PL83093B1 - - Google Patents

Description

Patent proprietor: GAF Corporation, New York (United States of America) A method for reproducing images on a television set from transparencies, film strips and non-transparent images and apparatus for reproducing images on a television set from transparencies, film strips and non-transparent images. The invention relates to a method of reproducing images on a television screen from transparencies, film strips and opaque images, and an apparatus for reproducing images on a television screen from transparencies, film strips and non-transparent images. Known devices such as a videocamera or an analysis lamp are used for opaque non-translucent devices. The analysis lamp emits an electron beam producing a scanning spot which corresponds to an image spot on a television screen. The electron beam is directed from the analyzer through the reproduced photographic slide and received by the photosensitive element producing an electric signal, the value of which corresponds to the intensity of the incident light. This signal is amplified and fed to the television electron beam intensity control. In this way, the brightness of the picture spot at each point e-. depends on the optical density (blackness) of the photographic transparency at the appropriate point. As a result of modulation, which runs at high speed of the spot, the image is reproduced on the screen. Due to the difficulty in maintaining the required synchronization for such devices and due to the high price of the necessary electronic components, devices produced so far are quite expensive. A suitable system for synchronizing with a prism is discussed in US Pat. No. 3,563,643. Due to the high price and complicated apparatus, such devices cannot be used in general use. The aim of the invention is to develop a simple method of reproducing images on a television screen from transparencies, film strips and non-transparent images, as well as the development of a simple device devoid of the above-mentioned disadvantages and complicated apparatus, which is used in common use. This goal was achieved by developing a method according to the invention, which consists in analyzing the reproduced image to the light emitted from the screen of a TV CRT lamp, detecting the light representing the blackening or color saturation of the selected image spot by the photosensitive element. The light-sensitive element produces electrical signals dependent on the light intensity under the influence of the incident nanlight; These signals are fed back to the TV CRT lamp and modulate its brightness in the corresponding picture spot according to the value of the signal produced by the photosensitive element to reproduce the image on the picture tube screen. from transparencies, film strips and non-transparent images, containing a TV CRT lamp emitting light from its screen selecting light on the image to be reproduced, elements for focusing this light on the image, and a light-sensitive element receiving this light representing blackness or saturation of the color of the selected image spot and generating electrical signals depending on the light intensity, according to the invention, it has a feedback circuit connecting the light-sensitive element and a TV cathode ray tube in order to modulate the screen illumination intensity in the respective image spot depending on the signal produced The advantage of the invention is that the known analyzing lamp is eliminated and instead a feedback device is used in one solution, and a feedback device with a sampling and holding system in the other. In which apparatus the cathode ray tube serves as an analyzer of the reproduced image. As will be described in detail below, the apparatus according to the invention may be adapted to reproduce images on a television screen from transparencies, film strips and opaque images, and also both in black and white and in color, and may also be capable of positively reproducing negatives and positives and negatively reproducing positives. In the case of a transparent film, a projection window is provided to support and / or guide the film in this position. in which he receives the light selecting from screen of the CRT screen. A spot of the screen selection light is focused by suitable elements, such as a lens, on a corresponding spot located in the window of a film transparency. The redness of the slide at this point determines the amount of light that passes through the slide. The photosensitive element may simply be one or more conventional photovoltaic cells, sensitive to light in all or a particular wavelength range and capable of producing electrical current signals, the value of which depends on the intensity of the light passing through the film and focused on the photovoltaic cell. Suitable photovoltaic cells or, as they are also called, photodetectors may be classified and grouped as photoresistors of cadmium sulphide, selenide cadmium, lead sulphide, lead selenide and indium arsenide, silicon and selenium type photovoltaic devices, photovoltaic detectors with photoelectron lamps and photomultipliers, and connector photodetectors, including germanium and silicon photodiodes and phototransistors silicon photoelectric switches due to their high sensitivity for the devices according to the invention, photomultiplier tubes having high output currents at low light levels and having a spectral response over the entire visible light range are preferred. By using appropriate color filters, sensitivity to light in a selected wavelength range can be obtained. These photovoltaic cells are readily available and can be selected to meet the requirements of the respective apparatus. The electrical signal produced by the photovoltaic cell is amplified and fed back to the TV CRT lamp via a loop response with a control circuit. This system modulates the brightness of the dots according to the photoelectrically generated signals. When the screen spot analyzes the transparency that appears on the television screen, the bright and dark portions of the image in the case of black and white reproduction, and the color portions of the image in the case of color reproduction, correspond directly to blackness or color saturation, or vice versa Depending on the particular photocell and / or circuit arrangement, the light and dark portions of the transparencies thus reproducing the image. Similarly, for opaque images, a viewing window may also be provided to keep the image within position so that it receives the selecting light from the screen. In this case, however, the photovoltaic cell is positioned so that it receives the selective light reflected from the image. The amount of light so received by the photocell depends on the reflectivity of the light on the image, which in turn is a function of the brightness. and dark portions of the image at a given point. Thus, the signals produced by the photovoltaic cell change according to the light and dark portions of the picture and modulate the intensity of the screen to reproduce the image. In the same way, a spot from the screen can be focused on and reflected by three-dimensional objects and refocused on one image. one or more suitably positioned solar panels. The current generated by the photovoltaic cells can be fed back to the TV CRT through a control circuit to reproduce images of objects on the screen. The control circuit can work with both positive and negative feedback. With positive feedback, the TV CRT lamp is controlled to emit a spot with minimum brightness normally and the control system increases the brightness of the screen in proportion to the signals received from the photovoltaic cell. Professionals will realize that with positive feedback, there is a tendency to stabilize the screen lighting to a minimum level. or at the maximum level, there is therefore a tendency to lose gray or semi-dark parts of the image. While this is generally unacceptable for reproducing photographic or similar images, it is even desirable for reproducing high contrast images such as printed matter. In the event that the screen dot is black or opaque or not the reflection of the image fragment, the light reaching the photocell decreases, resulting in a reduction of the generated current. Likewise, the brightness of the screen is reduced by the control. When a spot from the screen falls on a black part of the picture, the photocell produces no current, so that the brightness of the screen is minimal, recreating a dark part of the picture on the screen. It should be noted that the minimum brightness is not the same as zero brightness. Although the screen is relatively dark at minimum brightness levels, some light is always emitted. This makes it possible to brighten the screen again in the positive feedback circuit. When a darkened spot from the screen falls on a half-dark part of the image, the light falling on the photo cell is increased because the half-dark part of the image transmits a certain amount of light, while the black part of the image does not pass through. The generated current is increased, and the brightness of the screen is also increased. Increased brightness of the screen causes the light intensity incident on the photocell to increase at the same time, which further increases the brightness of the screen, thus it quickly reaches its maximum level, which brightens the gray parts of the image, and a bright spot appears on the screen. the image consists of only bright and dark parts, this type of positive reproduction is of course ideal. With negative feedback, the screen normally emits a spot with maximum brightness, and the control circuit is designed to suppress the brightness of the screen in proportion to the signals from the solar cell . In such a manner it is possible to stabilize the brightness of the screen at any level between its maximum and minimum values, and is therefore advantageous for the reproduction of images having a wide luminance ratio. Although the term negative feedback suggests that the device reproduces a positive image on the screen. from negative reproduced images, or vice versa, as will be discussed below, the negative feedback control is also suitable for the positive reproduction of the positives. In any case, the control circuit with negative feedback loops the brightness of the spot from the screen, resulting in a relatively constant current in the photovoltaic cell, regardless of the luminance levels of the reproduced image. operation of the device is as follows. When a spot from the screen falls on a selected spot of a transparency, the photovoltaic cell starts to generate an electric current, the value of which depends on the blackness of the transparency. The control circuit powered by this current begins to suppress the brightness of the spot on the screen so that when the screen spot falls on the corresponding spot on the transparency, its brightness is reduced to the correct brightness. If the negative transparency is not darkened, the photocell receives the maximum light intensity 3 093 6 screen and in response to this it produces the maximum signal. When this signal is fed back to the TV CRT lamp, the brightness of the screen is reduced. This in turn reduces the output current of the solar cell, which also contributes to the brightening of the screen. The feedback process continues until an equilibrium is reached between the brightness of the screen spot and the solar cell current. Since unshaded transparency produces a dark image, and dark transparency produces a bright image, the intensity of the light entering the photovoltaic cell is always approximately constant, the photovoltaic cell therefore maintains a relatively constant output current. Once again, it is an attempt to achieve equilibrium, there is a fluctuation, but for each spot it is very short. Besides, there is one deviation from the constant output current, when the image is completely black, the light does not reach the solar cell at all. In this case, the screen is maximized and no electricity is produced at all. According to a second aspect of the invention, there is provided a modified video reproducing apparatus using a TV CRT lamp on which the image is reproduced, for selecting the image to be reproduced, and photoelectric elements, excited by a scanning light passing through or reflected from the image to produce a feedback signal to modulate the intensity of the screen illumination. The basic modification from the previously described solution is that, instead of using a simple feedback circuit, in which the screen illumination is normally kept at the maximum level of intensity in the event of negative feedback, or at a minimum intensity level, in the case of positive feedback, and stepped appropriately reduced or increased by the feedback signal, the circuitry of this solution is adapted to cyclically excite the TV CRT tube to generate the emission of sampling streams of constant intensity. at many points on the raster, which streams are focused on the reproduced image, their intensity is modulated according to the luminance levels of that image, and then they are picked up by the photosensitive elements. The photoelectric signal produced is fed back through the circuit to energize the lamp picture tube in the period between laps The method of emitting sampling streams to illuminate the screen to a brightness directly or inversely dependent on the luminance degree of the reproduced bronze at a point illuminated by the immediately preceding sampling stream. The durations of the pulses are such that the analysis pulses are not noticeable by the observer, and only the feedback pulses producing the image on the screen of the TV CRT tube are noticeable. 