JPH01501089A - Electronic/optical spatial position measurement device with background light correction function - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Electronic/optical spatial position measuring device with background correction function [Field of the Invention] The present invention provides an adaptive electronic/optical filter for measuring changes in the position of objects in the air. Regarding ta.

[Brief explanation of conventional example] Devices that accurately measure the position of a point in the air relative to a reference object are required in many technical fields. continues to be desired. This type of system or device is used to determine the coordinate values of a point to be measured. high resolution to capture transient phenomena, high frequency response to capture transient phenomena, and the ability to obtain real-time output of data. It is necessary to have

There are various applications that have the above purpose, but all of them involve It is required to be able to accurately measure position. As a specific application example, for example, Aircraft fluttering analysis (FLUTTER) and BUFFET analysis , Determination of flight load, Flight test measurement device, Function recovery and Aircraft inspection auxiliary device , landing aids, monitoring and collision avoidance devices (systems), bridge deflection evaluation devices, There are operation measurement devices, etc.

A conventional example of measuring the deflection of an aircraft wing during flight will be considered. The strain gauge Its use is limited by the material and structural design of the wing. Because the size of the wings This is because, regardless of deflection, only low-level and non-repetitive strain can be measured. . Furthermore, accelerometers are unsuitable for measuring steady-state or low-frequency wing deformations. . Video capture techniques are inadequate in terms of resolution and precision and are used for qualitative measurements. There are many things.

Patented to Barbert Seymour on January 30, 1979 and assigned to the assignee of this application. The technology disclosed in U.S. Pat. No. 4.1)6156 solves the problems of the conventional example The purpose is to remove points. This system using 4S child/light sensor is , quantitative measurement with accuracy comparable to or better than strain gauges or accelerometers. At the same time, target tracking using video technology is possible. It has the credibility and design flexibility of a trace system.

The electronic/optical sensor (head) of the above patent converts light from a distant light source into a circular lens. Instead of converging as a point as in the case of using ). This line image is processed by photoelectric conversion (photoelectric conversion). The output of this optoelectronic device is A typical photosensitive device is a photosensitive diode array. The array is electrically scanned to locate the line image. Can) be done.

Is the digit 1 of the line image the neutral plane of the lens? Since it uses a 0 cylindrical lens that indicates the direction of the light source, the electronic/optical sensor can be It does not detect changes in position in the direction, only changes in position perpendicular to the neutral plane of the lens.

When using the above electronic/'optical head to solve the conventional problems mentioned above, In this method, multiple light emitting diodes (light sources) are installed over the entire underside of the aircraft wing. These light emitting diodes are energized sequentially by the control circuit, and each light emitting diode The light enters an electronic/optical sensor mounted on the fuselage of the aircraft. This sensor is The position information is added to the control unit, and the control unit processes the position information to Outputs data regarding changes in the position of the gate (element).

Each light-emitting diode is energized for a period of about 6 gs (i.e., it is turned on). During the scanning period), the electronic/optical head (Senna) performs multiple scans (the number of scans is determined by the control unit). The control unit captures the image of the light emitting element during the period (preset in the The cutter receives each scan result, averages all scan results, outputs all scan results, and outputs the light emitting element. The location information is output together with the information (ID) specifying the location, and this operation is repeated.

The scanning speed of the above system was adjusted to be appropriate for the measurement of the vibrating body. It will be done.

For example, when acquiring quasi-steady-state data, it is important to minimize the effects of high-frequency oscillations. effectively use scanning rate averaging to − Location information from distant Sugi corpses (hereinafter referred to as targets) may be used for tracking purposes or as necessary. If necessary, for vibration studies, the first or second differential coefficient with respect to the time opening (deri ~ - Can be used to determine e11-'e). One-dimensional application example is load There is a flexure for testing, and two-dimensional applications include alignment measurement or range measurement. 3D applications include relative positioning in the air, such as aerial rendezvous and aerial refueling. This is the position control of aircraft, etc. whose position changes.

