FR2838904A1 - Facial motion capture imaging unit for video game generation has color video camera viewing subjects face through mirror with white light illumination - Google Patents

Abstract

A facial motion capture imaging unit (10) has a color video camera (24) on a chin strap (21) fixed helmet (12) viewing the wearer's face through a support (30) mounted oblique mirror (32) using reflected or direct white light illumination (26, 28).

Description

source. The present invention relates to an acquisition device

dtimages for

be worn by a user.

  Wile applies in particular to the production of animations using digital means. We already know in the state of the art an image acquisition device intended to be worn by a user, of the type comprising a helmet intended to style the

  head of the user and a camera for image acquisition.

  Such a device is used in particular to capture in the form of digital data the movements (expressions) of the face of an actor. The camera is of the infrared radiation type. Markers sensitive to this wind radiation placed on the face of the actor, the latter evolving in an illuminated environment in infrared. The camera is associated with data storage means in which the facial movements are memorized in the form of curves. These wind curves

  used later for the realization of an animation.

  The facial images obtained by this technique, commonly referred to by the Anglo-Saxon terms "motion capture", present a degree of realism that we

wish to improve.

  The object of the invention is to propose a tool intended for the production of nu meric images of the face of an animation character representing a degree of realism greater than that generally obtained by the conventional technique of capturing movement, this in particular in view of integrating these images into interactive animations, such as video games, capable of being implemented by

  ordinary domestic or family type equipment.

  To this end, the invention relates to an image acquisition device, of the precise type, characterized in that it comprises a support, connected to the helmet, extending longitudinally in cantilever to [' front of the helmet, the optical path between the camera and the face of the user comprising at least one part extending between this face of the user and optical means in cantilever, carried by the support, provided with 'a mirror, so as to allow the acquisition of images of at least part of the face of

  The user reflecting in the mirror.

  According to other characteristics of different embodiments of this

  device: - an artificial light source connected to the helmet and positioned relative to this helmet in order to allow the lighting of at least part of the face of the user; ? -2 - the light source directly illuminates at least part of the face of the user; - the cantilever optical means comprise the light source; - The light source indirectly illuminates at least part of the face of the user; - the cantilever optical means comprise means forming a mirror reflecting, towards the face of the user, the light coming from the source; - The device comprises two light sources; - the camera is of the color video type; - The helmet comprises a ridge, intended to come to bear on the head of the user, provided with means of adaptation to the morphology of the head of the user; - the helmet includes a chin strap for immobilizing the helmet on the head

1 5 the user.

  The invention will be better understood on reading the description which follows,

  given solely by way of example and made with reference to the drawings in which: - Figure 1 is a perspective view of an image acquisition device according to a first embodiment of the invention; - Figure 2 is a perspective view of an image acquisition device

  according to a second embodiment of the invention.

  FIG. 1 shows an image acquisition device, according to a

  first embodiment of the invention, designated by the general reference 10.

  The device 10 can be used for example for the production of images

  digital for interactive animations in video games.

  The device 10 is intended to be worn by a user to capture images of the face of this user. This user is generally an interpretative actor

a scenano.

  The device 10 comprises a helmet 12 intended to style the head of the user.

  To this end, the helmet 12 is provided with an openwork cap 14, for example in material

  plastic, provided with means of adaptation to the morphology of the head of the user.

  In the example illustrated, the cap 14 comprises a part 16 forming a belt of the cranium. The tightening of this part 16 around the cranium is regulated,

  for example, using a wheel 18.

  It will be noted that the base 14 is provided with internal pads 20 for bearing on the

user head.

  J The helmet 12 is immobilized on the head of the user by means of a

chinstrap 21 connected to the jaw 14.

  In what follows, the orientations of the various elements described, such as the front and rear orientations, will be considered with respect to the usual orientations of a user wearing the device 10. A frame 22, of generally longitudinal shape, is hooked, so , con

known per se, on the cap 14.

  The frame 22 carries a camera 24, for the acquisition of video images, in particular color images. This camera 24 is positioned on the frame 22 a

near the cap 14.

  In the first embodiment of the invention, the helmet 12 carries at least one source of artificial light indirectly illuminating at least part of the face of the user. More particularly, in the example illustrated in FIG. 1, the device 10 comprises two sources 26,28 of light, hung on the helmet 12, of

  preferably on the left and right sides of the colffe 14.

  The two sources 26, 28 act relative to each other to suppress

  shadows on the user's face.

  The camera 24 and the sources of wind light 26, 28 connected to the helmet 12 and positioned relative to this helmet 12 so that, respectively, the acquisition of images of at least part of the face of the lens is allowed. user and lighting

minus part of that face.

  The frame 22 comprises a front part forming a front support 30 connected to the helmet 12. This front support 30 extends longitudinally as a scabbard at the front

helmet 12.

  Means forming a wind mirror 32 connected to the front support 30 preferably using articulated means 34 authorizing the adjustment of the mirror 32 in azimuth and height. The mirror 32 forms optical means cantilevered doors by the support

before 30.

  The optical path between the camera 24 and the face of the user comprises at

  at least one part extending between this face of the user and the cantilever mirror 32.

  The mirror 32 thus allows the acquisition by the camera 24 of images of at least part of

  the user's face reflecting in the mirror.

  The shape of the mirror 32 is adapted to reflect a relevant part of the user's face towards the camera 24. The shape of the mirror 32 may in particular be

  adapted to reflect the lateral limits of the user's face towards the camera 24.