7 83 093 8 Thus, the image selection and image production functions performed by the lamp are visible. The CRT tubes are clearly separated, resulting in better image reproduction. Moreover, the latter has the advantage compared to the simple feedback solution that only a single photocell is required for the positive reproduction of the positive and the positive. negative reproduction, both in black and white and in color, which simplifies the device and increases its efficiency and reliability. Furthermore, it is provided here to feed back photoelectric signals representing only the rise time of the sample stream, and not both the rise time and fall time as was the case in the preceding solution, with the result that the visual afterglow of the screen is minimized, which leads to the distortion of the image reproduction. In general, the modified apparatus according to the invention comprises a TV CRT lamp, adapted to periodically emit a plurality of sampling streams from the screen raster each time it is selected, elements for focusing the profiles. of the sampling streams on the object whose image is to be reproduced on the screen, the light element is positioned to receive that part of the sampling streams which is focused on the object and represents the degree of luminance of the object at its particular points, the photosensitive element giving the answer the intensity of these jets, producing electrical signals with a value corresponding to this intensity, and a feedback control circuit, connecting the light sensor element with the TV CRT tube and adapted to cyclically excite this lamp to generate the emission of said sampling fluxes and to modulate the intensity of the screen illumination cyclically in each case. its point corresponding to the point of the object on which each sampling stream is focused, according to the signals produced by the light-sensitive element, in order to reproduce the image of the object on the cathode ray tube screen. In the basic form for reproducing the black and white feedback system includes a single sampling and holding circuit, adapted to cyclically generate constant level analysis pulses, which feeds the TV CRT tube, controlling the brightness level and causing the emission of sampling and holding streams at a constant intensity. store that each electrical signal produced by the light-sensitive element during the duration of each analysis pulse and then emits an output pulse corresponding in value to the signal produced by the light-sensitive element to feed the TV cathode ray tube to a brightness level representing a luminance table point of the object illuminated by the immediately preceding sampling beam. In this way, the image of the object is reproduced on the screen of the TV cathode ray tube. The feedback circuit also includes a pulse generator which cyclically generates control pulses which excite the sampling and holding circuit to produce analysis pulses. In the excited state, the sampling and holding system stores the input pulses - produced by the photosensitive element. For clarification, an example in which the reproduced object is a film strip will be considered. A projection window is then provided to hold and / or guide the film in a position to receive an image from a TV tube lamp. Each such sample stream is focused on a point of the transparency by means of focusing elements, for example, an objective. The blackening of the transparency at this point determines the amount of light transmitted, and thus the value of the electrical signal produced by the light-sensitive element. Like the device according to the first solution, the light-sensitive element can simply be one or more ordinary photovoltaic cells, sensitive to light in the whole or specific range - of frequencies and adapted to produce - electric signals, the value of which corresponds to the intensity of the light passing through the film. The electrical signals produced by the solar cells are amplified, fed back to the input of the sampling and holding system and stored therein. Upon termination of each control pulse, the sampling and hold circuit is turned off, the analysis pulse fades, and the stored signal from the photovoltaic cell is output as an output pulse to modulate the brightness of the spot on the screen in accordance with the photoelectrically generated signal. The duration of the output pulse is at least six times greater than the duration of the analysis pulse, so that, in the view of the observer, the image spot is dominant, which is the reconstruction of the corresponding spot in the transparency. When the sampling and holding system is cyclically moved by the pulse generator, the sampling streams emitted from the screen analyze for one year, so that the blackness of the light and dark portions 50 appearing on the screen of the picture tube in the case of black reproduction. -white - and the color saturation of different-colored parts of the image in the case of color reproduction, depends directly or inversely on the blackness or color saturation of light and dark portions - 55 slides of the slide, reproducing the image. White. However, in order to adapt the system to reproduce colors, it is only necessary to add two sampling and holding circuits to the feedback system. In black-and-white reproduction, the sampling and holding sequence receives input signals from the photovoltaic cell which change. depending on the darkness of the object. Similar to the output pulses from the sampling and receiving sub-circuits only represent changes in the luminance degrees of the object and only control the brightness of the image produced. In color reproduction, the analysis pulses and output pulses from each of the three sampling and holding circuits are marked to power three electron guns to control the red, blue, and green brightness of a color picture tube. The pulse generator of the color reproducer is arranged to sequentially activate the red, blue and green color sampling circuits, each of which feeds the red, blue and blue electron beam respectively. d green, cathode ray tube - to illuminate the reproduced image at its individual points. It should be noted that this device satisfactorily reproduces color images, although only a single photocell is used, unlike other devices that They require a separate solar cell for each of the three primary colors. However, since only a single cell is used, it is important that there is no overlap between the sampling streams emitted from the screen and received by the solar cell. Although the pulse generator is capable of producing split control pulses such that all the red, blue, and green color analysis pulses are sequentially produced in such a way that there is no overlap in time, The phosphor of the screen used in color television is such that there may be an overlap at the respective sampling streams if the analysis pulses produced by the three sampling and holding circuits are closely spaced. Typical afterglow times of up to 10 percent brightness for color CRTs are 600 microseconds for red, 25 microseconds for blue and 60 microseconds. seconds for the green color. Since one raster has a duration of 63.5 microseconds, one short red electron gun pulse emits 10 percent of the initial luminosity for color picture tubes of 600 microseconds for red, 25 microseconds for blue. and 60 microseconds for green. Since the duration of one raster is 63.5 microseconds, one short pulse of the red electron gun causes the emitting corresponding to 10 percent of the starting brightness 10 lines later. This is very weak, possibly up to obtain ^ resolution. However, it has been found that this phenomenon does not affect the brightness of the phosphorescent material, so it is possible to obtain the information necessary to reproduce the image only from a part of the increasing sample stream and thus avoid the phenomenon of occurrence due to afterglow. To achieve this, a high-pass filter must be used between the photosensitive element and the sampling and backup circuit, which passes only high-frequency signals. Since only the signal rise time from the photovoltaic cell has a high frequency, the input signal is to the sampling and holding circuit, it only represents the rise time of the sampling stream emitted from the screen. As for each analyzing pulse there is one corresponding output pulse, the number of analysis pulses on the raster line determines the image resolution. For example, for 400 characters per line, use 400 analysis pulses per line. The ratio of the duration of the output pulse to the repetition time of this pulse determines the average brightness viewed by the observer. The feedback control may be adapted to operate either with positive or negative feedback, in both black-and-white and color reproduction. With positive feedback, the control circuit 25 modulates the screen brightness in a manner directly proportional to the input signals received from the photosensitive element, the dark spot of the object is thus imaged as a dark spot reproduced on the screen. Since the sampling streams are emitted cyclically, the tendency to stabilize the brightness of the screen at a maximum or minimum level, as is the case with the first device of the invention shown, is eliminated here. Each analysis pulse creates an independent output pulse which controls the brightness of the screen. The brightness of the TV CRT tube is normally stabilized at the minimum level. Each analysis pulse brightens the screen temporarily to eliminate the maximum intensity sampling beam. After the pulse analyzing the resultant feedback input 45, having a value corresponding to the luminance degrees of the image spot illuminated by the beam, has expired, it is fed to the picture spot as an output pulse to the sampling and holding system, producing a corresponding spot on the beam. screen, the brightness of which is equal to the minimum brightness level increased by the brightness value caused by the output pulse. For example, if the sampling beam touches this bright spot of the transparency 55 *, the light element receives the maximum light intensity from the faucet and produces maximum light accordingly. signal. When this maximum signal is returned to the kinescope as an output from the sampling and hold circuit 60, it is added to the signal corresponding to the normal minimum brightness, creating a minimum brightness spot on the screen corresponding to a bright spot of the transparency. If, on the other hand, the sampling stream strikes a black or opaque spot on the transparency, the photosensitive element produces a zero or minimum signal which, when brought to the picture tube and added to the minimum brightness level, produces a speck of Minimum brightness, corresponding to the dark spot of the transparency. With negative feedback, the control system modulates the brightness of the screen in the opposite way to the signals received from the photosensitive element, the dark spots of the object appear as bright spots on the screen. In this case the brightness of the screen. it is also stabilized at the minimum value. The sampling beam temporarily brightens the screen to its maximum brightness to emit a sampling beam. After the termination of each analyzing pulse, an output pulse from the sampling and holding circuit representing the feedback signal is fed to the kinescope, giving rise to a spot on the screen having a brightness level equal to the maximum level reduced by the intensity value corresponding to the output pulse. May. A known system is used for the subtraction of the pulses. If at some point on which the sampling beam falls, the negative transparency is clear, the photosensitive element receives the maximum amount of light from the screen and produces a maximum signal in response. When this signal is fed back to the sampling and holding circuit, a maximum output pulse is produced. Subtracting the brightness corresponding to this output maximum from the minimum brightness produces a dark spot on the screen. If the next analysis pulse falls on a black or opaque spot of the negative transparency, the photosensitive element current is not produced, the output is zero, and the reconstructed spot is at maximum brightness. The invention is illustrated, for example, in the figure in which Fig. 1 is a block diagram of an example of an embodiment of the apparatus of the invention using a negative feedback circuit after positive negative transparent images reproduction, Fig. Z is a block diagram of an example of an embodiment of the apparatus of the invention using a feedback to positive circuit from 3 is a block diagram of another embodiment of the apparatus of the invention adapted to positively reproducing color negative transparent images, Fig. 4 is a block diagram of another embodiment of the apparatus of the invention adapted to the invention. for reproducing moving pictures on a television screen, Fig. 5 is a block diagram of an apparatus adapted to positively reproduce color positive moving pictures, Fig. 6 is a front view of a preferred embodiment of the invention in the form of a home television reproducing apparatus. Fig. 7 is an error view of an embodiment of the apparatus shown in Fig. 6, Fig. 8 is a block diagram of another embodiment of the apparatus of the invention using a positive feedback circuit to positively reproduce positive opaque images. Fig. 9 is a schematic diagram of a negative feedback circuit for positively reproducing black and white images, Fig. 10 is a schematic diagram of a positive feedback circuit for a positive reproduction of positive black and white images, Fig. 11 is a block diagram. another solution example of an apparatus according to the invention having a modified feedback control system adapted to reproduce black and white images, Fig. 12 is a schematic diagram of a preferred sampling and holding system, Fig. 13 is a block diagram of another embodiment according to FIG. 14 is a schematic diagram of the pulse generator used in embodiment 1, FIG. 13, FIG. 15, and FIG. 15 is the output pulse waveforms of the logic gates of the pulse generator 25 of FIG. 14, and FIG. Fig. 16 shows the waveforms of the pulse generator output pulses of Fig. 14. Fig. 1 shows a CRT screen slideshow apparatus adapted to positively reproduce negatives and to negatively reproduce black still images. -white ^ This is the simplest form of the device according to the invention. This apparatus employs a conventional black-and-white television receiver 10 having a cathode ray tube 11. The optical feedback system 12 is adapted to support at least one negative year 17, frame detection II and feed. 40 return electric pulses, the value of which corresponds to the amount of light passing through the transparency 17 to the television receiver 10 through the amplifier 19 and the control circuit 20. The optical 12-projector and feedback circuit * includes a chamber with an opening 22 for light receiving from the cathode ray tube 11 and the film frame 14 positioned transversely opposite the aperture 22 and used to support the transparency 17. The lens 13 located in the aperture 22 is adapted to focus the light received from the screen on the transparency placed in the frame 14 A light-sensitive element 16 is placed in the cell 22, which receives the light transmitted through the translucent glass 17. The capacitor 15 refocuses the light on the photosensitive element. The light-sensitive element 16 is a photomultiplier. which is sensitive to the intensity of the light focused thereon and in response to this light produces an electrical signal whose value is proportional to the intensity of the light. The generated signals are fed through line 18 to an amplifier 19 which is a video amplifier with a frequency band of about 4 to 5 MHz. Although in Fig. 1 the amplifier 19 is shown as an external device 13, it can also be built into the chamber 21. The