JPS61213609A - Edge detector of photoelectric measuring instrument - Google Patents

Abstract

PURPOSE:To adjust sensitivity accurately and speedily by adjusting the level of the output signal of the photodetection sensor while monitoring it on a display means. CONSTITUTION:An edge detector 27 consists of the 1st comparator 36A, the 2nd comparator 36B parallel to it, and an exclusive OR gate 38 to which output signals (k) and (l) of those comparators 36A and 36B are inputted. Then, an edge detecting means is constituted including the photodetection sensor, a differential computing element which outputs a differential output signal (c), and an area signal generator 30 which outputs an area signal in specific area. Further, a monitor device 29 consisting of a signal sectioning device and a proximity display device is provided. The edge detecting means turns on an edge display means 76 when the output signal (c) coincides with a zero reference level signal at any time regardless of the inclination of the waveform of the output signal (c) and turns off the means 76 a time (t) later. Further, the sensitivity of the edge detecting device is adjusted properly by adjusting the amplifier of the photodetection sensor while monitored on the device 29 including a display means.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a photoelectric measuring device for measuring the dimensions, displacement, etc. of an object, and in particular detects transmitted light or reflected light to directly or indirectly measure the object to be measured. This invention relates to the improvement of an edge detection device in a photoelectric measuring instrument for measuring the dimensions, etc. of objects.

[Conventional technology]

Conventionally, this type of rechargeable measuring device, for example, a magnifying projector, illuminates an object to be measured on a stage with parallel light beams, and projects the object onto a screen based on the transmitted or reflected light. is formed into an image, and the dimensions and shape of the object to be measured are measured from this image. However, the edge (part 1) of the object to be measured projected onto the screen generally has so-called blur, and therefore It is difficult to move the object to be measured on the stage and read the measured value accurately from the coincidence of the image formed on the screen and the hairline. In order to solve this problem, conventionally, the edge of the image is moved relative to the light-receiving element. Changes in the magnitude of the electrical signal output from the element,
Some detect the edges of the projected image by comparing it with a reference voltage. However, this method has problems in that it is greatly affected by noise such as ambient light, and the measurement accuracy is greatly reduced due to fluctuations in the signal or reference voltage obtained from the light receiving element. Furthermore, the light receiving element is moved relative to the boundary (edge) of the projected image on the screen, the output signal at that time is second-order differentiated to obtain a waveform signal, and the edge is detected by comparing this with a reference voltage. However, the position of the detected edge may differ depending on the speed of relative movement between the light receiving element and the projected image, and furthermore, as mentioned above, there is a problem that measurement accuracy is greatly reduced due to fluctuations in the reference voltage. There is. Furthermore, a light receiving element 211 is arranged and moved relative to the edge of the projected image, a waveform signal is obtained from a plurality of output signals obtained by this, and the edge is detected by comparing this with a reference voltage. However, as mentioned above, the measurement becomes very unstable due to relative changes between the output signal obtained from the light receiving element and the reference voltage, level fluctuations, etc.
The applicable range for the illuminance of the irradiated light is narrow, and the measurement! g
However, there are problems in that the number of applications is limited and a part of the sensor or circuit part becomes sloppy. In particular, in projectors, fatigue of the light source lamp for irradiation,
The brightness of the projected image on the screen changes due to the lens characteristics of the projection system and ambient light, and the brightness of the projected image changes due to switching of the projection magnification. The suitable brightness for work differs depending on the color of the eyes of the person (which differs depending on the race), so this must be selected appropriately, but if the range of illuminance of the irradiation light is narrow as described above, the resulting projection This will reduce the capacity of the machine. Further, in the conventional edge detection method, when the projection me is out of focus, the output waveform of the light receiving element becomes gentle, so there is a problem that accurate edge detection cannot be performed. This problem is common not only to projectors but also to edge detection in photoelectric measuring instruments that detect transmitted light or reflected light to directly or indirectly measure the dimensions of objects to be measured. This is a problem. On the other hand, as disclosed in JP-A-58-173408, for example, optical measuring instruments for directly or indirectly measuring the dimensions of an object by detecting transmitted light or reflected light. In the edge detection device, at least two
a sensor consisting of 411!1 light-receiving elements disposed in a plane substantially parallel to the moving surface so as to generate a set of phase shift signals, and a first and second sensor for calculating the difference between the phase shift signals of each set.
a third calculating means for calculating the difference between the output signals of the first and second calculating means, and a fourth calculating means for calculating the sum.
