RU2448431C1 - Method of forming interference pattern signal and apparatus for realising said method - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: "long" and "short" accumulation of signal charges in adjacent frames (half-frames) is realised in a CCD matrix; a multiplexed video signal is formed at the output of a photodetector, and a multiplexed television signal is formed at the output of a television signal sensor; the multiplexed television signal is delayed by a frame (half-frame), and based on the observed image, weighted summation of the immediate and delayed video signals is performed via summation of the immediate video signal with a unit weighting coefficient K and the delayed video signal is summed with coefficient K selected based on the inequality 0<K<1, and that adjustment is augmented with selection of the optimum duration of the "short" accumulation in the CCD matrix.

EFFECT: high accuracy of recursive filtration as a result of a higher signal-to-noise ratio of the output interference pattern signal through further control of the accumulation time of the delayed component of said video signal.

3 cl, 5 dwg, 2 tbl

Description

The invention relates to television technology and can mainly be used in interferogram analysis systems in which charge-coupled device arrays (CCD matrices) are used as video signal sensors.

The closest in technical essence to the claimed invention should be considered a method of generating an image signal of interferograms [1], which consists in the fact that the light flux from the interference pattern of the controlled object is separated in two directions and simultaneously projected onto the first and second targets (photodetector sections) of a specialized CCD moreover, the illumination of the first target with respect to the illumination of the second target is set with a coefficient K selected from the inequality 0 <K <1, the information e charges on the targets of the CCD matrix with a period of frames (half frames) (hereinafter in the description of the claimed solution, the frame period means the period of following frames of progressive scanning, and the period of half frames - the period of following fields of interlaced scanning), information charges are transferred from the interval of reverse scanning of frames cells of the second photodetector section to the cells of the memory section, and information charges from the cells of the first photodetector section to the freed cells of the second photodetector section, transferring information line by line e charges from the memory section to the output register in the interval of the flyback of the horizontal scanning, and in the interval of the forward stroke of the horizontal scanning, the information charges are transferred element by element from the output register to the output block of the CCD with the simultaneous conversion of the charge into the voltage of the video signal.

In the prototype of the solution, directly in the photodetector — a CCD matrix with the organization of “personnel transfer”, operating with image signals in charge form, by the method of recursive filtering of the video signal, the random vibrations of the optical image of the object are averaged, caused, for example, by vibrations. The accumulation interval of the delayed component of the output image signal of a single-link recursive filter is fixed and equal to the accumulation interval of the direct component of the video signal at the output of the recursive filter. The adjustment of the degree of filtration is achieved only by controlling the magnitude of this component of the signal with a coefficient K, which is determined by the attenuation coefficient of illumination for the first target of the CCD matrix.

The disadvantage of the prototype [1] is the impossibility of this method of generating an image signal of interferograms to achieve control of the degree of filtration depending on the accumulation time of the delayed component of the output image signal, which leads to a limitation of the accuracy of the recursive filtering operation itself.

The objective of the invention is to increase the accuracy of recursive filtering as a result of increasing the signal-to-noise ratio of the output signal of the image of interferograms by additionally controlling the accumulation time of the delayed component of this video signal.

The prototype of the device of the present invention should be considered a device [2], containing sequentially located and optically coupled lens and target of the television signal sensor, as well as an RS-trigger, a clock selector, a counter-divider, a switch, a delay unit per frame, consisting of series-connected analog- digital converter (ADC), random access memory (RAM) and digital-to-analog converter (DAC), and the output of the “Video” sensor is connected to the input of the delay unit per frame and corresponds to to the input of the clock selector, the output of which is connected to the clock input of the RS-trigger and, accordingly, to the input of the counter-divider and switch connected in series, the control input of which is connected to the first control input of the sensor and connected to the direct output of the RS-trigger, the second control input of the sensor is connected to the switch output, the S-input of the RS-trigger is the “Start” input, and the R-input of the RS-trigger is the “Stop” input of the prototype device.