optical feedback and feeder 21 corresponds to a conventional slide projector, except that it is adapted to receive light from outside. a source, that is, from a picture tube, rather than projecting light onto a reflecting surface. A conventional transparent projector may be used for this purpose by replacing the projection bulb with a photomultiplier and associated system. Note that while Fig. 1 shows a system for supporting a single slide 17, a more complex projection system may also be used. , adapted to insert a container with a plurality of slides and intended to be fed into the projection frame of a selected transparency. The control circuit 20 is a negative feedback circuit for modulating the intensity of the electron beam in the cathode ray tube in accordance with signals received from the photosensitive element 16. So , the stronger the signal received by the control circuit 20 produces a darker spot on the screen 11 and produces a positive reproduction of negative black and white images. The schematic diagram of the photocell amplifier and feedback loop control is shown in Fig. 9 Note that the video signals produced by the control system can be fed to an ordinary television transmitter. Another solution is to eliminate the video-generating part of the control system and feed the amplified video signal to the control system. control signals directly to the brightness control of the television receiver. This bypasses most TV systems and simplifies the entire device. However, if no external leads are provided, the connection of the feedback circuit to the appropriate points of the brightness control system requires a skilled person. Therefore, when using an optical projector and feedback loop as a reference to an existing television receiver, it is recommended to make the control circuit for direct connection. connect to the antenna socket of the TV set. However, where such a setup is performed in conjunction with a universal television system, such as the television set shown in Figs. 6 and 8, the simplified setup is preferred. During operation, the television set is turned on and set to unused. channel. It should be noted, however, that if control signals are directly applied to control the brightness of the kinescope, it is preferable to turn the television on to the channel in use, this provides a more uniform raster without interference, since the feedback signals eliminate the normal signals received from the transmitting signal. ka. Transparency 17 is housed in the projection frame 14 of the optical system 12 which is directed at the screen of the picture tube. It should be noted that although in Fig. 1 the optics are coaxial, such alignment is not necessary as long as the lens 13 is positioned so that. it is capable of receiving the entire illuminated screen surface. However, to avoid trapezoidal distortions, the lens 13 and the transparency 17 must be aligned in planes parallel to the screen 11. The selection spot on the screen of the cathode ray tube is condensed by the lens. 13 on the transparency 17 and then refocused by the condenser 15 on the photosensitive element 16. The signal produced by the photosensitive element is proportional to the intensity of the incident nanlight. 15 Amplified and fed back to the television receiver by the control system 20, this signal suppresses the brightness of the spot appearing on the screen in a manner proportional to the light falling on the photosensitive element 16. The bright 20 portions of the transparency 17 thus appear as dark fragments on the screen, and dark portions of the slide appear on the screen as bright portions, with the result that a positive image is recreated from the negative slide. For example, a certain spot SA with the maximum brightness on the screen 11 produces light that is focused on the corresponding spot Tt on the transparency 17. If the point T is a completely black or opaque area, the light from that point on the transparency does not enter to the photosensitive element 16. Therefore, the photosensitive element 16 produces no current at all, and the control circuit 20 allows the spot St of the screen 35 to be illuminated further to its maximum brightness. When a spot is at point S2 of the screen, it is focused on the transparency 17 at point T2. If the point T2 on the transparency is a point of maximum transparency, the photosensitive element 16 is focused on the maximum amount of light from the point S2 of screen 11, and this light-sensitive element in turn produces a signal of maximum value. On control circuit 20, the brightness of the screen spot S2 is reduced, darkening the screen at that point. At this point, the photocell 16 receives a minimum amount of light, the photocell produces a minimal signal, and at the same time the control circuit increases the brightness of the screen spot, aiming to brighten the screen 50 again. If the screen spot is now focused on the gray part of the transparency 17, the photosensitive element 16 produces the appropriate current, and the control circuit 20 suppresses the brightness of the spot, allowing only half of the screen brightness to be reached, which represents an instantaneous balance point between the screen light output and the photosensitive element output current. Fig. 2 shows an example of an embodiment according to the invention using a negative feedback circuit allowing positive reproduction. In this device, the optical system 24 of the projector and feedback loop comprises an objective 25-3 adapted to focus on a transparency 2683 ° 15 of light received from the screen of a kinescope 11, and a capacitor 27 adapted to recompose passing through the transparency 26 light on the photosensitive element 28. The second lens 29 focuses on the second photosensitive element 30 and selects light received directly from the screen. Both photosensitive elements 28 and 30 are adapted to produce electrical signals proportional to the intensity incident on them and lights, and both are connected by the respective wires 31 and 32 to the differential video amplifier 33, which produces an amplified signal representing the absolute difference between the current values of the signals produced by the photosensitive elements 28 and 30. This amplified signal is fed back to the television set 10 via control circuit 20, which As described with reference to the embodiment of FIG. 1, proportionally to this amplified signal, the screen brightness is dulled so that a larger signal to the control circuit 20 causes a given point of the image to appear darker on the screen. The operation of the apparatus 25 of FIG. 2 will be discussed below. The spot appearing on the screen of the kinescope 11 is selected by the projector and feedback system 24 and simultaneously focused on both photosensitive elements 28 and 30. The photosensitive element 28 perceives only transmitted light. through the transparency 26 and re-focused by the condenser 27, while the light-sensitive element 30 receives the undamped light directly from the screen of the kinescope 11. If the spot appearing on the screen of the kinescope 11 has maximum brightness, the light-sensitive element 30 produces a maximum signal If the maximum brightness spot is focused on a corresponding black or opaque part of the transparency 26, on holiday 4 <the pressed element does not fall light and it does not generate electricity. Consequently, the amplified differential signal from amplifier 33 has a maximum value. Powered by this maximum signal, the control circuit 20 suppresses the spot on the screen of the CRT 11 to its minimum brightness darkens the screen in proportion to the darkening of the spot on the slide 26. However, as the screen becomes dark, the light sensitive element 30 receives a minimum amount of light, producing a minimal signal. Likewise, the photosensitive element 28 receives a minimum amount of light due to obscuration of the transparency and it also produces a minimum signal. At this point, the absolute value of the signals 55 produced by the two photosensitive elements tends to decrease. In response to the reduced signal, circuit 20 allows the screen spot to expand again, prompting the screen to brighten again. However, if currently a spot from the screen falls onto another non-transparent portion of the transparency 26, there will be no differential signal change and the screen will darken according to the blackness of the transparency 26. When the screen selecting spot falls on a relatively bright or low-blackened portion of the transparency 26, both photosensitive elements 28 and 30 receive substantially undamped light from the screen and, in response, produce approximately equal signals. The difference between the signals produced by the photosensitive elements 28 and 30 will have a minimum value, a low current will come to system 20 and in response will cause the screen to brighten to its maximum brightness, recreating a spot whose brightness corresponds to the brightness of the bright spot on the translucent 26. a spot with maximum brightness falls on a gray or partially obscured fragment of the transparency 26, the intensity of the light falling on the light-sensitive element 28 of the current generated in response to this light will have values equal to half of their maximum values. the light from the screen continues to be unmuted and produces a maximum signal. The differential amplifier 33 thus produces an amplified signal, equal to half its maximum value, representing the differences in the signals received from the two light-sensitive components. In response to this signal, circuit 20 simultaneously reduces the brightness of the screen spot by half as much as corresponds to the gray area of the transparency 26. The device thus produces a positive image on the screen of the cinema 11 which corresponds very closely to the positive image of the transparency 26. (The device according to this embodiment is also capable of reproducing positive images from negative slides. A switch 100 arranged in the line 32 allows the photosensitive element 30 to be disconnected from the system. When the light-sensitive element 30 is disconnected, the device operates identically to the device of Fig. 1. It should also be noted that, as with the embodiment of Fig. 1, the optical feeder and feedback system 24 is common to many possible types of projection equipment. Fig. 3 shows an example of an apparatus design that is capable of reproducing. on the CRT screen 35 of positive color images from negative color slides. In this example, the color television receiver 34 design is equipped with a conventional color CRT 35. The optical and feedback circuit 36 is similar to that of FIG. 1, except that it comprises three light-sensitive elements 41, 42 and 43 which are sensitive only to green, blue and red light respectively. The lens 37 focuses the selecting light received from the screen of the cathode ray tube 35 on a colored transparency 39 located in the frame 38 of the arrangement 36. The light passing through the transparency 39 is simultaneously refocused on the photosensitive elements 41, 42 and 43 by means of the capacitor 40. The value of the signal produced by each of them The three photosensitive elements depend on the brightness of the primary color to which it is sensitive, which is positioned at a given point in the transparency illuminated by a spot from the screen. The signals produced by the photosensitive elements 41, 42 and 43 are amplified by the vision amplifiers 44, 45 and 46 and are fed back to the control circuit 47, which is a negative feedback circuit and modulates the intensity of the electron beam corresponding to the three the colors in the telescope 35, inversely proportional to the light intensity of that color at a given point in the transparency. For example, if transparency 39 is a color negative over the entire green field, it will be composed of the complementary color which is purple. consists of the original colors red and blue, so the transparency 39 will only transmit red and blue light. 'The photosensitive elements 42 and 43 will therefore produce maximum signals as they will receive all the light transmitted through the translucent 39 On the other hand, the light-sensitive element 41 will not receive any light from the screen, so it will not produce any signal. the system 47 reduces the light of individual colors on the screen in proportion to the signals produced by the appropriate photosensitive elements, the brightness of the 35 streams of red and blue color falling on the screen of the picture tube will be minimal, and the brightness of the green color will be maximum, so all green will be reproduced field on the screen. Table I illustrates the operation of this system for several other colors. Note in Table I that the combination of red, blue and green produces white light on a typical color TV screen, and that the combination of red and green produces yellow light. contains color images that are negative to the gradation of the shades of the original object and are complementary to the colors of the object. Thus, a bright red object produces a dark blue-green negative. The negative acts as a color filter and only transmits light of the same colors as it is complex. Table I gives only examples of the colors that can be produced and is not intended to limit any circumstances. Moreover, each slide may contain separate or overlapping portions of different or mixed colors. The image spot on the color cathode ray tube 35 analyzes the slide 39 in the same way as in the examples of Figs. 1 and 2 for black and white reproduction, so that the image appearing at a given point on the screen corresponds directly to the position and vice versa. lor and the brightness of this point on the slide. Table I 'Color' of the object Nude color that complements the colors of the illuminated photocells 1 Color reproduced on the screen red cyan (blue-green) blue- red-green red blue yellow red green than blue yellow blue blue yellow (red-green) orange blue-blue-green: gel blue-blue-green orange (red-green) -yellow) purple green green purple (red-blue) cyan (blue-green red red cyan blue-green black white red-blue-green black (none of the colors white black white (red-blue-green 1 gray gray Jun red-blue-green (partially illuminated) gray (red-blue-green, not fully intense) [The photosensitive elements 41, 42 and 43 are photocells that are used in the black and white system and have appropriate green, blue and red color filters (not shown) associated with them to filter out unwanted light. This ensures that the photosensitive elements are only supplied with light with a particular wavelength corresponding to its filter, although the photosensitive element itself is sensitive to all light. As in the black and white system, amplifiers 44, 45 and 46 The colors are intended to enhance the currents produced by the respective photosensitive elements. Likewise, feedback control 47-83 C 19 operates in substantially the same manner as control gear 20 in the black and white system described above. However, circuit 47 comprises three separate circuits, one for each color of the electron beam, which flows are controlled by the amplified receive signals. wound from light-sensitive elements of the three primary colors. As with the examples of the embodiment of Figs. 1 and 2, the optical projector and feedback system 36 is only an example of the different arrangements that can be used, both slides and moving image projectors. the optical light appearing on the screen of the picture tube 35 need not be straight-line. As described below with reference to the embodiment of Figs. 6 and 7, light selecting from the cathode ray tube screen may be reflected towards the optical projector 36 and feedback with a mirror. . Fig. 4 shows an apparatus according to the invention for reproducing moving pictures. In this example, the optical projector and feedback system 50 is in the form of a moving image projector having a feed spool 51, a winding spool 52, and a drive mechanism cooperating with said spools to advance the film 57 through the projection window 53. 