and a detection means for outputting a cross signal between the output signal of the third calculation means and a reference level, which occurs while the output signal of the fourth calculation means is at a predetermined level. ing. This edge detection device uses light intensity that irradiates the measurement target,
It is possible to detect the edge of the object to be measured with a simple configuration without being affected by noise such as ambient light during measurement, fluctuations in the output signal of the light receiving element, or reference voltage. This method has the advantage that edges can be detected accurately even if the projected image is out of focus, and edges of the object to be measured can be detected by directly processing analog signals from the light-receiving element. be. Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 59-162404, the difference signal between the output signals of two charging elements in the bright area and the dark area of the image of the object to be measured and the intermediate position of these photoelectric elements Some devices are provided with circuit means for outputting a coincidence signal at the point of intersection with a reference signal output from a reference photoelectric element. The edge detection device disclosed in Japanese Patent Application Laid-Open No. 58-173408 and the device disclosed in Japanese Patent Application Laid-Open No. 59-1624O4 are designed to enlarge and project an image of the object to be measured on a screen, for example. In the case of a magnifying projector, the brightness of the colored image on the screen changes depending on the state of the light source, optical system, or object to be measured, as well as the preference of the operator. On the other hand, the light-receiving element for edge detection also changes over time, and therefore, if the brightness on the screen is too high, the calculator for calculating the output of the light-receiving element becomes saturated, making it impossible to guarantee accuracy. At the same time, if it is too low, the sensitivity will decrease and edge detection will become impossible. Therefore, the sensitivity of the edge detection system must be set to an appropriate level. That is, the peak values on the plus and minus sides of the S-curve signal waveform, which is calculated from the output signal generated when the light-receiving element passes the edge of the image on the screen, are set to the zero level in the middle of the S-curve waveform. The sensitivity level must be set within an appropriate range to ensure linearity in the area where the signal crosses. As a method for this purpose, for example, a mechanical analog meter consisting of a center zero type DC ammeter is used to measure the S
It is used as a monitor of curved output signals, and there is a maximum amplitude of the left and right or top and bottom of the pointer that can be taken according to the S-curve output that occurs when the edge of the projected image passes through the center of the sensor consisting of multiple light receiving elements. Adjust the sensitivity of the device to stay within a certain range. This sensitivity 111i is increased by adjusting the gain of the voltage amplification stage of the detection output. In this way, a mechanical analog meter can be used to
When used as a monitor for Im, analog meters generally use a moving coil, and there is a time lag between the current flowing through the coil and the movement of the pointer, and the pointer cannot follow rapid changes in the current. The problem is that work efficiency decreases due to poor responsiveness, and analog meters are susceptible to photography and shock, so the zero point tends to go awry, making it necessary to frequently adjust the zero point. . Another problem is that there are restrictions on the posture when installing an analog meter.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an edge detection device for a photoelectric measuring instrument that allows accurate and quick sensitivity adjustment without using a mechanical analog meter. shall be.

[Means to solve the problem]

This invention relates to an edge detection device in a photoelectric measuring instrument for directly or indirectly measuring the dimensions of a measurement object by detecting transmitted light or reflected light. It includes a plurality of light-receiving elements arranged in a plane substantially parallel to the moving surface, and the level of the output signal at the output terminal can be adjusted so as to generate a phase-shift signal based on changes in the amount of light received at the time. a light-receiving sensor, a difference calculator connected to the output terminal of the light-receiving sensor and calculating the phase shift signal and outputting a differential output signal, and a cross point between the differential output signal of 4 and the M-level signal. A region signal generator outputs a region signal in a specific region including a region, and a region signal is output from this region signal generator.
A detector for outputting an edge detection signal at the cross point constitutes an edge detection means, and a value of the differential output signal while the area signal is being output from the ship recording area signal generator. a signal divider that divides the signal into multiple stages;
an approach display device that includes display means of the same number as the divisions provided corresponding to the divisions divided by the signal divider, and that operates the display means corresponding to the division to which the mouse of the differential output signal belongs; The above object is achieved by using a monitoring device which adjusts the level of the output signal of the light receiving sensor while monitoring with the display means. Further, the present invention achieves the above object by forming the same number of sections into which the signal sectioning section is to be divided on both sides of the cross point. Further, the present invention achieves the above object by forming the signal segmenter so that the width of the segment becomes smaller as the value of the slope signal approaches the value of the reference level signal. Further, the present invention achieves the above object by making the signal divider adjustable to increase or decrease the width of each division of the signal to be divided. (Function) In the present invention, the differential output signal outputted from the plurality of light receiving elements and calculated by the difference calculation unit, which intersects the zero level reference signal, determines the point corresponding to the edge of the image of the object to be measured. The center is divided into a plurality of sections whose width can be increased or decreased, and display means provided corresponding to each section displays the section to which the value of the differential output signal belongs, thereby using a meter. By monitoring the presence of a differential output signal near the edge detection point and quantitatively capturing its range, the sensitivity of the edge detection device can be easily adjusted.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an edge detection device for a projector, and as shown in FIGS. The measurement target 16 on the stage 14 is irradiated from below the stage 14 or from above the stage 14 via another optical path, and the projection lens 18 is set based on the transmitted light or reflected light. The object to be measured 1 is placed on the screen 21 through the
The projection plane 44) 16A of 6 is imaged, and this projected image 16
A is used for the projection 1II20 for indirectly measuring the dimensions of the measurement object 16, and the projection image 16A
It includes first and second light receiving elements 22A and 22B that are arranged concentrically in a plane substantially parallel to the moving surface so as to generate a phase shift signal based on the brightness and darkness that occurs when moving relative to the moving surface. a light-receiving sensor 24 formed so that the level of the sensor output signal at the sensor output terminals 23A, 23B based on the outputs of the sensors 22A, 22B is equal to each other during brightness and darkness occurring during the relative movement; and the light-receiving sensor 24. The sensor output terminals 23A, 23B in
a difference calculator 26 which calculates the difference between the phase shift signals a and b outputted from there and outputs a differential output signal c-a-b that crosses the zero level reference signal; A region signal generator 30 outputs a region signal in a specific region including the cross point between the signal C and the reference level signal, and while the region signal @j is output from the region signal generator 30, , a detector 27 that outputs an edge detection signal m, and constitutes an edge detection means 28, and the differential output signal @C while the area signal @j is being outputted from the area signal generator 30. A signal divider 32 that divides - into a plurality of stages, and display means provided corresponding to the divisions divided by the signal divider 32, the number of which is equal to the number of the divisions, and the value of the difference, the auxiliary output signal C. an approach display device 34 that activates a display means corresponding to the category to which it belongs;
The monitor device 29 is configured to adjust the level of the output signal of the light receiving sensor 24 while monitoring the display means. The level adjusting means for the output signal of the sensor 24 is composed of amplifiers 94A and 94B, which will be described later. As shown in FIG. 3, the edge detector 27 receives output signals from a first comparator 36A, a second comparator 36B in parallel with the first comparator 36A, and the first and second comparators 36A and 36B. , ρ is input to the exclusive OR gate 38
It is composed of. The positive sides of the first comparator 36A and the second comparator 36B are grounded via resistors 40A and 40B. Further, the tilt signal C is inputted to the minus side. Furthermore, these first comparator 36A and second comparator 36
The positive side and output side of B are each a diode 42A.
