DE2415173C3 - Method and device for the color display of black betting images via color television picture tubes - Google Patents

Description

Kind of known at which the amplitude of the black-and-white signal broken down into stages and each of these stages is assigned a color that was previously determined by hue and Saturation must be set (DE-OS 20 53 555). This procedure and the corresponding arrangement bring the disadvantage that with economical Justifiable effort, only a relatively rough subdivision is possible, which may lead to conversion cartoons in color, but not suitable for converting e.g. X-ray images. The same color is present within the individual stages and it is even possible that if the brightness is in the vicinity of a switching threshold / between cl; n · steps, the result caused disturbances lead to local color changes from one to a completely different color. For certain use cases, e.g. B around x-ray images for better differentiation in color images to convert or other oath / white images, for example satellite images, for scientific purposes The known method is not suitable for precisely resolving the evaluation.

A low-pass filter is provided there, which is intended to avoid that at the Schalischwellc-n between malfunctions occur in the individual stages. This low-pass filter has its own disadvantage that there is a limit frequency of 0.5 MHz for a Signal of about 5MMz bandwidth. This means that because of this low-pass filter, gray tone gradients in the black-and-white picture structures that are smaller than the length of the line (1 to 1.5 cm), in the case of which Reproduction via picture tubes with a diagonal of 60 cm cannot be reproduced in color.

In the known arrangement, the amplitude is also broken down with limiters. This means that the 35 Black and white signals must also appear in the image. So precautions must be taken that the black-and-white signal is rearranged in such a way that these two end values are also present are and remain unchanged, because otherwise the known arrangement is not functional.

In contrast, the present invention is based on the increase, even the smallest differences in height to assign different colors or shades of the black and white image - thus a for The color image is easily evaluated by the eye - without the reproduction of the smallest image structures must be dispensed with.

The invention has the features indicated in the characterizing part of claim I. Through this Measures in which the amplitude of the black-and-white Fcrnschsignal Serving as a control for the coloring, it becomes possible to use the entire color gamut for the To reproduce a black and white picture that but is not changed in its basic structure with regard to the light wedge differences. The invention therefore creates a color image that all gray tones in different color gradations and color saturation, so that even very small differences in brightness in the black and white image Changes in hue or color saturation can be recognized. Since the invention A low-pass filter does not have to be provided for the method, so there is also a very fine geometric resolution of the process Black and white picture possible. The method according to the invention is therefore particularly suitable for scientific evaluation of black and white images, such as /. B. X-ray images or satellite images od, the like. Appropriately, it is provided with the amplitude of the black-and-white television signal one of the Fernschtechnik known reference carrier to rotate accordingly in its phase and to use two synchronous demodulators to be fed to the color television picture tube.

To a large extent adaptation of the color tone to the subjective characteristics of the viewer of the television picture can also be achieved in an advantageous development of the method according to the invention still be provided, the reference color carrier arbitrarily via a further adjustable phase modulation rotate in phase so that the start and end points of the color scale are shifted as desired can be. You can use it to place the image area of interest in such a way that it coincides with the maximum Sensitive area of the eye collapses.

To finally create the opportunity, just one to pick out the relevant part of the entire image and the differences in brightness that occur therein over the whole signal area to be able to enlarge is before i_s? r phase modulation and influencing the IJezuts dye carrier Clamped contrast intensifier, which separates the areas of interest that are not of interest and only the The remaining area passes on, so that the full color scale is again assigned to this sub-area can be. It is thereby possible. Details of a different shade of gray at certain points, for example, to be able to divide and graduate a picture of a king in a manner as it is with optical means and means of the human eye would not have been possible.

