JPS6128288B2 - - Google Patents

Description

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

[Conventional technology]

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

[Problems to be solved by the invention] 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 it is difficult to obtain the measurement results at the measurement site. Therefore, it cannot be used immediately for purposes such as adjusting the brightness of an object to be measured. 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 brightness range of the object to be measured is limited. When large, it is impossible to measure either bright or dark areas. Furthermore, since areas unnecessary for measurement are also scanned, measurement time is wasted, and video signals for one frame period must be integrated at frame intervals in order to measure areas with low brightness.

The present invention has been made to solve the above problems, and provides a two-dimensional brightness measuring device with a large dynamic range that can measure the brightness distribution of a two-dimensional object having an extremely wide brightness range. The purpose is to

[Means for solving problems]

To this end, the two-dimensional brightness measuring device of the present invention includes a pulse counter and a minute current meter that can set the discrimination level, which are switchably connected to the output terminal of the image dissector tube, and an output of the pulse counter and minute current meter. a recording means whose end is switchably connected; a deflection drive power source that deflects and drives the image dissector tube in accordance with the measurement position instruction signal; and a deflection drive power source that sends a measurement position instruction signal to the deflection drive power source; The present invention is characterized by comprising a measurement position controller that sends synchronized position signals to recording means.

[Effect]

In the two-dimensional lightness measuring device according to the present invention, a measurement position signal is applied from a measurement position controller to a deflection drive power source that drives a deflection coil of an image dissector tube to select a measurement position, and at the same time, a position signal synchronized with the measurement position signal is transmitted. In addition to the recording means, the output of the image dissector tube is recorded via a pulse counter or a microcurrent meter that can set the discrimination level, thereby increasing the dynamic range and making it possible to measure two-dimensional objects with a wide brightness range. It becomes possible to measure the brightness distribution of

〔Example〕

Examples will be described below with reference to the drawings.

Fig. 1 is a block diagram of the two-dimensional brightness measuring device according to 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 diagram of the structure of the image dissector tube used in Fig. 1. FIG. 3 is a block configuration diagram of a pulse counter. In the figure, 1 is an object to be measured with two-dimensional expansion, 2 is an optical lens, 3 is an image dissector tube, 4 is a pulse counter, 5 is a microcurrent meter,
6 and 7 are changeover switches, 8 is a printer, 9 is a measurement position controller, 91 is a deflection drive power source, 31 is a photocathode, 32 is an electrode, 33 is an aperture, 34, 35
is a deflection coil, 36 is a dynode, 37 is a collection electrode, 41 is a preamplifier, 42 is a main amplifier, 4
3 is a discriminator, 44 is a waveform shaping circuit,
45 is a gate circuit, and 46 is a counting 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 deflection coils 34 and 35 in the Y direction and Y direction, and only the electron beam corresponding to the desired portion of the optical image is passed through the aperture 33. The luminance signal of a part of the optical image is multiplied and detected as a current from the collection 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, a signal corresponding to the brightness of each part of the optical image, that is, the brightness of the object to be measured, can be obtained from the collecting electrode 37. This image disector tube 3
The sensor does not accumulate input signals, and has the detection ability to output a pulse in response to one photon with a probability of a fraction of a second.

Next, a two-dimensional lightness measuring device according to the present invention will be explained with reference to FIG. Now, an image of the object to be measured 1 having a two-dimensional spread is projected onto the photocathode 3 by the optical lens 2.
As described above, each part on the photocathode 31 is sequentially selected by supplying predetermined deflection drive currents to the deflection coils 34 and 35, respectively, and as a result, each part of the projected optical image is A pulse signal corresponding to the brightness is output from the image dissector tube 3, and the output signal is supplied to a pulse counter 4 or a minute ammeter 5 via a changeover switch 6. The pulse counter 4 counts only pulses having a magnitude greater than or equal to the value indicated by the signal input from the control terminal 47, and does not count pulses less than the indicated value. deliver a common type of electrical signal, either an analog current or a digital signal pulsed with the same encoding type. The output of the pulse counter 4 or minute ammeter 5 is applied to a recorder or printer 8 via a changeover switch 7 which is linked to a changeover switch 6. By the way, the above-mentioned deflection drive current applied to the deflection coils 34 and 35 is generated when, for example, a desired point on the monitor screen of an imaging device installed in parallel with the image dissector tube 3 and having the same field of view is specified with a light pen. , a measurement position controller 9 configured to send out voltages in the X direction and Y direction corresponding to the position.
At the same time, the measurement position controller 9 applies a position signal synchronized with the measurement position instruction signal to the recorder or printer 8. Therefore, a pattern corresponding to the brightness of each part of the optical image of the photocathode, that is, the brightness of the object to be measured, is drawn on the recorder or printer.