and resistor 44A1 are connected via diode 42B and resistor 44B. The diode 42A on the side of the first comparator 36A has such a characteristic that when the potential on its output side is at a high level rHJ, it divides the potential to make the plus side potential ΔVrer. Further, the diode 42B on the second comparator 36B side is configured to lower the positive side potential by ΔV rer with respect to the output side potential of the second comparator 36B. Here, the first comparator 36A and the second comparator 36
B outputs a high level signal rHJ when the input on the positive side is larger than the input on the negative side, and outputs a low level signal rLJ when the difference between the two is less than zero. Here, the relationship between "H", rLJ, and ΔV ref is set as shown in the following equation. H-ΔVref -1, +Q The region signal generator 30 compares the differential output signal C of the difference calculator 26 with high-level and low-level reference signals, and determines whether the differential output signal C is high-level or low-level. When the sensor output signal is between the levels, a hold signal d, e is formed to hold one of the sensor output signals a, b, and the output signal is between the held high-level hold signal and the low-level hold signal. Because of this, a signal is output in a certain area including the cross point of the phase shift signal C with the reference level signal. That is, the region signal generator 30 compares the differential output signal C of the difference calculator 26 with a high level reference signal, and outputs a hold signal d when the differential output signal is lower than the high level. a comparator 44A, a fourth comparator 44B that compares the differential output signal C with a low-level reference signal and outputs a hold signal e when the differential output signal C is higher than the low level; and the third and fourth comparators. first and second sensors that hold one sensor output signal of the sensor 24 based on the hold signals d and e inputted from the sensors 44A and 44B, and sample the sensor output signal when no hold signal is input; 2 sample hold circuit 46A
, 46B and the output signals ``, q'' of these first and second sample-and-hold circuits 46A and 46B are compared with the sensor output signal S, and when the output @f is smaller than the sensor output signal S, the signal @ A fifth comparator 48A outputting h
a sixth comparator 48B that compares the output signal Q and the sensor output signal S and outputs a signal i when the output signal g is larger than the sensor output signal S; An exclusive OR gate 50 generates a region signal j when only one of the comparators 48A and 148B outputs a signal. The output side of this exclusive OR gate 50 is connected to the proximity display device 34 via an amplifier 52. The signal divider 32 includes first to fifth comparators 5 on the positive side.
A positive side comparator array 54 consisting of 4A to 54E, a negative side comparator array 56 consisting of negative first to fifth comparators 56A to 56E, a positive side resistor array 58 to which a positive voltage 9 is applied, and a negative side and a negative side resistor string 60 to which a voltage V- is applied. The plus side resistor array 58 includes in series a plus side first to fifth resistors 58A to 58E on the ground side and a plus side variable resistor 58F. Similarly, the minus side resistor array 60 also includes first to fifth minus side resistors 60A to 60E and a minus side variable resistor 60F in series from the ground side. Here, the resistance value of each resistor in the plus side resistance array 58 and the minus side resistance array 60 is configured to gradually increase from the first side to the fifth side. That is, as shown in FIG. 4(A), the signal divider 32
Division of trust @a - a - b by 85 ~ S + , S
The width of +' to Ss' is made smaller as it approaches the cross point (edge) with the zero level reference signal. The positive side first to M5 comparisons 154A to 54E are as follows:
It is arranged corresponding to the positive side first resistors 58A to 58E, and the high potential side of each resistor is connected to the negative input side of the corresponding comparator. Similarly, the negative side first to fifth comparators 56A to 56E are connected to the negative side first to fifth resistors 60A to 6.
0E, and the high potential side of each resistor is connected to the plus input side of the corresponding comparator. Therefore, from the first plus side comparator 54A to the fifth comparator 54E, the voltage y applied to the plus side resistor string 58 is
A positive partial voltage is applied to the negative input sides of the first comparator 54A on the positive side to the fifth comparator 54E on the positive side at successively higher potentials. Similarly, negative side first comparator 56A to fifth comparator 5
The voltage - applied to the negative resistor array 60 is sequentially divided and applied to the positive input side of 6H starting from the lowest potential side. Said positive side and negative side variable resistors 58F and 60F
are the positive side and negative side first to fifth resistors 58A to 58E and 60A by changing their resistance values.