The problem is solved in that in the inventive method of generating an image signal of interferograms, namely, that the light flux from the interference pattern of the controlled object is projected onto a single target of a typical CCD matrix, according to the invention, a “long” and “short” accumulation of information is compulsorily implemented in the photodetector charges in adjacent frames (half frames), form a multiplex video signal at the output of the photodetector, and a multiplex at the output of the television signal sensor xx television signal, the multiplex television signal is delayed per frame (half frame), and the observed image performs weighted summation of the direct and delayed video signals by adding the direct video signal with a unit weight coefficient K and the delayed video signal with a coefficient K selected from the inequality 0 <K <1 , and supplement this adjustment with the choice of the optimal duration of the “short” accumulation in the CCD matrix.

The problem in the inventive device for generating an image signal of interferograms intended for the implementation of the claimed method is solved by the fact that in the prototype device containing sequentially located and optically coupled lens and target of the television signal sensor, as well as an RS-trigger, clock selector, counter-divider, a switch, a delay unit per frame, consisting of ADCs, RAM, and DACs connected in series, and the Video output of the sensor is connected to the input of the delay unit per frame and, respectively, to the input of the clock selector, the output of which is connected to the clock input of the RS-trigger and, accordingly, to the input of the counter-divider and switch connected in series, the control input of which is connected to the first control input of the sensor and connected to the direct output of the RS-trigger, the second control input of the sensor is connected to the output of the switch, the RS input of the RS-trigger is the “Start” input, and the R-input of the RS-trigger is the “Stop” input of the prototype device, an analog key and a weighting adder are connected in series, while m the control input of the analog key is connected to the direct output of the RS-flip-flop, and the information input of the analog key is connected to the output of the delay unit per frame (half frame), the input of which is connected to the second input of the weighing adder, the “Video” output of which is the output of the inventive device.

Comparative analysis with the prototype [1] shows that the inventive method is distinguished by the presence of new features, namely the presence of the following actions:

- forced implementation of the “long” and “short” accumulation of information charges in adjacent frames (half-frames) in the CCD matrix;

- the formation of a multiplex video signal at the output of the photodetector, and a multiplex television signal at the output of the television signal sensor;

- the implementation of the delay multiplex television signal per frame (half frame);

- adjusting the weighted summation of the direct and delayed video signals;

- adjusting the duration of the “short” accumulation in the CCD matrix.

The combination of known and new features is not known from the prior art, therefore, the claimed method meets the requirement of novelty.

Comparative analysis with the prototype [2] shows that the inventive device is characterized by the presence of new features, including:

- new structural elements (blocks), which are an analog key and a weighing adder;

- electrical connections of the new units in the device.

The combination of known and new features of the claimed device is not known from the prior art, therefore, the proposed technical solution meets the criterion of novelty.

In the claimed solution, the intervals of accumulation of adjacent frames (half-frames) in the CCD matrix do not coincide and are separated in time, which increases the possibility of adjusting the degree of recursive filtering of the video signal of the interferograms, increasing the quality of their reproduced image on the screen of the video monitor due to the growth of the signal-to-noise ratio.

Therefore, according to the technical result and the method of its achievement, the proposed solution meets the criterion of the presence of an inventive step.

Figure 1 shows a structural diagram of the inventive device that implements the inventive method; figure 2 shows an example of the electrical circuit of the switch; figure 3 schematically shows the relative position of the intervals of accumulation by the CCD matrix in adjacent frames (half frames); figure 4 presents a timing chart explaining the operation of the counter divider; figure 5 shows an illustration of the process of anti-blooming runoff in a CCD matrix.

