DE2100896A1 - Light projection system for recording or viewing transparent colored photographic or radio graphic images - Google Patents

Description

210089S

AGFA-GEVAERTAG LEVERKUSEN

Light projection system for recording, or viewing more transparently color photographic or radio graphic images.

Priority: Great Britain, January 12, 1970, note no. 1 ^ 70/70 Gevaert-Agfa N.V., Mortsel, Belgium.

The invention relates to a light projection system for recording or Viewing of transparent color photographic or radiographic images is used.

If such a transparent bid consists of adjacent areas with the same color, but w ⁴ '. If there is or has such areas of different color density, the image details reproduced by the color density difference are sometimes not clear enough when the image is recorded or viewed by means of transmitted light.

It is an object of the invention to modify the visible contrast to create such images.

According to the invention, a light projection system is used to light to send through a transparent color image, which has at least a part of that from adjacent areas with the same image color density consists, this system being characterized by a light source or light sources, one or more of which light passes through at least a part the image is sent, a filter or filter that gradually can be exposed to the luminous flux running to at least a part of the image, the filter or filters of this type Has or have light absorption properties that the gradual exposure of the filter or filters leads to a gradual increase in the Irradiation light leads, which in the part or don Tt-Lbin of the visible

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available spectrum, which or which to the part or parts of the spectrum that contains the wavelengths or the predominant wavelengths of the same image color, complementary is or are.

In the above definition, "image color" is the color of light This means that is sent through the picture or the part of the picture in question when this or this is illuminated with white light. With the The term "irradiation light" means the light falling on the relevant image or the relevant image part.

If the irradiating light is sent through the filter or filters Light acts, the visible contrast of the illuminated images is improved, especially in the case of areas with low density. . The filter or filters will hereinafter be referred to as the "contrast" filter ".

In order to be able to increase the visible contrast by a considerable amount, such a contrast filter or such a contrast filter is or are preferably used with a light absorption characteristic in which one end of the range of variation in the composition of the irradiation light mainly in the complementary part or parts of the visible spectrum lies. In the ideal case, the composition of the irradiation light at the end of the variation range lies entirely or essentially entirely in such a complementary part or such complementary parts of the spectrum. In order to achieve a wide range of contrast variation, the system is preferably constructed in such a way that the amount dee of irradiation light lying in the complementary part or parts of the visible spectrum is equal to zero or substantially equal to zero or at least less than that in the other part or parts of the visible spectrum. the amount of irradiation light lying in the other parts of the visible spectrum. Depending on the spectral composition of the light emitted by the light source or light sources, this can be achieved by using unfiltered light as irradiation light, if and to the extent that the contrast filter (s) is not ofT-iktLv: v.ö -netetzt ist b-iW. : ind. It can also be achieved by : ■, .. ■ :. L-? N.,

that the composition of the irradiation light at such times by means of a filter or by means of filters with appropriately different ones Absorption characteristics are influenced by the filter · If, for example, "white" light sources in a system for viewing cyan blue If monochromatic images are used, one or more orange-red filters can be used as contrast filters, and if and as far as such or such a contrast filter is not effective for the Image leading luminous flux is or are or can be exposed to the irradiation light remain unfiltered or a neutral color filter or a cyan filter can be used so that the irradiation light is im is essentially within the same spectral band or the same spectral bands as the image color »

Preferably, the irradiation of the image or the image part that or which is subjected to a variation in the visible contrast, is kept essentially constant during this variation. This can can be achieved in that a compensation filter or compensation filter is or will be applied, the density of which corresponds to the density of the Contrast filter corresponds. Such compensation filters are such arranged that the amount of light sent through them is within the contrast variation range for all settings, which is the The amount of light sent through the compensation filter or filters is inversely proportional The double purpose is to keep the illumination of the image essentially constant and the spectral composition of the above-mentioned irradiated light au influence so that a wide range of contrast variation is possible:

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'■ "''■ *. The gradual suspension of or the contrast filter may by its \ or its gradual shift in the light radiation carried, which is sent from the light source or the light sources to the image, or by gradual displacement of an opaque mask or opaque Masks from a blinding position with respect to such a filter or such.

The contrast filter or filters can take the form of a coating or coatings on a transparent substrate. Example

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such filters can be provided with a coating on the jacket Lamp or lamps that are used as the light source (s) or are made · In this case, a sliding Mask or sliding masks can be used, through the movement of which light is sent through the contrast filter or filters gradually covered and prevented from reaching the image

The filter (s) is or are preferably from the lamp or from the Lamps separated.

