IL103633A

IL103633A - Device for simulating infrared images

Info

Publication number: IL103633A
Application number: IL10363392A
Authority: IL
Inventors: Miller Hanoch
Original assignee: Israel State
Priority date: 1992-11-03
Filing date: 1992-11-03
Publication date: 1998-12-27
Also published as: DE4335618A1; ZA937541B; FR2697643B1; SE9303231A0; SE9303231D0; CA2108413A1; FR2697643A1; GB2272128A; GB9321711D0

Abstract

The method comprises the steps of (a) providing a transparency (20) of an optical image of a scene (22) in the visible band; (b) directing the infrared radiation from an infra-red source (34) through the transparency and collimating the radiation with a collimator (30); (c) detecting the infra-red radiation which passes through said transparency with a device which generates an electronic image corresponding to the scene (22), and (d) providing a visible output of said detected infra-red radiation using a device (40) such as a video printer. <IMAGE> [GB2272128A]

Description

103,633/2 A DEVICE FOR SIMULATING INFRE-RED IMAGES" 'DI"TN-N"iD3 Ή ni ' IDl JT 'DTfiVZ ΙΡΊΙΠ' 1 - 3127 l4647raf.pan 9 - 10 - 92 FIELD OF THE INVENTION The present invention relates to simulated infrared images.

BACKGROUND OF THE INVENTION Methods for providing simulated infrared (IR) images are known.

U.S. Patent 4 , 760 , 267 describes a method in which an intensity pattern of IR radiation of a selected wavelength band is detected and a visible light intensity pattern is crea-ted which corresponds thereto. The visible light pattern is projected onto photographic film havin only a backing and an emulsion layer. The film is processed, resulting in a specularly reflecting silver pattern corresponding to the original IR pattern. One or both sides of the film are illuminated with radiation of the selected wavaelength, resulting in a new IR pattern corresponding to the original IR pattern.

U.S. Patent 4 , 679 , 910 describes a visible-to-IR dynamic image converter including 2 liquid crystals on both sides of a photoconductive substrate, a voltage supply, a wire grid polarizer adjacent the first crystal and a mirror adjacent the second crystal. The two liquid crystal layers spatially modulate an incident IR beam by polarization rotation. The polarization rotation is varied by applying voltage across the two liquid crystal layers. The photoconductive substrate receives and absorbs a visible image and spatially modulates the voltage across the two liquid crystal layers in accordance with the spatially, varying image... intensity. The incident IR beam is reflected by a mirror back through the liquid crystal layers and, as a result, is polarization rotated in proportion to the visible image. The polarizer converts the IR beam polarization rotation to output intensity modulation, thereby to provide an IR image.

U.S. Patent 4, 299.864 describes a method for manufacturing a visible- to-IR transducer by depositing radiation absorber onto a thin thermally insulating film in a soft inert vacuum.

U.S. Patent 4, 723 , 077 describes a visible-to-IR image converter including a source of IR light and a polarizing beam splitter which separates the IR light into two polarized beams whose polarities are mutually 'perpendicular . Two image converters respectively receive and modulate the two polarized beams, using identical visible information. The modulated IR beams are analyzed and recombined into a single beam.

U.S. Patent 4, 820 , 929 describes a device for transforming visible images into IR images using a photoconductive layer sandwiched by conductive layers across which current is passed. One of the sandwiching conductive layers is transparent and has a modulated resistivity in relation to incident visible radiation.

U.S. Patent 4, 767 , 122 describes a 3D thermal target simulator. Orthogonal thermographs of a target are reproduced on a plastics medium and are formed onto a model of the target which is transparent to radiation from internal sources. The thermographs are covered by a filter passing only a preselected portion of the spectrums of visible-light sources. The model is illuminated from outside with visible light. A visible-light television camera with a filter passing the preselected spectrum portion yields a visible-light simulation of the target. An additional visible-light television camera without the filter yields a signal which will appear as an infrared image on a TV monitor.