The inventive device for generating an image signal of interferograms, see figure 1, contains sequentially located and optically coupled lens 1 and the target of the sensor 2 of the television signal, as well as RS-trigger 3, clock selector 4, counter-divider 5, switch 6, delay unit 7 per frame, consisting of series-connected ADCs 7-1, RAM 7-2 and DACs 7-3, as well as series-connected analogue key 8 and a weighting adder 9, the “Video” output of which is the output of the device, S-input of the RS-trigger 3 is the start entry, and its R-input - input “Stop” of the device, and the output “Video” of the sensor is connected respectively to the input of the delay unit per frame, the second input of the weighing adder 9 and to the input of the clock selector 4, the output of which is connected to the clock input of the RS-trigger and, respectively, to the input in series connected counter-divider 5 and switch 6, the control input of which, respectively connected to the first control input of the sensor 2 and the control input of the analog key 8, is connected to the direct output of the RS-trigger 3; the second control input of the sensor 2 is connected to the output of the switch 6, and the information input of the analog switch 8 is connected to the output of the delay unit 7 per frame (half frame). The video signal from the output of the weighting adder 9, as shown in figure 1, can be fed to the input of the video monitor 10.

As in the prototype [2], the open-frame camera VSI-746 [3], which is based on the CCD matrix with the number of elements 582 × 752 and can be used as a sensor 2, can be used by the Russian company “EVS” (St. Petersburg) 1/2 inch diagonal target size.

The CCD matrix has an “horizontal transfer” organization, and its photodetector section is equipped with an electronic shutter that performs electronic sensitivity adjustment by controlling the accumulation time of charge carriers during the personnel period. In fact, the electronic shutter is a shutter of the anti-blooming (sink) region GA, technologically performed in the photodetector section of the CCD, as shown in Fig.5.

If a high level of pulsed bias is applied to the GA gate, the potential barrier is removed, the gate opens, and photoelectron accumulation is excluded on the target. Charge carriers, not lingering in potential wells under phase electrodes, for example, under Ф2Н buses with three-phase transfer organization, rush into deeper wells created by the potential DA of the drain region, and then recombine into the photodetector substrate (see Fig. 5b).

When the lower level of the pulse bias is applied to the shutter GA of the CCD matrix, closing it, the accumulation mode is implemented with a reduced carrier collection time inside the frame (see Fig. 5a).

A feature of the sensor 2 in the claimed solution is the presence of the first and second control inputs.

For the VSI-746, the first control input is pin 20 of the CXD2463R. If you need to enable automatic adjustment of accumulation time (ARVN), you need to send a logical "0" to this output, to switch to manual control of the accumulation time - logical "1" in the TTL levels.

The second control input of the VSI-746 device is formed by the terminals 11, 12, 13 of the CXD2463R microcircuit. To work in ARVN mode, these conclusions must be “hanging in the air”, because using high-resistance resistive dividers, they are supplied with the corresponding potentials in the range 1.3-3.5 V. When it is necessary to switch eight values of fixed exposures in the range from 10 μs to 10 ms, then code combinations of zeros should be applied to them ("0 ") And units (" 1 ") indicated in the table below.

Table 1 Pin number The exposure time (accumulation) of the photodetector, μs 10.0 100.0 200,0 500,0 1000,0 2000.0 4000,0 10,000.0 Code combination eleven 0 one 0 one 0 one 0 one 13 0 0 one one 0 0 one one 12 0 0 0 0 one one one one

In this solution, six code combinations are used: “000” - 10 μs; “100” - 100 μs; “011” - 200 μs; "110" - 500 μs; "001" - 1000 μs; "111" - 10,000 μs.

Note that the combination “000” determines the shortest accumulation time, and the combination “111” determines the longest. All of these code combinations are installed on switch 6.

A possible electrical circuit of this unit (see figure 2) contains the first element "AND" 6-1, the second element "AND" 6-2, the third element "AND" 6-3, the first element "OR" 6-4, the second the "OR" element 6-5, the third "OR" element 6-6, the first switch 6-7, the second switch 6-8, the third switch 6-9, as well as the first switch S1, the second switch S2 and the third switch S3.

Suppose that the switches S1 ... S3 are in the initial (depressed) position. Then, when applying a high logical level of the signal from block 3 to the inputs of the resolution of the switches 6-7, 6-8, 6-9 and a high logical level of the signal from block 5 to the first inputs of the elements "And" 6-1, 6-2, 6- 3 at the output of the switch 6 is formed a logical combination "111".

