JPH03183272A - Video camera - Google Patents

Abstract

PURPOSE:To adjust the white balance of the camera output signal with a high precision by displaying a reference white picture on a part of the display screen of a color electronic view finder. CONSTITUTION:When a changeover switch 21 is switched to the side of a manual white control circuit 23 for the purpose of adjusting the white balance by the manual operation, a white signal generating circuit 30 is operated by the command signal from the manual white control circuit 23 to generate an electric white signal. This white signal is partially cut by a gate circuit 31 and is sent to a mixing circuit 32, and a pure white signal is mixed in a part of a composite video signal and is outputted from the mixing circuit 32 and is sent to a color electronic view finder 5. A photographer uses this signal as a reference color to match the color of a white object projected on a main screen 62 to a small screen 61.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a color electronic viewfinder for a video camera.

[Prior Art] Fig. 3 is a block circuit diagram of the video signal system of a conventional color electronic viewfinder video camera. 11) is an imaging lens, (12) is an image sensor, (13) is a timing pulse generator, (14) is a drive circuit, (15) is a Y/C separator, (ta) is a luminance signal processing circuit, (17) ) is a composite signal processor, (18
) is the color signal processing circuit, (19) is the white balance circuit, (20) is the color modulation circuit, (21) is the auto/manual changeover switch, (22) is the auto white control circuit, and (23) is the manual white control circuit. , (24) is a variable resistor for adjustment, (51) , (
52) are first and second signal processing circuits, (53) is a drive circuit, (54) is a color display element, and (55) is an eyepiece.

Next, the operation will be explained. The optical information passing through the lens (11) forms an optical image on the surface of the image sensor (12).

This optical image is converted into an electrical signal by an image sensor (12) driven by a drive pulse generated by a drive circuit (14) based on a timing pulse from a timing pulse generator (13). It is sent to the C minuter (15). The luminance signal (Y) separated by the Y/C separator (15) passes through the luminance signal processing circuit (16) to the composite processor (
17). On the other hand, the color signal C separated by the Y/C separator (15) is processed by the color signal processing circuit (18) into color separation signals such as three primary color signals or color difference signals, and then sent to the white balance circuit (19). The signal is sent, undergoes color balance processing, is modulated by a color modulation circuit (20), is mixed with a luminance signal by a composite signal processor (17), and is output as a composite signal to an external monitor, VTR, etc. (not shown). .

The white balance circuit (19) has a selector switch (21).
) is connected to an auto white control circuit (22) or a manual white control circuit (23), and is controlled by a control signal from either circuit. Manual white control circuit (2
The control level 3) allows the photographer to arbitrarily adjust the white balance. On the other hand, the composite processor (17
) output from the first signal processing circuit (51) of the color electronic viewfinder section (5).
), the first and second signal processing circuits (51),
At (52), it is processed into an electrical signal that has passed through the characteristics of the color display element (54) and is sent to the color display element (54). The color display element (54) is driven by the drive circuit (53) and converts the electric signal input manually from the second signal processing circuit (52) into an optical signal for display. You can watch the video through.

[Problems to be Solved by the Invention] Conventional video cameras with color electronic viewfinders are configured so that the white balance can be adjusted automatically or manually in response to changes in the color temperature of illumination light, which is important in color video cameras. In particular, manual white balance, which can be adjusted to the photographer's preference, is unique in that it can be adjusted while viewing the color tone in the color electronic viewfinder. However, in this case, the color tone (not limited to white) of the color electronic viewfinder is different from the color tone (not limited to white) of the video camera itself.
In other words, the prerequisite is that the original image is matched with that of another monitor (such as a home television), and if there is a difference in color tone between the two, the color tone matched with the color electronic viewfinder will be When viewed on another monitor, the screen may have a different color tone than the photographer intended.

This invention was made to solve the above-mentioned problems. Even if the color tone of the color electronic viewfinder differs from that of a home TV, it can be adjusted using the white standard to produce a color image that does not look strange. The purpose is to obtain a video camera that can project images.

[Means for Solving the Problems] A video camera according to the present invention includes a white signal generating means that electrically generates a white signal, and when manually adjusting the white balance, the white signal is inserted into the imaging signal for viewing. The present invention is characterized in that a part of the display screen of the finder is provided with means for displaying the electrically white signal.

