JPS6129646B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for measuring the brightness of a two-dimensional pattern.
The present invention relates to a dimensional luminance measuring device.

[Conventional technology]

Conventionally, in order to measure the brightness of a two-dimensional pattern, one method has been to take a photograph of the object to be measured and carefully measure the density of the film, or to measure the magnitude of the video signal obtained from television imaging using an oscilloscope or pen recorder. The method of drawing is used.

[Problem that the invention seeks to solve]

However, the method of measuring the brightness of a two-dimensional pattern by taking a photograph of the object to be measured requires time to obtain the measurement results, so the measurement result is obtained at the measurement site and the brightness of the object to be measured is immediately adjusted. cannot be used for such purposes. Also,
The method of plotting the magnitude of the video signal obtained from television imaging on an oscilloscope or pen recorder has a dynamic range of only 10 ² at most due to the characteristics of normal industrial image pickup tubes, and the luminance range of the object to be measured is limited. When large, it is impossible to measure either bright or dark areas. Furthermore, since parts unnecessary for measurement are also scanned, measurement time is wasted. Furthermore, when the luminance is low and a sufficient signal-to-noise ratio cannot be obtained by accumulating the video signal for one frame period,
There is a drawback that the video signals of the same portion on the raster must be integrated at the frame period.

The present invention has been made in order to solve the above problems, and is a dynamic range that can measure the luminance distribution of a two-dimensional pattern having an extremely large luminance range without using an accumulation method that narrows the dynamic range. An object of the present invention is to provide a two-dimensional luminance measuring device with a large brightness.

[Means for solving problems]

To this end, the two-dimensional luminance measurement device of the present invention includes a standard light source, an image dissector tube that projects an image of the object to be measured, a deflection device for the image dissector tube, and a deflection position signal that sends a deflection position signal to the deflection device. A generator, a counting device that counts the output pulses of the image dissector tube, and an arithmetic device that calculates and outputs the ratio of each output signal of the counting device when the standard light source is projected and when the measured object is projected. The present invention is characterized in that it includes a data multiplexing device that combines the output signal of the arithmetic device and the position signal sent out from the deflection position signal generator.

[Effect]

The two-dimensional brightness measuring device of the present invention counts input light pulses using an image dissector tube, and combines the obtained brightness signal with a deflection position signal sent to the deflection device of the image dissector tube to obtain data. By multiplexing, the dynamic range can be widened due to the photoelectron emission effect of the image dissector tube, and the brightness at any position can be displayed in a desired format.

〔Example〕

Examples will be described below with reference to the drawings.

Fig. 1 is a block diagram of the two-dimensional luminance measuring device of the present invention, Fig. 2 is a cross-sectional structural diagram of the image dissector tube used in Fig. 1, and Fig. 3 is a block diagram of the pulse counting device of Fig. 1. Figure 4 is a block diagram of the arithmetic unit shown in Figure 1, and Figure 5 is a block diagram of the arithmetic unit shown in Figure 1.
FIG. 6 is a time chart for explaining the operation of the dimensional luminance measuring device, and is a diagram showing an example of measurement points on the photocathode of the image dissector tube.

In the figure, 1 is a standard light source or an object to be measured with two-dimensional spread, 2 is an optical lens, 3 is an image dissector tube, 4 is a pulse counter, 5 is a calculation device, 6
is a data simultaneous multiplexing device; 61, 62, and 63 are first, second, and third input terminals of the data multiplexing device 6;
7 is a display device, 8 is a deflection position signal generator, 8
1, 82 and 83 are the first, second and third output terminals of the deflection position signal generator 8; 88 and 89 are deflection drive circuits; 31 is a photocathode; 32 is an electrode; 33 is an aperture; 34 and 35 are deflection Coil, 36 dynode, 37 collecting electrode, 41 input gate circuit, 4
2 is a preamplifier, 43 is a main amplifier, 44 is a discriminator, 45 is a waveform shaping circuit, 46 is a counting circuit, 47 and 48 are control terminals, 51 is a changeover switch, 52 is a memory, and 53 is a division circuit.

First, the image dissector tube 3 used in FIG. 1 will be explained with reference to FIG. 2.

In FIG. 2, a photocathode 31 on which an optical image is projected
An electron beam corresponding to an optical image from X is accelerated by an electrode 32 having an aperture 33 in the center
The electron beam is deflected in a direction perpendicular to the plane of the paper by the deflection coils 34 and 35 in the Y direction and the Y direction, and only the electron beam corresponding to the desired portion of the optical image is passed through the aperture 33, and the passing electrons are deflected by the dynodes 36...36. The luminance signal of a portion of the optical image is detected as a current from the collecting electrode 37. Therefore, the measurement positions of the optical image on the photocathode 31 are sequentially selected by supplying predetermined deflection drive currents to the deflection coils 34 and 35 in the X direction and the Y direction, respectively, and the electron beams corresponding to the selected positions are sequentially If the light passes through the aperture 33, the luminance signals of each part of the optical image can be obtained from the collecting electrode 37. The image dissector tube 3 performs an operation of accumulating input signals, and has a detecting ability of outputting a pulse corresponding to one photon with a probability of one-fraction.

