JPH0224436B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a device for photographing an image projected on the tube surface of a cathode ray tube kinescope device on a photographic film, in which the input voltage of the cathode ray tube kinescope device and the density of the photographed photographic film are This invention relates to a method of adjusting the input signal of a cathode ray tube kinescope device so that the relationship between the two is linear.

It is necessary to record the image projected on the tube surface of a cathode ray tube kinescope device on photographic film, in addition to taking waveform photographs of electrical signals and still photographs of the screen of a television picture tube. Photographs may be taken for the purpose of using them as original plates for printing. Furthermore, photographs such as computer image information are also used as originals for hard copies. When photographing to create such printing master plates, a flying spot scanner tube (hereinafter referred to as an FSS tube) is used to improve the resolution of the image and reduce distortion. In order to obtain the correct tone, the gamma characteristics of the FSS tube and the gamma characteristics of the film used are corrected.

By the way, the γ characteristic of the FSS tube has an upwardly concave exponential curve as shown in Figure 1, and generally γ=
2.2, it can be corrected by combining it with an electric circuit with γ=0.45 on the input side of the FSS tube. On the other hand, since the film has an S-shaped gamma characteristic as shown in Figure 2, conventionally it has been combined with a correction circuit having an inverted S-shaped characteristic as shown in Figure 3 to obtain overall linearity. I had adjusted it so that it would work. The method is to set the correction circuit to an appropriate inverted S-shaped characteristic, create a large number of test films by varying the input level of the FSS tube, draw a curve of density versus input voltage, and then make this curve a straight line. The correction circuit is reset in a direction that approaches the line, and the same operation is repeated again to draw the γ characteristic, gradually drawing it closer to a straight line. However, according to this method, it is necessary to repeat exposure, development, density measurement, and correction circuit adjustment using graph plotting many times, and it takes time to perform tasks such as development and density measurement, and the amount of film used increases. I had a lot of flaws. Furthermore, since the adjustment of the correction circuit was carried out by trial and error, there was a drawback that variations occurred due to development. Therefore, an object of the present invention is to provide a method for easily and reliably adjusting the correction circuit.

The present invention will be described in detail below with reference to the drawings.

FIG. 4 is a system diagram showing the configuration of the device according to the present invention, where 1 is an FSS tube, 2 is a camera used to photograph the FSS tube 1, 3 is a film loaded in the camera 2, and 4 is a system diagram showing the structure of the FSS tube. This is a rotatable reflector for optically switching the test adjustment circuit. 5 is an optical lens for receiving light from the reflecting mirror 4; 6 is a stage for setting a sample film; the bright spot on the FSS tube 1 is imaged by the lens 5 on the set sample film 6; It's becoming like that.
7 is a condenser lens, 8 is a photomultiplier tube (hereinafter simply referred to as PMT) as a photoelectric conversion means,
Condenser lens 7 captures the raster light from FSS tube 1.
The light is focused on PMT8. 9 is γ
The characteristic adjustment circuit is composed of adjustment circuits 9A and 9B for adjusting the γ characteristics of the FSS tube 1, an adjustment circuit 9C for adjusting the γ characteristics of the film, and on/off switchers 91 to 93. There is. Reference numeral 10 designates a test signal generator that generates a test signal TS having a stepped waveform and a rectangular waveform, 11 a cathode ray tube oscillography device for waveform observation, and 12 to 16 switching devices, respectively. 20 is an input terminal for inputting an arbitrary signal, 21 is this amplifier, and 22 is an amplifier for large amplitude image signals.

FIG. 5 is a diagram showing the connections in the first step for determining the adjustment point of the γ characteristic adjustment circuit 9.
12 contacts each for 13, 14, 15, and 16
a, 13a, 14a, 15a, and 16a. As a result, the test signal generator 10 is connected to the FSS tube 1 via the amplifier 22, and the reflector 4 is set on the optical axis connecting the FSS tube 1 and the camera 2 so as to be at 45 degrees to the optical axis. The light flux from FSS tube 1 passes through the optical system.
The output PS is input to the PMT8, and the output PS is input to the switch 12.
After being adjusted by a gamma characteristic adjustment circuit 9, it is connected to a cathode ray tube oscillography device 11. The γ characteristic adjustment circuit 9 closes the switch 93 and short-circuits the adjustment circuit 9C for the film. In this way, the test signal generator 10 generates a step waveform test signal.
When TS is applied to the FSS tube 1, vertical stripes with sequentially changing contrast appear on the screen, and the bright spots are picked up by the PMT 8, and an index as shown in FIG. A curve appears. This is the so-called γ curve, and by adjusting the γ adjustment circuit 9B of the FSS tube 1,
If the γ curve in the figure is made a straight line, the γ characteristics of the FSS tube 1 will be corrected. Note that the γ value of the FSS tube 1 is approximately 2.2, and in order to correct this to 1, the overall γ value of the adjustment circuits 9A and 9B should be approximately 0.45. The adjustment circuit 9A is a γ circuit with γ=0.45, and the adjustment circuit 9B is a variable γ circuit with γ=±0.3, and both can use known circuits.
The total value of the adjustment circuits 9A and 9B thus obtained is defined as _γ1 .

