  The detection element 6 is configured, in the example considered, to transmit to the housing 5 by a wireless, radio frequency or infrared link,

  information from sensor 7.

  As a variant, the detection element 6 can be integrated into the housing 5, the source 3 or the projector 4, and comprise for example an optical sensor associated with a system of

  aiming allowing to carry out measurements on the screen remotely.

  The processing device 2 comprises a processor 15, shown diagrammatically in FIG. 2, configured to process the incoming video data from

  as to generate the outgoing video data, as will be explained later.

  Incoming or outgoing video data can be analog A or digital N. When analog, incoming data can be converted

  in digital data by a converter 17 before being processed by the processor.

  The box 5 comprises, on its rear face for example, at least a first connector 8 allowing the connection of a cable 9 connecting the source 3 to the box 5, and a second connector 10 allowing the connection of a cable 11 connecting the housing 5 to the projector 4. These cables 9 and 11 may include several electrical or optical conductors.

  Outgoing video data can be digital or analog.

  When they are analog, they have been converted from digital data

  delivered by processor 15 by converter 18.

  The processing device 2 may include, in particular on the front face of the housing 5, an indicator 12 constituted for example by one or more light-emitting diodes, the ignition of which is controlled by the processor 15, to signal to 30 user that certain conditions of light environment to view a film in good wind conditions satisfied, for example that the level of ambient light is acceptable. The processing device 2 can be configured to measure, using [

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  of the detection element 6, the ambient light level and to compare the measurement result with data stored in the processor 15, in order to warn the user, by means of the indicator 12, that the ambient lighting is sufficient falble so as not to harm

  excessively to the quality of the projection.

  In a particular implementation example of the invention, two brightness measurements can be made, a first on the screen, while the projector 4 is off or in the absence of projection of an image, and a second , always on the screen, while a predetermined image is sent by the processing device 2 to the projector 4 and projected on the screen, thereby illuminating the detection element 6. This double measurement makes it possible to determine the ratio, on the screen, between the ambient brightness and that due to the projected image and therefore to take into account, to determine the degree of lighting

  maximum acceptable ambient, of the brightness of the projector.

  Thus, for dimly lit projectors, the acceptable ambient light level will be lower than for very bright projectors, and [information

  provided by the indicator 12 may depend on the projector 4 used.

  The processing device 2 may include a display 13 allowing the user to be informed of a possible step to be taken in order to improve the quality of the projection, for example proposing to further obscure the room.

  projection or change the brightness or contrast of the projector 4.

  The processing device 2 can, alternatively or additionally, be configured so as to process the incoming video data to take account of the ambient brightness, in order for example to make the images brighter on the screen, the

optionally.

  In accordance with another aspect of the invention, the processing device 2

  can be configured to determine the color response of projector 4.

  To do this, the processor 15 sends to the projector 4 reference data and at least one measurement is carried out on the projected image, by means of the element of

detection 6.

  The processor 15 can be configured, for example, so that several different colors are successively projected filling the screen, for example a white background, a red background, a green background and a blue background, at least one acquisition being

  performed using the detection element on each projected image.

  The processor 15 can be configured so that several image sequences for each color are projected, the images of each sequence having

  a light intensity which varies from one image to another.

  During the measurements, the detection element can be fixed or mobile.

  The device 2 can also cause the display, on the screen, of a charter comprising several colors and / or the same color with several zones corresponding to different saturations and / or luminosities, and the detection element 6 can be moves

  on the screen to perform a measurement on each zone.

  The detection element 6 can be configured, for example, so as to measure color coordinates of the color of at least one area of the projected image and to send the corresponding information to the processor 15 which can determine, by comparison with the reference data sent to the projector, the color difference between the color of the image as appeared on the screen and that which would have been obtained if the response of the projector had followed a predetermined law. The processor 15 can thus determine the response of the projector and calculate a correction function

  allowing to modify in a predetermined way the rendering of projected images.

  If necessary, several measurements can be made with the detection element 6 at different points of an image corresponding to a plain background, in order for example to know the variation in brightness or color at different points of the image and allow processor 15 to take this into account when processing incoming video data. Of course, it is not going beyond the scope of the present invention when the processing device 2 is at least partially integrated into the source 3 or the projector 4

of the manufacture of these.

  The electronic circuits contained in the box 5 can for example be housed inside the source 3 or the projector 4. The electronic circuits of the source 3 and of the projector 4 can also be configured so as to execute at least some

  functions of the processing device 2.

  Once the response of the projector 4 has been determined, the processor 15 can for example process the incoming video data taking account of the response of the projector to project a corrected image having a rendering closer to that desired by the

director.

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  The processor 15 can in particular process the incoming video data so that the combined response of the processing device 2 and of the projector 4 is

  that of the projector with which the film was validated by the director in the laboratory.

  The processor 15 can in particular process the incoming video data according to a color table, also called LUT, the variables of this behind having been calculated by knowing the response of the projector 4. The color table can in particular be several, in particular trots, dimensions and translate the influence of colors on each other. If applicable, information concerning the rendering made by the director can be transmitted to the processing device 2 by the source 3, this information being

  for example recorded on the DVD optical disc.

  In this case, the processor 15 can process the incoming video data, knowing the response of the projector 4, so that the rendering corresponds to that

sounded by the director.

  The processing device 2 may include, if applicable, a selector 16 allowing the user to choose between several different renderings, for example several

  tones (hot, cold), or correspond to several types of film.

  According to another aspect of the invention, no detection element can be used, the processor 15 being able to be configured to transform the incoming video data into outgoing video data as a function of at least one piece of information entered.

  by the user, for example by means of the selector 16.