It increases or decreases the voltage applied to ~60E, and functions as a sensitivity adjustment means. On the positive input sides of the positive first to fifth comparators 54A to 54E and the negative input sides of the negative 111111 to fifth comparators 56A to 56E, respectively,
A slope signal (c
-a-b) are connected so that they are input. On the output sides of the positive side first to fifth comparators 54A to 54E and the negative side first to fifth comparators 56A to 56E, positive side terminals are provided with positive side first to fifth analog switches 62A to 62E, respectively. switch row 62
A minus side switch row 64 consisting of first to fifth minus side analog switches 64A to 64E is connected. Moreover, these analog switches 62A to 62E and 6
4A to 6.4E, positive side first to fifth display means 66A to 66E, which are made of light emitting diodes and constitute the plus side display means column 66, and minus side first display means which constitute the minus side display means column 68. to fifth display means 68
A to 6 and 8E are connected to each other. The switch row 62, 64 and the display means row 66, 68 constitute the proximity display device 34. Here, the plus and minus side fifth display means 66ε,
The lighting color of 68E is green, and the fourth to first display means 66
The lighting color of D to 66A and 680 to 68A is amber. The positive side second to fifth analog switches 6287'
) to 62E are input with the output signals of the first to fourth comparators 54A to 54D on the positive side as trigger signals, are turned on when the signals are at high level rHJ, and are turned on when the signals are at low level rL
It is set to turn off when the signal is J. Moreover, the negative side second to fifth analog switches 64
B to 64E are the negative side first to fourth comparators 5;
The output signals of 6A to 56D are input as trigger signals, and are turned on when the output signals are at a high level rHJ and turned off when they are at a low level I''LJ. , 62A is N
OT episode ri! 70 to the output side of the first comparator 36A, the output signal k of the first comparator 36A is converted to a signal '' as a trigger signal, and '' is a high level signal. It is set to be turned on at times. That is, when the output of the first comparator 36A is "L", NO
High level signal rHJ whose polarity is reversed by the V circuit 70
It is turned on when input. The negative first analog switch 64A is turned on when the output signal 1 of the sixth comparator 48B is at a high level using the output signal λ of the sixth comparator 48B as a trigger signal. The positive first to fifth display means 66A to 66E and the negative first to fifth display means 68A to 68E are connected to the output side of the amplifier 52 via a resistor 72. Further, the output side of the amplifier 52 and the edge detection device 2
An edge display means 76 consisting of a red light emitting diode is arranged in series between the edge display means 76 and the exclusive OR gate 38 at 8 through a resistor 74. Here, each of the display means 66E to 66A, 76.68A to
68ε are arranged in this order as shown in FIG. 4(C). FIG. 4(B) shows the range in which the display means is lit. Further, as shown in FIG. 5, a part of the first light receiving element 22A of the sensor 24 adjacent to the outer periphery is a first dead zone 78A, and a part of the first light receiving element 22A of the sensor 24 is a first dead zone 78A.
A part of B adjacent to the outside in the radial direction of the first dead zone 78A is a second dead zone 78B extending from the inner circumference to the outer circumference, and also serves as the signal lead line 80 of the first light receiving element 22A.
is connected to the first light receiving element 22A in the first dead zone 78A, and is arranged so as to be led out to the outside of the second light receiving element 22B through the second dead zone 78B. The first dead zone 78A and the second dead zone 78B are part of the same fan-shaped area that extends in the radial direction at a constant angle from the center of the first light receiving element 22A.
A and the second light receiving element 22B are cut out and formed in the space. The signal lead line 80 is connected to the light receiving element 22A within the first dead zone 78A, and is connected to the second recessed portion.
It is wired so as to pass through the dead zone 78B and reach the outside of the second light receiving element 22B. As shown in FIG. 6, the connection end 81 of the signal extractor 180 on the first light receiving element 22A side has a fan-shaped connection tip 81A that fills the fan-shaped first dead zone 78A, and a fan-shaped connection tip 81A that fills the fan-shaped first dead zone 78A. The second dead zone 78 extends from the proximal end side.
It consists of a small-diameter pull-out portion 81B that penetrates the inside of B without contacting the end of the second light-receiving element 22B, and this pull-out portion 81B
The main body of the signal lead line 800 is connected to the outer end of the signal lead line 800. In FIGS. 5 and 6, reference numeral 58 indicates a chip to which the first light receiving element 22A and the second light receiving element 22B are attached, and 84 indicates a signal lead line of the second light receiving element 22B. The gap l1186 between the first light receiving element 22A and the second light receiving element 22B may be about 10 μ- without being filled with an insulating material. Further, in this embodiment, the first light receiving elements 22A, 2
The light-receiving surfaces 88A and 88B of the light-receiving sensor 24 are formed on the same plane perpendicular to the central axis of the light-receiving sensor 24. Furthermore, these light-receiving surfaces 88A and 88B are designed to have the same effective light-receiving area. The connection end 81, which is a part of the signal extraction [180], is arranged at a position retracted from the light-receiving surfaces 88A and 88B of the first light-receiving element 22A and the second light-receiving element 22B. The sensor has a projection [20
The screen 21 is provided integrally with a transparent plate 90 that is rotatably placed on the upper surface of the screen 21 in parallel thereto, so that the projected image 16A as the stage 14 moves is projected onto the sensor 2.
It is possible to move relative to 4. Here, the sensor 24 includes, in addition to the first and second light receiving elements 22A and 22B, a current-voltage converter 9 for converting the outputs of the first light receiving element 22A and the light receiving element 22B.
2A, 92B and the amplifiers 94A, 94B for amplifying their output voltages. These amplifiers 94A and 94B are
The offset is adjusted to cancel the dark voltage of the second light receiving elements 22A and 22B, and the gain is adjusted so that the outputs at the sensor output terminals 23A and 23B are at the same level when fully open. When automatically storing dimensions, etc. based on the detected edges, a pulse signal generator 96 generates an edge pulse signal based on the high level signal output from the exclusive OR gate 38; , and an AND gate 98 that outputs an edge detection signal only when signals are output from both the pulse signal generator 96 and the area signal generator 30. The output signal from this AND gate 98 is adapted to output an edge detection signal to a counter 102 of a displacement detection device 10o that moves on the stage 14. This displacement detection device 100 includes an encoder 1 that is linked to the document table 14 and generates a pulse signal according to the amount of movement thereof.