54 focuses the selecting light from the kinescope screen 60 on a film frame 57 positioned at a given moment in the projection window 53. The light passing through the film 57 is focused by a capacitor 55 on a photosensitive element, which is a photomultiplier 56. Produced by The photomultiplier 56, the signal is amplified by the amplifier 61 and fed back to the television set to control the brightness of the image on the CRT screen 60 by the control circuit 62. The operation of the photomultiplier tube 56, the amplifier 61, and the control circuit 62 are the same as described herein. With reference to the embodiment of FIG. 1, the apparatus shown in FIG g. 4 is thus adapted to reproduce on the screen of the picture tube 60 a positive image from a negative film placed in a projection window 53. The projector system 50 may of course also be used in an apparatus for the positive reproduction of positive black and white images. 1 in the negative color image positive reproduction apparatus shown in Fig. 3 and the positive color image positive reproduction apparatus described in connection with Fig. 5 below. . 55 With normal 8 mm film projection, the film is advanced through the viewing window at approximately 16 frames per second. This movement, however, is not continuous. The film advances by leaps and bounds and is stopped during the brief period of time that light from the projector is shone onto the screen. Every second the film stops and advances 16 times. During each period of panning, the light from the lens is blocked by the shutter, preventing the image from blurring or flickering on the screen. Every second, a series of 16 still images is displayed. To advance the film the required distance for each frame, shifting means, often in the form of a gripper, are used to engage the perforations of the tape. In a television film apparatus according to the invention, shown in Fig. 4, it is necessary that each frame is played on the screen. of the picture tube 60 was either stationary in the film window 53 or was moving at zero speed with respect to the raster as it was analyzed by the image spot emitted from the screen of the picture tube 60. If the film is shifted during selection, a distorted image appears on the screen. must be equal to or be a multiple of the film frame rate. As mentioned above, an ordinary television receiver produces 30 rasters per second. This is almost twice the number of frames displayed in an ordinary movie projector. Accordingly, the speed of the film frame through the projection window 33 of the projector and feedback system 50 is set at 15 frames per second, which corresponds to the speed of each raster on the kinescope screen, whereby the sampling stream is directed on a series of consecutive still images. The slight reduction in the speed of the shutters does not noticeably affect the optical properties of the reconstructed image. Alternatively, the speed of the picture tube 60 can be increased to 32 frames per second, which gives the same timing between the frames and the louvers. In a conventional projector, a movable mechanical shutter is placed between the projection lamp and the screen to eliminate the illumination of the screen. as the film advances between frames. The same design may be used in the television movie apparatus of FIG. 4. An alternative snapshot system is the electronic circuit that is recommended for this example of embodiment. For complete blanking of the screen during the advance of the film between frames, a switch may be used which cooperates with the control circuit 62. There may be a simple miniature switch (not shown) associated with the frame shifting gripper which turns on and off parts of the control circuit 62 alternately. , constituting an electronic blinker that operates in a manner synchronized with: the motion of the film 57. For the temporary blanking of the screen, a photocell may be electrically connected to the television system, which receives direct light from the e-tap when the film is stationary and obscured from the light by the gripper moving the film. In this way, the screen is not illuminated during the advance of the frames and is illuminated according to photoelectrically generated feedback signals when the film is stationary. Another solution is possible which has the advantage of eliminating the mechanical gripping system. advance of the film and will allow the film to advance continuously without pausing it periodically while displaying each frame. This is achieved by synchronizing the film advance speed with the raster analysis rate and the frequency of that raster, that is, the number of these rasters per second. In this way, the relative movement between the raster and each frame and the telescope can be adjusted so that the selection light is focused on a relatively still image. The system for making such synchronization between the film speed and the raster speed of the telescope is absolutely simple. A continuously driven gear or friction wheel moves the film through the projection window at a constant speed. The drive element of the gear wheel may be an ordinary AC or DC motor mechanically connected to a rotatable multi-surface prism. This prism enables the projection of still images from the film moving with a constant speed synchronized with the rotational speed of the prism, so that always the deflection of the sampling stream from the screen caused by the refractions in the prism is equal and opposite in the direction of the displacement of the film, so that there is no relative movement between each raster and each frame. The photoelectric projector and feedback system works normally because the selection light is focused on the cage which gives the impression of being motionless. This is illustrated in Fig. 5 Motorized gear 77 moves the moving film 76 through the projection gear. Thin 78 with constant continuous speed. The drive motor (not shown) of the toothed wheel 77 is connected and synchronized with the rotatable prism 79. The prism 79 is designed to synchronize the speed of the screen 35 of the screen with the speed of the film frame. Frame 75 in box 78 is selected by raster from screen 35. When frame 75 exits the window, raster selection is complete and spot jumps to incoming frame 74. This is automatically repeated for each frame. with constant continuous speed, it may also have a magnetic audio recording path 10, and the optical feeder and feedback system may have a suitable transducer 102, providing a moving image and accompanying audio reproduction, saws of the audio path along the elimin converter These are the sound distortions that occur in many humanized film systems due to the intermittent movement of the tape. 5 also shows a positive color image reproduction system according to the invention. Like the device for positive reproduction of black and white positive images, this device includes a dual set of photosensitive signal producing elements. The first set of photosensitive elements 64 and 65, which are sensitive only to the respective screen colors, green, blue and red, receive the scanning light which is focused on the film 76 through the lens 54. The second set of photosensitive elements 66,6T and 68, sensitive only to the corresponding colors, green, blue and red, receive the light incident directly from the screen of the picture tube 35 through the lens 10 72. The signals from both sets of photosensitive elements are fed to the differential amplifiers 69, 70 and 71 for the colors green, blue and red, respectively, in which the differential signals of the current signals of both sets of photosensitive elements are amplified. The amplified signals are fed to the control circuit 73 negative feedback, which modulates the intensity of the electron beam of the primary colors in the cathode ray tube. 35 in a manner inversely proportional to the size of the amplified differential signals, causing the formation of or positive image. The following is an example that illustrates the operation of this device. Make frame 75 of film 76 25 a positive slide with the entire green field. Since the photosensitive element 63 is only sensitive to the color - green, it receives the light passing through the cage 75 and produces the maximum signal. The photosensitive elements 64 and 65 are only sensitive to blue and red light, respectively, and do not produce a signal in response to the green light focused on them. If we assume that at the initial moment, the image spot on the screen 35 is white, Representing the radiation produced by electron beams of green, blue and red colors focused on the phosphor of the screen with the appropriate brightness, the photosensitive elements 66, 67 and 68 receive the appropriate light intensities; 40 suitable colors and produce maximum signal. The maximum signal produced by. The light-sensitive element 66 connects to the maximum signal with the photosensitive element 63, driving the differential amplifier 69. As the difference between these maximum signals is zero, the control circuit 73 is equal to the minimum value of the electron beam of green. So, the intensity of the beam, 50 of the new green color, will remain at maximum. Maximum signals from photosensitive elements? 67 and 68 in combination with the minimum signals from photosensitive elements 64 and 65 produce an absolute difference signal with a maximum value. 55 The amplifiers 70 and 71 provide the controlling u-; the maximum blue and red signals, and this system suppresses the minimum value of the minimum electron beam of the blue and red sets, creating an entire green field on the screen, corresponding to the green half of frame 75. If the next input frame 74 is red, when this frame is brought to the position of being analyzed by the picture tube raster 35, the picture tube of the picture tube emits only green light. The photosensitive elements 64, 65, 67 and 68 therefore do not generate any electric current. Similarly, the light sensitive element 63, which is sensitive to green light, also produces no electricity, since the red cage 74 blocks the green light. Only the green light receiving the green light directly from the screen produces a signal. This signal in the amplifier 69 is compared with the zero signal from the photosensitive element 63 and produces a maximum signal in the control part of the circuit 73 responsible for the green color. This maximum signal immediately attenuates the green electron beam in the TV, reducing the brightness of that color on the screen. As amplifiers 70 and 71 produce minimal signals, the control circuit 73 increases the blue and red electron beam intensity in the cathode ray tube, aiming to recovery of the screen equilibrium. At this time, the light-sensitive element 66 no longer receives light, its signal is reduced, and the control circuit 73 causes the intensity of green to increase again, all three streams tend to activate simultaneously and the cycle may be repeated again. started by producing a red image on the screen. It should be noted that a state of equilibrium is achieved between the resulting brightness and color of the screen and the final state of the light-sensitive elements, as a result of which the perceived brightness and color of the screen each time reproduce the image of the transparency. A similar reasoning can be made in relation to the photosensitive element. blue-sensitive or a combination of all three colors, for a multi-color image or a color being a mixture of the three primary colors. Table II shows the operation of the apparatus for the different colors. Figures 6 and 7 show a preferred embodiment of a home television display apparatus according to the invention. The apparatus comprises a television receiver 80 with a housing 81 and a color cathode ray tube 82. The housing 81 is mounted on a transparency projector 83 having a horizontally oriented, rotating container 84. The housing 81 also has a projector apparatus 85 arranged on it. for films, adapted to receive a roll 86 of motion picture film. Object color Annual color Colors, the photosensitive elements of which receive light through the transparencies. Colors, which photosensitive elements receive light from the screen. - the difference to the TV screen Color of the screen red red red ez rwQno -blue-green blue-green red] blue blue blue red blue green red-green blue Green green green red blue herbs red-blue green bales II 1 yellow yellow red-1 -very red blue green blue yellow (red-green- cyan blue-green blue-green lons red blue green red cyan (blue-green) purple red-blue red-1-blue red blue green green purple (red-blue) orange red-yellow red 1 red-green red blue green red (1) (2) blue and orange (red- (1) (2) green) An angled mirror 90 is attached to the lower front of the housing 81, mounted on an extendable bracket 91. In shown in Fig. 7, in the extended position, the mirror 90 reflects the light emitted from the screen 82 towards the optical focusing lens 92 mounted on the housing 81, above the cathode ray tube screen. A recess 93 is provided in 60 65 of the lower front part of the housing 81 to accommodate the mirror 90 when not in use. The screen light reflected by the mirror 90 and captured by the lens 92 is focused by additional mirrors and lenses (not shown) on a film slide, placed in a projection window in the housing 81, 83 093 25. Light passing through the slide is received. by means of a series of photosensitive elements and fed back to the cathode ray tube through the positive color positive slides