To explain the operation of the pulse counter 4, the preamplifier 41 outputs a voltage pulse with a wave height corresponding to the amount of charge, this voltage pulse is amplified by the main amplifier 42, and the voltage pulse sent out by the main amplifier 42 is transmitted to the disk. The discrimination input to the control terminal 47 of the liminator 43
A constant voltage is output only when the level signal is exceeded. Then, the rectangular wave pulse corresponding to the pulse exceeding the discrimination level is input to the waveform shaping circuit 44, 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,
Accurate signal detection becomes difficult. However, the wave height of the noise pulse is smaller than that of the signal pulse, so by setting the discrimination level in the discriminator 43 to an appropriate value, the noise pulse can be removed and only the signal pulse can be detected. can be detected.

In addition, the number of pulses counted is proportional to the counting time width, and since the image dissector tube 3 does not use an accumulation method, even if the deflection position is stopped at an arbitrary measurement position, the electron beam from the stopped position is Since the counting circuit 46 sends out a constant pulse corresponding to
A gate circuit 45 is provided at the input end of the control end 4.
8, by setting a desired counting time, it is possible to deal with objects to be measured having a wide brightness range.

Further, the minute current meter 5 amplifies the output current of the image dissector tube 3 and outputs it to a recorder or printer 8.
The analog voltage, current, or predetermined digital signal that can be input is sent to the terminal.

When the image dissector tube 3 is connected to the pulse counter 4 as described above, single photon pulses can be counted with a fraction of a probability. The luminous intensity corresponding to photon input can also be measured. However, according to this method, continuous pulses cannot be separated when the amount of light is large. This depends on the electrode structure of the image dissector tube 3, the capacity of the amplifiers 41 and 42, etc.
Since the resolution is usually around 10 MHz, it is possible to detect pulses of 10 ⁶ photons per second, even at random time intervals. Therefore, since the image dissector tube multiplies the secondary electrons by a factor of approximately 10 ⁵ , the output current during large-volume counting using the pulse counting method is approximately 10 ² μ
A or higher.

Since the dark current contained in the output of the image dissector tube 3 is less than 1 nA, it can be sufficiently measured by switching the switches 6 and 7 and connecting the image dissector tube 3 to the microammeter 5.

In addition, the image dissector tube 3 has an output current of approximately
Output signals with good linearity can be obtained up to 100μA.
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, according to the present invention, an image dissector tube is used as the brightness measuring means, and a pulse counter and a microcurrent meter are connected between the output end of the image dissector tube and the recorder or printer. By switching and connecting the output signal of the image dissector tube and the measurement position, the output signal of the image dissector tube corresponds to the measurement position by synchronously driving the deflection coil drive power source of the recorder or printer and the image dissector tube by the measurement position controller. By recording, it is possible to measure the brightness distribution of a two-dimensional object having an extremely large dynamic range.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the two-dimensional brightness measuring device according to 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 diagram of the structure of the image dissector tube used in Fig. 1. FIG. 3 is a block configuration diagram of a pulse counter. DESCRIPTION OF SYMBOLS 1... Object to be measured with two-dimensional expansion, 2... Optical lens, 3... Image dissector tube, 4... Pulse counter, 5... Ammeter, 6, 7... Changeover switch,
8... Printer, 9... Measurement position controller, 91... Deflection drive power source, 31... Photocathode, 32... Electrode, 33... Aperture, 34, 35... Deflection coil, 36... Dynode, 37... Collection electrode, 41... Preamplifier, 4
2... Main amplifier, 43... Discriminator,
44... Waveform shaping circuit, 45... Gate circuit, 46...
Counting circuit.

Claims (1)

[Scope of Claims] 1. A pulse counter and a minute current meter that can set discrimination levels and are switchably connected to the output terminal of the image dissector tube, and the output terminals of the pulse counter and minute current meter are switchable. a recording means connected to the recording means, a deflection drive power source that deflects and drives the image dissector tube according to the measurement position instruction signal, and a position signal that sends the measurement position instruction signal to the deflection drive power source and is synchronized with the measurement position instruction signal. A two-dimensional lightness measuring device comprising: a measurement position controller that sends the lightness to a recording means; 2. Claim 1, wherein the pulse counter counts the image dissector tube output through a gate circuit whose counting time can be set.
Two-dimensional lightness measuring device as described in section.