It is very suitable to use a number of contrast filters that are distributed over the cross-sectional area of the light beam emitted by the light source or light sources in the direction of the image, such filters being carried by a common carrier so that there are a number of masks which are similarly attached to the contrast filter carriers are distributed and thus a relative displacement of the carrier over a range of variation is possible at one end the contrast filters are aligned with the masks and the exposure light is light transmitted between the contrast filters and the masks while at its other end the contrast filters are aligned with the spaces between the masks, so that the Lamps are fully effective. At an intermediate relative position of the filter and mask carriers, the light is partly composed of light, that was sent through the contrast filters, and partly made up of light that did not pass through these filters. · The contrast filters can consist of coatings on a glass plate or on another carrier

According to the presently described embodiment, there are a number of the above-mentioned contrast filters which have a number of stripe-like areas on a common support and a corresponding one Take a number of appropriately shaped masks. These filters and masks are aligned with their length dimension in such a way that they are opposite the axes of a number of elongated light sources, e.g. tubular discharge lamps, run obliquely · Such a relative arrangement of the

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Filters and lamps result in an even distribution of the irradiation light at the image plane.

According to another possibility of the filter and mask arrangement are both arranged in a checkerboard pattern on relatively sliding supports.

For the primary goals, it is important that the Control system is designed so that the gradual variation of the spectral composition of the irradiation light at each point within of the total variation range can be ended instantly.

Since the invention is primarily directed to the consideration To facilitate transparent monochromatic or polychromatic images, especially monochromatic X-ray images, it is in the sequence in this context described in more detail. However, it is obvious that the same modification as the one who Spectral composition of the irradiation light, which improves the visible contrast of the image, makes it possible to record the image details with improved contrast »if the transmitted light is to be recorded or copying of the image onto radiation sensitive material is used.

In order to have an essentially homogeneous spectral composition of the irradiation * To achieve light at all settings within the range of variation, it is desirable to use a light mixing device or devices between the light source! ») and the transparent picture. For viewing transparent images by means of forwarded Light, a light mixing device in the form of a diffuser is preferably used. Preferably the device used whiten means by which the transparent image is held over the diffusing screen.

The applied device can be designed so that it is the whole an exposed and developed film or "plate" conventionally used in medical radiography, or illuminates two or more such films or panels at the same time. The contrast filter (s) can or can be used over the entire

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cultivation area or a limited zone within it Be effective in the area. In the latter. Trap can be the visible contrast each selected part of an image can be varied, provided that the film or plate with the part of the image in the Tariation zone lies. One or more apertures or masks can be used be provided to cover any part of an image that is not to be viewed at any given time.

Depending on the extent of the viewing area over which the possibility of contrast variation is to be effective, it may be desirable to provide a number of light sources that lie in a plane that is essentially parallel to the viewing plane (plane of the illuminated image) Given the viewing area in a substantially uniform manner, the depth of the space occupied by the device, measured from the viewing plane to the light sources, can then be small in relation to the depth of the space required when using a single light source.

The invention includes an apparatus suitable for viewing radiographic Pictures is suitable, and which is characterized by a diffusion screen, a light source or light sources that are essentially used serve for uniform lighting, and a filter or filter that resp. which are gradually brought into the path of light sent to the screen can or can, wherein the filter or filters have light absorption properties has or have, in which the gradual exposure of the filters results in the spectral composition of that irradiating the screen Light is gradually varied over a range of variation, at one end of which the irradiation light in the part or parts of the visible spectrum, which belongs to the part or parts of the spectrum which the irradiated light at the other end of the Range forming wavelengths or predominant wavelengths contains or contain, is or are complementary.

Applied to Betraohtungssyeteme for monochromatic radiographic images, the invention entails particular particularly good results, wenri dan radiographi3ohe photo is Gyanblau-color-area and the B * - ■■ ^f "nhlua ^ - 'are light übßr a Bareich varies canoe, nn whose one

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The irradiation light ends entirely or mainly from within of the cyan-blue region, i.e. if it is essentially the same color as the image or a neutral one Color, while the irradiation light at the other end is composed entirely or mainly of wavelengths that are in a band or lie in bands of the spectrum corresponding to the band or bands is or are complementary, which contains or contain the wavelengths or the predominant wavelengths of the image color. For example, can the irradiation light at the other end of the variation range is in the yellow or orange-red range.

Various devices for practicing the invention will now be discussed described with reference to the schematic drawings. 1 shows a cross-sectional view of a device according to the invention; Fig. 2 is a front view of a contrast filter plate in the device

according to FIG. 1; and
3 to 6 cross-sectional views of part of three further devices according to the invention.

The device according to FIG. 1 has a viewer housing 1 which a set of tubular discharge lamps emitting white light and including a diffuser 3. The drawing shows only three lamps, while in practice it is desirable to use more than three lamps arranged horizontally one above the other.