reproduction apparatus shown in Fig. 5. It is preferred to use separate projection windows for the slides placed in the container 84 and for the film placed on spool 86. Mechanical linkage between a suitable set of lenses and mirrors and the switch may be used to switch the apparatus to the projection of slides and moving images. It should be noted that in addition to the shown transparency dispenser with a horizontally oriented container, other transparencies may be used in the home television display device. This also applies to a moving image display apparatus with a tape-advance mechanism. Note that in the embodiment example shown in Figs. 6 and 7, the positive color image reproduction apparatus shown in Fig. 5 may also be used for other types of reproduction. The on / off switch 100 of FIG. 5 can be used to disconnect the photosensitive elements 66, 67 and 68 from the system. Then the light from the screen is received only by the photosensitive elements 63, 64 and 65, the method of operation is this 3, and the apparatus provides the reproduction of positive color negative slides. If a black and white negative is placed in the projection window, the photosensitive elements 63, 64 and 65 are supplied with light of such same intensity passing through the negative. As mentioned above, when the intensity of all three color streams in a color CRT lamp is appropriate, white light appears on the screen. Thus, all three photosensitive elements are subjected to the same intensity. lights, the image displayed on the screen is black and white. By turning on the photosensitive elements 66, 67 and 68, which receive the light directly from the screen, and by applying a positive black and white image, a positive black and white image is obtained on the screen. The desired mode of operation is set by the switch 94, which has positions for normal television reception, transparency and playback of moving pictures. Further items may be provided for the positive reproduction of positives and the positive reproduction of negatives. To obtain an image on the screen, the mirror 90 is extended from recess 93 to the position shown in Fig. 7 and the television is turned on. When set to playing back moving images, the film from reel 86 will be moved through the projection window in a manner described with reference to Figs. 4 and 5, and the image contained in this film will be played on the screen 82. The film may have an audio track reproduced by an appropriate reading system 26. When set to display slides, slides. from the container 84 are successively fed to the projection window and the images thereon are displayed on the screen 82. Appropriate mechanisms may be provided for reinserting the slides into the container 84 and advancing the container to the next position. Fig. 8 shows the display device according to the invention using a positive feedback circuit adapted for use with an opaque image projector. The beam includes a picture tube 105 which emits sampling beams to the projector optical unit 106 and feedback. Assembly 106 includes a mirror 108, a receiving lens 107 for focusing light from the screen onto mirror 108, and a lens 109 for refocusing mirror reflected light 108 on an opaque image 110 disposed in holder 111. Element 112 supports assembly 106 in response. less distance from the opaque image 110 and allows the position of this unit to be adjusted to obtain the correct sharpness. The third lens 113 receives light reflected from the opaque image 110 and focuses this light on the photomultiplier 114, which produces an electrical signal proportional to the amount of light focused on it. This signal is amplified by the video amplifier 120 and fed from it to the photomultiplier tube. back to the telescope 105 through the positive feedback control system 121. The circuit 121 increases the intensity of the screen illumination in a manner directly proportional to the value of the amplified light generated by the incident light current received from the amplifier 120. In operation, an image spot from the screen .105 is focused on the opaque image 110 by means of lenses 107 and 109 and mirrors 108. When a spot falls on a white or bright area of an image 110, the maximum amount of light focused by the lens 113 on the photosensitive element 114 is reflected from the surface of the image. Reinforced and brought to the picture tube 105, using the control circuit 121, the signal increases the brightness of the screen causing a bright spot of the image to be reproduced on that screen. If a spot from the screen 105 falls on a black or poorly reflective image area 110, a small portion of the incident light is reflected and the light-sensitive element 114 produces a low or zero signal. The control signal fed to the kinescope 105 is reduced and the screen brightness is reduced accordingly, reproducing a darkened image on the screen. As described above, in a positive feedback device there is a tendency to brighten gray areas, leading to the appearance of the screen on the screen. corresponding bright spots. This apparatus is therefore suitable for reproducing high contrast images, for example printed matter, but is less suitable than reproducing images containing variations in brightness. Figures 9 and 10 show typical controls for black and white reproduction apparatus of the present invention. The negative feedback circuit shown in Fig. 9 may be used in the embodiment of the apparatus of the invention of Fig. 1. Photomultiplier 200 has an anode 212 connected to a 300 V positive source via a lead 210 and a resistor 213, and a cathode 214 connected to a 300 V negative source via wire 211. Both voltage sources are derived from the Vcc power supply via upstream transformer 215 and voltage divider 216. Transformer 215 has a primary winding 217 connected to one end of the Vcc power supply and the other The end of this winding is connected to an npn transistor 218, and a secondary winding 220 with its center lead out. Secondary winding 220 is connected on one side to the anode of diode 221 and on the other side to the cathode of diode 222 and its center lead is grounded. divider 216 includes diodes 221 and 222, filter capacitor 227 attached, one end to the cathode of diode 221 and the other end to ground, filter capacitor 229 attached to diode anode 222 and ground, filter resistor 232 connecting diode anode 222 and another filter capacitor 228. Other ends of capacitors 225 and 228 are grounded. Oscillator 219 contains NPN transistor 218 and winding 234 connected on one side to the base of transistor 218 through resistor 233, and on the other side to the emitter of transistor 218 and to ground. Upon power-up, the initial current in winding 217 induces an electromotive force in winding 234 which saturates the base of transistor 218, causing transistor 218 to flow its maximum alternating current. As a result, diode 221 receives a positive current. the half-wave pulses from the secondary winding 220 which charge capacitors 227 and 225, providing a positive potential of 300 V. Similarly, diode 222 receives negative half-wave pulses which are charged by capacitors 229 and 228, providing a negative potential of 300 V. Capacitors 225 and 228 maintain relatively constant voltages at the anode and cathode of photomultiplier 200. The multiplier 200 has nine dynodes 241-249 and corresponding leads 201-209 which are connected to the corresponding points of a voltage divider containing resistors 251-258. Additional resistors 250-259 are placed between the leads of the dynode 241 and cathode 214, and the nodes 249 and anodes 212. These resistors are used to divide the voltage approximately in equal ranges from the voltage - 300 V at the cathode to the voltage - 300 V at the anode. Dynoda 245 thus has a zero potential and is connected to the ground. To ensure a uniform voltage drop, a potentiometer 260 is provided for the voltage distribution on the photomultiplier dynodes. When the cathode 214 receives the image spot from the television screen *, free electrons are emitted, accelerated towards the nodes 241. The electrons incident on the dynode 241 knock out the extra electrons which hit the dye-node 242 and increase the number of electrons again. This takes place between successive dynodes, until the electrons are picked up by anode 212, causing the current to flow through the resistor. 213 and the corresponding voltage drop across this resistor. The signals thus evoked are amplified and fed through the transistor circuit 261 to the brightness control circuit 265 of the television 266 in such a way that the intensity of the screen illumination at a given point is attenuated proportionally to the signal produced by the photomultiplier 200. Circuit 261 includes a series of NPN-type transistors 271-274 and associated re high-voltage polarization circuits. Resistor 276 connects the emitter of transistor 271 to ground, resistor 277 connects the base of transistor 271 to ground, and resistor 275 connects the base and emitter of this transistor. The base of transistor 271 is also connected to anode 212 of photomultiplier 200 by capacitor 301, and its emitter is connected via resistors 290 and 288 to a voltage source Vcc. Similarly, resistors 279 and 280 connect to ground the emitter and base of transistor 272, respectively, and resistor J # 278 connects the base and collector of this transistor. A capacitor 302 connects the base of transistor 272 to the collector of transistor 271. The collector of transistor 272 is connected through a resistor 289 to the voltage source Vcc and to capacitor 303. Resistors 282 and 283 connect the emitter and base of transistor 273 to ground, and the resistor 281 connects the base and collector of this transistor. In addition, the base of transistor 273 is connected to the coupling capacitor 303, and the collector of this transistor is connected via resistor 287 to the voltage source Vcc. Via resistor 284, the collector of transistor 273 is also connected to the base of transistor 274. To raise the current gain. of transistor 273, a decoupling capacitor 305 is provided in parallel with transistor 282. Resistor 285 connects the emitter of transistor 274 to ground, and the collector of this transistor is connected to a voltage source Vcc by means of a resistor 286. The emitter of the transistor 274 is connected via a capacitor 304 to the brightness control circuit 265 of the TV 266. When powered up, a positive voltage from the source Vcc appears at the collectors of all transistors 271-274. A decoupling circuit with a resistor 288 and a capacitor 300 is provided to prevent voltage oscillations. For example, the collector voltage of transistor 271 is relatively high and causes a relatively high current at the base of the transistor through resistor 275. This is the syntax for increasing the current in its circuit. collector which in turn causes the voltage drop across resistor 290 to increase. The voltage to ground across the collector of transistor 271 is thus reduced, the base current is reduced, and the collector current is also reduced. Resistor 275 controls the flow of current so that, in a state of equilibrium, the collector voltage of transistor 271 is approximately equal to half the voltage from the Vcc source. When the television screen is blacked out, the photomultiplier 200 receives no light and does not flow through resistor 213. electricity. There is a positive potential of 300 V in relation to ground on pin 210. If light is incident on the photomultiplier 200, a current flows through the resistor 213 causing it to drop in voltage, so that the lower end of this resistor is at a potential lower than a potential of 300 V to ground. When generating a pulse, the left end of capacitor 301 it has a lower potential, which in turn causes a lower potential at its right end. This produces a negative voltage shift at the base of transistor 271, which reduces the current in the collector circuit and reduces the voltage drop across the resistor 290. This increases the voltage across capacitor 302 and correspondingly increases the base voltage of transistor 272. This increases the collector current of transistor 272. and increases the voltage drop across resistor 289. This voltage increase is transferred to the base of transistor 273 through capacitor 303, thereby reducing the collector current of the transistor. The voltage drop across resistor 287 is also reduced, causing the voltage across the collector of transistor 273 to increase. Prior to the impulse, a steady state voltage from the collector of transistor 273 is applied to the base of transistor 274 through resistor 284. 284 is small, the voltage at the base and emitter of transistor 274 is thus approximately equal to the collector voltage of transistor 273. Thus, normally there is a small current flow and a corresponding voltage drop across resistor 285. slight obscuration of the transparency area, the collector voltage of transistor 273 and based on transistor 274 is increased. The emitter and collector current of transistor 274 also increases, which increases the voltage drop across resistor 285. This in turn increases the voltage supplied to the cathode tube through the capacitor 304 with respect to the control mesh. Electron emission is thus reduced and the screen is dimly illuminated, giving a positive image from the negative transparency. It is clear to those skilled in the art that the above circuit can also function as a positive feedback circuit by connecting a capacitor 304 to the control grid of the cathode ray tube. The increased voltage applied to this grid in response to the signal produced, allows the flow of electrons to increase, leading to a brightening of the screen. The positive feedback circuit of FIG. 10 is substantially the same as the negative feedback circuit described above, except that the decoupling circuit also includes a resistor 325 and a capacitor 326, and that transistor 274 and its biasing circuit are replaced by a transistor circuit 310 connected to the collector of transistor 273 through capacitor 311. Circuit 310 includes an NPN transistor 312 and 093 30 a bias circuit consisting of a resistor 313 connecting the emitter of this transistor to ground, a resistor 320 connecting its base to ground, and a resistor 321 connecting the base and collector of transistor 312. The bypass capacitor 322 of the frequency compensation is connected in parallel with resistor 313 and serves to increase the current gain in transistor 312. When a pulse is received The luminous light corresponding to the faint obscuration and obscuration of the transparency region, as in the negative feedback circuit, increases the voltage in the collector circuit of transistor 273. This increase is transferred by the capacitor 311 to the base of transistor 312, and the collector current of this transistor is thus increases. This increases the voltage drop across resistor 286, thereby reducing the voltage across the left side of capacitor 304. The voltage on the right side of this capacitor also drops accordingly and a reduced voltage is applied to the cathode of the kinescope. This increases the emission of electrons in the cathode ray tube and brightens the screen according to the intensity of the signal received. Fig. 11 shows another apparatus for displaying photographic slides on a television screen which is adapted to positively reproduce negative and / or Live black and white still images. This embodiment is similar to the example of Fig. 1 and similar or identical components have the same reference numerals here. In the example of the embodiment of Fig. 11 a control system 420 is provided. The sampling and holding system 424 is adapted to cyclically generate analyzing pulses of constant amplitude which, when amplified by a conventional video amplifier 426, feeds the electron guns of the kinescope 11, causing the emission of sampling streams of maximum brightness from particular points of the raster. analyzing the slide 17 in the form of a pulsating image spot d 420 also includes a pulse generator 425 which, through a feed 427 45, starts the sampling and hold circuit 424. The pulse generator 425 cyclically generates control pulses to turn on the control circuit 424 and to generate sampling pulses whose duration is equal to 50 control pulses. In addition to outputting the analysis pulses of the sampling and holding system 424, when it is active, it stores the feedback input pulses received from the photosensitive element 16. 