Patent No. 5194008 Subliminal image modulation projection and detection system and method

 

Patent No. 5194008

Subliminal image modulation projection and detection system and method (Mohan, et al., Mar 16, 1993)

ASSIGNEE: Spartanics, Ltd., Rolling Meadows, IL

Abstract

Weapon training simulation system including a computer operated video display scene whereon is projected a plurality of visual targets. The computer controls the display scene and the targets, whether stationary or moving, and processes data of a point of aim sensor apparatus associated with a weapon operated by a trainee. The sensor apparatus is sensitive to non-visible or subliminal modulated areas having a controlled contrast of brightness between the target scene and the targets. The sensor apparatus locates a specific subliminal modulated area and the computer determines the location of a target image on the display scene with respect to the sensor apparatus.

Notes:

BACKGROUND OF THE INVENTION

This disclosure relates generally to a weapon training simulation system and more particularly to means providing the trainee with a (multi-layered) multi-target video display scene whose scenes have embedded therein trainee invisible target data.

Weapon training devices for small arms employing various types of target scene displays and weapon simulations accompanied by means for scoring target hits and displaying the results of various ones of the trainee actions that result in inaccurate shooting are well known in the arts. Some of these systems are interactive in that trainee success or failure in accomplishing specific training goals yields different feedback to the trainee and possibly different sequences of training exercises. In accomplishing simulations in the past, various means for simulating the target scene and the feedback necessarily associated with these scenes, have been employed.

Wilits, et al, in U.S. Pat. No. 4,804,325 employs a fixed target scene with moving simulated targets employing point sources on the individual targets. Similar arrangements are employed in the U.S. Pat. No. 4,177,580 of Marshall, et al, and U.S. Pat. No. 4,553,943 of Ahola, et al. By contrast, the target trainers of Hendry, et al in U.S. Pat. No. 4,824,374; Marshall, et al in U.S. Pat. Nos. 4,336,018 and 4,290,757; and Schroeder in U.S. Pat. No. 4,583,950 all use video target displays, the first three of which are projection displays. In the Hendry device, a separate projector projects the target image and an invisible infra-red an hot spot located on the target which is detected by a weapon mounted sensor. Both Marshall patents employ a similar principal and Schroeder employs a "light pen" mounted o the training weapon coupled to a computer for determining weapon orientation with respect to a video display at the time of weapon firing.

Each of these devices of the prior art, while useful, suffers from either or both of realism deficiencies or an inability to operate over the wide range of target-background contrast ratios encountered in real life while simultaneously providing high contrast signals to their aim sensors, and efforts to overcome these deficiencies have largely failed.

SUMMARY OF THE INVENTION

It is a principal object of the invention to provide a trainee with a target display that appears to the trainee as being readily and continuously adjustable in visually perceived brightness and contrast ratio of target brightness to scene background/foreground brightness, i.e., from a very low contrast ratio to a very high contrast ratio.

Yet a further principal object of the invention is to provide a trainee with a target display that is either monochromatic, bi-chromatic, or having full chromatic capabilities, that appear to the trainee as being readily and continuously adjustable in visually perceived hue, brightness and contrast of target scene to background/foreground scene.

It is a further object of the invention to simultaneously provide to the systems aim sensors a target display area that appears to the sensor as being modulated at an optimal and constant contrast ratio of target brightness to background brightness to thereby make the operation of the system's sensor totally independent of the brightness and contrast ratio perceived by a human trainee viewing the display.

Another object of the invention is to utilize an aim sensor which comprises a novel "light pen" type pixel sensor which when utilized in conjunction with the inventive target display, has the capability of sensing any point in a displayed scene containing targets which, when perceived by the trainee, is either very dark or very bright in relation to the background or foreground brightness of the scene.

Yet another object of the invention is to provide in a weapon training simulator system a novel "light pen" type pixel sensor combined with a target display which provides a specific high contrast area modulated at a specific frequency associated with each visual target to ensure a high signal-to-noise ratio sensor output independent of the visually perceived, variable ratio image selected for the trainee display.

Still further, a primary object of the invention is to provide a weapons training simulator whose novel, point-of-aim sensor means is capable of spectral-selective discrimination of said target area, wherein said target area scene, a specific area is chromatically modulated at a specific frequency, to ensure a high signal-to-noise ratio of sensor's output, independent of the visually perceived colored image selected for the trainee.

The foregoing and other objects of the invention are achieved in the inventive system by utilizing a computer controlled video display comprising a mixture of discrete and separate scenes utilizing, either alone or in some combination, live video imagery, pre-recorded real-life imagery and computer generated graphic imagery presenting either two dimensional or realistic three dimensional images in either monochrome or full color. These discrete scenes when mixed comprise both the background and foreground overall target scenes as well as the images of the individual targets the trainee is to hit, all blended in a controlled manner to present to the trainee overall scene and target image brightnesses such as would occur in real life in various environments and times of day. Simultaneously, the target scene and aim sensor are provided with subliminally displayed information which results in a sensor perceived high and constant ratio of target brightness to background and foreground brightness independent of the trainee perceived and displayed target scene brightness and contrast. The objects of the invention are further achieved by providing a simulator system for training weapon operators in use of their weapons without the need for actual firing of the weapons comprising background display means for generating upon a target screen a stored visual image target scene, generating means for showing upon said visual image target scene one or more visual targets, either stationary or moving, with controllable visual contrast between said one or more visual targets and said visual image target scene, said generating means further comprising means for displaying one or more non-visible modulated areas, one for each of said one or more visual targets, sensor means aimable at said target scene and at said one or more targets and sensitive to said one or more non-visible modulated areas and operable to generate output signals indicative of the location of one of said one or more non-visible modulated areas with respect to said sensor means, computing means connected to said background display means to control said visual image target scene and said one or more targets generated thereon so as to provide said controllable contrast therebetween, and said computing means connected to said sensor means effective to utilize said sensor means output signals to compute the location of the image of said one of said one or more targets with respect to said sensor means. The nature of the invention and its several features and objects will be more readily apparent from the following description of preferred embodiments taken in conjunction with the accompanying drawings.

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In addition to the various methods of special area modulation described in this disclosure, other methods of special area modulation will become apparent to those skilled in the arts; one such method being brightness modulation based upon the polarization characteristics of light.

From the foregoing description, it can be seen that the invention is well adapted to attain each of the objects set forth together with other advantages which are inherent in the described apparatus. Further, it should be understood that certain features and subcombinations thereto are useful and may be employed without reference to other features and subcombinations. In particular, it should be understood that in several of the described embodiments of the invention, there has been described a particular method and means for providing a target display which contains invisible to the eye high contrast areas surrounding targets and means for identifying designated targets. Even though thus described, it should be apparent that other means for invisibly highlighting targets in either high or low contrast target scenes and utilizing video display projectors and their video drivers for effecting this result, could be substituted for those described to effect similar results. The detailed description of the invention herein has been with respect to preferred embodiments thereof. However, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.