JPS59181876A - Device for correcting video signal - Google Patents

Abstract

PURPOSE:To attain automatically the correction with high accuracy by correcting a video signal after selecting a correction waveform among correcting waveforms from plural different correcting waveform generating means and adjusting it in response to the characteristic of a video signal by means of a preset program. CONSTITUTION:An operating section 55 selects the correction waveform among waveforms from plural correcting waveform generators 51-54 and polarity and amplitude adjusting devices 58-61 in interlocking with the devices 51-54 in response to a program from an ROM56 in which a correcting program is stored. The selected correction waveform is applied to a synthesizer 62, where a required correcting waveform is synthesized. An output signal of the synthesizer 62 is applied to a shading correction circuit 63, where a prescribed correction is applied to a video signal fp outputted from an image pickup tube. Further, the ununiformity of the video signal not corrected is measured by an automatic measuring means and a correcting program is formed automatically from the result of this measurement, allowing to automate the correcting work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a video signal correction device suitable for use in, for example, a television camera.

[Technical background of the invention and its problems]

Generally, the light/N and negative signal characteristics of an image pickup tube used in a television camera are not uniform in each part. That is, as shown in FIG.
Directly face the uniformly white subject 13 through the lens 12,
When uniform light is incident on the image pickup tube 11, the output signal thereof, as shown by the solid line in FIG. 2(a), partially varies with respect to the ideal output signal shown by the dotted line. Advantageously, the dark current when the light incident on the image pickup tube 11 is cut off also partially varies with respect to the ideal output (shown by the dotted line), as shown by the solid line in FIG. 2(b).

Generally, in image pickup tubes known by trade names such as Sachicon and Calnicon, in order to improve the afterimage characteristics, a lens system 3 and a photocathode 32. A light source 33, 34 called a bias light is provided between the photocathode and the photocathode, and this light source 33, 34 often provides weak light to the photocathode. However, it is extremely difficult to uniformly apply the bias light to the entire surface of the photocathode 321 using the light sources 3.9 and 34, and it is necessary to compensate for the inconsistency using an electric circuit.

FIG. 4 shows a conventional video signal correction device. A video signal fp output from an image pickup tube (not shown) is supplied to a well-known shading correction circuit 41. This shading correction circuit 41 is supplied with output signals from a horizontal correction waveform generator 42 and a vertical correction σv type generator 43.

These correction waveform generators 42, 43 generate parabolic waves and triangular waves corresponding to horizontal and vertical periods, respectively, and these correction waveforms are generated by variable resistors 44, 45, 46.4.
7, the levels can be adjusted respectively.

In such a configuration, in a state in which uniform white light is incident on the image pickup tube (not shown) and in a state in which the incident light is cut off,
The variable resistors 44 to 47 are operated to correct the image signal. However, in such a method, the adjustment work is performed manually, resulting in poor work efficiency and, moreover, the adjustment work must be performed for each image pickup tube, which is extremely complicated. In fact, with this method, there are basically two types of correction wave signals: parabolic waves and triangular waves, so it was difficult to perform sufficient magic on the video signal.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to provide a video signal correction device that can easily perform video correction work, can perform correction with high precision, and can also automate the work. This is what we are trying to provide.

[Summary of the invention]