Next, FIG. 7 is a diagram showing the connection in the second step for photographing a sample film, and shows the connection of the switching device 1.
Contact points 3, 14, and 16 are 13a and 14, respectively.
a, 16a, and the reflector 4 is the FSS tube 1 and camera 2.
parallel to the optical axis of the FSS tube 1, and make the light flux of the FSS tube 1 enter the camera 2. When a test signal TS having a stepped waveform is applied to the FSS tube 1 from the test signal generator 10, vertical stripes are projected on the surface of the FSS tube 1 in the same manner as described above, and these are photographed on the film 3 by the camera 2. Ru. Then, if you develop this film, FSS
By combining the gamma characteristics of the tube 1 and the gamma characteristics of the film 3, a sample film 3A with vertical stripes whose density changes sequentially can be obtained.

FIG. 8 is a diagram showing the connection in the third step for adjusting the γ characteristic of the film, and shows the connection of the switch 12,
Contact points 13, 14, 15, and 16 are 12a, 13a, 14a, and 14a, respectively, as in the first step described above.
15a and 16a, and the reflecting mirror 4 also reflects the light beam from the FSS tube 1, as in the first step, so that it is incident on the PMT 8 through the optical system. At this time, the sample film 3A created in the second step above
is loaded into sample film stage 6,
Switches 91 to 93 are each left open. Then, when a flat rectangular wave is applied from the test signal generator 10 to the FSS tube 1 as the test signal TS,
The tube surface of the FSS tube 1 serves as a light source that is scanned by a bright spot having a constant brightness. In this way, FSS tube 1
can be used as a bright point light source because it has little afterglow.
This is because an FSS tube was used, and a regular television cathode ray tube cannot be used as a bright point light source like this. FSS for sample film 3A
Although the gamma characteristics of the tube 1 and the film are added, since the gamma characteristics of the FSS tube 1 have been corrected by the gamma adjustment circuits 9A and 9B, only the gamma characteristic of the film 3A remains. Therefore, on the tube surface of the cathode ray tube oscillography device 11, a γ characteristic curve that changes depending on the γ characteristic of the sample film 3A is projected.

The gamma characteristic curve of a film generally has an S-shape as shown in Figure 2, but to correct this, it is generally necessary to perform contrast correction that determines the slope of the curve as shown in Figure 9A, and contrast correction as shown in Figure 9B. The printing color simulator uses a three-part adjustment method: parallel movement, which determines the top and bottom of the entire curve, and brightness adjustment, which determines the local slope of the curve at the bottom and top, as shown in Figure C. You can use this as is. In this way, the γ characteristic of the film can be easily corrected, and this γ correction value is defined as _γ2 .

FIG. 10 is a diagram showing the connections in the fourth step for obtaining a γ-corrected sample film. As in the second step, the reflector 4 is parallel to the optical axes of the FSS tube 1 and camera 2 so as not to block the light flux, and the test signal generator 10 outputs a test signal TS with a stepped waveform. , this test signal TS is supplied to the adjusted γ adjustment circuits 9A, 9B and 9C.
is added to FSS tube 1 through. A vertical striped shading pattern is projected on the surface of FSS tube 1, which is reflected by camera 2.
The photograph is taken using film 3 of . The sample film thus obtained has all γ characteristics adjusted and has a density proportional to the input voltage.
Since this fourth step is for creating a sample film that has been γ-corrected, it may be omitted when actually used. In addition, the γ adjustment circuit 9C
To adjust the γ-corrected sample film of the FSS tube 1, use the circuit shown in FIG. 10 with the switch 93 closed, and then close the switch 91 and 92 in the circuit shown in FIG. The adjustment circuit 9C may be adjusted using a closed circuit.

When actually using this circuit to shoot film, switch switches 12, 13, 14, 15, 1
6 contacts are respectively 12b, 13b, 14b, 1
5b and 16a, and if an arbitrary input signal is applied to the input terminal 20, the input signal will be transmitted to the γ characteristic adjustment circuit 9.
It is added to the FSS tube 1 through the FSS tube 1, and a desired screen is projected on the surface of the FSS tube 1. If this screen is photographed with the camera 2, a γ-corrected image of the FSS tube 1 and the film can be obtained on the film 3. At this time, if the picture tube has already been subjected to γ correction and γ = 0.45, such as a television signal or a signal from an image pickup tube, it is possible to close the switch 91 and remove the adjustment circuit 9A. good. When γ correction is not applied to signals such as signals from a computer or a special-purpose imaging device, all switchers 91 to 93 are opened, and adjustment circuits 9A to 9C are used.
Just insert it into the circuit system. Also, FSS tube 1
When observing the image on the screen of the camera, the switch 93 is closed in the same circuit as described above, and the film γ adjustment circuit 9C is set to pass.When the signal is coming from a computer, the switch 91 and 92 are opened. Adjustment circuits 9A and 9B may be inserted into the circuit system. Furthermore, in the case of a television signal, it is sufficient to close the switch 91, open the switch 92, and perform only the correction for γ=0.45. When the need for correction is not recognized, the contact point of the switch 16 is set to 16b, and the amplifier 20
It can be added directly to FSS tube 1 through .