U.S. Patent 4 , 824 , 37 describes a screen which depictsa terrain, a target projector which projects the image of a moving target onto the screen, a weapon which projects an IR spot onto the screen, and a camera sensitive to the IR spot. When a trainee activates the weapon, the camera produces a video signal representing the position of the IR spot projected into the center of the target. The video ^signal controls a projector which produces a visible spot on the screen which represents the position of the spot.

Published GB Application 2081049 describes an IR emitting target simulator including a UV illuminated target mounted on a terrain board and a TV camera for scanning the terrain board and target. The target is at least partly fomed of a substance which fluoresces in response to UV illumination, thereby to simulate an IR emitting target.

Published GB Application 2067273 describes a low light level simulator comprising a projector with an adjustable filter which provides a screen image with IR and visible components, and 103,633/2 a weapon fitted with an image intensifier which is responsive to IR radiation and which produces a visible image.

The radiation emitted by the screen target image simulates a poorly illuminated or poorly visible target.

According to the U.S. Patent Number 5,151 ,595, an apparatus is described for developing, printing or duplicating graphic media. The apparatus contains an intense flash of visible light from the light source, which causes latent heat properties of the infra-red layer, in order to generate heat and convert the visible light into a far infra-red light. 103, 633/2 BRIEF DESCRIPTION OF THE INVENTION The apparatus for providing simulation of an infra-red image of a scene of the present invention comprises: • a transparency of an optical image of a scene in the visible band; • an infra-red source directing infra-red radiation through said transparency; • a collimator operating on the infra-red radiation; and • an infra-red imaging means comprising a forward looking infra-red imager which detects the infra-red radiation passing through said transparency and said collimator and provides a visible output of said detected infra-red radiation.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated from the following detailed description, taken in conjunction with the drawings in which: Fig. 1 is a simplified block diagram of apparatus for providing a simulation of an IR image, which is constructed and operative in accordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference is now made to Fig. 1 which illustrates apparatus 10 for providing a simulation of an IR image. The apparatus 10 includes an IR- transparency 20 of a scene characterized in that it is transparent to IR radiation. IR-transparency 20 may be generated by performing the following steps: a. Photographing a scene 22 using an ordinary, visible light detecting camera 2 , such as a Canon Al , whose field of view is alpha; and b. Printing the processed negative film from step a in a positive mode, on a substrate transparent to IR radiation, such as a suitable plastic.

The transparency 20 is disposed in or adjacent the focal plane of an IR collimator 30. The field of view covered is close to alpha. A black body 3^. such as a CI-SR8 extended area differential black body, is arranged facing the opposite side of the slide and provides IR irradiation of the slide. The IR radiation passing through the transparent portions of transparency 20 impinges upon collimator 30.

A FLIR 36 views the transparency 20 and generates an electronic image 38 which resembles the image that the FLIR would have produced in response to directly viewing the scene represented by the transparency 20. The field of view of the FLIR 36 does not exceed alpha, and the dimensions of the aperture thereof do not exceed those of the collimator , 30. A suitable FLIR is a TD32 Imaging System, commercially available from RAFAEL, Armament Development Authority, POB 2250, Haifa, Israel, The electronic image 38 generated by the FLIR is transformed to a visually sensible image 40, using a video printer such as a Mitsubi. i CP-200.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention is defined only by the claims that follow:

Claims

103, 633/5 C L A I M S :-

1. An apparatus for providing simulation of an infrared image of a scene comprising: • a transparency of an optical image of a scene in the visible band; • an infra-red source directing infra-red radiation through said transparency; • a collimator operating on the infra-red radiation; and • an infra-red imaging means comprising a forward looking infra-red imager which detects the infra-red radiation passing through said transparency and said collimator and provides a visible output of said detected infra-red radiation.

2. The apparatus described in Claim 1, wherein said transparency is disposed in the focal plane of said collimator.

3. The apparatus described in Claim 1, wherein said transparency is adjacent the focal plane of said collimator.

4. An apparatus for providing simulation of an infrared image, substantially as illustrated in the drawing with reference to the description and the above Claim. For the Applicants, Simon Lavie Patent Attorney