JP3208769B2 - Television imaging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup tube or a solid-state image pickup device having improved operability when performing particularly shading correction of a black level or a white level of a captured television video signal waveform. The present invention relates to an image pickup apparatus using the same.

2. Description of the Related Art In recent years, the performance and automatic adjustment of color television imaging devices have been advanced. In particular, in order to improve the quality of an image picked up by a color television camera, there is a demand for an automatic technique of shading correction of a black level or a white level.

Conventionally, a shading correction technique used in this type of imaging apparatus will be described by taking as an example the correction of the black level of a solid-state imaging apparatus (hereinafter, referred to as a CCD camera).

In FIG. 2, the light image from the subject is an imaging lens, 16
Is condensed by CCD17 and converted to video signal by CCD17
It is configured to be output through 8 and the signal processing unit 19.

In the CCD camera having the above configuration, shading near the black level as shown in FIG. 3 tends to occur even when the input light is cut off due to dark current of the CCD itself or uneven transfer of electric charges. In addition, the dark current is generally 10
When the temperature rises by about ° C, the shading due to the dark current also increases about twice.

As shown in FIG. 2, a shading correction circuit in a conventional CCD camera includes a horizontal triangular wave generating circuit 20, a vertical triangular wave generating circuit 21, and a horizontal parabolic wave generating circuit.
The gains of the respective signals generated by the signal 22 and the vertical parabolic wave generator 23 are adjusted and added. The obtained shading correction signal having a waveform as shown in FIG. 4 is added to the output signal from the CCD 17, and even when the input signal is cut off, a black level signal is obtained as shown in FIG. The signal is corrected so that it becomes a flat signal without shading.

Problems to be Solved by the Invention As described above, four gain adjustments (2
4, 25, 26, 27), it is needless to say that adjustment is complicated and difficult in 12 places, especially in the case of a three-plate type color television camera. Further, while the above-mentioned shading correction circuit is effective for a specific shading waveform, when a CCD camera is used for a long time, the ambient temperature of the CCD rises due to heat generation or the shading waveform increases as described above. In consideration of such a case, it is necessary to adjust the shading correction circuit each time, which requires a great deal of labor.

In recent years, there has been a circuit in which shading correction is automatically performed due to digitization of signal processing or the like. However, a change in ambient temperature must be corrected again, and complicated adjustment means must be taken. There is such a problem.

To solve the above-mentioned problem, it is only necessary to provide a new trigger switch for starting the shading correction in the camera. However, for this purpose, one switch must be added to the camera switch operation mechanism, and the malfunction is prevented. Means must be taken, the mechanism becomes complicated and the cost increases.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a color television imaging apparatus capable of easily starting shading correction without changing a conventional camera switch operation unit.

Means for Solving the Problems To achieve the above object, the present invention comprises a microcomputer, a shading correction circuit, a black level balance circuit or a white level control circuit for controlling a black level or a white level, and a trigger switch. The microcomputer detects an ON time of the trigger switch, and operates the black level balance circuit or the white level balance circuit when the ON time is shorter than a predetermined time,
If the ON time is longer than the predetermined time, the shading correction circuit is operated.

Operation The present invention has the above-described configuration and provides a trigger switch for operating a black level balance circuit or a white level control circuit that automatically adjusts a black level or a white level.
By detecting and determining the ON time, the shading correction circuit can be easily operated without changing the switch operation mechanism of the conventional color television camera.

