JPH04373394A - Television camera device - Google Patents

Abstract

PURPOSE:To easily adjust the luminance by incorporating a means, which measures the video level of the white signal in a color bar signal, and a means, which superposes message indicating the measured level on the video signal a to output a video monitor connected to a camera, in the camera. CONSTITUTION:The color bar signal generated by a color bar generator 3 is selected as the output of the output of a switching circuit 4 for switching between a picked-up image signal and the color bar signal, and the luminance adjustment signal outputted from a luminance adjusting circuit 8 is changed by the control of a CPU 13 so that the white part of the composite signal output of the color bar signal is in a prescribed level. The CPU 13 controls measurement of the white level of the color bar signal and display of the measurement result. A character generator 14 is controlled to output the message indicating a prescribed calculation result, and the output of the character generator 14 is superposed on the video signal by a superposing circuit 15 and is outputted to an output terminal 7. Thus, a user adjusts the luminance while seeing the displayed message.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to adjusting the brightness level of a television camera.

0002

[Prior Art] A conventional brightness adjustment method for a television camera involves generating a color bar signal, connecting a measuring device called a waveform monitor to the video signal output terminal of the camera, and measuring the whiteness of the color bar signal observed on the waveform monitor. The method was to adjust the level to the rated level.

0003

[Problems to be Solved by the Invention] Conventionally, a waveform monitor has been required to adjust the brightness of a television camera. Furthermore, there are many cases in which multiple cameras are operated simultaneously in studios, relay vans, etc., and in such cases, a waveform monitor is usually connected to each camera and the video signals are monitored while the cameras are operated. In this case, it is required to match the brightness characteristics of each camera, but if there are variations in the characteristics of the connected waveform monitors, there is a problem that the video signals of each camera will vary. The present invention aims to eliminate these drawbacks and realize a television camera that can adjust brightness without a waveform monitor.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a means for measuring the video level of the white portion of a color bar signal inside the camera, and a means for displaying the measured level on a video monitor connected to the camera. It has built-in means for superimposing a message on a video signal and outputting it.

[0005]

[Operation] According to the present invention, it is possible to adjust the brightness level of the camera without using a waveform monitor. In addition, when operating multiple cameras at the same time, first adjust the brightness level of one camera using the present invention, and then calibrate the waveform monitor sequentially using the adjusted camera as a reference. By using the waveform monitor, it is possible to match the characteristics of each camera and waveform monitor by adjusting the brightness level of other cameras using the same method as before.

[0006]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In normal use, the signal from the imaging unit 1 is processed by the signal processing circuit 2, and then converted into a composite video signal (hereinafter referred to as composite signal) by the color encoder circuit 5, and the signal is sent to the main video signal output terminal 6 and the video monitor. The signal is output from the signal output terminal 7. From the video signal output terminal 7 for video monitoring, it is also possible to output red, blue, and green signals, or a mixed signal of a plurality of these signals, in a pre-processing stage to form a composite signal.

When adjusting the brightness level of a composite signal, a control signal from a microprocessor (hereinafter referred to as CPU) 13 causes the output of the imaging signal and color bar signal switching circuit 4 to be changed to the color bar generated by the color bar signal generator 3. The brightness adjustment signal output from the brightness adjustment circuit 8 is changed under the control of the CPU 13 so that the white portion of the composite signal output of the color bar signal reaches a specified level. In the above process, the CPU 13 measures the white level of the color bar signal and controls the display of the measurement results, as will be described later. FIG. 2 is a flowchart showing the above processing performed by the CPU 13.

[0008] A sample and hold circuit (hereinafter referred to as S/H) 9 is under the control of the CPU 13 and serves to sample and hold the voltage level of the video signal at any position on the screen. The input signal switching circuit 11 to the A/D converter 12 is
Under the control of the PU 13, the input signal of the A/D converter 12 is switched to the output of the S/H 9, the output of the +1V precision voltage source 10, or the ground potential. +1V precision voltage source 1
An example of 0 is a circuit in which the output of a precision reference voltage source IC is divided by a resistor with a tolerance of 0.1%.

[0009] The CPU 13 controls these circuits, and as shown in FIG.
By performing the processing shown in , the voltage of the white part of the color bar signal (hereinafter referred to as V1), the voltage of the black part of the color bar signal (hereinafter referred to as V2), and the voltage of the +1V precision power supply 10 (hereinafter referred to as V3)
, and the ground voltage (hereinafter referred to as V4). In FIG. 2, the portion where the predetermined time elapses is because the S/H 9 requires one field period or more to sample the voltage at the sample position, and the CPU 13 may perform other processing during this period.

The formula for calculating the level of the white portion of the color bar signal (hereinafter referred to as VW) from the detected values V1, V2, V3, and V4 is as follows: In the case of the NTSC system, 100% video level = 0.
Since it is 714 [V], it is given by the following formula (1). P.A.
In the case of the L method, since 100% video level=0.7 [V], it is given by the following equation (2).

[0011]

[Math 1]

By performing subtraction and division as shown in equation (1) or equation (2), errors in the detection circuit system are removed. Controls the character generator 14 and outputs a message indicating the calculation result based on Equation 1 or Equation 2. The output of the character generator 14 is superimposed on a video signal by a superimposition circuit 15, and outputted to a video signal output terminal 7 for video monitoring. The above message may be of any type as long as it specifically represents the calculation result based on Equation 1 or Equation 2. Further, the above display can always be displayed when the output of the switching circuit 4 is a color bar signal, but in this embodiment, the output of the switching circuit 4 is switched from the signal processing circuit 2 output to the color bar generation circuit 3 output. The display shall be displayed for a few seconds from the moment the brightness is adjusted, or only while the brightness is being adjusted.

[0013]

[Effects of the Invention] According to the present invention, brightness adjustment is possible without a waveform monitor. It is also possible to calibrate the waveform monitor using a camera whose brightness has been adjusted using the method according to the present invention as a reference.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the operating procedure of the present invention.

[Explanation of symbols]

2 Signal processing circuit 3 Color bar signal generation circuit 4 Switching circuit 7 Video signal output terminal for video monitor 8 Brightness adjustment circuit 9 Sample hold circuit (S/H) 10 +1V
Precision voltage source 11 Switching circuit 12 A/D converter 13 is a microprocessor (CPU) 14 Character generator 15 Superimposition circuit

Claims (1)

[Claims] Claim 1: A television camera device (hereinafter referred to as a camera) having a function of generating a color bar signal, comprising means for measuring the image level of the white portion of the generated color bar signal, and a means connected to the camera. A television camera device comprising means for superimposing and outputting a message indicating a measured level on a video signal to a video monitor.