  The shape of the mirror 32 is also adapted to reflect the light coming from the sources 26, 28 towards the face of the user, this by ensuring a good distribution of the light on this face, favorable to the acquisition of quality images by the

camera 24.

  Note that the mirror means shown in the figures have only one reflective element. Alternatively, the mirror means

  could include several reflective elements.

  It will also be noted that, in the first embodiment of the invention, the optical paths between the light sources 26, 28 and the face of the user comprise, for each source 26, 28, a part extending between the source 26,28 and the mirror 32 carried by the front support 30 and a part extending between this mirror 32 and the

face of the user.

  If necessary, the camera 24 is connected to the armature 22 by means of articulated means allowing the adjustment of the aiming angle of the camera 24. Of course, the field of vision of the camera 24 can be adapted for ['acquisition of images of a party

  or the entire face of the user.

  If necessary, the rear end of the frame 22 is extended by means 36 forming a counterweight to optical means comprising the mirror 32. However, the mirror 32 can be relatively light. Iumibre camera 24 and sources 26,28

  being positioned near the cap 14, the mass of the counterweight 32 can be limited.

  The light emitted by sources 26, 28 is preferably white. This light can be filtered, if necessary, by a color filter. Sources 26, 28

  can also emit colored light directly.

  The user wearing the device 10 may be an actor intended to evolve, in accordance with a conventional technique for capturing movements, in an environment illuminated by infrared radiation with a view to the acquisition of data.

  relating to the movement of parts of the body of the actor distinct from the face of this actor.

  The infrared radiation usually used for this motion capture technique is of the near infrared type, of wavelength included

between 0.7 and 3 µm.

  Preferably, the spectral composition of the light emitted by the sources 26, 28 is chosen by a person skilled in the art so as not to interfere with infrared radiation. This choice can be made by a person skilled in the art, for example by successive tests of white or colored lights (filtered white source or color source) by verifying that the spectral composition of the light emitted by the sources -5 26.28 does not have an undesirable impact on the images captured by an infrared camera intended for capturing the movement of the body parts of the actor other than his face. In Figure 2, there is shown an image acquisition device according to a second embodiment of the invention. In this figure 2, the elements similar to those of figure 1 are designated

by identical references.

  In this case, the device 10 is equipped with at least one light source directly illuminating at least part of the face of the user, for example two

  26.28 light sources as shown in Figure 2.

  A first light source 26, intended to illuminate the teas of the face of the user, and connected to an arm 38, secured to the support 30, by means of articulated means 40 authorizing the adjustment of the angle of the light beam emitted by this source 26 in azimuth

eVou in height.

  The second light source 28, intended to illuminate the upper face of the user, is connected to the support 30 by means of articulated means 42 allowing adjustment

  of the angle of the beam of light emitted by this source 28 in azimuth eVou in height.

  The two sources 26, 28 act relative to each other to suppress

  shadows on the user's face.

  It will be noted that the mirror 32 is connected to the arm 38 by the articulated means 34.

  In the second embodiment of the invention, the light sources 26,28 form part of the optical means cantilevered by the front support 30. Preferably, each light source 26,28 comprises a fluorescent tube , for example of the type sold by the company Kinoflo under the trade name Micro-Flo. Fluorescent tubes provide diffuse lighting and

  relatively uniform part of the face exposed to each source 26, 28.

  Among the advantages of the invention, it will be noted that this makes it possible to capture a part of the user's face extending along a relatively large angular sector (between the left and the right of the face). The facial images acquired by means of the device according to the invention can be projected on a material support or

  virtual by possibly processing the projection by anamorphosis.

  The helmet 12, provided with the chin strap 26 and the adjustment means of the cap 14, makes it possible to effectively fasten the image acquisition device with the head of the user and, thus, to avoid any undesirable relative movement between optical means

  worn by the helmet and the user face.

-6

Claims (10)

  1. An image acquisition device intended to be worn by a user, of the type comprising a helmet (12) intended to style the head of the user and a camera (24) for the acquisition of images, characterized in what it includes a support (30), connected to the helmet (12), extending longitudinally in cantilever at the front of the helmet, the optical path between the camera (24) and the face of the user comprising at least one part extending between this face of the user and cantilevered optical means, carried by the support (30), provided with a mirror (32), so that ['image acquisition   at least part of the user's face reflecting in the mirror.   2. Device according to claim 1, characterized in that it comprises at least one source (26, 28) of artificial light connected to the helmet (12) and positioned relative to this helmet (12) so as to allow the lighting of at least part of the face of the user.   3. Device according to claim 2, characterized in that the source of   light (26,28) directly illuminates at least part of the face of the user.   4. Device according to claim 3, characterized in that ies means   cantilever optics include the light source (26, 28).   5. Device according to claim 2, characterized in that the source of   light (26,28) indirectly illuminates at least part of the face of the user.   6. Device according to claim 5, characterized in that the cantilever optical means comprise means forming a mirror (32) reflecting, towards   the face of the user, the light from the source (26, 28).   7. Device according to any one of claims 2 to 6, characterized in   that it includes two light sources (26, 28).   8. Device according to any one of the preceding claims,   characterized in that the camera (24) is of the color video type.   9. Device according to any one of the preceding claims,   characterized in that the helmet (12) comprises a ridge (14), intended to come to bear on the head of the user, provided with means (18) for adapting to the morphology of the head of the user.   10. Device according to any one of the preceding claims,   characterized in that the helmet (12) comprises a chin strap (21) for immobilizing the   helmet (12) on the user's head.