FR3015161A1 - RECOVERY INSTALLATION FOR RESTITUTION WITH RELIEF PRINTING - Google Patents

Abstract

The invention relates to an installation (1) for shooting a restitution in the form of animated sequence with relief printing. This installation comprises: - two cameras (21, 22) forming a first line: - two lighting devices (31, 32) distributed along a second straight line parallel to the first line respectively associated with the cameras view ; - Two measurement modules respectively associated with the shooting devices, arranged to measure a light intensity received at a shooting device from the associated lighting device; - a control module (10), arranged to control one of the two lighting devices to obtain a variation in light intensity, as long as the light intensity measured at the first camera and the light intensity at level of a second camera are not equivalent.

Description

The invention relates to the general field of shooting techniques, and more particularly to lighting during these shots.

The invention relates more particularly to a shooting installation for rendering in the form of animated sequence with relief printing, comprising at least two cameras, and a method of calibrating the lighting for this setting installation. of view. This invention is intended for shooting installations making it possible to obtain, when rendering these views, a relief impression. It is thus a stereoscopic shooting, for which the restitution in the form of animated sequence with three-dimensional effect requires that the user has a complementary device, for example adapted glasses, or a socket auto-stereoscopic viewpoint that does not require any additional device to reproduce the three-dimensional effect. These views are then assembled to form a content to be rendered as an animated sequence with a relief print, also called 3D-relief content. The rendering takes the form of a display of synthetic objects giving an effect of depth and perspective on a purely 2D display (flat screen / flat) with a single view. This is for example a movie or even a real-time content for a videoconferencing application. These shooting installations generally include several cameras or lenses distant from each other and synchronized or not between them for simultaneous shooting. It is understood that for this synchronization, the lenses or cameras are coupled together and that the shooting is simultaneous. This shooting installation usually includes a single lighting device or light source, distributing to the cameras or lenses of the light. The light distribution of the lighting device generally depends on the distance between an illuminated device and the lighting device and the angle of incidence of the main luminous flux on the illuminated device. Thus for a plurality of lenses or cameras distributed in a lighting zone of a lighting device, it is understood that the light distribution is generally not homogeneous. Each lens or camera thus receives a light whose illumination intensity is different. This can create visual discomfort for the user when rendering views in the form of stereoscopic or auto-stereoscopic animated sequences. More particularly, shadows may appear and give the user that the animated sequence has anomalies. One of the aims of the invention is to remedy the shortcomings / disadvantages of the state of the art and / or to make improvements thereto.

According to a first aspect, the invention relates to a shooting installation for a restitution in the form of animated sequence with relief printing. This photographic installation comprises two cameras forming a first line and is characterized in that it further comprises: two lighting devices distributed along a second straight line parallel to the first straight line; lighting being respectively associated with a shooting device; - Two measurement modules respectively associated with the two cameras, a measuring module being arranged to measure a light intensity received at a camera from the associated lighting device; a control module, arranged to control one of the two lighting devices in order to obtain a variation in light intensity, as long as the light intensity measured at the level of the first camera associated with the first lighting device and the light intensity at a second camera are not equivalent. The camera installation thus comprises for each camera (camera, lens) an associated lighting device. For example, for a shooting installation with four shooting devices filming the same scene under the same angle with identical magnification, for example for an auto stereoscopic application, four lighting devices are provided, each being dedicated to shooting device. By equivalent light intensities, it is meant that the light intensities measured at the level of the cameras are homogeneous in terms of the light power received for a user to whom the animated sequence will be restored.

The animated sequence can correspond to a film or even for a videophone application, at the sight of a distant interlocutor. In this shooting installation, the cameras all receive an equivalent luminous intensity. Indeed, to see a relief, each eye must simultaneously perceive two slightly offset images, one for the left eye, one for the right eye. Thanks to this installation of shooting, these two images have the same brightness. The visual comfort of the spectators is thus improved. Thus, the anomalies are reduced. The various modes or characteristics of realization mentioned hereafter can be added independently or in combination with each other, to the installation of shooting as defined previously.