Next, a two-dimensional luminance measuring device according to the present invention will be explained with reference to FIG.

In FIG. 1, an image of a standard light source with a predetermined brightness is projected onto the image dissector tube 3, and
The deflection signal generator 8 sends a horizontal axis deflection position signal X and a vertical axis deflection position signal Y corresponding to the position of the image of the standard light source to deflection drive circuits 88 and 89. The deflection drive circuits 88 and 89 send out deflection drive currents to the deflection coils 34 and 35 in accordance with the horizontal axis deflection position signal X and the vertical axis deflection position signal Y sent out by the deflection position signal generator 8. When the deflection position signals X and Y are, for example, points _A , B, C, _and D as shown in FIG. 6, the deflection position signals X _{and Y} are as shown in FIG _. , Y _C , X _D , and Y _D , these voltages have a stepped waveform that sequentially switches every predetermined time width _t1 . At the same time, the signal is transmitted from the third output terminal 83 of the deflection position signal generator to the control terminal 47 of the input gate circuit 41 of the pulse counting device 4, with a delay of time t ₂ from the switching timing of the deflection position signal as shown in FIG. A rectangular wave control signal a having a predetermined rise time width t ₂ is sent out. The delay time _t2 of this control signal a is such that after the deflection position signal generator 8 sends out the deflection position signals X and Y, the deflection position of the image dissector tube 3 changes as shown in FIG. The time width is sufficient to deflect the beam to the desired position.
In this way, the pulse counting device 4 counts the number of pulses corresponding to the brightness of the standard light source over the time width _t3 . This time width _t3 is the time required for the pulse counting device 4 to count pulses, and may need to be changed depending on the frequency of pulses. Note that the time width t ₁ of the deflection position signal must be larger than t ₂ +t ₃ .
By the way, while the pulse counting device 4 counts the number of pulses corresponding to the brightness of the standard light source, the arithmetic device 5
A changeover switch 51 is connected to the divisor end side of the division circuit 53, and the count signal of the pulse counting device 4 is stored in the memory 52. Subsequently, a desired image of the object to be measured 1 is projected onto the image dissector tube 3, and the changeover switch 51 of the arithmetic unit 5 is switched to the dividend input end of the division circuit. Then, the deflection signal generator 8 sequentially sends out deflection position signals corresponding to desired measurement points from the output ends 81 and 82. for example,
When measuring points A, B, C, and D in FIG. 6 sequentially, the voltages X _A , Y _A , X _B ,
Y _B , X _C , Y _C , X _D , and Y _D are sequentially switched and transmitted every time _t1 . That is, first the first output terminal 81
When the voltage X _A is sent from the second output terminal 82 and the voltage Y _A is sent from the second output terminal 82, the image dissector tube 3 is deflected to the point A in a time shorter than _t1 , and the output pulse corresponding to the input light amount at the point A is sent to the pulse counting device. Send to 4. Subsequently, after a time t ₂ , a rectangular wave pulse c is transmitted from the output terminal 83 of the deflection signal generator 8 to the control terminal 4 of the pulse counting device 4.
7, the gate 41 is opened and pulses are counted for the time width _t3 of the rectangular wave pulse a. Subsequently, the count signal of the pulse counting device 4 is sent to the division circuit of the arithmetic device 5, and division is performed using the output signal of the memory 52 as a divisor.
Send to 1. At this time, the data multiplexing device 6
Since the voltages X A and _{Y A} corresponding to the measurement points are input from the first output terminal 81 and the second output terminal 82 of the deflection signal generator 8 to the second input terminal 62 and third input terminal 63 of the is stored as one set of data. For example, when the data multiplexing device is a two-dimensional random access memory, the deflection position signal sent from the first output terminal 81 and the second output terminal 82 of the deflection position signal generator 8 is digitized, and the two-dimensional random access memory is The output signal of the arithmetic unit 5 may be stored in the memory location of the address as the X-axis address and Y-axis address signal of the memory, or the data start signal and the input signal of the first input terminal may be stored on one magnetic tape. , the input signal at the second input terminal, the input signal at the third input terminal, and the data completion signal may be stored in order.

Pulse counting for measurement point A as described above,
Calculation and multiplexing operations from the start of the deflection position signal t ₁
Then, the deflection position signal generator 8 sends out position signals X _B and Y _B corresponding to point B, and performs the same signal processing on point B as the series of signal processing on point A described above. conduct. Then, similarly, point C, D
Similar signal processing is performed for the points.

