FR2754343A1 - METHOD FOR REPRESENTING THE LIGHT DISTRIBUTION OF A PROJECTOR TO BE CONTROLLED - Google Patents

Abstract

Method for representing the light distribution of a projector to be controlled. A real scene is recorded with an analysis projector and the clarity is corrected locally according to the reproduction of the scene. The degree of transmission of a liquid crystal display (18) which defines the clarity is changed in partial ranges independently of each other with control voltages.

Description

STATE OF THE ART The present invention relates to a method of

  presentation of the light distribution of a projector to be controlled, according to which a real scene is recorded with an analysis projector and when the scene is reproduced

locally corrects clarity.

  According to document DE-38 26 813-A1, a method is known for representing the light distribution of a light

  jector to control; according to this method, first of all a recording of a real fixed or mobile scene is carried out with an analysis projector. When reproducing the scene, the clarity is corrected using a mask with a degree of transmission depending on the location. For each performance or simulation, a mask is required under these conditions, for example made by a photographic process; mask density

  is calculated from knowledge of the predeter data-

  mined from a projector to control.

  Another exemplary embodiment proposes to record the real scenes below mobile with a camera. The film impressed and developed by the photo camera is then detected to obtain an image signal.

  electronic. When the recording is reproduced, the light intensity of each point is multiplied with a coefficient

  cient to represent the scene visible on the reproduction image screen, as if it were lit by the projector

to control.

  The first example of realization presents

  the disadvantage of requiring the manufacture of a mask

  tinct for each simulation or each projector to control

  and thus be very expensive. The second embodiment has the disadvantage that to represent the mobile scenes

  them, you need a powerful calculator and therefore expensive. Advantages of the invention The method according to the invention for representing the light distribution of a projector to be controlled makes it possible, for the same scene, to rapidly modify the lighting of the

  projector to simulate several projector lights in a very short time. Given the value of

  riation of the degree of transmission of a device in the partial ranges, independently of one another, it is possible to simulate any different conditions, which may

  be reproduced through variations in the degree of transmission

  sion produced in the different independent partial ranges. According to an advantageous development of the invention, the degree of transmission of the device is modified by

  the application of control voltages. This allows a cor-

  precise rection of clarity and simple implementation of the device.

  According to another advantageous development of the process

  As of the invention, there is a liquid crystal screen composed of a matrix with a large number of pixels, the degree of transmission of the pixels being adjusted separately. We can thus have a flexible adjustment and offering multiple possibilities of variants for the matrix with degrees of transmission

  different, which makes it possible to simulate a large number of pro-

  connectors to check. In addition, the method offers the advantage that the representation of a scene can be done with a

  resolution much higher than that allowed by a mo-

  high definition television (HDTV) editor. In addition, such a method offers the advantage of allowing representation with a large diagonal image. This allows a simulation

very close to reality.

  An advantageous development of the method consists in adjusting in stages the degree of transmission of the pixels. This allows, thanks to the advantageously high number of levels, to have a fine adjustment of the degree of transmission so that

  reproduction is once again close to reality.

  According to other advantageous features of the invention:

  * the number of pixels is defined by the resolving capacity

  tion of the transparent recording, a black and white screen or a color liquid crystal screen is used,

  ò the liquid crystal screen is provided near a

  transparent registration, * the liquid crystal screen is placed behind

  recording in the direction of projection.

  The present invention will be described below in more detail with the aid of an exemplary embodiment of the method of the invention, with the aid of the accompanying drawings in

  which: the only figure is a schematic view of a dis-

  positive projection to reproduce the recordings on

  a liquid crystal display (LCD display).