An X-ray film 4 bearing an X-ray image is produced by means of any suitable means such as a clamp (not shown) held on the diffuser 3.

A filter plate and a mask plate 6 are provided between the light sources and the ^{diffusion screen 1.} The filter plate, which is shown in a front view in FIG. 2, has a number of obliquely arranged orange-red filter bands (shown hatched). These filter belts consist of coatings on the plate, which is made of glass. The parts of the plate lying between the orange-red filter bands have coatings that form gray filters with a density that corresponds to the density of the orange-red filters. The filter plate is mounted in guides that allow vertical displacement of the filter plate

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according to the arrows in FIG. The shift is through a remote control device (not shown) is made. It is very beneficial if this shift is done with the power of an electric motor is made, which is switched on and instantly at any time by pressing a push button accessible to the viewer can be turned off.

The mask plate 6 is attached and is made of an inclined strips silver reflective sheet that catches light rays that are sent through the parts of the filter plate that lead to a given time are optically aligned with the strips of the web.

When the filter plate is in the position shown in Fig. 1, the orange-red filters are aligned with the clear areas of the mask plate, and the irradiation light, i.e. the light with which the X-ray film is irradiated, settles essentially exclusively composed of light in the orange-red band of the visible spectrum. This irradiation light is particularly effective in showing the details in the areas of the X-ray image with low density in that case show that this image is colored cyan. When the filter plate is moved down, unfiltered, i.e. white light reaches this Image and the proportion of white light decreases with continuation of the downward movement too. At the lower end of the filter plate movement, the light is essentially completely collected by the silver ribbon masks located on the mask plate 6. This white Irradiation light is very suitable for general image viewing and is definitely required at high density to show the details in the areas of the X-ray image. The last-mentioned consideration can also be done by means of cyan blue irradiation light and for this purpose the orange-red filter bands on the filter plate can alternate with cyan-blue bands instead of gray bands.

So much for the density of the gray filters compared to the orange-red band filters corresponds, the irradiation of the diffuser remains essentially constant over the range of variation. This causes fatigue

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of the eye due to frequent adjustments to changing light intensity avoided.

Instead of the bias tape pattern, you can use for the filter and mask areas a checkerboard pattern can be applied.

As a modification, the device can be equipped with a fixed filter plate and a sliding mask plate.

The device according to FIG. 3 operates with a series of tubular discharge lamps 2, only three of which are shown and with which the X-ray film 4 held on the diffusing screen 3 is irradiated. Each of the lamps is surrounded by filters 7, 7 * which extend around complementary halves of the lamp jacket. The filter 7 is orange-red and the filter 7 ^{1 is} gray. The filters can consist of layers on the lamp shells, whereby a mechanism is provided with which the lamps are set in rotation about their axes over 180 ° in such a way that either the orange-red or the gray filters gradually move into the path d & f rays of light running to the diffuser can be brought. When the orange-red component in the irradiated light decreases, the component of neutral light that is sent through the gray filters decreases, and vice versa.Instead of a coating of the lamp sheaths, bowls with a semicircular cross-sectional profile can be provided as filters, which are rotated in relation to the lamps can be.

Venn the filters are rotated together in phase the upper © and the lower end of the screen reach slanting rays may have a different ink composition "This may take avoiding ₅ by at least the upper and lower lamps assigned to F are arranged so that they except Rotate phase.

Fig. 4 shows part of another system using a series of lamps and associated rotating mirrors. Only two of the laps of the mirrors are shown in Fig. * F. The lamps 8 used in the system geigBS Fig. K are all the same, and each lamp is surrounded by two filters. One of the filters that d & rgfefcfcilit with voilinien

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and is denoted by 9 _s is orange-red and covers the upper half of the Laiapengehäusee, and the other filter, shown with dashed lines and denoted by 10, is gray and covers the lower half of the lamp housing. When the mirrors 11 are in the position shown, the gray coated part of each lamp is covered by the mirror underneath and all the light reaching the diffuser is that which is sent through the orange-red filter. When the mirrors are swiveled clockwise by means of a remote control device 12, the gray filters become free. With continued swiveling movement of the mirrors, the amount of light sent through the gray film filters to the screen increases to a maximum. Then the amount of orange-red light sent to the diffuser begins to decrease, as the mirrors move into the covered position above the orange-red filters. At the end of the mirror movement, the orange-red filters are completely covered and all light reaching the diffuser is light that is sent through the gray filters *

The filters 9, 10 can be parts that are separate from the lamps, However, they should be kept close to them · However, they can also be made from coatings insist on the lamp coats.

In the system according to FIG. K , the densities of the orange-red and gray filters are such that the irradiation of the diffusing screen remains essentially constant over its full adjustment range during the movement of the mirrors *

The system according to Fig. K , like that Systea g§aast Fig «1 and 3», is primarily intended for the observation of cyan-blue radiographic images.

