SU1628221A1 - Device for correcting colour distortions of camera tubes - Google Patents

Description

(21) 4629754/09

(22) 02.01.89

(46) 02.15.91. Bnsh. N 6 (72) B.N. Bychkov, O.I. Betska, N.N. Kuznetsov, B.A. Romashov, B.S. Timofeev and A.P. Ogarkov

(53) 621.397 (088.8)

(56) USSR certificate of authorship If 1264373, cl. H 04 N 5/208, 10/15/86.

(54) DEVICE FOR CORRECTION OF COLOR DISTORTIONS BY TRANSMITTER OF TELEVISION CAMERA

(57) The invention relates to broadcast and applied television systems for the automatic correlation of distortion. The goal is to improve the accuracy of the correction. The device contains

color test table 1, video signal sensor 2, color correction matrix 3, switch 4, error signal extraction block 5, integrator 6, minimum detector 7, two blocks 8 and 16 registers, color coordinate signal generator 9, switch 10 reference signals, driver 12 color difference signals, two comparators 13 and 17, a decoder 14 and a block of 15 digital keys. Controlled by block 15, it is possible to vary the weights in the color correction matrix 3, which is adequate to the change in color correction. The control of the unit 15 is carried out by means of a code that is specified by the comparators 13 and 17, which determine the polarity of the color difference signals, 1 slug.

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The invention relates to television and can be used in broadcast and applied television as part of television systems for automatically correcting distortion of feedback images operating in real time.

The aim of the invention is to improve the accuracy of the correction.

The drawing shows a functional diagram of the device for correcting color distortion of a transmitting television camera.

A device for correcting color distortions of a transmitting television camera contains (FIG. 1) a color test table 1, a video signal sensor 2, a color correction matrix 3, a switch 4, an error extraction block 5, an integrator 6, a minimum detector 7 and the first 8 block of registers. Consistently connected generator 9 signals of color coordinates and the switch 10 reference signals, the synchronizer 11, the driver 12 color-difference signals, the first comparator 13, the decoder 14 and the block 15 keys, the second block 16 registers, the second comparator 17,

The device for correcting color distortion works as follows.

Video signal sensor 2 carries out a photoelectric scan of test table 1 and generates three color-separated video signals at the outputs of the colored channels. Since spectral

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the characteristics of the color separation optics of the sensor 2 of the video signal are different from the calculated ones, then the amplitudes of the video signals at the outputs of the sensor 2 will differ from the calculated ones, i.e. such that you can get if you have perfect spectral characteristics. Synchronously with the scan of the color test table 1, the generator of 9 signals of color coordinates generates three signals, each of which is a calculated signal of the corresponding color separation channel. To obtain the calculated amplitudes of the video signals, the color coordinates, the colors of the test table 1 are found and are recalculated into the camera holimetric system. The obtained color values for the first, second and third channels are digitally recorded in the permanent storage devices of the generator 9. The color-correcting matrix 3 by forming at each of its outputs a signal as a weighted sum of three input signals performs color correction of the signals generated by the sensor 2 of the video signal . Nine single-byte codewords input to the control of the color correction matrix of the matrix 3 determine the weights and phases of the weighted signals during the correction. The task of color correction is to select such control codes that would allow as close as possible (with minimal error according to the selected criterion) the amplitudes of real video signals from the color test table 1 to their reference values. Video signals are compared in series through channels, for which switch 4 passes one of the three real video signals acting on its inputs, and the channel number is determined by a two-bit control code at the address input of switch 4. Consistent with switch 4 comm ator 10 produces a switching reference signal of the reference signal. The signal extraction unit 5, an error, compares in amplitude the current values of the real and reference signals and generates the error signal as the square of the difference between the amplitudes of the real and reference signals. Integrator 6 calculates the errors for all colors of the test using the summation method. Reset integrator at the end of the active part of the frame allows 1628221l