To carry out the method according to the invention and the advantageous Vcrfahrcnsausgcstaltungen a circuit can be provided in which a known bridge circuit with two constant resistors at one Asl and a variable resistor and a capacitor at the other Asl is provided for phase modulation, with a variable resistor from the black /.wcißsignal controlled field effect transistor is used and the voltage of the reference color carrier is applied to one diagonal, while the phascngcdrchlc signal is picked up on the other diagonal. As it has been shown in practice. Such an arrangement allows a proper phase rotation only ctv / a 120 ° phase angle, three Brückcnschaltungen be a hintcreinandergeschaltet to form over 360 "acting phase modulator in an expedient embodiment. The phascngcdrchtc signal may further two Synchrondnmodulatoren in the Farbdiffercnzsignale R- Kund B- Y These signals then correspond to the color difference signals customary in color telephoto technology.

In order to achieve a range enhancement, the phase modulation can be a contrast enhancer, a so-called Window amplifiers, to be connected upstream. Before the contrast enhancer is then advantageously a Clamping circuit arranged on the one sync pulse separation circuit is connected, together with the contrast enhancer to which the first phase modulator is applied, via an Adoitionsstel-Ic transmits the density signal directly to the color television tube. In this way the sync pulse separated from the frequency modulation and range amplification, which has certain advantages in the Signal forwarding results.

The invention is based on an exemplary embodiment

shown in the drawing and is in the explained below. (Is shows

E i g. 1 is a block diagram of a device for Implementation of the method according to the invention,

Fig. 2 shows the schematic representation of the Phase modulation generated color signal in the color wheel.

P i g. J a block diagram similar to the I 'i g. I. However with the additional possibility of subjective adjustment of the eartone.

Egg g. 4 the circuit arrangement for generating a norm-compliant Ecrnsch signal.

E i g. j a l'hascnmodulaior. how he according to the present invention for phase rotation of the reference lens carrier is used.

E i g. 5a shows the phasor diagram for the phase modulator the E i g. 5 generated partial voltages.

E i g. b the combination of three phases

exercise.

Cig. 7 shows a circuit in which the phase modification arrangement a clamping circuit with a contrast amplifier is connected upstream for the selection of the range,

E ig. 8 the schematic representation of the through the Circuit of the prop. 7 from the original black and white signal hideable area of interest and

I i g. 9 the representation of the Schwarz-Weil university. how it is used to assign the color of the phase-modulation system is forwarded after tier area selection.

In the E ig. A phase modulator 2 is switched on in line I, which is connected, for example, to an Eernsehkaniera or to a black and white receiver, through which a BAS signal in the form of a black and white television signal is passed, which changes the phase of a reference color carrier 3 as a function of the amplitude of the / MS signal, whose erequency is chosen to be 13.5b MIIz. The mode of operation of the phase modulator 2 is explained in detail with reference to the proper. 5 described. To explain the basic idea of the invention, it is sufficient that this phase modulator 2 rotates the phase of the auxiliary carrier 3, which is then dcmodulated in the two synchronous demodulators 4 and 5 into the red and blue difference signals R- Kund B-Y in the manner known from Earbfcrnschtechnik. The black-white input signal BAS is also fed directly to the color television tube in the form of the> signal via line 6.

To understand this process, it should be briefly explained that the signals usually coming from a color television camera, Red Ur. Green ίΛ, and blue Un can be summarized in an analogous way in a brightness signal (. '> According to the following equation:

Ui = 0.30 ■ Ur + 0.59 Uc. + 0.1 1 -Ub

In this equation derived from colorimetry. the spectral sensitivities of the decomposition filters in the camera and the properties of the phosphors in the display device have already been taken into account. This luminance signal Uy can also be processed properly by a black and white television set (compatibility). In addition to this luminance signal, the color information must also be transmitted. From the above equation one can see that it is sufficient to additionally transmit two of the three color signals, so that the color difference signals Ur- Uy = Ur _, = 0.7 χ Ur- 0.59 χ Uc: - 0.11 χ <7s and Ub- Uy = U _e -y = 0.3 χ Ur- 0.59 Ur. + 0.89 Ub can be formed.