System according to FIG. $ Has a strainer from six light sources in the form of discharge lamps on * Three of the lamps, which are fceseiehnet lit 13, met orange-red * riiterbeöchichtüiigeli 1%, wälreät üe other three L & Äpen 15 are uncoated. In front of tier i £ ipeareitie feefiadet see a leaf 16, which güiii the arrows vertically ve £ 6§ÄiefeteW? is. This plate has alternating clear and ofcitke i & äer * & ** & «$ ■ 4«? * In the set position of the plate, see etiö tr "M ^ WNMI%" ft "Äftiier

the orange-red light sources and are the other light sources with opaque bands so that only light in the orange-red wavelength band reaches the diffuser. When the plate moves vertically the orange-red light sources are gradually covered and the white light sources gradually exposed, so that the proportion of orange-red light that reaches the diffuser screen is reduced. At the limit of the upward movement of the plate 16, the orange-red Light sources are covered by the opaque bands of the plate and all light that reaches the diffuser screen is unfiltered light that is emitted by the white light sources 15.

The irradiation of the diffusion screen can be varied over the range of variation Using light-sensitive devices that affect the output power of the lamps are kept essentially constant. on the other hand the lamps 15 could be coated with gray filters with such a density that those through the orange-red and the gray The amount of light emitted by the filter is the same. The amount of light reaching the diffuser from the sources 15 is inversely proportional to the amount of light which the diffusion screen at all intermediate divisions of the Plate 16 reached by the orange-red light sources

Reference is now made to Fig. 6 In this device A number of blue filter strips 17 and orange-red filter strips 18 are provided, which are a curtain between the lamps 2 and the diffuser 3 form, with an X-ray film carrying an X-ray film on the diffusion screen 3, is held. The filter strips are articulated to one another, so that they can pivot about horizontal axes 20 with respect to one another. The top and bottom filter strips are jB pivotable. In the position of the curtain shown, the Partially wading through the irradiation light, and partly passing through blue filters sent the orange-red filter. By means of a lever system with links 21, the articulations 20 can be pulled to the right to the Bring blue filter strips 17 into the vertical plane 23. In this position of the curtain, the orange-red filter strips 18 are horizontal Levels, with adjacent strips lying on top of one another, while the irradiation light is light that passes through the blue filter entirely

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is sent. When the blue filter is in the full operating position move, the contrast of the images decreases, which leads to the consideration of details can be useful in the denser parts of the picture · By means of another lever system with links 22, the articulated connections between the orange-red filter strips can be pulled to the right from their position shown to the orange-red filter strips 18 in the vertical plane 23, with the blue filter strips eich move into the horizontal position. Instead of the second lever system with the links 22, the lever system with the links 21 can be slidable to the articulated connections 20 from their illustrated To move positions to the left. In this way, the orange-red filter strips can be in a vertical plane between plane 23 and the Lamps 2 are brought.

The densities of the blue and orange-red filters can correspond, so that the irradiation of the diffuser remains constant over the range of variation

The viewing of monochromatic images was given special attention, however, it can be seen that the invention can be usefully applied to systems for viewing polychromatic images. By arranging light sources, the irradiation light lying in different complementary to the spectral bands of the different image colors Give up spectral bands and through the possibility of such-different Using light sources independently of one another can arbitrarily improve the contrast within image areas with any given color by switching to the appropriate irradiation light color.

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Claims (2)

Patent claims *) Light projection system, with the light through a transparent colored image is sent, which has at least a part consisting of adjacent areas with the same image color density, identified by a light source or light sources from which light is sent through at least a portion of the images, and a JiIter or «Filter, which or which gradually to at least a portion of the image can be exposed to a current of light current, the filter or filters having such light absorption properties has or have that the gradual exposure of the filter (s) leads to a gradual increase in the irradiation light which is present in the part or parts of the visible Spectrum, which or which belongs to the part or parts of the spectrum which or which the wavelengths or the predominant Contains or contains wavelengths of the same image color, is or are complementary. 2. Light projection system according to claim 1, characterized in that the filter or filters in which the luminous flux running from the light source or light sources to the image can be shifted. 3 · Light projection system according to claim 1, characterized in that at least one opaque mask in which the luminous flux running from the light source or the light sources to the image is mounted displaceably. ** ·. Light projection system according to one of the preceding claims, characterized characterized in that a light mixing device between the light source and the image is switched. 5 · light projection system according to claim ^, characterized in that the light mixer consists of a diffuser. 6, light projection system according to claim 1, characterized in that a device is provided with which the irradiation of the image or of the image part is kept essentially constant during the exposure of the filter (s) * 109836/0873 GV Acc