65 After each control pulse terminates, the appropriate stored feedback signal is stored. it is outputted as an output pulse and fed through the amplifier 426 to the kinescope 11, brightening the screen at a point 60 corresponding to a point on the transparency 17 illuminated by the incoming sampling stream and causing the image of that point to be reconstructed on the screen. Rapid reproduction of all such points gives the whole image of the transparency on the screen. * As can be seen above, the sampling-and-hold circuit 424 is designed to sample the input from the photosensitive element 16 for a short period of time, corresponding to the duration of the control pulse generated by the a controller 425 pulses, and then emits an output pulse of equal value and duration equal to the time interval between successive control pulses, the interval being approximately six times greater than the duration of the control pulse. During sampling, the brightness of the screen and the sampling stream is maximum. After the sampling time, the value of the output pulse and the brightness of the kinescope are proportional to the value of the signal from the photosensitive element 16. As the duration of the sampling pulse is relatively short compared to the duration of the control pulse generated by the pulse generator 425, and then emits a pulse. output having an equivalent value and duration equal to the time interval between successive control pulses, the interval being approximately six times greater than the duration of the control pulse. During sampling, the brightness of the screen and the sampling stream is at maximum. After sampling, the output pulse value and the brightness of the kinescope are proportional to the value of the signal from the photosensitive element 16, because the duration of the sampling pulse is relatively short compared to the duration of the output pulse. Each analyzing pulse and the corresponding output signal is independent of the previous and stepped pulses, so the image reproduced at each point is not affected by the amount of light emission from the screen at neighboring points. In this way, the brightness of the screen can be stabilized at the proper level without introducing excessive contrast in both positives and negatives reproduction. In addition, to prevent distortion of the feedback signals caused by screen shine after each sampling stream, a high-pass filter 428 is provided to pass only the high-frequency range generated by the incident light signals. As mentioned above, the high-frequency signal is only produced as the sampling stream is rising, so the filter 428 prevents any signals caused by the afterglow of the screen from being fed to the controller 420. To produce positive images on a television screen. transparency 17, the output pulse is fed directly through the video amplifier 426 to the kinescope electron gun to bring the screen to a brightness level directly proportional to the size of the output pulse. To produce a negative image of the transparency 17, the output pulse fed to the electron gun of the kinescope has a value equal to the difference between the value of the feedback signal and the value of the sampling pulse. 32 To achieve this, the sampling and holding circuit comprises additional circuits adapted to normally feed the kinescope to its maximum brightness, as does the evaluation pulse, between the analysis pulses, and to subtract from such maximum pulses. the feedback signal, therefore, if the feedback signal has a large value representing a relatively autumnal transparency, the output pulse will be of a small value, producing a relatively dark image. Conversely, if the transparency is dark, the feedback signal is small and the output pulse is large, resulting in a relatively bright image. For positive reproduction of positive images, the sampling and holding circuit 424 shown in FIG. 12 is preferred. it includes a FET 450, the source of which is connected to the input terminal 451 of the feedback circuit, a gate is connected via diode 453 and capacitor 454 to control input 452, and a drain is connected to capacitor 455. Diode 457 connects the capacitor 455 to output 456 and diode 458 connects the control input 452 to this output 456. In normal or off state, when input 452 has no control pulse, the gate of FET 450 is negatively biased with respect to its source. through a negative potential of about -10 V connected to terminals 459. In this state, no current is flowing between the source and the drain of the FET. Also, there is no current flow between controlling input 452 and output 456, the voltage on capacitor 455 therefore appears through diode 457 on the output terminal. When a pulse generator 425 is applied to input 452, a control pulse which has a positive With a potential equal to the negative potential applied to terminal 459, capacitor 454 raises the cathode voltage of diode 453 to a positive value relative to its anode voltage, causing a polarity reversal to result in a loss of current flow through diode 453. Resistance 460 and 461 and capacitor 454 input the required time constant for the control pulses applied to input 452. Simultaneously with the clogging of diode 453, connecting the source and gate of FET 450, resistor 462 allows the source and gate potentials to be equalized. This is the on-state of the FET and allows the bi-directional flow of current between the source and the drain that charges capacitor 455 to a voltage that is equal to the feedback signal fed to input 452. Note that the drive pulse is always 60 a value greater than the maximum value of the feedback signal, so that the sampling pulse at the output 456 of the hold and sampler is substantially equal to the command pulse applied to input 452. This is because the higher control pulse voltage 4533 biases diode 457 in the reverse direction. When the pilot pulse is removed, the FET is restored to its shutdown state, isolating the capacitor 455 from any feedback signals appearing on input terminal 451. Under these conditions, diode 457 goes on conduction due to voltage applied to the anode than to the cathode, and the diode 458 is clogged due to the reverse bias, so that the output pulse generated at 456 has the same value as the charge on the capacitor 455, supplying the cathode ray tube according to the generated by the incident light by feedback signals. In operation, the transparency 17 is placed in the projection window 14 of the projector and feedback optical system 12, and this system 12 is directed at the television screen. The sampling streams emitted from the television screen are focused by the lens 13 on the transparency 17 and then refocused by the capacitor 15 on the photosensitive element 16. The signal produced by the photosensitive element is proportional to the intensity of the light falling on them. After amplification and fed back to the television via control circuit 420, the signal modulates the next spot appearing on the screen in a manner proportional to the light intensity incident on the photosensitive element 16. Consider an example of a control circuit 420 having a circuit subtraction not shown. Pulse transitions and adapted to the positive reproduction of negatives, during which the bright portions of the slide 17 cause dark portions on the screen, and the dark portions of the slide 17 produce bright portions on the screen, giving a positive image of the negative slide. When turned on, the control pulse from generator 425 triggers the sampling and hold circuit 424, producing an analysis pulse which powers the kinescope and causes the sampling stream to be emitted from point Sj of screen 11. Light emitted from point S! is focused on the corresponding point Tx of the transparency 17. If there is a completely black or opaque area at the point Tt, the light from this spot does not reach the photosensitive element 16 at all. The light-sensitive element 16 does not generate any current, but the control No input signal is applied to the 420 circuit. After the control pulse expires, the sampling circuit produces a maximum output signal that produces a spot on the screen with maximum brightness. If the sampler is output from the screen point S2, it is focused on screen 17 at point T2. If the point T2 is the point of maximum transparency, the maximum part of the light from point S2 of the kinescope screen 11 is focused on the photosensitive element 16, and the photosensitive element in turn produces the maximum signal. This signal is supported by the sampling circuit S3 093 34 and of the holding, subtracted subtraction of the maximum pulse and the drained egg im-, the output pulse of a small value, causing a darkened image at that point of the e-tap. Likewise, if the next sample stream is focused on a half-half point? When the sampling stream is terminated, the control circuit 420 produces an output pulse equal to half the maximum value, causing a gray spot on the screen to appear on the screen. .When this solution is used for positive reproduction of positive, the output pulse is directly proportional to. values of the feedback signal and feeds the cathode ray tube by producing points on the screen whose brightness corresponds to the brightness of the points of the illumination transparency. smoldered by sampling streams. The embodiment of FIG. 13 is intended to produce positive images of color transparencies 434 on a TV screen of a CRT 430. A typical color CRT 430 emits from the screen of the CRT screen 430 sampling beams of red, blue, and green light, which beams are are focused on the color slide 434 by the lens 432, This light that passes through the slide 434 is received by the photo cell 433. 30 The lens, the appropriate projection window for positioning the transparency, and the photo cell 433 can be placed inside the projector and feedback loop like this. to the assembly of Fig. 11. The photocell 433 is sensitive to the entire frequency range of the light and, depending on it, produces electrical signals whose magnitude is proportional to the intensity of the focused light on it. The signals produced by the photocell 433 are amplified by video amplifier 435, filtered by high pass filter 436 and then fed back to the control circuit it produces. pulses corresponding to the output red, blue and green pulses, causing the image of the transparency to be recreated on the screen of kinescope 430. The control circuit used in the embodiment of Figure 13 is quite similar to that in Figure 11 but includes three circuits 437, 438 and 439 sampling-and-hold for producing red, blue, and green sampling pulses and output pulses to drive the respective red, blue and green electron guns 430 in the kinescope 430. The video amplifier 463 amplifies the sampling and output pulses from sampling and holding circuits 437, 4S8, and 439 before feeding them to the telescope 430. 60 A pulse generator 440 is included with each sampling and holding array 437, 438, and 439. adapted to activate each of the above mentioned circuits, whereby they send to the kinescope 430 red, blue and green sampling pulses, producing the corresponding sampling streams of these colors. The pulse generator 440 may be made using logical gates 441, 442 and 443 and the RC circuits 447, 448 and 449 connected as shown in the diagrams © in Fig. 14. The values of the resistors and capacitors in all three circuits are the same. The logic gates and the associated RC circuits form a generator, whose frequency is determined by the RC time constants, and the delay of each gate. 15 shows the waveforms of the logic outputs of the logic gates 441, 442 and 443. These outputs are "applied to three NOR gates 444, 445 and 446, adapted to produce positive control pulses, when both their inputs are not driven, then it is between the outputs shown in FIG. 15 which actuate the respective red, blue and green sampling and sustaining circuits. As can be seen from Fig. 16, the duration of the positive control pulse is shifted by one third of the repetition time, so they are equidistant from each other. red sampling and sustaining system 437 is activated, generating a red color sampling pulse which, when amplified by the amplifier 463, feeds the red color electron gun of kinescope 430, causing the red color sampling beam 430 to be emitted from the screen raster of kinescope 430 with a maximum red color. brightness. As can be seen in Fig. 16, while circuit 437 is active, the blue and green color sampling and holding circuits are inactive or off because NOR gates 445 and 446 are no control pulses are produced. When the sampling pulse is emitted, the red sampling and holding subsystem 437 also receives and stores the photoelectrically generated signals from the solar cell 433, the value of these signals being proportional to the red light focused on it. the color of the point on the transparency 434 hit by the red sampling stream contains red, the photocell 433 produces a feedback signal stored in the sampling and holding system 437. If this point does not contain red, no feedback signal is produced because the transparency is a filter illumination to prevent red sampling beam investigation to solar cell 433. Upon completion. control pulse from NOR gate 444, and before the start of the next control pulse from that NOR gate, the sampling and holding circuit 437 releases an output pulse, the value of which corresponds to the value of the feedback signal received from the photocell 433, which energizes the electron gun of the kinescope 430 is red, reproducing a red spot with the brightness and position corresponding to that struck by the red stream sampling the point on slide 434. Upon completion of the output pulse from array 437, sampler 438 is triggered. The pulse generator 440 is maintained by a control pulse from NOR gate 445, whereby a green analysis pulse is applied to the green electron gun 430 for elimination of the green color sampling stream at maximum brightness. When this occurs, as can be seen in Fig. 16, both red and blue sampling and sustaining circuits 437 and 439 'are off, thus producing no analysis pulses. If illuminated by the sampling beam, the green point is Transparency 434 is not green in color, no light is received by the photocell 433, and no feedback signal is produced. Accordingly, after the expiration of the control pulse for turning subsystem 438 on, no output is produced and the green color does not appear at the corresponding point on the screen. The next control pulse is emitted from the pulse NOR gate 446, generator 440, turns on the sampling and hold circuit 439, and this circuit produces a blue color sampling pulse. As has already been described for the other colors, if this flux falls on the blue part of the translucent 434 by the photocell 433 a signal is produced, which is stored by circuit 439 until the control pulse from the NOR gate 446 expires. 