04, and the counter 102 that reads the pulse signal output from the encoder 104. This counter 102 is configured to output its read value to a storage device 106 when an edge detection signal is input from the AND gate 98. Next, the operation of the above embodiment will be explained. The projected image 16A of the measurement object 16 formed on the screen 21 is moved in one direction relative to the sensor 24 so that the edge of the projected image f116A crosses the sensor 24. When the projected image 16A approaches the sensor 24 and passes through it, it is obtained by the first and second light receiving elements 22A and 22B, and the current-voltage converter 92A
, 92B and adjusted by the amplifiers 94A, 94B, the output signals generated from the sensor output terminals 23A, 23B are phase-shifted signals with equal amplitudes, as shown by symbols a and b in FIG. 7(A). Become. These output signals are sent to the difference calculator 26 as shown in FIG. 7(B).
is calculated into c-a-b by the am signal generator 3.
0 to third and fourth comparators 44A and 44B, respectively. 'Meanwhile, the output signal from the sensor output terminal 23B is input to the first and second sample and hold circuits 46A and 46B of the area signal generator 30, respectively. As shown in FIG. 7(C), the third comparator 44
A compares the reference voltage Vrer+ and the input signal C, and when the signal @C is smaller than vrer+, outputs the sampling signal S to the first sample hold circuit 46A. Further, as shown in FIG. 7(D), the fourth comparator 44B compares the input signal C and the reference voltage Vrer-, and performs sampling when the signal C is smaller than Vref-. The signal e is output to the second sample and hold circuit 46B. Note that the third and fourth comparators 44A, 44
B has a hysteresis characteristic as shown in FIG. 7(B) to prevent chattering. The first and second sample and hold circuits 46A, 46
B samples the sensor output signal when the third comparator 44A outputs the sampling signal d and the fourth comparator 44B outputs the sampling signal e, and also samples the sensor output signal d and When e is not output, the signal value at the final point of sampling is held. Therefore, these sample and hold circuits 46A and 146B send the high hold signal and the low hold signal Q to the fifth comparator 48A and the sixth comparator 48B, respectively, as shown by the broken line and the dashed line in FIG. 7(E). These fifth comparator 48A and sixth comparator 48B are configured to output:
As shown in FIGS. 7(F) and (G), the input high-hold signal "and low-hold signal Q" are compared with the sensor output signal a, and these high-hold signal "and low-hold signal R" are compared. Exclude the signals h and i, respectively, when the sensor output signal is greater than O.
Output to R gate 50. When a signal is output from only one of the fifth comparator 48A and the sixth comparator 48B, the exclusive OR gate 50 is set to "1" as shown in FIG.
” is output as a digital signal j. On the other hand, the differential output signal C output by the difference calculator 26 is input to a signal divider 32, as shown in FIG. As mentioned above, this signal divider 32 is connected to the plus side resistor string 5.
8 and a negative side resistor string 60, and divides the voltages y+ and V-'' applied thereto to form the corresponding first to fifth comparators 54A to 54E on the positive side and first to fifth comparators on the negative side. 56A to 56E.The differential output signal C is applied to the positive side first to fifth comparators 54.
The signals are input to the positive input sides of the comparators A to 54E, and to the negative input sides of the first to fifth comparators 56A to 56E on the negative side, respectively. A case will be described in which the value of the differential output signal @C approaches the zero reference level signal from the positive side, for example. First, the value of the differential output signal C is S5 in FIG. 4(A).
When reaching the division of
4E, the positive side fifth comparator 54E receives a low level signal r.
LJ is output to the positive fifth analog switch 62E. At this time, since the voltage of the differential output signal C is higher than the voltage applied to the negative side of the positive fourth comparator 54D, the positive fourth comparator 54D receives the high level signal r.
Output HJ. The output signal rHJ of the fourth plus-side comparator 54D acts as a trigger signal for the fifth plus-side analog switch 62E, turning it on. On the other hand, the positive side first to fifth display means 66A to 6
6E and minus side first to fifth display means 68A to 6
Differential signals are outputted to each of 8E via an amplifier 52 based on the area signal outputted from the area signal generator 30. Therefore, when the positive side fifth switch 62E is turned on, it is turned on, and the positive side fifth comparator 54E is turned on.
Since the output of is rLJ, the positive side fifth display means 6
A potential difference is generated between both terminals of 6E, and this causes the plus side display means 66E to be lit. At this time, since the outputs of the fourth to first comparators 54D to 54A on the positive side are all at the high level rHJ,
Positive side fourth to first analog switches 62D to 62
Even if any of A is turned on, other display means will not be lit. Next, when the value of the differential output signal C enters the section S4 in FIG.