  Description of the exemplary embodiment

  The single figure shows a device for a method of representing the light distribution of a projector to be controlled. A slide projector 11 consists of a light source 12, a mirror 13 and a

  condenser 14. A transparency record 15 is placed

  between the condenser 14 and the objective 16. The objective 16 projects the image of the transparent recording 15 which can

  be for example a slide, on an image screen 17. In-

  be recording 15 and objective 16, we have a device

  18 close to record 15 and whose degree of trans-

  mission is modified in the partial ranges, independently of one another by the control voltages. The device 18 is advantageously produced in the form of a liquid crystal screen which can be a black and white screen or a color liquid crystal screen. As a variant, the liquid crystal screen 18 can also be placed in

  upstream of recording 15 in the direction of projection.

  Instead of a slide projector 11, it is also possible to use a writing projector or the like for which the liquid crystal screen 18 is as close as possible to the transparent model or recording 15. In the representation method according to the invention, for the light distribution of a spotlight with

  control, during a first step, we carry out

  recordings of an actual scene such as a street scene. For dynamic scenes, you need a film while

  for static scenes, just use slides-

  tives. We can have black and white recordings or

  color recordings. At the reproduction of the static scene

  that or mobile, we correct the clarity according to the projector

  to control. For the observer, the scene then appears

  che of reality, as if it were enlightened by the pro-

jector to control.

  Correcting the clarity of a headlamp

  trôler is obtained by the modification of the degree of transmission-

  if we. The liquid crystal screen 15 consists of a matrix with a large number of pixels. The degree of transmission of each pixel can be adjusted by control voltages and be modified. We can thus have an exact correction of the

  projector to be controlled and by the control voltage applied

  the level of transmission for reproduction is fixed

  by localized correction of clarity. The degree of trans-

  pixel mission offers a sufficiently large adjustment range with a sufficiently large number of steps to allow

  put to modify the degree of transmission with very small steps. The advantageous arrangement of the LCD liquid crystal screen 18 near the recording 15 makes it possible to

  copy the liquid crystal display 18 with a net fault

  imperceptible sharpness on the image screen 17. In addition, this method offers the advantage that the number of pixels of an LCD screen 18 is less than the resolution power of a recording.

  15, because the stage lighting is practically in con-

  continuous with respect to the projector to be controlled.

  This process also offers the advantage that reproduction is possible with a large diagonal image and thus being very close to reality. Likewise, this method30 makes it possible to reproduce with a light distribution of a projector to be controlled, with a resolution much higher than that of current HDTV monitors. In particular, this method is characterized in that it is more advantageous and more powerful than the known embodiments according to the state of the art and makes it possible to modify the lighting of the projector according to a rapid succession throughout the scene. in that the control voltages and so the

  degree of transmission of each separate pixel can be mo-

  quickly defined. To modify the degree of transmission, techniques analogous to those of a screen can be used.

  liquid rates which allow a modification of the degree of transmission as a function of an electrical voltage.

Claims (6)

R E V E N D I C A T IONS   1) Method for representing the light distribution of a projector to be controlled, according to which a light is recorded   real scene with an analysis projector and reproduc-   tion of the scene we correct the clarity locally, characterized in that   the degree of transmission that defines the clarity of a device   tif (18) is modified in independent partial ranges   your. 2) Method according to claim 1, characterized in that the degree of transmission of the device is modified in the   partial ranges by the application of control voltages.   3) Method according to claim 1 or 2, characterized in that the degree of transmission is modified with a liquid crystal screen (18) composed of a matrix of pixels, the degree of   pixel transmission being set independently.   4) Method according to claim 3, characterized in that   the degree of pixel transmission is adjusted in steps.    ) Method according to one of claims 3 or 4,   characterized in that the number of pixels is defined by the resolution capacity   transparent recording (15).   6) Method according to claim 3, characterized in that   we use a black and white screen or a color screen liquid rates.   7) Method according to any one of claims 3 to 6,   characterized in that the liquid crystal display (18) is provided near a transparent recording (15).   8) Method according to one of claims 3 to 7,   characterized in that the liquid crystal display (18) is placed behind   the recording (15) in the direction of the projection.