35 If the blue sampling beam is the part of the slide that does not contain blue at all, the photocell 433 produces no feedback signal, and after the end of the control pulse emitted from the NOR 446 gate, the blue color does not appear in the corresponding point of the screen 431. as discussed above, for each line of the raster present on the screen of the kinescope 430, there may be as many as four hundred or more individual analysis pulses and corresponding output pulses produced by the control system, so the viewer perceives the correct color mixture to receive an accurate and clear color mixture. the reproduction of the image of a transparency rather than a series of sparkling red, blue and green pu In the example of the embodiment of Fig. 13, positive reproduction of the color positives and negatives 55 can be obtained in the same way as the black-and-white reproduction of negatives and positives described in relation to embodiment 1 of Fig. 11. However, in in the case of reproducing color images, each of the three separate sampling and holding systems is arranged to produce output pulses that are either in value proportional to the feedback pulse received from the photo cell 433, in the case of positive reproduction, 65 or represents the difference in the value of the feedback signal and the signal corresponding to the maximum brightness in the case of negative playback. In the case of negative playback, if the year 434 is a color negative of the entire green area, it has a complementary purple color. which includes the primary colors red and blue. The transparency 434 thus transmits only red and blue light, and the photocell 433 produces feedback signals only when it is illuminated by red and blue sampling jets during the operation of sampling and holding circuits 437 and 439. receives light from the television screen during the analysis pulse of the sampling and holding circuit 438, because the green light does not pass through the slide 434. In negative operation, the control circuit reduces the screen color in a manner proportional to the output pulses of the generator The brightness of the red flux and the blue flux appearing on the screen 431 is therefore kept to a minimum as the feedback signals caused by the color sampling streams red and blue go are large, while the brightness of the green color is maximized because the feedback signals from the green stream sampling the feedback are zero. This results in a reproduction of the entire green area on the screen. The multiple sampling streams emitted from the color screen 431 select the transparency 434 in the same way as in the black-and-white reproduction example of Fig. 11 that appears on the screen. at each point the image corresponds in position to a point on the slide and has a complementary color and inverse brightness to that point on the slide. As with the first embodiment of the invention, Table I illustrates the operation of the arrangement of Fig. 13. for some other colors. Table I can also be used to illustrate the operation of positive reproduction devices. In this case, each of the sampling and holding subsystems produces an output pulse whose amplitude is proportional to the amplitude of the feedback signal. of the feedback received from the photovoltaic cell 433, whereby the color of the object on the transparency is directly reproduced on the screen of the picture tube 430. This is achieved by eliminating the subtracting portion of the control system. The stored feedback signal is converted directly into an output signal that directly controls the brightness of the screen. As follows from the above, the sampling and holding control circuit of Figs. 11-14 can also be replaced by the simple feedback circuit 3 093 38 described above. in relation to <Figures 4-8. It is further understood that the embodiments described herein are intended to be illustrative and not limit the invention. Other systems will be apparent to those skilled in the art, with the use of a feedback loop through the screen of a picture tube, for the reproduction of photographic or other images. and for example, this system may be adapted for use in television broadcasting studios to display movies. It is particularly useful for closed-circuit or cable-based television. The invention also has application to video telephone systems. PL PL

Claims (7)

1. Claims 1. A method of reproducing images on a television screen from transparencies, film tapes and non-transparent images, characterized in that the reproduced image is analyzed with the light emitted from the screen of a TV CRT lamp and the light is perceived, representing the blackening or saturation of the color of the selected image spot by the photosensitive element produces electrical signals dependent on the intensity of the light falling on the photosensitive element, these electrical signals are fed back to the TV CRT lamp and the brightness is modulated. of the TV CRT lamp in the corresponding picture spot depending on the value of the signal produced by the photosensitive element to reproduce the image on the screen of the picture tube. 2. A method of reproducing images on a television screen from transparencies, film tapes and non-transparent images, characterized in that the transparency is analyzed with the light emitted from the screen of a TV CRT lamp, this light is perceived as passing through the film and showing the blackening of the transparency. in its selected spot, on the first light-sensitive element, unshielded light is received from the screen of the TV cathode ray tube on the second light-sensitive element, the first electric signals are generated in response to the light intensity received by the first light-sensitive element, it produces second electrical signals in response to the light intensity received by the second photosensitive element, produces a differential signal representing the difference between the values of the first and second signals, leads the differential signal back to the cathode ray tube in the corresponding screen spot, according to the value signal u a differential in order to reproduce a positive image on the CRT screen. 3. A method of reproducing images on a television screen from transparencies, film strips and non-transparent images using a color picture tube television set, characterized by analyzing the reproduced color image with light from the screen containing a red component, a blue component and a green component, emitted from a TV tube lamp, this light is perceived, representing the color saturation in the selected spot, on the first, second and third light-sensitive elements, sensitive respectively to red, blue and green light, the first, second and third electrical signals are produced in response to the intensity of red, blue and green light received by the respective first, second and third light-sensitive elements mentioned above. the first, second and third electrical signals are exchanged back to the TV CRT lamp, and the light intensity is modulated red blue and green, illuminating the screen in the corresponding spot according to the value of the corresponding signals produced by the first, second and third, light-sensitive elements, in order to reproduce a color image on the screen. 4. A method for reproducing images on a television screen from transparencies, film tapes and non-transparent images using a color CRT television set, characterized by analyzing the image-based film with the color light emitted from the color picture tube screen containing a specific component red, blue and green, one perceives this light passing through the image and representing its blackness and color saturation in the selected spot, the first set of photosensitive elements having photovoltaic cells sensitive to red, blue and green light, respectively, one perceives the different light emitted from a screen of a color picture tube containing red, blue and green components, a second set of photosensitive elements having photocells sensitive to red, blue and green light, respectively, a first group of electric signals is produced in response to the intensity of red light respectively , blue and green, perceived by said photocells of red, blue and green color, of said first set of photosensitive elements, a second group of electric signals is produced in response to the intensity of red, blue and green light received by said photovoltaic cells, respectively, of red, blue and green colors, of the second set of photosensitive elements mentioned, red, blue and green color difference signals are produced, representing the difference in size between the corresponding signals produced by the red, blue and green photovoltaic cells, the former and the latter of the second set of photosensitive elements, the red, blue, and green differential signals are fed back to the color picture tube, and the red, blue, and green light is dimmed to illuminate the screen in its corresponding spot according to the size of the signals the differentials of red, blue, and green, respectively, to reproduce a positive color image on the CRT screen. 5.; 5. The method according to p. The method of any of claims 1 or 2 or 3 or 4, characterized in that the brightness of the TV CRT lamp 3093 is modulated by screen brightness attenuation in proportion to the size of the signals produced. 6. The method according to p. 5. The method of any of claims 1 or 2 or 3 or 4, characterized in that the brightness of the TV tube is modulated by increasing the brightness of the screen in proportion to the value of the signals produced. 7. Apparatus for reproducing images on a television screen from transparencies, film tapes and non-transparent images, comprising a TV cathode ray tube lamp emitting from its screen light analyzing the image reproduced, means for focusing this light on the image and a light-sensitive element receiving this light falling on the image, representing the blackness or saturation of the color of the selected spot in the image and generating electrical signals depending on the light intensity, characterized by the fact that it has a feedback system 20 (12, 24, 36, 50, 106) connecting the element (16, 41, 42, 43, 56, 63, 64, 65, 114, 433) lighted and a TV cathode ray tube lamp in order to modulate the intensity of the screen illumination in the corresponding image spot depending on the signal produced by the light-sensitive element in in order to reproduce an image on a picture tube screen, has support elements (14, 26, 38, 53, 78, 111, 434) for supporting an image carrier in this manner If it receives light from a television screen, it brings together elements (13, 25, 37, 54, 109, 432) for focusing the light on an image carrier placed in the supporting elements, the light-sensitive element comprising at least one a photocell (16, 41, 42, 43, 56, 63, 64, 65, 114, 433) adapted to produce an electric current, the value of which is proportional to the light intensity it receives, and has a second focusing element ( 15, 27, 40, 55, 113) to focus incident light from the photosensitive element 40, and the supporting elements include a projection window (14, 26, 38, 53, 75, 111, 434) positioned so that it receives light from a TV CRT lamp and the projection window, which gathers the elements and the photosensitive elements, forms at least part of the optical projector and feedback system. 8. Device according to claim The apparatus of claim 7, characterized in that it comprises a video amplifier (19, 33, 44, 45, 46, 61, 69, 70, 71, 120, 435) adapted to amplify the electrical signals produced by the photosensitive element. 9. Device according to claim 7. The apparatus according to claim 7, characterized in that the photosensitive element comprises a first photosensitive element 55 (28) which receives light that passes through a transparency <2 transparency in a specific spot thereof and is sensitive to the intensity of this light, producing electrical signals whose value corresponds to The intensity of this light, the second light element (30) receiving light directly from the picture tube (11) and sensing the intensity of this light, producing signals whose value corresponds to the intensity of this light, and a differential amplifier (33) connected to the first and the second of photosensitive elements 83093 41 (28, 30) and providing an amplified signal representing the difference in the value of signals received from the first and second photosensitive elements, while the feedback circuit combines a differential amplifier and a TV tube to suppress the screen brightness in response to ¬ giving a screen spot in accordance with the value of the amplified differential signal received from the line amplifier for reproduction of a positive image on a television screen. 10. Device according to claim The apparatus of claim 8, characterized in that it has reproduction means for alternatively reproducing positive images from either positive or negative slides, said reproducing means comprising a switch (100) connecting the second light-sensitive element (30) and a differential amplifier (33) and enabling their connection and disconnection in the first and second positions, respectively, while the apparatus is adapted to reproduce a positive image of a positive slide in the first position of the switch and a positive image of a negative slide in the second position of the switch. 