Method and device for recording and restitution in relief of animated video images

An animated scene viewed simultaneously at two different angles is recorded in the form of video signals on two videodisks which thus contain after recording a sequence of left-hand images and a sequence of right-hand images respectively. The images are restituted in synchronism by two readers, the signals of which are transmitted for visual display to two monitors associated with mirrors for reflecting the displayed images respectively to the left eye and to the right eye of a viewer.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to techniques for recording animated pictures 
in the form of video signals, then subsequently restituting them from the 
recorded signals in the form of stereoscopic animated images or pictures 
which the observer sees in relief. 
2. Description of the Prior Art 
The problem of reproduction of animated pictures in stereoscopy has often 
claimed the attention of research workers and inventors alike. Among the 
solutions considered, it has been proposed in particular to superimpose 
two motion-picture images picked up simultaneously at different angles 
corresponding to the spacing of the two eyes of a viewer and to observe 
these superimposed images through eyeglasses equipped with corresponding 
filters. Three-dimensional vision is thus effectively achieved but can 
only be monochrome, which constitutes a severe limitation in certain 
applications. Moreover, the need to ensure that all viewers are equipped 
with specially designed eyeglasses is often prohibitive. Monochrome vision 
and the need to wear special glasses are also major handicaps in methods 
for producing similar images by electron-beam scanning. In television as 
in motion-picture projection, it is necessary at the time of restitution 
to separate the portion of image to be observed by the left eye from the 
portion of image to be observed by the right eye. More recently, it has 
been proposed to employ eyeglasses fitted with electrooptical lenses which 
are controlled so as to be opaque and transparent in alternate sequence 
and in opposition in order to observe images which are displayed in 
synchronism, namely those produced for the right eye and those produced 
for the left eye in alternate sequence. The pictures can accordingly be in 
color but this does not remove the disadvantage arising from the fact that 
viewers need to wear special glasses, if it is intended to obtain a relief 
effect. Furthermore, this technique entails the use of video scanning in 
two half-frames reserved respectively for the right-hand images and for 
the left-hand images and, since they are occulted in alternate sequence, 
this results in a not-negligible reduction in resolution. 
SUMMARY OF THE INVENTION 
The present invention makes it possible to overcome the disadvantages of 
prior art techniques and more particularly those which have just been 
recalled. Accordingly, the object of the invention is to provide a novel 
and original method which leads to a simple and attractive design in the 
field of amusement-hall games but also in the field of firing simulation. 
With this objective, the invention utilizes the distinctive properties of 
videodisks. 
It is known that, in the specific field of videodisks, the successive video 
images are each recorded in turn in concentric circles having 
progressively variable radii. Furthermore, it is possible to synchronize 
the reading of two videodisks in rotational velocity with a very high 
degree of accuracy. 
The method in accordance with the invention essentially consists in 
recording an animated scene, viewed simultaneously at two different 
angles, in the form of video signals on two videodisks which thus contain 
after recording a sequence of left-hand images and a sequence of 
right-hand images respectively, in also forming synthetic images or 
symbols in electronic form, and in restituting the animated images 
combined with the synthetic images in synchronism by means of two 
corresponding visual display monitors associated with means for reflecting 
the displayed images respectively to the left eye and to the right eye of 
a viewer. 
A device in accordance with the invention for the practical application of 
the above method comprises a first and a second videodisk reader 
respectively for the restitution of a sequence of left-hand images and a 
sequence of right-hand images, means for synchronizing the speed of 
rotation of the two corresponding disks within the readers, means for 
initiating simultaneous startup of the two readers on one and the same 
image of the two sequences, two monitors respectively for display of the 
images restituted by the two readers, insertion means of a left-hand and 
right-hand type respectively associated with the two readers for inserting 
synthetic images or symbols in the left-hand and right-hand images 
restituted by the readers, and associated means for reflecting the 
displayed images respectively to the left eye and to the right eye of a 
viewer. 
The signals corresponding to the synthetic images or symbols determined 
beforehand in order to define a shape and a position which are either 
stationary or moving in the left-hand and right-hand animated images are 
combined with the video signals restituted by the readers, with the result 
that the synthetic images or symbols are displayed by the monitors in 
superimposed relation or mixed with the animated images restituted by the 
corresponding readers. 
In amusement-hall games, the device in accordance with the invention can 
advantageously be designed in such a manner as to ensure that the 
displayed animated images can appear at the same time, with relief for a 
principal viewer and in particular for a player but without relief for 
spectators who are standing by.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As illustrated in FIG. 1, a device in accordance with the invention 
comprises two videodisk readers 11 and 21, and two monitors 12 and 22 
which are associated with the readers and display on their respective 
screens the video images restituted by the corresponding readers. The 
speeds of rotation of the disks within the two readers are synchronized in 
order to remain continuously identical, the synchronization being ensured 
in a manner known per se. The internal mechanisms of the first reader 11 
also serve to drive the disk within the second reader 21 (as indicated by 
the arrow 2). In addition, the two readers 11 and 12 are placed under the 
control of a digital computer 1 containing all the data and instructions 
which are necessary for operation of the device as a whole. 