2 Summary of the present invention] The present invention relates to an improvement on the above-mentioned patented invention. The device related to the above patent operates satisfactorily. However, the problem is that the effective measurement range is limited. In other words, Light uses an analog comparator, which allows background light (noise) to be removed. Only detected optical signals exceeding a preset threshold without special consideration of effects This is because we are measuring. Therefore, the present invention first quantizes the background optical signal, A background optical signal is generated from a composite signal consisting of a background optical signal component and a target information signal component. It uses signal processing to digitally subtract the minutes. Therefore, the extremes of tolerance A large digital threshold (level) can be obtained and the effective measurement range can be expanded. Ru.

When the present invention is applied to the displacement of a target, that is, the displacement of an aircraft wing during flight. The test distance (range) between the aircraft and the measurement receiver was compared to the conventional example, and the test distance (range) between the aircraft and the measurement receiver was can be reduced. Furthermore, the present invention can be used to measure the displacement of a wing during flight. The points can be listed as follows.

Virtually eliminates flight test data loss due to background light (light in the atmosphere) It is possible to eliminate all costly repeated test flights.

The effective measuring distance of the device can be extended by using a low-power light emitting element (attached to the target). ) can be used. Therefore, the use of low-power light-emitting devices is not only less expensive, but It has a long service life, improves the flexibility of the device, and keeps maintenance costs low. Can be done.

The expanded scope of use of the present invention means that the value of use will increase for the user. It can contribute to expanding the scope of use and the number of users.

The invention can be easily installed in conventional equipment.

lastly, The technical idea of the present invention applies to the processing of data obtained from any photodiode array. It is applicable.

The objects and features of the present invention described above will become clearer with reference to the accompanying drawings.

Brief description of the drawing Figure 1 is a diagram showing a cylindrical lens in a painterly style.

FIG. 2 is a diagram showing the geometrical relationship in FIG. 1.

FIG. 3 is a diagram showing the arrangement of optical elements and electronic elements.

FIG. 4 is an electronic circuit diagram of the portion shown in FIG.

FIG. 5 is a diagram showing use in aircraft testing.

FIG. 6 is a circuit diagram of a conventional example.

FIG. 7 is a diagram showing a typical pulse train obtained from a conventional device.

FIG. 8 is a diagram showing a typical comparator output obtained from a conventional device.

FIG. 9 shows a digital detector used in the present invention in place of the comparator of conventional devices. Block diagram.

Figure 10A shows the start command timing used in the digital circuit of Figure 9. diagram. Figure 10B is the target enable used in the digital circuit of Figure 9. Timing diagram of the signal.

Figure 10C shows the video output type from the diode array of the digital circuit in Figure 9. Mining diagram.

Figure 10D shows the array and illumination timing during the operating cycle of the digital circuit of Figure 9. diagram.

Figure 10E is the target data acquisition frame period of the digital circuit in Figure 9. Timing diagram of the threshold signal in.

[Detailed description of the invention] In order to explain the present invention in detail, first, we will begin with the United States, which is the conventional example most related to the present invention. The electro-optical device disclosed in Patent No. 4,136,568 will be described. This servant In FIG. 1, which relates to the previous example, the light source 10 forms a line in the focal plane 12 of the lens 11. Focus as 13. This line 13 is parallel to tJIt of lens 11. Ru. As shown in FIG. 2, the light source 10 is placed on a plane parallel to the plane 14 of the lens 11 and The light source 10 is placed at a distance X from the plane 14 of the lens 11, and the light source 10 is placed at the neutral plane of the lens 11. 15, the line image of the light source 10 on the focal plane 12 The lens 13 is located behind the lens by a distance 1ef from the plane 14 and by a distance p from the neutral plane 15. Located at location d. α=tan-’d is β=tan-’x/y= Identify F(a). Here, f and F(α) are for lens calibration in the laboratory. more predetermined. If the open number F(α) of α is equal to α, then β=α and y / x = d / f. This relationship is practically true and can be easily explained below. Assume that this relationship holds.