It is possible to capture a changing pattern of distortion measurement with changes in correction. If there are no color distortions in the signal, then at the output of integrator 6 by the end of the accumulation there will be zero potential, and the stronger the distortion, the greater potential will be at the output of integrator Q 6 of the minimum 6. Detector 7 of the minimum generates such a control code the potential at the output of integrator 6 was minimal. Control codes are not sequentially configured. To configure one control code, an address code is displayed, the two high-bits of which control the operation of switches 4 and 10, and the six remaining 2Qs select the address of one of the registers in the first 8 or second 16 blocks of registers. After that, the program of searching for the minimum of the objective function is executed, the values of which are represented by the potential at the output of integrator 6, for the control code (which is the argument of the objective function) of the selected source address. As a minimization program, a program can be used in which a quadratic approximation of the objective function is used to find the minimum. The voltage at the output of the integrator 6 displays the value of the value of the objective function, on the front of the personnel damping pulse generated by the differentiator circuit of the synchronizer 11, performs digital-to-analogue conversion. With the completion of the conversion, a pulse is generated on the sync output that synchronizes in. The digital code that displays the analog signal at the first input of the detector 7. By changing the address code at the address output of the minimum detector 7 and running the optimization program (finding the minimum for this parameter), all 36 registers of the first 8 and second 16 blocks are filled. register. However, the connection of these registers (only 9 out of 36) will depend on the control code that exists at the first input of the key block 15, which consists of four groups, in turn each group contains 9 single-byte 55 keys. Opening one of the key groups means connecting to the control input of the color correction matrix 3 control codes recorded in

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the first 8 or second 16 block of registers, i.e. By controlling the key block 15, it is possible to vary the weighting factors in the color correction matrix 3, which is adequate to the change in color correction. The key block 15 is controlled by the decoder 14, generating at one of its four outputs a signal to open a group of keys. The decoder 14 is controlled in turn by a double-byte code arriving at its first and second inputs. This code sets the first 13 and second 17 comparators, which determine the polarity of the color difference signals received at the outputs of the shaper 12 color difference signals. Color difference signals are formed from three color difference signals on the summing-subtractive amplifiers forming the driver 12. If both color difference signals are positive, then the outputs of the comparators 13 and 17 will be, for example, 1, which will determine the opening of the first group of digital keys of the block 15 and the matrix 3 will control the first register block 8. Various combinations of color difference polarities; signals will determine the appropriate connection registers of blocks 8 and 16, and hence the change of control codes. Therefore, signals from colors that have certain polarities of color difference signals will have their own, different from signals with different color difference signals, and optimal correction codes for this group.

Claims (1)

Claims An apparatus for correcting color distortions of a transmitting television camera, comprising a video signal sensor, a color correction matrix, a switch, an error signal extraction unit, an integrator, a minimum detector and a first block of registers connected in series by a color coordinate signal generator and switch 82216 reference signals, the output of which is connected to the second input of the error signal extraction unit, synchronizer, the first and second outputs of which are connected respectively to the reset input of the integrator and the synchronization input of the minimum detector, while the second and third outputs of the sensor JQ video signals are connected to the second and third inputs of the color correction matrix, the second and third outputs of which are connected to the second and third inputs of the switch, the address output of the minimum vector is connected to the address inputs of the first block of registers, the switch of reference signals and the switch, the second and third outputs of the color signal generator 20. coordinates are connected to the second and third inputs of the switch of reference signals, and the sync output of the video signal sensor is connected to the synchronous inputs of the synchronizer and the color signal generator 25 coordinates, characterized in that, in order to improve the accuracy of the correction, the sequentially connected driver of color difference signals, the first comparator, The decoder and key block, as well as the second block of registers and the second comparator, the first, second and third outputs of the video signal sensor. Are connected to the first, second and third signal inputs of the color-difference signal generator, the second output of which is connected to the second comparator. connected to the second input of the decoder, the second - the input of the key block is connected to the output of the first block of registers, the first and address outputs of the minimum detector are connected respectively to the first input and the address input of the second block .j registers, the first, second and third outputs of which are connected to the third, fourth and fifth inputs of the key block, the output of which is connected to the control input of the color correction matrix. 35 Compiled by G. Kn of the pharynx Editor 0 „Laughing Tehred L. Oliynyk Order 349 Circulation 402 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 Proofreader L. Pilipenko Subscription