These color difference signals are transmitted in what is known as quadrature modulation, in that the signal U _{H is} modulated onto a suitably selected color carrier S. For modulation mil Un> same color carrier is previously turned in its phase by 90 ". Adding now vektoricll these two Modulalionsproduklc, the chrominance signal is produced Ur. Shown in FIG. 2, the so-called Earbkrcis. In

The phase position, ie the size of the angle i /> corresponds to the hue and the amplitude, ie the length of the vector U / the color saturation, corresponds to this earbeard signal Ui . As the coordinate and the abscissa, the earbdiffcrcnzsignalc 1) r _v and Un , are plotted and it can be seen that, depending on the C j, cracks in the angle ψ. which is achieved as a function of the phase modulation of the reference color carrier 3 in the phase modulator 2, the color changes depending on the blackness / white color ;;;! V; :: x! C:!. '/.·.:■. (iricülieriüi »are in

to the diagram in fig. 2 the color points 7, 8, 9, 10, 11 and 12 taken from the l'arbseehseck, with 7 being the l'arbe gastric la. 8 KoI. 9 (JeIb. IO green, 11 cyan and 12 corresponds to the color blue. With a JbO 'rotation of the phase of the reference color carrier 3, a specific chrominance signal Ui can be assigned to each I lelligkcilswert depending on the amplitude of the K signal (BAS) This enables a fine division of a black and white image into color tones, so that the black and white image converted into color can be clearly identified.

In FIG. 3, a second phase modulator 13 is also shown, which is not dependent on the signal, but can be adjusted manually by means of a potentiometer. This additional rotation of the phase for the Synchronmodulatorcn 4 and 5 can be the initial or. End point in which in the E i g. 2 move the color circle shown as desired. This gives you the opportunity. to be able to optimally adapt the color of the image areas of interest to the eye of the beholder. Reference 14 denotes a phase mechanism which shifts the phase by 90 "in order to obtain the signal U- _t . The entire circuit in FIG of the present invention.

In FIG. 4, only one possible wedge is shown which is associated with the arrangement of FIG. I e> to be able to process the 3 common color sniffing signals into corrected signals, which can be processed in commercially available devices. For this purpose, the signals R-Y. B- Kund taken from the phase modulator III are not subjected to any PAL display 15, and then passed to a PAL modulator 16.

which is preceded by a reference color carrier generator 17 with 4.43 MHz and which then emits the standard signal FBAS for monitors, which is converted via a parallel-connected video modulator 18 into the signals for channels 2 to 4 or 5 to 11 for standard color television receivers. This signal processing represents a favorable design option because it is then possible. to be able to reproduce color images derived from black and white signals via standard television receivers.

6s FIG. 5 shows the manner in which the phase position of the signal HF of the reference color carrier 3 can be changed as a function of the amplitude of the black-and-white signal BA (S) . Sent ahead

may be the well-known fact that a bridging hall. which consists of three resistors and a capacitor, one of which is variable and can be used as a phase shifter. It is known that the voltage tapped on the diagonal / between one branch consisting of the two fixed resistors and the other branch with the variable resistor urKdcm capacitor is advanced by a certain phase angle with respect to the input voltage, depending on the size of the variable resistor. which rests on the other diagonal of the bridge. The partial voltages in one branch of the bridge with the variable resistor and the capacitor are always perpendicular to each other, because in the resistor current and voltage is in phase, in the capacitor, on the other hand, current and voltage are phase shifted by 90 ". So if the variable resistance is changed , so rlf * r Ki'hntt IrmiiL I / l «» r K » ^l ul *» n TmlcniM-iriiirnTnn; i 11Γ »ίηοιη · - ι '1 r-' ·

I loaf circle over the input voltage with simultaneous change of the phase angle on the diagonal tapped tension.