When in the initial position of the switches S1 ... S3 and the logical inputs “1” on the resolution inputs of the switches, the logical inputs “0” are sent to the first inputs of the “And” elements 6-1, 6-2, 6-3 from block 5, the output of the block 6 the logical combination “000” is set.

When a logical “1” level is supplied from block 3 and a logical “0” level is received from block 5, four additional code combinations can be obtained depending on the position of the switches S1 ... S3, as shown in Table 2.

table 2 Code combination Switch position S1 S2 S3 "one hundred" Pressed Wrung out Wrung out "010" Wrung out Pressed Wrung out "110" Pressed Pressed Wrung out "001" Wrung out Wrung out Pressed

Obviously, the choice of the position of the switches S1 ... S3 allows you to adjust the "short" accumulation time in the sensor 2 from 10 to 1000 μs.

If a low logic level is applied to the permission inputs of the switches 6-7, 6-8, 6-9, then, regardless of the state of the inputs of the "And" elements 6-1, 6-2, 6-3 and the position of the switches S1 ... S3 , the outputs of the switches will be isolated from the inputs.

Lens 1, RS-flip-flop 3, clock selector 4, counter-divider 5 and delay unit 7 per frame in circuit design do not differ from similar prototype units [2].

We add that the RS-trigger 3 is a tactile RS-type trigger device with a high active level at the control inputs.

The clock selector 4 is designed to extract from the composite video signal at the input of the receiver synchronization signal (MSS) with the subsequent formation of a frame synchronizing pulse (CSI) at the output.

Counter-divider 5 is intended for dividing the frequency of pulses of CSI into two (from 50 Hz to 25 Hz) for progressive scan and, accordingly, into four (from 50 Hz to 12.5 Hz) for interlaced scanning of the video signal.

Block 7 is designed to delay the input video signal for a duration of one frame. If the device uses a progressive scan with a frame frequency of 50 Hz, then the delay time is 20 ms. When arranging a standard interlace scan in a device, the duration of the required delay will be two half-frames, i.e. 40 ms The technical implementation of block 7 can be carried out by serial connection of an analog-to-digital converter (ADC) 7-1, random access memory (RAM) 7-2, digital-to-analog device (DAC) 7-3.

Analog key 8 can be performed on the basis of one of four managed keys with normally open contacts of the domestic chip KR590KN2 [4].

The weighing adder 9 is designed to perform the operation of adding two input video signals with weight (scale) factors and can be performed according to the recommendations [5]. For the video signal arriving at its first input, the weight coefficient K is adjustable, which is selected from the inequality 0 <K <1. For the video signal arriving at its second input, the weight coefficient must be equal to unity (K = 1).

A method of generating an image signal of interferograms is as follows. We use the structural diagram of the claimed device (see figure 1) that implements the claimed method.

Suppose that the interference pattern of an object located in the field of view of the device is in a perfectly static position, without experiencing random vibrations due to vibration and other regular mechanical effects of low frequency. At the same time, suppose that the device itself operates in progressive scan mode, and the illumination of the control object allows you to set the working illumination on the target of the CCD matrix, which is necessary to obtain a video signal with a maximum signal to noise ratio.

Then the automatic adjustment of the accumulation time (ARVN) of the photodetector in the sensor 2 of the television signal will set the maximum value of the current exposure, i.e. the duration of the accumulation of information charges will be 10,000 μs.

In this case, the clock selector 4 selects output pulses with a period of T _n (see figa), and the counter-divider 5 divides the input frequency by two, forming a square wave with a period of T _∂1 = 2T _n at the output (see Fig. .4b).

Let a low-frequency mechanical effect occur at the control object. Then, a smear inevitably appears in the generated video signal, and in the image observed from the screen of the video monitor 10, its quality noticeably deteriorates due to a decrease in the signal-to-noise ratio.

