SU395797A1 - DEVICE FOR INDICATION OF HALF-TONE OPTICAL IMAGES - Google Patents

Description

one

The invention relates to applied optics, photography and optical information processing.

BACKGROUND OF THE INVENTION There are known devices for indicating zero-current optical images containing a film coated with a magnetic colloidal coating lens, a screen, located on the same optical axis, and light sources.

However, on the film, areas corresponding to only one tone of the image are observed.

The proposed device differs from the known ones in that the light sources are located relative to the common optical axis of the film, lens and screen at an angle of diffraction of light on the film and at different azimuthal angles.

This allows simultaneous observation of all halftones of images.

The proposed device is shown in the drawing.

It consists of a thin magnetic film / on a solid substrate 2. A magnetic colloid 3 is deposited on a film with a hidden half-top image, enclosed in a sealing transparent coating 4. On the axis passing prependicular to the bar / through its center, are the lens 5 and the screen 6 The film / is in the subject 1 plane.

lens 5, and screen 6 - in its image plane (instead of lens 5 with screen 6, the camera or the observer’s naked eye can be on the same axis).

Above the plane of the film, sources of light along an arc of 90 ° in a circular horizontal cross section of a cone accommodating a vertex in the center of the film and an angle at the apex equal to

double the angle of diffraction of light on a colloidal lattice with normal incidence of light. The number of light sources equal to the number of semitones, which is required to be distinguished, is chosen from two to several tens. The light sources 7 can be real (for example, incandescent bulbs) or imaginary, i.e., formed with the help of mirrors, prisms and a real source located elsewhere. The light sources 7 are electrically or optically coupled to the light source controllers S. The light source controllers can be of the electrical type in the power supply of individual sources 7 or of the type of absorbing filters or diaphragms placed between the light sources 7 and the magnetic film.

Each light source 7 sends a monochromatic uniform and sclimated beam of light to the entire surface of the film /.

Parts of this bundle falling into different

sections of the film with different orientation of the gratings, corresponding to different semitones, are diffracted in different ways: the diffracted meeting spreads out to. perpendicular to the film only in the case when the lattice strips are perpendicular to the plane of incidence of light from this source.

Thus, each light source visualizes (makes light on the screen 8) only one tone of the image. With the help of the light source controllers, the relative intensities of the sources 7 are set to be the same as the luminances of the respective tones in the original recorded image. Then, after lens 5 in the plane of images on screen 6, a real image with a natural half-tone ratio is observed.

By changing the strength of individual sources, you can adjust the brightness of the original halftones of a recorded image, in particular, you can transform a positive image into a negative image or select individual halftones and images recorded in them against a dark background.

Subject invention

A device for indicating halftone optical images containing a film coated with a magnetic colloidal coating, a lens, a screen located on the same optical axis, and light sources, characterized in that, in order to simultaneously observe all half-tones of the image, light sources are located in it relative to the overall optical axis of the film, lens and screen at an angle of diffraction of light on the film and at different azimuthal angles.