In order to switch from J to rLJ, the plus-side fifth analog switch 62E is turned off, and the corresponding plus-side fifth display means 66E is turned off. Further, the plus-side fourth analog switch 62D is turned on, and the corresponding plus-side fourth display means 66D is lit. In this way, as the differential output signal approaches the zero reference level signal, the plus-side fifth to first display means 66E to 66A corresponding to the sections S5 to 81 are sequentially turned on and off. Here, as a trigger signal for the positive side first analog switch 62A, the output signal side of the first comparator 36A of the edge detection means 28 is sent via the NOT circuit 7o.
is entered as . As long as the value of the differential output signal @C input from the negative side is positive, the output signal of the first comparator 36A is
O-level rLJ, which is converted in the NOT circuit 70 to produce a high level signal 1. HJ and is input to the positive side first analog switch 62A. Note that if the sensitivity of the sensor 24 is too high, even if the projection surface ti16A approaches the sensor 24, the display means will not light up easily, and after lighting, the display will not turn on even if the projection image 16A moves a small amount. 5 to first display means 66E to 66
A lights up and goes out in a short period of time. Also, sensor 24
If the sensitivity is too low, the outer display means 66D may turn on. In such a case, adjust the amplifiers 94A and 94B,
The sensitivity of the sensor 24 is increased or decreased to an appropriate value. ζ where the value of the differential output signal C matches the zero reference level signal
As shown in FIG. 8(B), the first comparator 3
The output signal k of 6A changes from rLJ to rHJ, is converted by the NOT circuit 70, and the signal ' becomes rLJ, and by inputting the tri signal of the positive side first analog switch 62A as a signal, the positive side first analog switch 62
A is turned off, and the corresponding plus side first display means 66A
is turned off. At the same time, the high level output signal of the first comparator 36A is output to the exclusive OR gate 38. On the other hand, while the differential output signal is positive, the output signal of the second comparator 36B is rLJ, as shown in FIG.
As a result, the signal value input to the positive side of the second comparator 36B is lowered to -Δref, so that after the value of the differential output signal C crosses the zero reference level signal, , the output signal of the second comparator 36B is maintained at rLJ until it reaches -ΔVref, and becomes rHJ when it becomes less than -ΔVrer. Therefore, as shown in FIG. 8 (8), the output signal of the first comparator 36A has IIIrHJ until it crosses the zero reference level signal, rLJ after crossing, and As shown in FIG. 8(C), the output signal β of the converter 36B is “L” until the value of the differential output signal C reaches −ΔVref, and after reaching −ΔVref, it becomes rHJ. Opening time of rising edge (only exclusive O
The input signals to the R gate 38 are both rLJ. Therefore, as shown in FIG. 8(D), this time

The output of the exclusive OR gate 38 is r
LJ, and a potential difference is generated across the edge display means 76 only during this time period, and during this time, the edge display means 76 is turned on as shown in FIG. 8(E). Also, when the differential output signal C reaches the zero reference level signal from the negative side, the negative side fifth
When the first display means 68E to 68A turn on and off in sequence and cross the reference level signal, the edge display means 7
6 is lit. In this case, as shown in FIG. 9 (A>(C)), the output signal of the second comparator 36B is "H" while the value of the differential output signal C is negative; From the level rHJ, a diode 4 is connected to the positive input side of the comparator 36D.
2B and the resistor 43B, a potential lowered by ΔVref, that is, a potential substantially equal to zero, is applied. Therefore, at the time when the value of the differential output signal C crosses the zero reference level signal, the output signal β of the second comparator 36B becomes rH.
Fall from J to rLJ. On the other hand, on the first comparator 36A side, while the differential output signal 0 is negative, the output signal @ is rHJ, but as shown in FIG.
As shown in B), the output side of the first comparator 36A is grounded via a resistor 43A, a diode 42A and a resistor 40A, and a second Since it is connected to the positive input side of the comparator 36A, rHJ
A partial voltage corresponding to ΔVrer of a signal having a value of is applied. Therefore, the output signal @ of the first comparator 36A is maintained at rHJ until the value of the differential output signal C reaches Δyrer, and becomes rLJ when it reaches ΔVref. Therefore, as shown in FIGS. 9(B) and 9(C), the input of the exclusive OR gate 38 is the differential output signal C.
Only when the value of is between zero and Δvrer, both are rLJ, and before and after that, one is "H" and the other is "IL", and the output steel of the exclusive OR gate 38 is as shown in FIG. 9(D). , while both input signals are [L] for 1 hour t)
Only rLJ, other questions are rHJ. Therefore, the output m of the exclusive OR gate 38
During rLJ, that is, during time t, the edge display means 76
A potential difference is generated before and after the edge display means 76 is turned on. That is, the edge detection means 28 always turns on the edge display means 76 when the differential output signal matches the zero reference level signal, regardless of the slope of the waveform of the differential output signal C, It operates to turn off the light after. The above has described the process up to detecting edges of the projected image 16A, but when measuring values are automatically read during edge detection, this is done in the following order. That is, the pulse signal p from the pulse signal generator 96 that is activated when the output of the exclusive OR gate 38 in the edge detection means 28 becomes rLJ, and the exclusive OR gate 50 of the area signal generator 30. When the output signals of both are input to the AND gate 98, the displacement detection device 10
0, and when the signal is input, the reading value of the counter 102 is output to the storage device 106, and the measurement target 1 on the stage 14 is operated.
Read the position of edge 6. In the above embodiment, the sections divided by the signal divider 32 are formed by dividing the values of the voltages y+ and V- applied to the plus-side resistor array 58 and the minus-side resistor array 60. However, if you want to increase or decrease the width of each section, use the positive variable resistor 5 in these resistor strings.
