JPH03220877A - color video camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a color video camera, and particularly to a technique for varying the brightness of a photographic screen.

[Prior Art] Figure 2 is a block diagram showing the configuration of a conventional color video camera. In the figure, (1) is a lens, (2) is an iris, (3) is an image sensor, and 0) is a photoelectric sensor. Conversion element (hereinafter referred to as CDS).

(5) is the iris control section, (0 is the first reference voltage,
The iris controller (5) compares the detected value of the output of the CD S (3) with the first reference voltage value, and controls the iris (5) so that the output of the image sensor (3) is maintained at a predetermined value. A first feedback system is configured to feedback control 2).

(7) is an automatic gain control circuit (hereinafter referred to as AGC'), (8) is an AGC control section, (8) is a second reference voltage, (lO) is a process and encoder signal processing circuit, (11) is At the output terminal, the detected value of the output of the AGC (7) and the second reference voltage value are connected to the AGCIljl.
A second feedback system is configured to perform feedback control of the A GC (7) so that the outputs of the A and GC (7) are maintained at predetermined values by comparison in the first part (8).

Next, the operation of the above configuration will be explained.

The optical image of the subject that has passed through the lens (1) and iris (2) is detected by the image sensor (3), and photoelectrically converted by the CD S (4).
The detected value of the output of (4) and the value of the first reference voltage (8) are compared in the iris control section (5) so that the output of the image sensor (3) is maintained at a predetermined level. While performing feedback control on the iris (2), A G
The detected value of the output of C (7) and the value of the second reference voltage (7) are compared in the AGC control section (8), and the above-mentioned A
This A
GC(7) is feedback-controlled.

In this way, the automatic control of the iris (2) and the
The automatic control of C(7) determines the value outputted to the output terminal (11) via the process and encoder signal processing circuit (lO), that is, the brightness of the photographic screen.

[Issue 1i to be solved by the invention] Since the conventional color video camera is configured as described above, the brightness of the shooting screen of the same subject is always constant regardless of the weather at the time of shooting. There was a problem in that it was not possible to change the brightness of the screen depending on whether it was cloudy or sunny.

This invention was made in order to solve the above-mentioned problems, and it is an object of the present invention to appropriately vary the brightness of the shooting screen of the same subject depending on the weather at the time of shooting, so as to always obtain a natural shooting screen. The purpose is to provide a color video camera that can.

[Means for Solving the Problems 1] A color video camera according to the present invention provides at least a second reference voltage value of a first reference voltage value for iris control and a second reference voltage value for AGC control. It is characterized by a variable configuration.

[Operation] According to the present invention, by varying the second reference voltage value or the first and second reference voltage values depending on the weather at the time of shooting, the output of AC/C or the output of the image sensor and AGC is adjusted. You can adjust the output to obtain screen brightness that adapts to the weather.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a color video camera according to an embodiment of the present invention, in which (1)
~(5), (7), (8), (1G), (
11) is the same as the conventional example shown in FIG. 2, so the corresponding parts are given the same reference numerals and detailed explanation thereof will be omitted.

In FIG. 1, (15) is a first variable reference voltage, which is compared with the detected value of the output of CD S (4) in the iris control section (5). (1B) is a second variable reference voltage, which is compared with the detected value of the output of AGC (7) in the AGC control section (8).

Reference numeral 12 denotes a changeover switch, which is changed over depending on the weather condition, and adjusts the values of the first and second variable reference voltages (15) and (+6) in accordance with the changeover.

(13) is a mark indicating the degree of APL, and the degree of APL is displayed on the viewfinder (14) in conjunction with the changeover switch (12).

Next, the operation of the above configuration will be explained.

Basically, the operation is the same as that of the conventional example shown in Fig. 2. Adjust the values of voltages (15) and (16).

such a first J3 and a second variable reference voltage +15),
By adjusting (+6), the output of C D S (4) and the output of A G C (7) under the control of the iris control section (5) and AGC control section (8) are changed, and as a result, the same subject The brightness of the shooting screen can be adjusted to suit the weather.

Further, at this time, since a mark (13) indicating the degree of APL is displayed on the viewfinder (14) in conjunction with the operation of the switch (12), operational errors can be prevented.

In the above embodiment, both the first and second variable reference voltages (15) and (16) are adjusted by operating the changeover switch (12), but only the second variable reference voltage (16) is adjusted. may be adjustable, and the same effects as in the above embodiment can be achieved.

[Effects of the Invention] As described above, according to the present invention, the brightness of the shooting screen of the same subject can be adjusted according to the weather conditions at the time of shooting, so that the brightness of the shooting screen of the same subject can be adjusted depending on the weather conditions at the time of shooting. This has the effect that a natural photographic screen can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a color video camera according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional color video camera. (2)...Iris, (3)...Image sensor,
(4)...CDS, (5)...iris control section, (
7)...AGC, (8)...AGC control unit, (12
)...Switching switch 2, (15)...First variable reference voltage, (16)...Second variable reference voltage. Note that the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) An iris, an image sensor, and an iris that performs feedback control of the iris so that the output of the image sensor is maintained at a predetermined value by comparing the detected value of the output of the image sensor with a first reference voltage value. A control unit, an automatic gain control circuit, and a control unit that compares the detected value of the output of the automatic gain control circuit with a second reference voltage value and adjusts the automatic gain so that the output of the automatic gain control circuit is maintained at a predetermined value. A color video camera equipped with an automatic gain control circuit controller for feedback controlling a control circuit, further comprising means for varying at least a second reference voltage value of the first and second reference voltage values. A color video camera with special features.