To accomplish the task of the invention, a pulse of positive polarity is supplied to the “Start” input of the device. At the moment of coincidence at the “S” input of the RS flip-flop 3 of a high level of this pulse with a high level of frame sync pulses at its clock input, the state of the trigger changes. On the direct output of trigger 3, a logic signal “1” is set. The latter is fed to the control input of block 6, to the first control input of sensor 2 and to the control input of analog key 8. Therefore, the ARVN circuit in sensor 2 is turned off, and its second control input is connected to the output of block 6. At the same time, analog key 8 is set to " closed ", connecting the output of block 7 with the first information input of block 9.

Note that, regardless of this switching, the clock selector 4 continues to emit frame pulses at the output, and pulses with a period T _∂ are formed at the output of the counter-divider 5.

(см. табл.1). Когда же с выхода блока 5 будет подан высокий уровень меандра импульсов, тогда на это время на втором управляющем входе датчика 2 установится логическая комбинация «111», гарантирующая время накопления матрицы ПЗС 10000 мкс -

(см. табл.1). По отношению к кадровому бланку, показанному на фиг.3а, импульсный сигнал, подаваемый на электронный затвор GA матрицы ПЗС в этой ситуации, представлен на фиг.3б.When connecting the second control input of the sensor 2 to the output of block 6 at this input for the duration of the low level of the meander of pulses from the output of block 5, the logical combination “000” is set, providing a duration of frame accumulation of charges in the photodetector equal to 10 μs -

(see table 1). When, from the output of block 5, a high level of the meander of pulses is given, then at this time the logical combination “111” will be established on the second control input of the sensor 2, which guarantees the accumulation time of the CCD matrix of 10,000 μs -

(see table 1). With respect to the frame blank shown in FIG. 3a, the pulse signal supplied to the electronic shutter GA of the CCD in this situation is shown in FIG. 3b.

Due to this, the sensor 2 generates a multiplex image signal, adjacent frames of which are “long” and “short” video signals in accordance with the mode of accumulation of charges in the photodetector.

This multiplexed video signal is simultaneously fed to the input of block 7 and to the second information input of the weighting adder 9. The delayed multiplex video signal is fed to the first information input of the weighting adder 9.

The synthesis of the output image signal of the inventive device is carried out in block 9, where the summation of the input video signals with the necessary weighting factors is performed. The weight coefficient K provided for at the first information input of block 9 within 0 <K <1 allows, as in the prototype, to change the degree of recursiveness of the performed video signal filtering, and therefore, to increase the signal-to-noise ratio.

On the other hand, in the claimed solution, the summed video signals, in comparison with the prototype, record various states of the process of accumulation of information charges in time. A peculiar illustration of this process for the proposed solution is the timing diagram in fig.3b, and for the prototype - the diagram in figv.

(см. табл.2 и фиг.3б), можно дополнительно регулировать степень рекурсивности фильтруемого видеосигнала, реализуя имеющийся резерв повышения отношения сигнал/шум.Temporary "centers of gravity" of the summed video signals (they are marked in FIG. 3 with filled circles) in the prototype are spaced exactly in the frame interval, and for the proposed solution, this temporary offset can be controlled. Therefore, choosing the accumulation duration using the switches S1 ... S3

(see table 2 and figb), you can further adjust the degree of recursiveness of the filtered video signal, realizing the existing reserve of increasing the signal-to-noise ratio.

для каждого. Аналогично, в течение действия низкого уровня нового меандра в датчике 2 будет совершаться не один, а два цикла экспонирования с «коротким» зарядовым накоплением по

. Блок 8 осуществляет задержку входного видеосигнала на два полукадра, т.е. по длительности на два T_n. В остальном работа устройства не отличается от ее функционирования в режиме прогрессивной развертки.Assume the device is in interlaced mode. Then, pulses with a half-frame period T _n are formed at the output of the selector 4 clock pulses. Counter divider 5 performs the division of the input frequency into four, i.e. the period of the output pulses will be T _∂2 = 4T _n (see Fig. 4c). During the action of the high level of this meander in the sensor 2, not one, but two exposure cycles with a “long” charge accumulation over

for everybody. Similarly, during the low-level action of the new meander in the sensor 2, not one, but two exposure cycles with a “short” charge accumulation by

. Block 8 delays the input video signal by two half frames, i.e. in duration by two T _n . Otherwise, the operation of the device does not differ from its operation in progressive scan mode.