This invention provides means for generating a plurality of different correction waveforms, selectively extracts these correction waveforms according to a preset program according to the characteristics of a video signal output from an image pickup tube, and corrects the extracted correction waveforms. The video signal is corrected after adjusting the polarity and amplitude of the waveform according to the program.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 5, a correction waveform generator 51. ．． 52゜5,
? , 54 generate four different types of correction waveforms, each corresponding to, for example, one thousand cycles of a television signal. These correction waveform generators 51 to 54 are, for example, analog waveform generation circuits, or ROM (IJ-only memory) in which a predetermined waveform is quantized into 4 to 6 pits in a band of about IM (z) and stored. ) The output signals of the correction waveform generators 51 to 54 are selectively extracted by a control section 55 consisting of a microcomputer, for example. is ROM56 in which the crafted program is stored.
is connected. The AtI recording correction gram is set in advance according to the characteristics of the video signal output from the image pickup tube, and includes, for example, correction information for each scanning line. The correction program stored in the ROM 56 is read out by the arithmetic unit 55. This readout is performed in response to a vertical drive pulse signal output from a synchronization signal generator 57 similar to that of a television camera. The arithmetic unit 55 controls the extraction of the corrected waveform according to the read correction program. This extracted correction waveform is supplied to the corresponding polarity amplitude adjusters 58, 59, 6θ, 61. The regulators 58 to 61 are composed of, for example, an inverting amplifier and a variable gain amplifier, and the polarity and amplitude of the input polarity correction waveform are adjusted under the control of the arithmetic unit 55 according to the correction program. These polar amplitude adjusters 5
The corrected waveforms outputted from 8 to 61 are supplied to a synthesizer 62, and the synthesizer 62 synthesizes Sanno waveforms as necessary. The output signal of this synthesizer 62 is supplied to a shading correction circuit 63, and this shading sleeve iE circuit 6
In 3, the video signal f output from the image pickup tube (not shown)
Pir constant correction is performed on p.

According to the above configuration, a plurality of correction waveforms are selectively extracted according to the predetermined extraction program. The image signal is corrected by supplying the shading correction waveform adjusted according to the correction program to the shading correction ILjl path. Therefore, it is more accurate than conventional manual adjustment! +Ii,i
It not only makes it possible to perform E, but also greatly improves work efficiency. Moreover, candy in the same lot, I;3
If the number of image pickup tubes is small, one supplementary program can be created for each lot and this program can be applied to all the image pickup tubes in that lot, thereby reducing the work time. is possible.

Unfortunately, because variable resistors are not used like in the past,
] Excellent stability.

However, the present invention is not limited to the above-mentioned embodiments, and the uncorrected image signal is determined by a well-known automatic measuring means, and the rtl 100F is automatically determined from this measurement result. If you do something like creating Zorograno, you can automate the IF work.

7. Imaging 'R' by installing a temperature sensor and a correction program according to the temperature. ;;If a predetermined correction program is selected and curved according to the change of 4 degrees, a wide range of temperature qi can be achieved.
It is always possible to make the best corrections within this range.

Furthermore, in the example given by Furukawa, the explanation is given using an example of construction 1, but the present invention is not limited to this. It is also possible to use it as a rough circuit for a focus circuit or a circuit for correcting dark current unevenness caused by a process problem in a solid-state image sensor.

If you use a high-speed microcomputer, you can do time-sharing processing! ] It is also possible to simultaneously perform multi-face 11ii and TE.

It goes without saying that various other modifications can be made within the range of q and ρ without changing the gist of the invention.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a video signal correction device that allows easy correction work, performs highly accurate correction, and can automate the work.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram to explain the optical/electrical characteristics of the image pickup tube, Figure 2 is a waveform diagram showing the optical/electrical characteristics of the image pickup tube, and Figure 3 is a diagram showing how to improve the afterimage characteristics of the image pickup tube. 4 is a diagram showing a conventional video signal correction device without showing the conventional video signal correction device, and FIG. 5 is a configuration diagram showing an embodiment of a video signal correction device according to the invention. Arithmetic unit, 56...ROM, 67.
. . . Synchronous signal generator, 58-6 . . . Polarity amplitude adjuster, 62 . . . Synthesizer, 63 . . . Shading surface circuit.

Claims (1)

[Claims] a plurality of waveform generating means for generating different correction waveforms corresponding to each period of the television signal; a storage section storing a correction program according to the output video signal characteristics of the imaging object; and a television synchronization signal. a calculation unit that reads the stored correction program according to the zologram and selectively extracts a predetermined correction waveform from the waveform generation means according to the zologram; and means that adjusts each of the extracted correction waveforms under control of the calculation unit; A video signal correction device comprising: means for synthesizing the adjusted correction waveform; and means for correcting a video signal output from the imaging body using the synthesized correction waveform.