This is done by adjusting 8F and negative side variable resistor 60F. In this embodiment, the sensitivity of the edge detection device is adjusted by adjusting the amplifiers 94A and 94B of the sensor 24 while monitoring with a monitor device 29 including a display means consisting of a light emitting diode, without using a mechanical analog meter. Can be adjusted appropriately. In particular, since it does not use a mechanical analog meter, there is no need for hunting operations, and the sensitivity can be adjusted quickly.There are also fewer deviations due to vibration**, etc., and there are no restrictions on the mounting direction. be. Furthermore, the positive side variable resistor 58F in the signal divider 32
Also, by adjusting the negative side variable resistor 60F@, there is an advantage that the sensitivity adjustment work can be done easily. Furthermore, edge detection can be performed reliably without time lag by the edge display means 76. Furthermore, when edge detection is performed automatically, the pulse signal generator 96 is operated based on the output signal of the exclusive OR gate 38, and the AND gate 98 and the displacement detection device 100 can easily and reliably detect the edge. can. Furthermore, in the above embodiment, the width of the division by the signal divider 32 is set to be narrower as it approaches the zero-level reference signal, that is, the edge position. This has the advantage that it is possible to prevent runs and hunting operations for their correction, and that edges can be detected more accurately. The above is for a normal measurement, but depending on the measurement environment, the differential output signal C may fluctuate temporarily due to optical or electrical noise, vibration of the stage 14, etc. may occur. In this case, in the conventional detection device, the area signal cannot be generated, or the area signal is output at the cross point of the differential output signal and the reference signal, that is, at a time point that is not at the edge position. Detection was sometimes impossible. In the above embodiment, for example, as shown in FIG. 10, the sensor output signals a and b are caused by the vibration of the stage 14.
When the sensor vibrates once about the ffiff center 1108, these sensor output signals a and b become as shown in FIG. 10(A). In the case of conventional edge detection devices, vibrations and fluctuations of the signals themselves to be detected, such as differential output signals, are not considered.
These sensor output signals a and b are the vibration center $1108
A signal is often erroneously generated when the vehicle falls in the position of . In this embodiment, as shown in FIG. 10(E), the high hold signal f fluctuates due to the slight movement of the sensor 24, and the fifth comparator 48A responds accordingly.
output signal 11 is output, and exclusive sieve O
A digital signal j is also output from the R gate 50, but the area signal j itself output from the exclusive OR gate 50 is not shifted by the vibration. That is, even if vibration or the like occurs in the differential output signal, the area including the cross point can be reliably specified without being affected by this. Therefore, the area signal j is output at the time when it overlaps with the output signal m from the edge detection device 28, so that the edge display means 76 is turned on and the edge signal m is output from the AND gate 98. . The signal stored in the storage device 106 will be output to another computing device, printed out, or displayed on a display. Further, in this embodiment, the signal lead line 80 of the first light receiving element 22A is connected to the first light receiving element 22A at the first dead zone 78A formed in the first light receiving element 22A. There is no need for a space for connecting the signal lead line 80 between the element 22A and the second light receiving element 22B. Therefore, the outer diameter of the second light-receiving element 22B can be reduced without reducing its light-receiving area, and the entire light-receiving sensor 24 can be made smaller. Therefore, these first light receiving element 22A and second light receiving element 2
The size of the chip 82 to which 2B is attached can be a square with a negative side of 1 square. Furthermore, since the overall outer diameter of the first and second light receiving elements 22A and 22B can be reduced, the minimum measurable external dimension of the object to be measured can be reduced. It is also possible to detect edges etc. Further, in the above embodiment, the signal lead line 80 of the first light receiving element 22A is led out to the outside via the lead part 81B passing through the second dead zone 78B formed by cutting out the second light receiving element 22B. Therefore, the signal extraction 1ii180 does not cast a shadow on the light-receiving surface 88B of the second light-receiving element 22B, and therefore the S/N ratio of the sensor output can be improved. Furthermore, the signal extraction 4180 is connected to the second light receiving element 22B.
The light receiving surfaces 88A, 8 of the first and second light receiving elements 22A122B are placed above the light receiving surface 88B of the first and second light receiving elements 22A122B in order to avoid interference between the screen 21 and the signal leader line 30.
8B and the screen 21, the light-receiving surfaces 88A and 88B of the first and second light-receiving elements 22A and 22B can be brought closer to the screen 21 and moved relative to each other. Therefore, the amount of received light can be increased and the S/N ratio can be improved. In the above embodiment, if the measurement object 16 is made of a material that cannot completely block light, such as a translucent glass product, as shown in FIG. 6(A) and FIG. 7(A), respectively. , the sensor output signals a and b in the dark area
is a value larger than 0 and close to ``1'' when the sensor output signal is ``1'' in bright light and ``0'' in complete darkness. In this case, when these sensor output signals a or themselves are compared with the reference voltage Vref-, it is not possible to obtain the intersection with the reference signal Vrer-, and for this reason, it may not be possible to obtain the area signal. be. In this embodiment, since the area signal is formed based on the differential output signal of the difference calculator 26, that is, c-a-b, even if the measurement object 16 is a semi-transparent material, Area signals can be reliably obtained. Further, in this embodiment, the first and second light receiving elements 22A and 22B constituting the sensor 24 are formed in a responsive circular shape, and the sensor output terminal 2 generated by these elements
Since the output levels of the signals at 3A and 23B are equal, the moving direction does not coincide with the boundary line between the first and second light receiving elements 22A and 22B, and the relative moving direction with respect to the projected image of the sensor 24 @16A. Regardless of the situation, a uniform output signal can be obtained, and therefore there is no restriction on the relative movement direction of the sensor with respect to the object to be measured, and edge detection can be performed with high precision. Here, when the directions of the first dead zone 78A and the second dead zone 78B match the moving direction of the sensor 24, there is a decrease in the sensor output, but these first dead zones 78A
Since the second dead zone 78B is formed in the radial direction only in one direction from the center of the first light receiving element 22A, light can be received in the opposite side of the first and second dead zones 78A and 78B. , even if the moving direction of the sensor 24 and the directions of the first and second dead zones 78A, 78B match,
Edge detection can be performed. Further, in the embodiment, the first and second light receiving elements 22A
, 22B have the same light-receiving area so that the sensor output terminals 23A and 23B are equal.