In parallel with such signal processing of each point or after signal processing of all points is completed, the display device 7
The signals multiplexed by the data multiplexing device 6 are displayed. The display device 7 displays the X position signal and the Y position signal.
The position signal is used as the position on the screen of a color cathode ray tube, and the luminance signal of each point sent out by the arithmetic unit is displayed in color for each signal level. Alternatively, a table may be created in which the X position signal, Y position signal, and brightness signal are simply written together using a printer.

In addition, the deflection position signal sent by the deflection position signal generator 8 may sequentially include artificial measurement points such as those specified by industrial standards as correction measurement points of the object to be measured, or, for example, as necessary. Accordingly, regular points such as points on a spiral starting from the origin may be set at equal intervals on the diagonal of the screen, or sequentially. In such a case, it is necessary to include a function generation circuit in the deflection position signal generation device 8. Furthermore, measurement points may be taken inadvertently, and in that case, it is necessary to incorporate a random number generation circuit into the deflection position signal generation device 8.

To explain the operation of the pulse counter 4, the output pulse of the gate circuit 41 to which the aforementioned rectangular wave pulse c of time width t ₃ is applied to the control terminal 47 is amplified by the preamplifier 42 and the main amplifier 43. The voltage pulse sent out by
A constant voltage is output only when the discrimination level signal input to the control terminal 48 of the discriminator 44 is exceeded. Then, the rectangular wave pulse corresponding to the pulse exceeding the discrimination level is input to the waveform shaping circuit 45, and after being shaped into a pulse having a constant wave height and a constant time width, the pulse is counted by the counting circuit 46. The number of pulses within this unit time is proportional to the brightness of the object to be measured.

By the way, the output of the image dissector tube 3 includes a signal pulse corresponding to the input signal and a noise pulse that does not correspond to the input signal, and when the product of the pulse height and pulse width is converted into current or voltage as in a normal amplifier, Low-level signals are buried in noise, making accurate signal detection difficult. However, since the wave height of the noise pulse is smaller than that of the signal pulse, by setting the discrimination level in the discriminator 44 to an appropriate value, the noise pulse can be removed and only the signal pulse can be detected. can be detected.

In the above embodiment, an electromagnetic deflection type image dissector tube is used, but it goes without saying that an electrostatic deflection type tube may be used instead.

〔Effect of the invention〕

As is clear from the above description, the present invention has a wide dynamic range of 10 ⁵ due to the photoelectron emission effect of the image dissector tube, and noise removal is facilitated by pulse counting, which reduces the brightness. In addition to being able to measure the low luminance of the object to be measured, since no accumulation method is used, only arbitrary measurement points can be measured, which also makes it possible to save measurement time.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the two-dimensional luminance measuring device of the present invention, Fig. 2 is a cross-sectional structural diagram of the image dissector tube used in Fig. 1, and Fig. 3 is a block diagram of the pulse counting device of Fig. 1. Figure 4 is a block diagram of the arithmetic unit shown in Figure 1, and Figure 5 is a block diagram of the arithmetic unit shown in Figure 1.
FIG. 6 is a time chart for explaining the operation of the dimensional luminance measuring device, and is a diagram showing an example of measurement points on the photocathode of the image dissector tube. 1...Standard light source or object to be measured with two-dimensional spread, 2...Optical lens, 3...Image dissector tube, 4...Pulse counting device, 5...Arithmetic device, 6...Data multiplexing device , 61, 62, 63
...First, second, and third input terminals of data multiplexing device 6, 7...Display device, 8...Deflection position signal generating device, 81, 82, 83...First of deflection position signal generating device 8 , second and third output ends, 88, 89...deflection drive circuit, 31...photocathode, 32...electrode, 3
3...Aperture, 34, 35...Deflection coil,
36... Dynode, 37... Collection electrode, 41...
...Input gate circuit, 42...Preamplifier, 43...
...Main amplifier, 44...Discriminator,
45... Waveform shaping circuit, 46... Counting circuit, 4
7, 48...control end, 51...changeover switch,
52...Memory, 53...Division circuit.

Claims (1)

[Scope of Claims] 1. An image dissector tube that projects an image of a standard light source and an object to be measured, a deflection device for the image dissector tube, a deflection position signal generator that sends a deflection position signal to the deflection device, and an image dissector tube that projects an image of a standard light source and an object to be measured; A counting device that counts the output pulses of the dissector tube, an arithmetic device that calculates and outputs the ratio of each output signal of the counting device when the standard light source is projected and when the object to be measured is projected, and the output of the arithmetic device. A two-dimensional brightness measurement device comprising a data multiplexing device that combines a signal with a position signal sent from a deflection position signal generator. 2. The two-dimensional brightness measuring device according to claim 1, wherein the deflection position signal generating device sequentially generates deflection position signals at preset points. 3. The two-dimensional luminance measuring device according to claim 1, wherein the deflection position signal generating device sequentially generates random deflection position signals.