FIG. 3 shows the optical components and optical position sensor that make up the electronic/optical head 20. The configuration utilizes the principle explained in FIG. The child/optical head 20 is the light source 21 used with The light source 21 is not affected by unnecessary light energy from other light sources. 6 cylindrical lens 22, preferably a light emitting diode operating in the infrared region to avoid lights infrared energy from light source 21 onto photosensitive diode array 24. The image is formed as a line image (ray line) 23. When the light source 21 moves vertically Then, the line image 23 is moved in the direction opposite to the direction of movement of the light source, i.e. It moves in proportion to the vertical direction of the ray 24. The light source moves laterally parallel to the lens However, the vertical position of line image 23 is not affected.

The infrared passing filter 25 provided in front of the lens 25 has a low return coefficient of approximately 0.78 μmf). (cutoff) wavelength, so visible light to the head 20 is blocked. Daio A second filter 26 provided in front of the light array 24 filters the wavelength of the light source 21 in the atmosphere. has a center wavelength equal to . This filter 26 is used for the light source 21 in the vicinity of the infrared region. Blocks all wavelengths of light except the wavelength of light. That is, filter 26 is a diode array. A24 blocks wavelengths other than those to which it responds most sensitively.

FIG. 4 is a diagram showing the circuit of the diode array 24, which has a total length of 1 inch. Approximately 0.5 at 2 mil (approximately 2.5 x 10-" m) intervals over a It has multiple photodiodes (photosensitive diodes) of mil (0゜5xlO'm)m. do. Each of the diode cells includes the photodiode 27<1@) and the diode A semiconductor switch is constructed using a capacitor 28<1@) connected in parallel to the board as a component. 29 to a common video bus 30.

The charge accumulated in the capacitor 28 is transferred to a plurality of switches under the control of the scanner 34. The signal is sequentially released to the video bus 30 via the Supplied to pull-hold circuit. Switch to take out the video charge. The circuitry that drives circuit 29 is included in diode array 24 on circuit board 31 (FIG. 3). included.

The diode array mentioned above is commercially available from Reticon Corporation. There is.

In an application example (Fig. 5) for detecting the true (wing) movement of an airplane, the lower side of the wing 35 is A plurality of light emitting diodes (light sources) 21 are placed on the It is provided in the fuselage 36. Arranged in this way, the light emitting diodes 21 are sent to the sales destination one after another and flown. Detects the position of multiple light emitting diodes on the underside of the wing, which are installed perpendicular to the aircraft's longitudinal axis. For example, approximately 200 light emitting diodes are provided, and each light emitting diode is Scan 8 times per 1000 seconds.

A light emitting element drive unit (light source driver) 40 (Fig. 6) drives each light emitting element (light source) 2. A drive current is intermittently supplied to 1. Continuously timed instructions (commands) ) drives the Darlint-connected power transistor circuit via line 41 to generate the Supplies power to the optical device assembly.

The duty cycle of each of the drive circuits making up the unit 40 is It is the reciprocal of the number of optical elements. Rise and fall of the combination of li2 dynamic circuit and light emitting element The times are about 1.5 μs and about 11.5 μs, respectively. T-stream supply for each light emitting element The source and drive circuits are contained within unit 40. Control unit 50 (uni (corresponding to all elements in Figure 6 except for 20, 21 and 40) are required for system operation. Controls the acquisition of required data and data processing.

The operation of the system is started using a pulse code model that receives the output of the control unit 50. from the modifier (P CM: Pu1seCode Modifier). This is done with a powerful end-of-frame pulse. This pulse is the start logic This start logic circuit 51 is supplied to the start logic circuit 51. A start command is sent to the diode array scanning logic that forms part of the electronic/optical head 20. It is added to the drive circuit, that is, the drive port R (drive) 52. IMHz clock generator 3 The output of and is added to the operation start logic circuit 51. Logic episode I! ! added to 51 The tally clock frequency determines the diode sample rate. The frequency is adjustable from 300KHz to 2MHz in the drive circuit 54. be.