It is sufficient that the output signals at 8 are at the same level. Therefore, an amplifier may be placed between the light receiving elements 22A, 22B and the sensor output terminals 23A, 23B, or
Without installing an amplifier, both sensor output terminals 23A,
The output levels of 23B may be made equal. In the above embodiment, the number of segments divided by the signal segmenter 32 is five each on the upper and lower sides of the cross point, but the present invention is not limited to this, and the number and each segment are The width is not limited. Further, the signal divider 32 is not limited to the configuration of the embodiment as long as it can divide the differential output signal C of the difference calculator 26 into an appropriate number. Furthermore, the difference calculator 26 is configured to operate the first light receiving element 22A and the second light receiving element 22A.
Any other configuration may be used as long as it can calculate the output signal of the light receiving element 22B and form a signal with an inclined waveform that intersects with the zero level reference signal. Therefore, for example, as disclosed in the above-mentioned Japanese Patent Laid-Open No. 58-173408 or Japanese Patent Laid-Open No. 59-162404, the output signals of three or more light receiving elements are processed to obtain a zero level reference signal. It is also possible to form a signal with an inclined waveform that intersects with . Furthermore, the area signal generator 30 is not limited to the circuit configuration of the embodiment as long as it can generate a signal in a certain area including the cross point of the slope signal and the zero level reference signal. Further, the approach display device 34 is not limited to the embodiment as long as it is provided corresponding to the signal segmenter 32 and displays the signal value when there is a signal value in the corresponding segment. Further, in the embodiment, the projection image 16A is moved relative to the sensor 24 by moving the stage 14;
4 may be moved. Further, although the above embodiment is for measuring the edge of a projected image on a screen of a projector, the present invention is not limited to this, and the present invention is not limited to this, but can be performed by detecting transmitted light or reflected light, It is generally applied to an edge detection device in a photoelectric measuring instrument for directly or indirectly measuring the dimensions of an object to be measured. Effects of the Invention Since the present invention is configured as described above, it has the excellent effect that the sensitivity of an edge detection device in an optical instrument can be monitored using a monitor device and adjusted efficiently and reliably. have

[Brief explanation of drawings]

Fig. 1 is an optical system diagram showing an embodiment in which an edge detection device in a photoelectric measuring instrument according to the present invention is implemented in a projector, Fig. 2 is a block diagram showing the configuration of the embodiment, and Fig. 3 is FIG. 4 is a block diagram showing the configuration of the main part of the same embodiment, FIG. 4 is a diagram showing the relationship between the differential output signal of the light receiving element, division section, and display means in the same embodiment, and FIG. FIG. 6 is an enlarged plan view showing the relationship between the first and second light-receiving elements and the signal lead line, FIG. 6 is a sectional view taken along line VI-VI in FIG. 5, and FIG. 7 is a diagram showing the signal processing process in the same embodiment. 8 and 9 are miniature diagrams showing the signal processing process in the same embodiment, and FIG. 10 is a diagram showing the signal processing process when the sensor output fluctuates in the same embodiment. 16A... Projection image, 22A... First light receiving element, 22B... Second light receiving element, 24... Light receiving sensor, 26... Difference calculator, 27... Detector, 28...・Edge configuration device, 29...Monitor device, 30...Area signal generator, 32...Signal@divider, 34...Approach display device, 58F...Plus side variable resistor (sensitivity II adjustment means), 6
0F...minus side variable resistance (sensitivity l111 means),
76... Edge display means, 94A, 94B-7 N7 (sensing means).

Claims (4)

[Claims] (1) In an edge detection device in a photoelectric measuring instrument that detects transmitted light or reflected light to directly or indirectly measure the dimensions of an object to be measured, when the object moves relative to the image of the object to be measured. A light receiving device that includes a plurality of light receiving elements arranged in a plane approximately parallel to the moving surface so as to generate a phase shift signal based on the change in the amount of received light that occurs, and the level of the output signal at the output terminal can be adjusted. a sensor, a difference calculator that is connected to the output terminal of the light receiving sensor and that calculates the phase shift signal and outputs a differential output signal; and a specific sensor that includes a cross point between the differential output signal and the reference level signal An edge detection means comprising: a region signal generator that outputs a region signal in the region; and a detector that outputs an edge detection signal at the cross point while the region signal generator outputs the region signal. and a signal divider that divides the value of the differential output signal into a plurality of stages while the domain signal is output from the domain signal generator, and a signal divider corresponding to the divisions divided by the signal divider. an approach display device comprising the same number of display means as the divisions provided in the table and operating the display means corresponding to the division to which the value of the differential output signal belongs; An edge detection device for a photoelectric measuring instrument, characterized in that the level of the output signal of the light receiving sensor is adjusted. (2) The photoelectric measuring instrument according to claim 1, wherein the signal divider is configured to form the same number of divisions on both sides of the cross point as the center. Edge detection device. (3) The signal segmenter is formed such that the width of the segment becomes smaller as the value of the slope signal approaches the value of the reference level signal. An edge detection device in the photoelectric measuring instrument according to item 2. (4) Claims 1 and 2 in which the signal divider can freely adjust the width of each division of the signal to be divided.
An edge detection device in the photoelectric measuring instrument according to item 1 or 3.