In a particular embodiment of the camera installation, the control module is furthermore arranged to determine for the first lighting device the variation of light intensity to be applied as a function of the light intensities measured at the first level. shooting device associated with the first lighting device and the second camera.

In this particular embodiment, the luminous intensity of one of the lighting devices can be controlled remotely by the control module. The determination of the variation of light intensity to be applied thus makes it possible to obtain the equivalent light intensities directly. In a particular embodiment of the camera installation, the control module is arranged to control a displacement of the first lighting device along the second straight line and the variation of light intensity is obtained at least partly by driving. said displacement. In this particular embodiment, the lighting devices are movably mounted on a rail. The variation in light intensity is thus obtained totally or partially by moving one of the two lighting devices.

According to a particular characteristic, the control module is arranged to determine said displacement as a function of at least a distance between the second fixed lighting device and the second camera. In a particular embodiment, the camera installation comprises a plurality of cameras uniformly distributed along the first line, a plurality of lighting devices respectively associated with the cameras, and in which the control module is arranged to control each lighting device to obtain the variation of light intensity with respect to one of the other lighting devices. Each lighting device can be adjusted relative to the lighting device which is directly adjacent to it, that is to say directly adjacent to the second straight line. It is also possible to adjust each lighting device with respect to the first lighting device. In all cases, the first lighting device is then the reference lighting device with regard to the light intensity. According to a second aspect, the invention also relates to a control module for a shooting installation for a restitution in the form of animated sequence with relief printing, comprising two cameras forming a first straight line, this installation comprising in addition two lighting devices distributed along a second line parallel to the first line, a lighting device being respectively associated with a camera. The control module comprises: - a collection unit, arranged to obtain a measurement of a light intensity received at a shooting device from the associated lighting device; a control unit, arranged to control one of the two lighting devices to obtain a variation in light intensity, as long as the light intensity measured at the first camera associated with the first lighting device and the light intensity at a second camera are not equivalent.

The advantages stated for the shooting installation according to the first aspect can be transposed directly to the control module.

According to a third aspect, the invention also relates to a method for calibrating a camera for rendering in the form of animated sequence with relief printing, said installation comprising two cameras forming a first line, two lighting devices distributed along a second line parallel to the first line, a lighting device being respectively associated with a camera. The method comprises the following steps implemented by a control module of said installation; a first step of obtaining a measurement of a light intensity received at the first camera from the first associated lighting device; a second step of obtaining a measurement of a luminous intensity received at the second camera from the second associated lighting device; a step of controlling one of the two lighting devices in order to obtain a variation in luminous intensity, the steps of obtaining measurement and control being implemented as long as the luminous intensity measured at the level of the first device of Shooting and the light intensity at the second camera are not equivalent. The advantages stated for the installation of shooting according to the first aspect are directly transferable to the calibration process. In a particular embodiment, the calibration method further comprises a step of determining the variation in light intensity to be obtained as a function of the light intensities measured at the first camera associated with the first lighting device and the second camera. In a particular embodiment of the calibration method, the control step comprises driving a displacement of the first lighting device along the second line in order to obtain at least partly the variation of light intensity. According to one particular characteristic, the calibration method further comprises, prior to the control step, a step of determining said displacement as a function of at least a distance between the second fixed lighting device and the second setting device. view.

According to a fourth aspect, the invention relates to a program for a control module, comprising program code instructions for controlling the execution of the steps of the previously described calibration method, when this program is executed by this control module and a recording medium readable by a control module on which a program for a module is recorded.

The advantages stated for the calibration method according to the third aspect can be transposed directly to the program for a control module and to the recording medium.