Starting from this known phase shifter, I 'i g. ^r i , a field effect transistor 19 is used as a variable resistor, in which the volume resistance / between the output 24 and the emitter of the transistor 20 changes with the amplitude of the voltage at the input. . Angclegt is at the input of the l.euchtdichtcsignal BA f.Sy corresponding to the inlet I in Figure I, then also the V. 19 must irchgangswidersland the field effect transistor in dependence on the Signalfrcqucn / RAS this or the>'- Sigmils change. At the input of a further transistor 20, the color carrier 3 is fed in. It appears on the limiter in the same phase position and is 180 'out of phase on the collector. If the resistors 21 and 22 are chosen to be of the same size, then both voltages are also of the same size and, based on the consideration of the known phase shifter, which is shown in FIG. 5a, in which the Tcilspannungcn (/ (- and LIr move with their intersection on a semicircle, the size of which is determined by the input voltage Ucf and the output voltage U. 21. 22 and is tapped from the field effect transistor 19 and the capacitor 23, remains unchanged in its amplitude, but can be varied in its phase angle ψ between zero and 180 ° depending on the change in resistance of the field effect transistor , whose output voltage is tapped between points 24 and 25, where 25 means the connection to ground, is supplied with energy via line 2b and also has a further capacitor 27 and two resistors 28.

It has been shown that the change in the phase angle ψ which can be realized with the change in the I i g. In practice, the arrangement of the phase modulator I shown in FIG. 5 is only sufficient to achieve a phase shift of approximately 120 ". three phase modulators I according to FIG. 5 in sequence, so that depending on the first luminance signal U, a phase rotation of the input signal /// of the reference color carrier connected at 3 is possible between 0 and 360. The output voltage U, \ can be found at 29.

In order to achieve that only the comprehensive range of a sub-area of the viewing image

" _Nrnmln [. '. I ₁ -ImLoI .. -, .., * _n ^. ^. L» _n »...: 4 ...: - 1 .- / 1 r ^: - π

^ v-IUiIiIk · miy.miiiu ruf it / 1 villt.1 WIIU, VT 11 U £ <-111 Cl IJ I Ig. / provided, the phase modulator III of FIG. 3 a clamping circuit 30 with a contrast enhancer 31 can be connected upstream. It is also possible, as shown in FIG. 7. a synchronizing pulse separator 32 to be connected in parallel or the synchronizing pulses are divided from the start if they are also supplied separately. However, it is then necessary to feed the signal taken from the contrast amplifier 31 both to the phase modulator III and to a summing lead 33 so that it can be assigned again to the black-and-white signal V ′ at 34.

By switching the F i g. 7 it is achieved that the sub-area '5 shown in FIG. 8 of a black-and-white signal. which encompasses the area ; i , is shown, and can be amplified over the entire color scale from the original size b to the size; i. With 36 are in the F i g. 8 and 9 denotes the synchronicity pulses. The areas c of the original black and white signal are separated. This configuration makes it possible to pick out an interesting sub-area of an image and to assign the entire color scale to the gray tones prevailing there, so that a very fine distinction is given for black and white images. This method enables good diagnosis, particularly in X-ray technology. Since the V signal of the color television tube is also passed on, the resulting picture is not only characterized by the assignment of the entire color scale to the black and white words, but also by the fact that there are differences in brightness within the color values, which are easy to interpret and Enable recognizability of the color image obtained.

For this purpose 2 sheets of drawings 909 613/263

Claims (8)