  We have shown in Figure 4 very schematically an example of response curve of the display device for a given color. This curve translates for example the luminous intensity of exit S or the screen according to the incoming data

  E which can be coded for example on eight bits, that is to say between the values 0 and 255.

  The user can for example exert an action which modifies for at least

  two input values E different from the corresponding output values S.

  As a variant, the selector 16 can be replaced for example by trots rows of control buttons, each row correspond to a color, the buttons of the same row making it possible to modify the response curve for the corresponding color,

  somewhat similar to setting an equalizer.

  The user can for example modify the intensity of a particular color in

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  low or high lights. The image can thus, for example, have a tonality

  different in high and low lights.

  We will now describe, with reference to FIG. 5, a part of a cinema laboratory processing chain 20, to which the invention can be applied according to one of its aspects. The processing chain 20 represented in FIG. 5 comprises an image scanner 21 used to digitize a silver film. The digital film can be

saves to a computer 22.

  The processing chain also includes a digital projector 23, which makes it possible to project the film into a laboratory room for validation by the

  director. The projector 23 receives video data recorded by the computer 22.

  A video data processing device 103 can be used to receive the video data recorded in the computer 22 and coming from the scanner 21, having undergone the case requiring processing, and to transmit outgoing video data to the digital projector 23. treatment 103 may be similar to device 2

previously described.

  The response of the headlamp 23 can be determined by proceeding in a manner similar to that which has been described with reference to FIG. 1, by means of a

  detection allowing measurements on the screen.

  The processing device 103 can for example send reference images to the digital projector 23, and colorimetric quantities of the projected image.

to be measured.

  The response of the projector 23 may depend in particular on the color temperature of the white, the spatial resolution, the geometric of the pixels, the dynamics of data storage, and in particular the number of bits used to store the information.

  concerning a pixel, or linear or logarithmic data storage.

  Once the response of the digital projector 23 has been determined, the video data which is intended for the digital projector 23 can be processed by the device 103 taking into account the response of the digital projector 23, so as to modify the rendering of the image projected for , for example, simulating the rendering of the image when projecting the

  film positive film correspond in a cinema room.

  According to another aspect of the invention, the processing of data intended for

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  projector 23, carried out by the device 103 when the film has been validated by the director in the projection room of the laboratory, can be communicated, as illustrated in the figure, to a processing device 50 in order to undergo an appropriate treatment, allowing 'on screen 41 of a cinema, after projection by means of a digital projector 40, the same rendering as in the laboratory. The device 50 may include a detection element 51 making it possible to determine the response of the digital projector 40, in a manner similar to what has been

described with reference to Figure 1.

  The video data can be supplied by a source comprising a medium on which the video data is recorded, for example an optical disc or a

  receiver 55 receiving video data by satellite.

  Of course, the invention is not limited to the examples which have just been given. The processing device 5 can in particular be used in combination with a display device comprising a cathode ray tube or a plasma or crystal screen.

1 5 liquids.

  Throughout the description, including the claims, the expression

  << comprising a >> must be understood as being synonymous with << comprising at least

  a >>, unless the contrary is specific.

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Claims (12)

  1. Video data processing device (2; 50; 103), characterized by the fact that it comprises: - at least one input for receiving incoming video data, - at least one output for delivering outgoing video data to a video device display, - at least one processor (15) for transforming the enchanting video data into outgoing video data, as a function at least of information supplied by a detection element (6) capable of measuring at least one color characteristic of a image produced by the display device and / or based on at least one piece of information entered by the user concerning the   sonimetric color response for different input data.   2. Device according to the preceding claim, characterized in that it comprises a housing (5) and, on this housing, at least two connectors (8; 10) connected to the processor (15) for the connection of cables serving respectively to the transmission   incoming video data and outgoing video data.   3. Device according to claim 1 or 2, characterized in that it comprises at least one indicator (12) for signaling if a predetermined condition   atmosphere is satisfied for the projection of a film.   4. Device according to any one of the preceding claims,   characterized by the fact that the detection element (6) is movable relative to the processor (15). 5. Device according to the preceding claim, characterized in that   The detection element (6) is connected to the processor (15) by a wireless link.   6. Device according to any one of the preceding claims,   characterized by the fact that it includes a selector (16) allowing a selection to be made between several possible treatments of the incoming video data, according to the desired rendering by the user.   7. Device according to any one of the preceding claims,   characterized by the fact that the detection element (6) comprises a configured sensor (7) 12 2840754   to measure the ambient light intensity.   8. Device according to any one of the preceding claims,   characterized by the fact that the detection element comprises a sensor (7) configured for   measure levels of red, green and blue.   9. Device according to any one of the preceding claims,   characterized by the fact that the processor (15) is configured to send to the display device reference data corresponding to a reference image, making it possible to view at least one image on the display device, and by the fact that the processor (15) is configured to determine, based at least on information transmitted by the detection element (16) when the image is viewed, the response of the display device.   10. Installation of "home cinema", characterized by the fact that it comprises: - a video source (13) comprising an optical disc player or a video data receiver, - a projection assembly comprising a projector (4 ) and a screen, - a video data processing device (2) as defined in one   any of the preceding claims for receiving data from the source and   transmit, after processing, to the display device.   11. Cinema room, comprising: - a video source comprising a player of a medium on which wind recorded video data or a video data receiver, - at least one projection assembly comprising a projector (40) and a screen ( 41) has in the room, - at least one processing device (50) for video data as defined   in any of claims 1 to 9, to receive data from the source and   transmit them, after processing, to the projector (40).   12. Method for processing digital video data, in which incoming video data is transformed into outgoing video data by applying a correction function taking into account the colorimetric response of at least one device