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

As shown in FIG. 1, the light condensed by the imaging lens 1 passes through a group of prisms 5, is received by CCD units 2, 3, and 4, and is photoelectrically converted. Where CCD2,3,4 are red, blue,
This is a solid-state imaging device that separates and captures images of three primary colors of green. Output signals from the CCDs 2, 3, and 4 are supplied to a preamplifier unit 6 where unnecessary noise components are removed and amplified to an arbitrary amplitude. The output signal of the preamplifier unit 6 is added to the correction signal from the shading correction circuit 13 to form a waveform without shading. After passing through the black level balance circuit 7, undergoing white level shading correction, and passing through the white level control circuit 8 The signal is supplied to the signal processing unit 9. The signal processing unit 9 performs various kinds of signal processing and outputs signals from the signal processing unit 9. Standard video signal (television camera output signal)
Is output as

The shading correction circuit 13 detects the signal level of the shading state of each channel from the signal processing unit 9 by the microcomputer 12 according to a certain trigger command, and writes an appropriate correction waveform in the readable / writable memory 14. The written contents of the memory 14 are read out by an address generation circuit 15 for driving the memory, and an appropriate shading correction waveform is obtained.

In addition, the black level balance circuit trigger switch 10 is ON
Then, the ON state is determined by the microcomputer 12, and the microcomputer 12 operates the black level balance circuit 7. The black level balance circuit 7 is a circuit in which the signal level detected by the signal processing section 9 is detected by the microcomputer 12 and is controlled by the microcomputer 12 so that the black level of each channel becomes the same. The trigger switch 10 of the black level balance circuit 7 is a three tube type or three
In a plate-type color television camera, it is generally called an ABB (auto brown balance) switch, and is widely used.

The ON time of the trigger switch 10 is detected by the microcomputer 12 and the black level balance circuit 7 is operated if the ON time is an arbitrary fixed time, for example, 5 seconds or less. If the ON time is 5 seconds or more, the shading correction is performed. The circuit 13 is operated.

As described above, by using both the operation trigger switch 10 of the black level balance circuit and the operation trigger switch of the shading correction circuit, the switch operation mechanism of the color television camera can be easily realized with the conventional configuration. Also, for color television camera users, the same black level is corrected, so it is easy to recognize, and by increasing the ON time of the switch, malfunction is prevented,
Very effective.

In the present embodiment, the microcomputer is used for time detection, but the same purpose can be achieved even if a new time detection circuit is provided. The trigger switch 10 of the black level balance circuit is also used. However, even when correcting white level shading caused by chromatic aberration of the lens, the trigger switch 11 of the white level control circuit, generally an AWC (automatic White control)
It is clear that it is effective to perform the same function as a switch called a switch.

Here, when using the white level control circuit,
Since the operation is the same as that of the black level balance circuit, the description is omitted.

Effect of the Invention As described above, according to the present invention, a color television imaging apparatus which can easily operate a shading correction circuit without changing an operation mechanism of a camera switch and can prevent a malfunction. Can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a CCD color television camera according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a configuration of a shading correction circuit of a conventional CCD camera.
FIG. 4 is a waveform diagram of a video signal having black-level shading, FIG. 4 is a waveform diagram of a correction signal generated by a shading correction circuit, and FIG. 5 is a waveform diagram of a corrected video signal. 7 black level balance circuit, 8 white level control circuit, 10 black level balance circuit trigger switch, 11 white level control circuit trigger switch, 12 microcomputer, 13 shading correction circuit,
14: Read / write memory, 15: Address generation circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/14-5/217 H04N 5/243

Claims (2)

(57) [Claims] 1. A microcomputer for detecting a video signal level, a shading correction circuit for correcting a black level by the microcomputer based on the video signal level, and a black for controlling a black level by the microcomputer based on the video signal level. The microcomputer includes a level balance circuit, and a trigger switch detected by the microcomputer.The microcomputer detects an ON time of the trigger switch, and operates the black level balance circuit when the ON time is shorter than a predetermined time. And a television imaging device for operating the shading correction circuit when the ON time is longer than a predetermined time. 2. A microcomputer for detecting a video signal level, a shading correction circuit for correcting a white level by the microcomputer based on the video signal level, and a white control for controlling the white level by the microcomputer based on the video signal level. A level control circuit, and a trigger switch detected by the microcomputer, wherein the microcomputer detects an ON time of the trigger switch,
A television imaging apparatus characterized in that when the ON time is shorter than a predetermined time, the white level control circuit is operated, and when the ON time is longer than the predetermined time, the shading correction circuit is operated.