The invention will be better understood with the aid of the following description of particular embodiments of the camera installation, with reference to the appended drawings, in which: FIG. 1 represents a shooting installation for a rendition under the animated sequence shape with relief printing in a particular embodiment; Figures 2a and 2b illustrate in a simplified manner two particular embodiments; FIGS. 3a and 3b illustrate steps of a calibration method of a camera installation according to particular embodiments; FIG. 4 represents a control module of the camera installation according to a particular embodiment. FIG. 1 represents a shooting installation 1 for a restitution in the form of an animated sequence with relief printing. This installation 1 comprises: three shooting devices 21, 22, 23; - Three lighting devices 31, 32, 33, a lighting device being respectively associated with a shooting device; three measurement modules, not shown in FIG. 1, respectively associated with the three cameras; - A control module 10 The devices 21, 22, 23 are for example shooting objectives or cameras. In a particular embodiment, they are synchronized with each other for shooting, in order to obtain an animated sequence with relief printing, in stereoscopy or auto-stereoscopy. The synchronization is in a particular embodiment carried out by the control module. The first two cameras 21, 22 for shooting form a first line, on which is also disposed the third device 23 for shooting. The cameras 21-23 are regularly distributed on this first line of a distance e measured between the optical axes of the cameras. The cameras 21-23 are for example mounted movably mounted on a mounting rail.

No limitation is attached to the number of cameras, the number of three being given as an illustrative example. The measurement modules are arranged to measure a light intensity received at a shooting device from the associated lighting device. Each camera device may comprise a measurement module. In a particular embodiment, a measurement module is placed at each camera device. For example, a first module measures a light intensity received at the camera 21 from the associated lighting device 31.

The lighting devices 31, 32, 33 are distributed along a second line parallel in space to the first line. In a particular embodiment, the devices 31-33 are offset relative to the associated 21-23 shooting devices in order not to dazzle them. More specifically, the main luminous flux of a lighting device forms a non-zero angle of incidence with respect to the optical axis of the associated camera. In another embodiment, the devices 31-33 are located opposite the associated cameras 21-23, that is to say that the angle of incidence is zero. In this case, mirrors are placed at the devices 21-23 shooting to avoid glare. In a particular embodiment, the lighting devices are identical in order to maximize the homogeneity and ease of adjustment and calibration. In particular, these lighting devices ensure an identical color temperature. The control module 10 is for example a microcomputer. In a first embodiment, the lighting devices 31-33 are fixed and regularly distributed on the second line according to the distance e between two cameras. FIG. 2a is a simplified illustration of the respective positions of the first two cameras 21, 22 for shooting and the lighting devices 31, 32 respectively associated in this first embodiment. Di is subsequently noted the distance between a shooting device and the associated lighting device. In this first embodiment, it is understood that Di is constant.

In a second embodiment, the lighting devices 31-33 are movably mounted on a second mounting rail. More specifically, a lighting device is fixed on a movable support on the second mounting rail. The position of the support is controlled remotely by means of the control module. Thus, the position of the lighting devices is remotely controllable by the control module. FIG. 2b schematically illustrates the respective positions of the first two cameras 21, 22 and lighting devices 31, 32 respectively. associated in this second embodiment. D12 is the distance between the lighting devices 31 and 32. In this second embodiment, the distances Di are different. The control module 10 is arranged to control one or more of the lighting devices 31-33 to obtain a variation in light intensity, as long as the light intensities measured at the level of the cameras are not equivalent. By equivalent light intensities, it is meant that the light intensities measured at the level of the cameras are homogeneous for a user to whom the animated sequence will be restored. By way of non-limiting example, a difference of less than five percent between the measured light intensities is not perceptible by a user and does not create visual discomfort.