11. Apparatus for reproducing images on a television screen from transparencies, film tapes and non-transparent images, the television cathode ray tube being a color con- cept emitting red, blue and green light from its screen onto the reproduced color image characterized in that it comprises first, second and third light-sensitive elements (41, 42, 43) which receive the light incident on the image (39), representing the darkness and saturation of the color of the image spot and depending on the intensity of red light, respectively, not blue and green, producing electric pulses, the value of which corresponds to the light intensity, and a system (47) connecting the first, second and third photosensitive elements to the color picture tube to modulate the intensity of illumination of the CRT screen (35) by red, blue and green light in the corresponding dot on this screen according to the magnitude of the signals produced by the three photosensitive e elements to reproduce a color image on the screen. 12. Device according to claim 12. The apparatus of claim 11, characterized in that said first, second and third light sensitive elements comprise photovoltaic cells (41, 42, 43) having red, blue and green light filters, respectively. 13. Device according to claim 12. The apparatus of claim 12, characterized in that the TV cathode ray tube is adapted to emit light of a certain maximum intensity and the circuit (47) is adapted to attenuate the brightness of the screen in a manner proportional to the value of the signals produced by said first, second and third photosensitive means (41, 42, 43) for producing a positive color image on a screen (35) from a negative color slide (39) and vice versa. - 14. Device according to claims 13. The apparatus according to claim 13, characterized in that said first, second and third light-sensitive elements (41, 42, 43) receive the light reflected from the image (39). Device according to claim 42 14. A method according to claim 14, characterized in that it has a first set of photosensitive elements (63, 64, 65) for receiving the light transmitted through the film (76) representing the darkness and saturation of the color of the image spot and having photosensitive elements of red, blue and green, responding to the light of these colors, generating electrical pulses, the value of which corresponds to the light intensity of red, blue and green respectively, has a second set of photosensitive elements (66, t | 7, 68) receiving light directly from the screen - the tube of the cathode ray tube (35) and having photovoltaic cells responding to the respective red, blue and green light, producing electric pulses whose values correspond to the intensity of red, blue and green light respectively, and has the first , second and third differential amplifiers (69, 70, 71) attached to the photocells of red, blue and green respectively sets of first and second photosensitive elements (63, 64, 65, 66, 67, 68) to provide amplified signals representing the difference in value of the signals received from the sets of red, blue and green photovoltaic cells, the arrangement being (73) combines the first, second and third differential amplifiers with a color kinoscope (35) to suppress the brightness of the red, blue and green light respectively illuminating the corresponding screen spot according to the size of the amplified differential signals received from three differential amplifiers (69, 70, 71) to reproduce a positive color image on a television screen. 16. Device according to claim 15. The apparatus of claim 15, characterized in that it comprises reproduction means for alternatively reproducing positive color images either from positive or negative color transparencies or other image carriers, said reproducing means comprising a switch (101) connecting said color photocells. red, blue and green of the second set of photosensitive elements 45 (66, 67, 68) with the mentioned first, second and third differential amplifiers (69, 70, 71) and allowing their connection and disconnection in the first and second respectively position, while said apparatus is adapted to positively reproduce color images from colored slides or positive images in the first position of the switch, and to positively reproduce color images from colored slides or negative images in this first position of the switch. the second position of the switch. 17. Device according to claim 16. A method according to claim 16, characterized in that the TV cathode ray tube lamp is adapted to emit light of a normal maximum intensity and the system is adapted to attenuate the brightness of the screen in proportion to the value of the signals produced by the photosensitive elements, for reproducing positively images on the screen. negative images and odT 65 inverse. 43 83 093 44 18. The device according to claim 1 16. The apparatus of claim 16, characterized in that the TV cathode ray tube is adapted to emit light normally of a minimum intensity and the system is adapted to increase the brightness of the screen in a manner commensurate with the size of the signals produced by the photosensitive elements. 19. Device according to claim 7 or 8 or 9 or 10 or 11, characterized in that said light is a sampling stream, a CRT TV lamp (10, 60, 105, 430) is adapted to cyclically emit a plurality of sampling streams from its screen during each selection, the focusing elements (13, 432, 54, 109) focus the sampling rays on the reproduced image (17, 434, 57, 110), light-sensitive elements <16, 433, 56, 114) are positioned so that they receive that part of each sampling ray that is focused on the image, representing the blackness of the image at its point, and responding to the intensity of this light by producing corresponding electrical signals, while the circuit (420, 441, 420 ') feedback is adapted to cyclically energize the tube to induce emission of sampling streams and to modulate the brightness of the screen cyclically at each point corresponding to the point in the image on which the beam is focused Sampling according to the value of the signals produced by the photosensitive elements to reproduce the image on a television screen. 20. Device according to claim A feedback circuit (420, 441, 420 ') and a sampling and holding circuit (424, 437, 438, 439) adapted to cyclically generate analysis pulses of a constant value to excite such a brightness level. screen of the cathode ray tube on which sampling streams are emitted, adapted to store all electrical signals produced by the photosensitive elements (16, 433, 56, 114) for the duration of each analyzing pulse, and adapted to send an output pulse the value of which corresponds to the signal produced by the photosensitive elements after the disappearance of the analysis pulse for the excitation of the kinescope screen to a brightness level corresponding to the blackening of the image at the point on which the immediately preceding sampling stream was focused, at the number of consecutive points thus reproduces the image on the screen. 21. Device according to claim The method of claim 20, characterized in that the constant analysis pulses sent by the sampling and holding circuit (424, 437, 438, 439) stimulate the screen to generate sampling streams at a substantially maximum intensity. 22. Device according to claim 21, characterized in that the feedback circuit (441, 420 ') further comprises a pulse generator (440) adapted to cyclically generate a steering pulse which activates the circuit (437, 438, 439) to probe and hold. for generating analysis pulses, and for storing the result signals produced by the photosensitive elements. 23. Device according to claim 22, characterized in that the sampling and sustaining circuit (424, 437, 438, 438) produces output pulses having a duration of at least approximately six times greater than the duration of the analyzing pulse, whereby the viewer perceives the dominant point. a screen reproducing the corresponding image point, not the sampling stream. 24. Device according to claim 23, characterized in that it has a high-pass filter (428, 436) connected between the photosensitive elements (16, 433, 56, 114) and a feedback circuit (420, 441, 420 '), adapted to filter this part of each case. each signal produced by the elements lightly during the extinction of each sampling stream to avoid screen ghosting. 25. Device according to claim The method of claim 24, wherein the TV cathode ray tube produces dots on the screen with minimum brightness between sampling streams or produces dots on the screen with maximum brightness between sampling streams. 26. Apparatus for reproducing images on a television screen from transparencies, film tapes and opaque images, characterized in that the television CRT lamp is a color kinescope (430) having electron guns for three colors, red, blue and green , adapted to cyclically and successively emit from its raster on the screen separate sampling streams, red, blue and green, during each selection of this screen, the focusing elements (432) focusing said sampling streams on the reproduced color image (434) the light elements (433) are positioned so that they receive that portion of each sampling stream focused on the image that represents the blackness and color saturation of the image at its point, and responds to the intensity of this red, blue, and green light, producing electric signals corresponding to its values, while the feedback system It combines light-sensitive elements and a color picture tube adapted to cyclically and sequentially energize the red, blue and green electron guns for the emission of the above-mentioned sampling rays and for the cyclical and subsequent modulation of the red light intensity, respectively, , blue and green, illuminating each point of the screen corresponding to the point in the image on which the sampling stream is focused according to the magnitude of the signals produced by the photosensitive elements, in order to reproduce a color image on the screen. 27. Device according to claim The feedback circuit of claim 25, characterized in that the feedback circuit comprises first, second and third sampling and holding circuits (437, 438, 439), each adapted to cyclically and sequentially generate analysis pulses of a constant value to be acquired. the brightness level of the electron guns of the corresponding colors red, blue and green, of the picture tube (430), at which the said red, blue and blue sampling streams are emitted. green each is adapted to store the corresponding electric signals produced by the photosensitive element during its analysis pulse, and each is adapted to emit an output pulse whose value corresponds to the value of the pulse produced by the photosensitive element after the expiry of its analysis pulse for the excitation of the electron guns, red, blue and green, respectively, n the telescope to a brightness level corresponding to the image color density and saturation (434) at the point on which the immediately preceding sample stream was focused, many consecutive points thus reproduce a color image on the screen. 28. Device according to claim 27, characterized in that the constant level analysis pulses emitted by the first, second and third sampling and holding circuits (437, 438, 439) stimulate the electron projections of red, blue and green colors, respectively, to produce sampling streams of substantially maximum intensity. 29. Device according to claim 28, characterized in that the pulse generator (440) is adapted to cyclically generate a control pulse which sequentially triggers the first, second, and third sampling and holding circuits (437, 438, 439) to generate analysis pulses and to store the resulting signals. By the light-sensitive element (433). 30. Device according to claim 29. characterized in that each of the first, second, and third, sampling and hold clusters (437, 438, 439) produces output pulses whose duration is at least about three times longer than that of the analysis pulses produced by Each of the mentioned sampling and holding systems, so that, in the view of the viewer, a point on the screen is a reproduction of the corresponding point in the image and not the sampling stream. 31. Device according to claim The method of claim 30, characterized in that the electron guns of the red, blue and green color of the telescopic television lamp (430) generate, between the sampling streams, said points on the screen of minimum brightness. 5 32. Device according to claim 29, characterized in that the electron guns of the red, blue and green color of the telescopic television lamp (430) generate the maximum brightness of said points on the screen between the sampling streams. 33. Device according to rules. The slide according to claim 7, characterized in that it comprises support means (84) for supporting the slide magazine, indexing means (83) for adjusting said slide magazine to the slide to bring the desired slide to a viewing position, and slide change means for carrying the selected slide between the slide magazine and the projection window. 34. Device according to claim 33, characterized in that it comprises support means (86) for supporting a supply of film with a motion image, projector means (85) for advancing the film through a projection window to reproduce the image contained in each frame thereof on the screen of the cinema, and shutter elements to prevent the screen from being illuminated while the film is moving. 30 35. Device according to claim The apparatus of claim 34, characterized in that the photosensitive element (114) is positioned to receive light reflected from the image supporting center (110). 36. Device according to claim 35, characterized in that a show device (80) is provided adapted to the conventional black-and-white and color television reception and to the visual reproduction of photographic, black-and-white and color transparencies comprising switching means (94) for alternative switching to normal television reception and video playback. 37. Device according to claim The apparatus of claim 36, wherein the guide means (90, 91) to direct light from the screen of the picture tube to the focusing means 45. 28. Device according to claim 37, characterized in that the light guiding element is a reflecting surface (90). 83 093 (Fig. 3). 36 41 39 40 43 R Fig. 4. 34, 79 Fig. 5.83 093 SS ^ C ^ L ort dl 94 l — 9l ^ C ~) n ^ and Fig 6 Fig. 7. IOt Fig a 300V v * and J. 2 * i w * 7J vcc __jm83 093 FIG. II, 450 if-r ^ 430 46383 093 F / GM t £ ^ vww ^^^ \ zma vwk 5 ^ m7m FIG. I5 mm \ m FIG. 16 PL PL