[Function] Of the display screens of the color electronic viewfinder, the white screen on which the white signal is projected is electrically a pure white signal, and is, so to speak, a reference white signal. Therefore, even if this white screen is not pure white, if you treat the color of the white screen as pure white and adjust the white balance so that the white part of the imaged screen is equal to the white screen, Appropriate white balance adjustment can be performed.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. In Fig. 1, (30) is a white signal generation circuit, (31) is a gate circuit, and (32) is a mixing circuit.
) is connected to send a signal to the Since the components other than the above are the same as those of the conventional embodiment shown in FIG. 3, the explanation will be omitted.

FIG. 2 is a diagram showing the state of the display screen of the display element (54) in the color electronic viewfinder (5).
) is the display screen of the display element (54), (61) is a partial small screen within the display screen (60), and (62) is the main screen.

When a photographer (not shown in FIG. 1) turns on the selector switch (21) to the manual white control circuit (23) side in order to perform white balance manually, a white signal is output by a command signal from the manual white control circuit (23). A generating circuit (30) is activated to generate an electrical white signal. This white signal is partially cut off by the gate circuit (31) and sent to the mixing circuit (32), and the mixing circuit (32) outputs a pure white signal mixed with a part of the composite video signal, and the color electronic display The image is sent to the finder (5). Looking at this state in Figure 2, the main screen (62) of the display screen (60) of the display element (54) of the color electronic viewfinder (5) shows the normal image captured by the imaging lens (11). However, the portion of the small screen (61) cut out by the gate circuit (31) becomes a pure white screen on which the white signal is projected. Note that the composite video signal is directly output from the composite signal processor (17) to a VTR or external monitor (not shown), so the external monitor has a pure white small screen (5) cut out by the gate circuit (31).
1) will not be visible. To take a picture of the white balance in this state, the photographer points the video camera (1) toward the white subject and points it at the display screen of the electronic viewfinder (5) (
Adjust the variable resistor (60) so that the color of the main screen (62) is as close as possible to the pure white color of the small screen (61).
24), it is possible to perform white balance adjustment with extremely high accuracy. In this case, the color of the small screen (61) does not necessarily have to be pure white. In other words, the display screen (60) of the color electronic viewfinder (5)
) does not necessarily match the white of an external monitor (not shown) or the so-called memory color of the photographer due to the characteristics of the display element (54), for example, the color of this small screen (61) is electrically pure white, so the photographer believes that the color of the small screen (61) is white, and uses this as a reference color to change the color of the white subject shown on the main screen (62) to the small screen (61). ), so there will be no hesitation or doubts for i-runners.

In the above embodiment, it was explained that the small screen display cut out by the gate circuit is displayed only on the electronic viewfinder, but it can also be displayed on an external monitor as long as it is not recorded on the recording tape of the connected VTR. Alternatively, a separate switch may be provided to turn on/off the small screen display according to preference, or a timer may be used to automatically display the small screen for a certain period of time.

Furthermore, it is not necessary to provide the gate circuit and the white signal generator solely for the function of displaying a small white screen, and there is no problem in using them for other purposes as well.

[Effects of the Invention] As described above, according to the present invention, since the reference white screen is displayed on a part of the display screen of the color electronic viewfinder, the color tone of the color electronic viewfinder does not require such high precision. This has the effect of providing a video camera that allows the photographer to easily and accurately adjust the white balance of the camera's output signal without causing any problems.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram of an embodiment of the present invention, Fig. 2 is a front view showing the display screen of a color electronic viewfinder in this embodiment, and Fig. 3 is a block circuit diagram showing the circuit configuration of a conventional video camera. It is. (1)...Video camera body, (5)...Color electronic viewfinder section, (23)...Manual white control circuit, (30)...White signal generation circuit, (31)...・Gate circuit, (32)...Mixing circuit, (54)...Color display element, (60)...
-Display screen, (61)...Small screen. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In a video camera equipped with an electronic viewfinder using a color display element for monitoring imaging signals, a white signal generating means for generating an electrically white signal, and inserting the white signal into the imaging signal during manual white balance adjustment. and means for displaying a white screen on a specified portion of the display screen.