As explained above, according to the present invention, it is possible to easily and reliably adjust the γ of the FSS tube and film by creating a sample film once, and the γ characteristic curve can be adjusted by creating a large number of sample films as in the past. Compared to the method of step-by-step adjustment to create a straight line, the work time can be significantly reduced. Moreover, the γ of FSS tube and film
Only adjustments can be made independently,
Since you can know the γ correction value γ ₁ of the FSS tube and the correction value γ ₂ of the film, once you know the values of γ ₁ and γ ₂ , you can simply set these values in the γ characteristic adjustment circuits 9A to 9C from the next time. So, γ= like a television signal
A film with linear contrast can be obtained both for signals adjusted to 0.45 and for unadjusted signals such as computer signals. Furthermore, by simply setting the correction value _γ1 , it is possible to freely observe an image on the FSS tube surface whose γ characteristics have been corrected.

Although the present invention is used as a method for correcting γ characteristics, it can also be used as a method for measuring γ values.

[Brief explanation of drawings]

Fig. 1 is a γ characteristic diagram of FSS, Fig. 2 is a γ characteristic diagram of film, Fig. 3 is a correction amount characteristic diagram of film, Fig. 4 is a system diagram showing the overall configuration of the device according to the present invention, and Fig. 5 The figure is a connection diagram of the step for correcting the γ characteristic of the FSS tube, Figure 6 is a diagram showing the correction range of the γ characteristic of the FSS tube, Figure 7 is the connection diagram of the step for creating the sample film, and Figure 8 is the connection diagram of the step for making the sample film. 9A to 9C are a set of γ curve diagrams for explaining the method of correcting the γ characteristics of a film. FIG. 10 is a diagram of the steps for creating a γ-corrected sample film. It is a connection diagram. 1...FSS tube, 2...camera, 3...film, 4...reflector, 5...lens, 6...sample film stage, 7...condenser lens,
8...PMT, 9...γ characteristic adjustment circuit, 10...
Test signal generator, 11...Cathode ray tube oscillography device, 12-16...Switcher, 20...Signal input terminal, 21, 22...Amplifier.

Claims (1)

[Scope of Claims] 1. Signal applying means for applying linearly varying amplitude electric signals and rectangular wave signals to the flying spot scanner tube, and a photoelectric device having linearity for picking up the luminous flux on the flying spot scanner tube. a converting means, a stage for setting a sample film in the optical path for the pickup, and a gamma characteristic of the flying spot scanner tube for changing the linearity of the electric signal input to the flying spot scanner tube or the picked up electric signal. comprising a correction means, a film γ characteristic correction means, and an observation means for observing the γ characteristic curve, and the signal application means applies a signal whose amplitude changes linearly to the flying spot scanner tube,
The gradation screen on the tube surface is converted into an electric signal by the photoelectric conversion means, and while the electric signal waveform corrected by the γ characteristic correction means of the flying spot scanner tube is observed by the observation means, the γ The gamma characteristic correction amount of the flying spot scanner tube is determined by adjusting the gamma characteristic correction means of the flying spot scanner tube so that the characteristic curve becomes a straight line, and the gradation on the surface of the flying spot scanner tube is determined. creating the sample film by photographing the screen; setting the sample film on the stage; applying a rectangular wave signal to the flying spot scanner tube by the signal applying means;
The gradation screen on the screen is converted into an electric signal by the photoelectric conversion means, and while the electric signal corrected through the corrected γ characteristic correction means of the flying spot scanner tube is observed by the observation means, the γ The gamma characteristic correction amount of the film is determined by adjusting the gamma characteristic correction means of the film so that the characteristic curve becomes a straight line. A method for adjusting film gamma, characterized in that gamma characteristic correction means for each of the flying spot scanner tube and film, which have been corrected in accordance with an input signal, are inserted into the input side of the flying spot scanner tube. 2. The sample film is created by adding an electric signal corrected by the gamma characteristic correction means of the flying spot scanner tube to the linearly varying signal by the signal applying means, to the flying spot scanner tube. , the γ characteristic correction of the film is carried out by setting the sample film on the stage, applying a rectangular wave signal to the flying spot scanner tube by the signal applying means, and
While converting the grayscale screen on the screen into an electrical signal by the photoelectric conversion means and observing it with the observation means,
The γ of the film is adjusted so that the γ characteristic curve becomes a straight line.
A film gamma adjustment method according to claim 1, wherein the film gamma adjustment method is carried out by adjusting a characteristic correction means. 3. The γ characteristic correction means of the flying spot scanner tube is composed of a γ=0.45 adjustment circuit and a γ correction circuit centered around γ=0.45, and the γ characteristic correction means of the film is configured to adjust contrast, parallelism, etc. 2. A film gamma adjustment method according to claim 1, wherein movement and brightness correction can be performed independently. 4. The film gamma adjustment method according to claim 1, wherein the output waveform from the signal applying means is stepped and rectangular.