Patent claims: 1. A method for color reproduction of black-and-white images on color television picture tubes with television technology means, in which, depending on the amplitude of the black-and-white television signal, auxiliary signals for influencing at least one of the three color signals are formed, characterized in that the high-resolution display is less Brightness differences the amplitude of the black-and-white television signal (Uy) is used directly as a control signal for rotating the phase of a reference color carrier (3), which forms a chrominance signal (Uy) with a certain phase position in the η color wheel, which is then converted into the usual red and blue color difference signals (Un-y, Ua-)) is demodulated and fed to the color television picture tube with the black-and-white television signal. 2. Statute of limitations according to claim 1, characterized in that «Let an additional phase modulation (13) of the reference color carrier (3) be carried out which can be arbitrarily set to choose the color tone. 3. The method according to claims I and 2, characterized in that before the phase modulation (III) of the reference color carrier (3) only a partial area (35) of the black-and-white signal is separated and only these partial values of the gray tint the entire range of the following Phase modulation serve as output values. 4. Einrientung for performing the method according to claim I, characterized in that for phase modulation CME known bridge circuit (I) mil two constant As rrsiändcn (21, 22) on one branch and a variable resistor (19) and a capacitor (23) on Another branch is provided, whereby a field-effect transistor (19) controlled by the black-and-white signal serves as a variable contradiction and the voltage (U _C e) of the reference color carrier (3) is applied to one diagonal, while the phase-shifted signal (Ua) is removed from the other diagonal will. 5. Device according to claim 4, characterized in that that three bridge circuits (I) / to form a phase modulator acting over 360 ° (2) are connected in series (Fig. 6). 6. Device according to claims 4 and 5, characterized in that the phase-shifted signal (Ua ) is converted into the color difference signals (R-Y and B-Y) via two synchronous demodulators (4,5). 7. Device for performing the method according to claim 3, characterized in that the Phase modulation (III) a contrast intensifier (window intensifier31) is upstream. 8. Device according to claim 7, characterized in that a clamping circuit (30) is arranged in front of the contrast intensifier (31), to which a sync pulse separating circuit (32) is connected, which is connected together with the contrast intensifier to which the first phase modulator (2) is applied , passes on luminance signal (Y) directly to the color television picture tube via an addition unit (33). 65 The invention relates to a method and a device for the color reproduction of black-and-white images via color television picture tubes according to the preamble of claim I. Methods and devices of this type are known. They arose out of the need for X-ray examination of living people a better way of differentiating bone structures of different types or to differentiate bones from soft tissues. It is known, that the eye on color differences and brightness differences after corresponding, joint reproduction, responds much better and differences can recognize better than when diagnosing different gray levels of a black and white image should be. In the known method (DE-OS 20 13 093) one makes use of the fact that bone structures or Weichicilinikturen im TV picture has a certain white distribution represent, which can be understood as a line grid, the dimension of which is a bcsiimmlc spatial frcqucnz. This spatial relationship is greater, the finer the structure of the object. Depending on the location of the black-and-white picture, certain colors are now assigned to the individual syrukiurs in that the frequency with the help of a frequency demodulator is converted into ck> e voltage that assigns certain colors to certain linear densities. The device provided for this purpose provides that the alternating voltage to be dcmodulicrcndc is transmitted via an amplifier tube is fed to a parallel resonance circuit, the resonance frequency of which is adjusted so that all occurring frequencies of the supplied alternating voltage either greater or less than the Are resonance frequency. | c more then the Zugcführlc frequency corresponds to the resonance frequency, the more so greater is the alternating voltage applied to the oscillating circuit, the amplitude of which can be measured, which means that at the output of the demodulator there is a voltage that is approximately linear over a small range is the frequency of the AC voltage supplied. With this voltage either the brightness one or more basic colors can be influenced, but it is also possible to use a Bc / .ugsfarblräcr. the off color television technology is known to influence. The disadvantage of this known method is that only a distinction between coarse and fine structures is shown in different colors, so that it is difficult to dculcii / 111 corresponding picture. For example, different thick bones would appear in the same color with no differences, for the brightness values are largely drowned out. There are other methods of coloring black and white images using photographic methods known (W. Bergcrhoff "Handbuch Medizinischer Radiologie", Vol. 3, Springer Verlag 1966), and it has also been proposed (DE-OS 20 53 894), a black and white image in two different Convert images, for example into a red and a blue image, which are then superimposed again will. The disadvantage of such a method is that the result is basically a black and white image with an upstream color filter and that a black and white image as a negative occurs, so that here, too, the desired clear distinction does not exist. It is also an arrangement of those mentioned in the opening paragraph