Such a control module is represented in a simplified manner in FIG. 4. The control module 10 comprises in particular: a communication unit 100, arranged to communicate with the cameras or the measurement modules placed at the devices shooting and with the lighting devices or supports of these lighting devices; a collection unit 101, arranged to obtain a measurement of a luminous intensity received at a camera and from the associated lighting device; a control unit 102, arranged to control one of the two lighting devices in order to obtain a variation in light intensity, as long as the luminous intensity measured at the level of the first camera associated with the first lighting device and the light intensity at a second camera is not equivalent. In the first embodiment, the control module 10, more precisely the control unit 102, is arranged to control a lighting device a variation in light intensity. This control can be transmitted by means of a voltage variation or else by means of a variation of electrical intensity. In a first variant, in order to calibrate the lighting device 32, the control module 10 is arranged to determine for the lighting device 32 a variation of light intensity to be applied as a function of the light intensities measured at the level of the first device 21. image and the camera 22 and then control the variation of light intensity at the lighting device 32. As an illustrative example, one can choose an ERCO brand lighting electronic ballast "dimmable", in tension but also in phase for better alignment and removal of any flicker. In a second variant, in order to calibrate the lighting device 32, the control module 10 proceeds by successive adjustment, obtaining by means of the measurement unit 101 a measurement of the light intensity at the level of the device 22 for taking light. view following a variation and again controlling a variation in light intensity, as the light intensities measured at the level of the cameras are not equivalent. The lighting device is for example LED technology lighting. In the second embodiment, the control module 10, more precisely the control unit 102, is arranged to control a lighting device to obtain a variation in light intensity, in particular by controlling a displacement of the lighting device. following the second straight. The variation in light intensity is obtained at least in part by controlling this displacement. In a particular embodiment, the control module 10 is arranged to determine a value of a displacement to be applied to a first lighting device 32, called said secondary device, as a function of at least a distance D1 between a second device 31 of fixed lighting, said main device, and the second 21 device shooting.

More precisely, with reference to FIG. 2b, h is the orthogonal projection expressing the distance of the second camera 22 from the second straight line passing through the main and secondary lighting devices 32. The illumination E varies as the inverse of the square of the distance between the lighting device and the camera. We denote by alpha the multiplier coefficient used for the calculation of illumination E in the inverse square law. The illumination is then defined by E = alpha / D2. The alpha parameter is equal to 1.7 for a point light source of 3200 Kelvin color temperature. In a particular embodiment, the angular orientation in the space of the secondary lighting device 32 vis-à-vis the camera 22 is identical to that of the main lighting device 31 vis-à-vis of the shooting device 21. This makes it possible to have a first rough adjustment of the luminous intensity. The camera installation is then calibrated more finely using measurements and controls. Thus, the distance d12 between the two lighting devices 31, 32 adjacent (respectively associated with the cameras 21, 22 adjacent) is determined to be equal to: equation (1): h d12 = e + which gives : equation (2):. \ / alpha / E d12 = e + -h Dl Once the distance d12 has been determined, the control module 10 commands the secondary lighting device 32 to move to obtain the distance d12. This ensures that a given lighting device will not dazzle a shooting device that is not associated with it. A priori, the light intensities at the cameras 21, 22 are not then homogeneous. Once this movement has been made, the control module 10 obtains measurement modules from the light intensities measured at the cameras 21, 22 and controls a variation in light intensity at the secondary illumination device 32 as previously described in FIG. relationship with the first embodiment.

The various embodiments are described for a camera installation comprising two cameras 21, 22 and two lighting devices 31, 32 associated. It will be understood that for the photographing installation shown in FIG. 1, the control module 10 is also arranged to calibrate the lighting device 33 vis-à-vis the lighting device 32. In one embodiment in particular, the control module 10 is arranged to calibrate the lighting device 33 vis-à-vis the lighting device 31. Thus for a plurality of devices 21, 22, 23 regularly distributed shooting according to the first straight the control module 10 is arranged to control the variation in light intensity of each secondary lighting device 32, 33 with respect to the lighting device 31, 32 which is directly adjacent or adjacent to it according to the second straight line or else by in relation to the main lighting device 31. In another particular embodiment, virtual sources of lighting replace the lighting devices (or real sources). These virtual sources can be created by mirror referrals. The control module 10 as described above also makes it possible to calibrate the camera installation. In another embodiment, the cameras can be artificially removed by mirrors. The control module 10 as described above also makes it possible to calibrate the camera installation. We will now describe the calibration method of a shooting installation for a rendering in the form of an animated sequence with relief printing in a first particular embodiment, as implemented by the module 10 of FIG. control for the camera installation of Figure 1, in connection with Figure 3a. The calibration method is used to calibrate a first lighting device 32, said secondary device, vis-à-vis a second lighting device 31, said main device. In a step F1, the control module 10 obtains a measurement of a light intensity received at a main camera 21 from the associated lighting device 31. In a step F2, the control module 10 obtains a measurement of a light intensity received at a secondary camera 22 from the associated lighting device 32. In a step F3, the control module 10 determines a variation in light intensity to be obtained for the secondary lighting device according to the light intensities measured at the main camera 21 associated with the main lighting device 31 and the secondary camera 22 associated with the secondary lighting device 32. In a step F4, the control module 10 controls the secondary lighting device to obtain a variation in light intensity. The steps F1 and F2 can again be implemented to verify that the light intensities measured at the cameras 21, 22 are equivalent.