The disks introduced into the readers 11 and 21 contain a recording in the 
form of video signals, of two animated image sequences corresponding to 
the same scene viewed in stereoscopy. In other words, the corresponding 
shots of the same scene have been taken simultaneously by means of two 
video cameras, the scene being viewed by these cameras at two different 
angles. By way of example, the two cameras are spaced at a distance of 
approximately one meter in the case of a scene filmed at a distance of a 
few tens of meters. 
The result achieved by the foregoing is that the images which are 
restituted by the readers 11 and 21 and displayed on the screens of the 
monitors 12 and 22 are stereoscopic animated image sequences corresponding 
respectively to the left eye and to the right eye of one and the same 
observer. It is assumed in FIG. 1 that the reader 11 is reserved for the 
disk of the sequence of left-hand images and that the reader 12 is 
reserved for the disk of the sequence of right-hand images. It will 
clearly be understood that the disks can contain a number of sequences of 
different successive scenes. 
As indicated by an arrow 3 in FIG. 1, the readers are controlled by the 
computer 1 so as to start-up simultaneously on the same image of their 
respective sequences, this condition being readily checked with high 
precision in the case of videodisks. It is also apparent from FIG. 1 that 
the same computer 1 equipped with suitable electronic interfaces ensures 
the operation of two insertion devices 13 and 23 which are associated 
respectively with the two readers. In accordance with known practice, 
these devices serve to insert in the images restituted by the readers 
synthetic images or symbols representing, for example, objects or targets 
at which the viewer is expected to aim. The viewer may in particular be a 
player stationed in front of an amusement-hall console or else an operator 
who is controlling a firing operation or sequence in a firing instruction 
simulator. 
The items of information which characterize these symbols or images, both 
in their intrinsic shape and in their position with respect to the scene 
in which they appear and in any movements which they may perform, are 
supplied by the computer which determines them from previously recorded 
rules and data in accordance with a technique which is conventional and 
known per se. However, the insertion operation is carried out in such a 
manner as to initiate the appearance of said symbols or images with a 
relief effect. To this end, the items of information which provide the 
insertion instructions are determined differently by the computer for the 
two insertion devices associated respectively with the left-hand reader 
and the right-hand reader in such a manner as to ensure that the image 
inserted by the left-hand reader corresponds to the viewpoint of the 
left-hand image and that the image inserted by the right-hand reader 
corresponds to the viewpoint of the right-hand image. In other words, the 
inserted images are restituted on the left-hand side and on the right-hand 
side as they would be seen with the same angular spacing as the images 
restituted by the readers. 
In order to reconstitute the relief effect, the two sequences of images 
which are visible on the screens simultaneously are observed respectively 
through the two eyepieces of an optical sight 4. Two symmetrical optical 
reflection systems consisting of total reflection mirrors designated on 
one side by the references 14 and 15 and on the other side by the 
references 24 and 25 transmit the left-hand images derived from the reader 
11 and the monitor 12 to the left-hand eyepiece 5 of the optical sight and 
the right-hand images derived from the reader 21 and the monitor 22 to the 
right-hand eyepiece 6. 
A control keyboard which is usually provided with a hand lever is placed 
within easy reach of the user and enables him to transmit instructions to 
the computer. The user can thus control a simulated projectile and thus 
aim at targets as they appear on the scene which is displayed in 
stereoscopy. It is worthy of note in this connection that, whether the 
fire simulation device is intended for games or for training in the 
handling of weapons systems, a considerable improvement in the device is 
achieved by the present invention. This improvement lies in the 
possibility of estimating or measuring the distance of objects located in 
a natural landscape environment. 
In FIG. 2, there is shown diagrammatically an alternative embodiment of the 
device which is particularly well suited for an amusement-hall game. There 
have been shown in this figure only the arrangements which differ from the 
embodiment illustrated in FIG. 1 in regard to visual display and 
observation of the sequences of restituted animated images. It is apparent 
that the screens of the monitors 12 and 22 are placed obliquely in 
divergent directions and that the mirrors 14 and 24 are of the 
semi-reflecting type. In consequence, the optical reflection systems 
transmit the respective images to the left and right eyepieces of the 
optical sight 4 as in the previous embodiment but, in addition, the same 
images are visible to spectators who are standing by, the left-hand images 
being visible at a left-hand side of the optical sight whilst the 
right-hand images are visible at a symmetrical angle on the right-hand 
side of the optical sight. The use of the optical sight may remain 
reserved for a single "player" who is the only person to benefit by a 
relief effect. 
As has already been pointed out, the particular features of the embodiments 
hereinabove described do not imply any limitation and have been given 
solely by way of example. Thus all alternative forms and all functional 
equivalents of the means described in the foregoing remain within the 
scope of the invention.