The diodes in the diode array 24 each have an internal MOS switch. are sequentially checked by connecting to the output video line via the . Respectively The λ10S switch is closed during the negative half cycle of the tarok period, and the diode Discharges the charge on the video bus capacitor to the video bus capacitor connected to line 55. do. After reaching steady state (approximately 5 ns), the video line voltage is applied to amplifier 56. The signal is amplified and applied to the holding capacitor 8 via an output line 57. die When the diode 27 is turned on, the capacitor connected in parallel with the diode (i.e., As the capacitor 28) discharges and the diode is scanned, as shown in 7I21 A peak 59 in the video output waveform appears. This peak position characterizes the lighting diode. Set.

When the scanning of diode array 24 is complete, an end scan pulse is output on line 60. The output signal is supplied to a blanking device (retrace blanking) 61. child The device 61 outputs a video blanking command to the switch 62 and turns on the video bus 63. hold the voltage at ground potential. The blanking pulse duration is adjustable within the circuit. , determine the dwell time before the next scan. In addition, 68 μs is appropriate. selected as the dwell time.

Video bus data is applied to voltage comparator 64 via intensifier 65. voltage comparison The device 64 compares the video bus data with the 'g width of the reference voltage 66 and determines the reference voltage 66. Detect pulses in the image bus data that exceed the amplitude of the rectangular pattern shown in Figure 8. output on line 67.

The width of n'1JA23<Fig. 3) formed in the diode array 24 is inconvenient. Particularly, one or more diodes (27) are irradiated. To resolve this issue , identify the “first” and “last” diodes turned on by light irradiation. It is necessary to The output 67 of the comparator 64 corresponds to the number of diodes turned on. The tarot generated after the blanking pulse output from the device 61, representing the number The number of pulses of clock 53 (i.e. the number of pulses of taroch 53 that occur from the beginning of a new scan) ) are counted by the line counter 68. Note that this line counter 68 is Connected to clock generator 53 through six clock gates to generate blanking pulses. It is closed during the period when , and is open at other times. turn first The counter 68 is set for the diode that is turned on (first-on diode). The counted value is output from the comparator 64 via the logic circuit 71 to the line 72. It is stored in register 70 at the leading edge of the output pulse. Similarly, the last turn on Value counted by counter 68 for diode (last on diode) is the output pulse of comparator 64 outputted to line 74 via logic circuit 71 is stored in register 70 at the trailing edge of . At the end of each scan period, first-on Recorded in diode register 70 and last-on diode register 73. The stored count value is transferred to the microprocessor 75, and the count value is transferred to the microprocessor 75, and the count value is transferred to the microprocessor 75. The average value of the two counts to number the diode in the center position of the diode. be criticized.

Completion of the first scan is notified to the start logic circuit 51, and the scan counter (scan ・Counter) 80 is counted up. Number of scans performed on one light emitting element is determined by presetting the number of scans during logic cycle F#I81.

The scanning of the Nth light emitting element continues until the scanning number counter 80 reaches the preset number. Subsequently, the pulse from the logic circuit 51 is applied to the light emitting element address counter 82. Advance the count value and select the light emitting element to be energized next ((N+1)th light emitting element). select.

Next, the system (or device) shown in Figure 6 waits for the next final frame pulse. , logic times FI? in response to the occurrence of the final frame pulse. 151 and next The 1-light-emitting element address counter 82, which performs a repetitive operation, continues counting and Which light emitting element repeats the operation for each number of light emitting elements selected by the numerical logic circuit 83? An operating signal is sent from the counter 82 via line 84 to the microcontroller. added to processor 75;

In the device described above, the motion of each light emitting element 21 is tracked along a line perpendicular to the wing 35. Ru. Since the position of each light emitting element provided on the wing 35 is known, one-dimensional tracking is appropriate. .

[Improvements according to the present invention] The present invention relates to the replacement of a portion of the circuit of FIG. 6, namely analog detector 86. Place An important part of the detector 86 to be replaced is the comparator 64 mentioned above. The above conventional In order to provide the present invention with unique and distinctive features, analog detector 86 is replaced by digital detector 86. It is replaced by a detector 86' (a detailed block diagram of which is shown in FIG. 9).

Figure 10D shows three basic frames to explain the operation of digital detector 86'. 3 shows frame periods A, B and C.