In an alternative to this embodiment, step F3 is not implemented. In this case, the measurement steps F1, F2 and control F4 are again implemented as long as the light intensity measured at the main camera 21 and the light intensity at the pickup device. secondary view 22 are not equivalent.

We will now describe the calibration method of a shooting installation for a rendering in the form of an animated sequence with relief printing in a second particular embodiment, as implemented by the module 10 of FIG. control for the camera installation of Figure 1, in connection with Figure 3b. The calibration method is used to calibrate a first lighting device 32, said secondary device, vis-à-vis a second lighting device 31, said main device. In a step G1, the control module 10 obtains a value of h corresponding to the orthogonal projection expressing the distance of the second camera 22 to the second straight line passing through the main and secondary lighting devices 31 and a value of D1 corresponding to the distance between the main camera 21 and the main lighting device 31. In a step G2, the control module 10 determines a displacement to be applied to the lighting device 32 as a function of the distance Dl and distance h. More specifically, the control module 10 determines d12 as previously described in relation to equation (2). In a step G3, the control module 10 controls a control of a displacement of the secondary lighting device 32 along the second line in order to obtain at least partly the variation of light intensity. In a step G4, similar to step F1 previously described, the control module 10 obtains a measurement of a light intensity received at a main camera 21 from the associated lighting device 31. In a step G5, similar to the previously described step F2, the control module 10 obtains a measurement of a light intensity received at a secondary camera 22 from the associated lighting device 32.

In a step G6, similar to step F3 previously described, the control module 10 determines a variation in light intensity to be obtained for the secondary lighting device according to the light intensities measured at the main camera. 21 associated with the main lighting device 31 and the secondary shooting device 22 associated with the secondary lighting device 32.

In a step G7, similar to the step F4 previously described, the control module 10 controls the secondary lighting device to obtain a variation in light intensity. Steps G3 and G7 form a control step of the secondary lighting device to obtain a variation of light intensity. In an alternative to this embodiment, step G6 is not implemented. In this case, the measurement steps G4, G5 and control G7 are again implemented as long as the light intensity measured at the main camera 21 and the light intensity at the pickup device. secondary view 22 are not equivalent. The embodiments of the shooting installation described above are based on synchronized shooting devices. It is understood that they also apply to unsynchronized cameras, this aspect of synchronization has no impact vis-à-vis the benefits provided by the installation. The invention is implemented by means of software and / or hardware components. In this context, the terms "module" or "unit" may correspond in this document as well to a software component, to a hardware component or to a set of hardware and / or software components, capable of implementing a function or a set of functions, as previously described for the module or unit concerned. A software component corresponds to one or more computer programs, one or more subroutines of a program, or more generally to any element of a program or software. Such a software component is stored in memory and then loaded and executed by a data processor of a physical entity and is able to access the hardware resources of this physical entity (memories, recording media, communication buses, electronic cards of a physical entity). input / output, user interfaces, etc.). In the same way, a material component corresponds to any element of a material set (or hardware). It may be a programmable hardware component or not, with or without an integrated processor for running software. This is for example an integrated circuit, a smart card, an electronic card for executing a firmware, etc. In a particular embodiment, the units 101, 102 are arranged to implement the previously described calibration method. These are preferably software modules comprising software instructions for executing the steps of the previously described calibration method, implemented by a control module. The invention therefore also relates to: a program for a control module, comprising program code instructions intended to control the execution of the steps of the calibration method described above, when said program is executed by said module; a recording medium readable by a control module on which the program for a module is recorded. The software modules can be stored in or transmitted by a data carrier. This may be a hardware storage medium, for example a CD-ROM, a magnetic diskette or a hard disk, or a transmission medium such as an electrical signal, optical or radio, or a telecommunications network.