If it is necessary to return the device to its original mode of operation, a pulse of positive polarity must be applied to the Stop input. At the moment of coincidence at the “R” input of the RS flip-flop 3 of a high level of this pulse with a high level of clock pulses (CSI), the state of the trigger changes. At the direct output of the RS-flip-flop 3, the logic signal “0” will be set, and in the sensor 2 the operation of the ARVN circuit will be restored. At the same time, the “open” state for analog key 8 will be restored due to the supply of a logical “0” signal to its control input. There is no video signal at the first information input, so a typical television signal from sensor 2 will be transmitted to the output of the weighing adder 9 from the second information input.

Compared with the prototype [1], the proposed method for generating an image signal of interferograms eliminates the need to separate the input light flux in two directions. Therefore, the possible inaccuracy of the recursive filtering of the video signal due to the optical misregistration of adjacent frames during the accumulation of information charges is fundamentally eliminated.

Currently, all the elements of the structural diagram of the device for generating an image signal of interferograms, which implement all the actions according to the claimed method and determine the inventive device, mastered or can be mastered by domestic industry. Therefore, the present invention should be considered as meeting the requirement for industrial applicability.

INFORMATION SOURCES

1. Patent No. 2068624 of the Russian Federation. IPC H04N 5/225, 7/18. Interferogram image signal forming device. / V.M.Smelkov // B.I. - 1996. - No. 30.

2. Patent No. 2362275 of the Russian Federation. IPC H04N 5/225. A television camera for observation in difficult lighting conditions and / or complex brightness of objects. / V.M.Smelkov // B.I. - 2009. - No. 20.

3. Television cameras of the EVS company, catalog, 2005

4. Digital and analog integrated circuits: a reference. / S.V. Yakubovsky, L.I. Nisselson, V.I. Kuleshova, etc. - M.: Radio and Communications, 1990.

5. Falkenberry L. Application of operational amplifiers and linear ICs: Translation from English. - M .: "World", 1985.

Claims (3)

1. A method of generating an image signal of interferograms, namely, that the light flux from the interference pattern of the controlled object is projected onto a single target of the CCD matrix, characterized in that the “long” and “short” accumulation of information charges in adjacent frames (half frames) are forcibly implemented in the photodetector ), form a multiplex video signal at the output of the photodetector, and a multiplex television signal at the output of the television signal sensor, delay the multiplex television isionic signal per frame (half-frame), and the observed image performs weighted summation of the direct and delayed video signals by adding the direct video signal with a unit weight coefficient K and the delayed video signal with a coefficient K selected from the inequality 0 <K <1, and supplement this adjustment by choosing the optimal the duration of the “short” accumulation in the CCD matrix. 2. A device for generating an image signal of interferograms containing a sequentially located and optically connected lens and target of a television signal sensor, as well as an RS trigger, a clock selector, a counter-divider, a switch, a delay unit per frame, consisting of series-connected ADCs, RAM and DACs moreover, the output of the “Video” sensor is connected to the input of the delay unit per frame and, accordingly, to the input of the clock selector, the output of which is connected to the clock input of the RS-trigger and, accordingly, to the input of the sequence properly connected counter-divider and switch, the control input of which is connected to the first control input of the sensor and connected to the direct output of the RS-trigger, the second control input of the sensor is connected to the output of the switch, the S-input of the RS-trigger is the “Start” input, and R- RS-trigger input - “Stop” input of the prototype device, characterized in that the analog key and the weighing adder are connected in series, the analog key control input is connected to the RS-trigger direct output, and the information input is log key - to the output of the delay unit per frame (half frame), the input of which is connected to the second input of the weighing adder, the “Video” output of which is the output of the device. 3. The device according to claim 2, characterized in that in a progressive scan of the video signal, the counter divider is a divider of the input frequency by two, and when interlaced, a divider in four, while the delay unit per frame in progressive scan mode is a delay unit for two half frame in interlaced mode.

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