When a start command, indicated by reference numeral 88 in FIG. 10A, occurs, period A starts. During frame period A, diode array 24 is scanned and the previous Residual charge accumulated during the data acquisition frame is removed. Reference to Figure 10C Number 90 indicates the above-mentioned residual charge amount, and in frame period A, the target light emitting element 2 1 is not activated and no data is captured during this residual charge removal period.

During frame period B, the target light emitting element 21 is not energized and the diode The array 24 is operated for a period of time (typically 1.5m5) (this period is shown in Figure 10D). Exposure or exposure), background light or background light The second time after the exposure period, the diode array 24 captures the data. A start 2 command is issued from start logic circuit R51 (Figure 6) to scan the This start command starts the A/D flash (flash) shown in Figure 9. ) Once transducer 96 is enabled, the second scan described above begins.

The A/D flash converter described above can be obtained, for example, from RCA, and converts the output (multiple) analog signals from the card array into digital signals (usually 6 bits) Convert to

A/D converter 96 receives input data via video bus line 57 (Figure 6). receive. Conversion sampling synchronization in converter 96 is input via line 98. controlled by the sample enable signal. Note that this sample enable The signal is obtained from a well-known sample/memory address logic circuit 100. . To obtain a favorable signal-to-noise ratio, the minimum target ′! j, width threshold value signal is applied to the device's digital signal. Application of this threshold signal from the cut amplitude threshold signal generator 106 to the buffer 110 via line 108. It is done by adding. That is, the buffer 110 receives the enable signal (start 2 command), the minimum target@width threshold is set via line 112. is output from the buffer 110 to the binary adder 114, and the adder 114 outputs A /D converter 96 (supplied via line 102). addition The output of the device 114 is read/written via a buffer 116 and a connection line 120. applied to memory 118. Scanned diodes in diode array 24 The output from the code is stored in a separate memory location within memory 118. memory Writing/reading to 118 is done via memory address signals applied via line 122. controlled by the number. Note that this memory address signal is a sample of a known configuration. /Output from memory address logic circuit 100.

The data from the diode array is the data from all diodes that make up the array. data is written to memory 118 serially until the data is sampled. this Thus, at the end of frame period B, all diodes making up the array are drained. data is collected. However, the target light emitting element 21 has not been energized so far. Therefore, the data from the diode array is based on the background light (background data ), the quantized signal of this background data is indicated by reference numeral 104 in FIG. 10C. ing.

Next, frame period C begins. In frame period C, the target light emitting element 21 is 10C and 10D, the diode array 24 is activated as shown in FIGS. 10C and 10D. is irradiated during the initial exposure period of frame period C. Ru. During this period, the third scan command starts at the start logic time H51 (sixth (Figure). This Start 3 command is designated by reference number 105 in Figure 10A. In response to the generation of the third start command shown in FIG. data is generated immediately.

The target light-emitting device consisting of the Once known, the target signal is digitized by the A/D flash converter 96. Then, a composite signal of background data and target data is sent to the A/D flash converter 9. The output signal is output to the video bus output line 102 of No. 6. The above operation starts in Figure 9. It is assumed that the enable signal is received during the application period of the 3rd command. third When scanning starts, the START 3 command reads the memory 118). The data stored during frame period B by this read cycle ・Word is called. This called data word contains background data and The data associated with the minimum target@width threshold composite signal applied from circuit 106 Contains data.

The stored data word from each diode is sent to the buffer via line 128. The background data is sequentially added to the buffer 130, complemented in this buffer This is a one's complement signal of the composite value of the data and the amplitude threshold value. Output 1 of buffer 130 32 is converted into a two's complement (negative number) in the binary adder 114, and the two's complement value is The addition subtracts from the composite value of the background data and target data. this If the value of the result of subtraction is correct, it is over from the sign bit (the most significant bit of the two's complement number). Flow occurs. The fact that the result of subtraction is positive means that the target data whether the data amplitude 109 (Figure 10C) is equal to the threshold value 136 (Figure 10C) or exceeds this value, a threshold 136 occurs during format period B. This is the maximum value obtained from the superposition of background data and offset 107.