Claims (12)

REVENDICATIONS1. Installation (1) for shooting in the form of animated sequence with relief printing, comprising two cameras (21, 22) forming a first line, said installation being characterized in that it comprises in addition: - two lighting devices (31, 32) distributed along a second straight line parallel to the first straight line, a lighting device being respectively associated with a camera; - Two measurement modules respectively associated with the two cameras, a measuring module being arranged to measure a light intensity received at a camera from the associated lighting device; a control module (10) arranged to control one of the two lighting devices in order to obtain a variation in light intensity, as long as the light intensity measured at the level of the first camera associated with the first camera device; lighting and light intensity at a second camera are not equivalent. 2. Installation according to claim 1, wherein the control module is further arranged to determine for the first lighting device the variation in light intensity to be applied as a function of the light intensities measured at the first camera associated with the first lighting device and the second camera. 3. Installation according to claim 1, wherein the control module is arranged to control a displacement of the first lighting device along the second line and the light intensity variation is obtained at least in part by controlling said displacement. 4. Installation according to claim 3, wherein the control module is arranged to determine said displacement as a function of at least a distance between the second fixed lighting device and the second camera. 5. Installation according to one of the preceding claims, comprising a plurality of cameras regularly distributed along the first line, a plurality of lighting devices respectively associated with the cameras, in which the control module is arranged to control each lighting device to obtain the variation of light intensity with respect to one of the other lighting devices. 6. Control module (10) for a shooting installation (1) for rendering in the form of an animated sequence with relief printing, comprising two cameras (21, 22) forming a first line, said installation further comprising two lighting devices distributed along a second straight line parallel to the first straight line, a lighting device (31, 32, 33) being respectively associated with a camera, said control module comprising: a collection unit (101) arranged to obtain a measurement of a light intensity received at a camera from the associated lighting device; a control unit (102) arranged to control one of the two lighting devices to obtain a variation in light intensity, as long as the light intensity measured at the first camera associated with the first camera device; lighting and light intensity at a second camera are not equivalent. 7. A method of calibrating a shooting installation (1) for a restitution in the form of animated sequence with relief printing, said installation comprising two cameras (21, 22) forming a first straight line, two lighting devices (31, 32) distributed along a second line parallel to the first straight line, a lighting device being respectively associated with a camera, said method comprising the following steps implemented by a control module of said installation; a first step of obtaining (Fi, G4) a measurement of a light intensity received at the first camera from the first associated lighting device; a second step of obtaining (F2, G5) a measurement of a light intensity received at the second camera from the second associated lighting device; a control step (F4, G3, G7) of one of the two lighting devices to obtain a variation of luminous intensity, the steps of obtaining measurement and control being implemented as long as the luminous intensity measured at the first camera and the light intensity at the second camera are not equivalent. The method according to claim 7, further comprising a step of determining (F3) the variation in light intensity to be obtained as a function of the light intensities measured at the first camera associated with the first lighting device and the second camera. 9. The method of claim 7, wherein the control step comprises driving (G3) a displacement of the first lighting device along the second line to obtain at least partly the light intensity variation. The method according to claim 9, further comprising, prior to the controlling step, a step of determining (G2) said displacement as a function of at least a distance between the second fixed lighting device and the second lighting device. shooting. 11. Program for a control module, comprising program code instructions for controlling the execution of the steps of the calibration method according to one of claims 7 to 10, when said program is executed by said module. 12. Recording medium readable by a control module on which the program according to claim 11 is recorded.