If the above-mentioned "value of the result of subtraction is positive", an output is sent to the upper column 134 of the binary adder. A bar flow signal is output.

This overflow signal is used to spread the target gA (line image) and Target image from the zero reference point of the diode array measured at the lowest value level The target position logic circuit 13, which indicates the position of the When enabled by the bit 3 command, the overflow signal bits listed above Further processing is performed in the logic circuit 135. Target position logic Ku times f! @135 has a conventional analog detector 86 (No. 1) connected to its output line 67. It outputs a signal equal to the comparator output in Figure 6). Load logic circuit 71 and microphone Data processing by the remaining circuitry including the microprocessor is described in the US patents mentioned above (prior art ).

It goes without saying that the present invention is not limited to the specific examples illustrated and described. Various modifications will be apparent to those skilled in the art.

Gukuhi A mummy]j F/69 international search report

Claims (8)

[Claims] 1. Regarding the device for determining the position of a preselected object, A plurality of light sources, means for individually and sequentially energizing the plurality of light sources, and a means for energizing the plurality of light sources individually and sequentially; It detects the light from the light source mentioned above and the background light, and converts the detected light into an analog signal. electronic/optical means and an output terminal of the electronic/optical means for transmitting the analog signal to the corresponding output terminal of the electronic/optical means. an analog-to-digital conversion means for converting the signal into a digital signal; means for storing a digital signal obtained only from background light; a) and b) below, i.e. a) do not energize the above light source when only background light is present; and b) energizing the light source when background light is present. Each digital signal is subtracted, and this subtraction eliminates the effects of background light. means for calibrating the output of the detected light from the electronic/optical means to only the light source of the object; , a device having. 2. A high threshold of maximum background light can be set by adding a constant value to the stored background light signal. means for obtaining a value obtained from the plurality of light sources; When the signal value of the detected light exceeds the above threshold, an overflow signal is output. means, and the overflow signal is an input signal detected by the electronic/optical means. Claim 1 comprising information regarding the width of the image and the position of the image. equipment. 3. Claim No. 1, wherein the analog-to-digital converter is a flash converter. The device according to item 1 or item 2. 4. Regarding equipment that analyzes the movement of aircraft wings, the position relative to the aircraft fuselage is Multiple light sources installed on the changing wings of the aircraft, installed in the fuselage of the aircraft, detects and detects the light from the light source and the background light. electronic/optical means for converting light into analog signals; connected to the output end of said electronic/optical means, converting said analog signal into a corresponding digital signal; analog-to-digital conversion means for converting into means for storing a digital signal obtained only from background light; a) and b) below, i.e. a) do not energize the above light source when only background light is present; and b) energizing the light source when background light is present. Each digital signal is subtracted, and this subtraction eliminates the effects of background light. The signal output of the detection light from the recording electronic/optical means corresponds to the light from the light source provided on the wing. means for calibrating the signal to A device with 5. A high threshold of maximum background light can be set by adding a constant value to the stored background light signal. means for obtaining a value obtained from the plurality of light sources; When the signal value of the detected light exceeds the above threshold, an overflow signal is output. means, and the overflow signal is an input signal detected by the electronic/optical means. Claim 4 has information regarding the width of the image and the position of the image. equipment. 6. Claim No. 1, wherein the analog-to-digital converter is a flash converter. The device according to item 4 or 5. 7. Regarding the method of analyzing the movement of loaded wings of an aircraft, An array of multiple photoelectric elements detects background light and converts it into an analog signal. Converts analog signals to corresponding digital signals and only detects signals caused by detected background light. A) When only background light exists, b) activating the light source when background light is present; and b) activating the light source when background light is present. subtracts each digital signal detected during the period to eliminate the influence of background light. By doing so, the signal output of the detection light from the photoelectric element is transmitted from the light source provided on the wing. corresponding to the light of Method. 8. Add a constant value to the stored background light signal to obtain a high threshold of maximum background light; If the signal value of the detected light obtained from the above multiple light sources exceeds the above threshold value, an error occurs. outputting a flow signal, the overflow signal being detected by said electronic/optical means; Claim 7 comprising information regarding the width of the image and the position of the image. The device described.