JP2002247422A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an image pickup device that facilitates focusing. SOLUTION: The image pickup device is provided with a focus area setting circuit 2 and 1st and 2nd selection circuits 6a, 6b. A display device 12 displays a sum of an input video signal V and a contour correction signal DTL resulting from multiplying an optional coefficient α with an original contour correction signal at the outside of a focus area. Furthermore, the display device 12 displays a sum of an optional offset level X and a contour correction signal DTL resulting from multiplying an optional coefficient β with the original contour correction signal within the focus area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image pickup apparatus equipped with a viewfinder (hereinafter, referred to as VF).

[0002]

2. Description of the Related Art In general, when focusing with an imaging device for business use or broadcasting, that is, a television camera, a cameraman looks at an image projected on a VF attached to the camera and manually controls a focus lens. Is going. In the related art, a contour correction signal is added to a video signal supplied to a VF so that a cameraman can easily perform focusing, and the cameraman focuses on a contour portion of a VF video.

[0003]

However, in the prior art, particularly in a television camera equipped with a small VF, the resolution of the VF is insufficient and the reproducibility of the contour correction signal deteriorates. The signal becomes difficult to see. For this reason, there has been a problem that focusing is difficult.

[0004] Further, since the method is a method in which the contour correction signal is added to the video signal, the level of the contour correction signal is small in an image having a small luminance difference, and it is difficult to distinguish the image from the background video. Similarly, in the case of a low-luminance subject, the level of the contour correction signal itself is low, and
There is also a problem that the darkened F-screen makes it difficult to see the outline portion of the image.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides an image pickup apparatus which enables a photographer to easily visually recognize a contour correction signal on a VF image under any photographing conditions. It is intended to provide a device.

[0006]

According to a first aspect of the present invention, there is provided a viewfinder for displaying a captured image of a subject, and a focus range for the subject at an arbitrary position of the image displayed on the viewfinder. A focus area setting circuit for setting a focus area for designating and outputting a focus area signal indicating whether or not the subject is in a focus range; and a contour correction signal generating circuit for obtaining a contour correction original signal of the subject from an input video signal. A first selection circuit that switches and outputs the input video signal or an arbitrary offset level based on the focus area signal, and switches a first coefficient value or a second coefficient value based on the focus area signal; A second selection circuit for outputting the switched coefficient value, an outline correction original signal output from the outline correction generation circuit, and a second A multiplier that multiplies the coefficient value selected by the selection circuit to obtain a contour-corrected signal whose gain has been adjusted, and adds the output of the first selection circuit and the contour-correction signal output from the multiplier, And an adder for outputting the added video signal to the viewfinder.

According to a second aspect of the present invention, there is provided a viewfinder for displaying a captured image of a subject, and a focus for designating a focus range for the subject at an arbitrary position of the image displayed on the viewfinder. A focus area setting circuit for setting an area and outputting a focus area signal indicating whether or not the subject is in a focus range; a contour correction signal generating circuit for obtaining a contour correction original signal of the subject from an input video signal; and the contour correction generating circuit A first multiplier for inputting the contour correction original signal output from the multiplier as a multiplicand and performing gain adjustment by multiplying by a first coefficient, and adding the output of the first multiplier and the input video signal A first adder, a memory for storing a contour correction original signal output from the contour correction signal generation circuit, and a focus area signal indicating a focus range. A write control signal group for writing the contour correction original signal to the memory, and a read control signal group for reading the contour correction original signal from the memory at an arbitrary position in a display area of the viewfinder. An R / W control circuit for generating a switching control signal for switching and outputting a video signal to the viewfinder based on the focus area signal; and outputting the contour correction original signal read from the memory. A second multiplier that performs gain adjustment by inputting as a multiplicand and multiplying by a second coefficient, a second adder that adds an output of the second multiplier and an arbitrary offset level, An output signal of the first adder and an output signal of the second adder are input, switched and output based on the selection circuit control signal, and are switched. Is characterized in that it comprises a selection circuit for outputting a video signal to the viewfinder, the.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows an example of the configuration of an image pickup apparatus according to Embodiment 1 of the present invention. This imaging device
It comprises a focus area setting circuit 2, an outline correction signal generation circuit 3, a first selection circuit 6a, a second selection circuit 6b, a multiplier 9, an adder 11, and a display device 12.

A focus area setting circuit 2 sets a focus area for designating a focus range for a subject at an arbitrary position of an image displayed on the display device 12,
This is a circuit for outputting a focus area signal FA indicating whether or not the focus is within a focus range. The contour correction signal generation circuit 3 is a circuit for obtaining an original contour correction signal of the subject from the input video signal V. The function of the contour correction signal generation circuit 3 can be realized by a high-pass filter, and is configured such that an arbitrary frequency band can be selected as a boost frequency.

The first selection circuit 6a converts the input video signal V or an arbitrary offset level X into a focus area signal F
This is a circuit for switching and outputting based on A. Multiplier 9
Is a circuit for multiplying the contour correction original signal output from the contour correction signal generation circuit 3 by using the coefficient value output from the selection circuit 6b to obtain a gain-adjusted contour correction signal DTL.

The second selection circuit 6b is a circuit that switches the first coefficient value α or the second coefficient value β based on the focus area signal FA and supplies the switched coefficient value to the multiplier 9. The adder 11 adds the output of the first selection circuit 6a and the contour correction signal output from the multiplier 9,
This is a circuit that outputs the added video signal to the display device 12. The display device 12 is a viewfinder that displays a captured image of a subject and a focused state of a specific area.

The operation of the imaging apparatus configured as described above will be described. When the input video signal V is input, the contour correction signal generation circuit 3 generates a contour correction original signal. This contour correction original signal is obtained by the photographer selecting a desired boost frequency. The multiplier 9 receives the contour correction original signal as a multiplicand, multiplies the coefficient by the coefficient selected by the selection circuit 6b, adjusts the gain of the contour correction original signal, and generates a contour correction signal DTL.

Next, the focus area setting circuit 2 is shown in FIG.
As shown in (2), an arbitrary size focus area is set at an arbitrary position in the vertical and horizontal directions of the input video signal V on the screen. This focus area signal is shown in FIG.
It is created by the logical product of the horizontal gate pulse in FIG. 2A and the vertical gate pulse in FIG. The logic level of the focus area signal FA becomes High inside the focus area, and the logic level becomes Low outside the focus area. Such a focus area setting is performed for a subject intended by the cameraman, that is, a subject portion for which it is desired to obtain just focus.

Next, when a video signal input V and an arbitrary offset level X are given, the selection circuit 6a switches its output using a switching control signal. The selection circuit 6a uses a focus area signal FA as a switching control signal, selects and outputs an input video signal V as shown in FIG. 3A outside the focus area, and sets an arbitrary offset level X inside the focus area. Select and output. At the same time, the selection circuit 6b switches the coefficient given to the multiplier 9. The selection circuit 6b uses the focus area signal FA as the switching control signal, and selects the first coefficient α outside the focus area and selects the second coefficient β inside the focus area.

Next, the adder 11 adds the output signal of the selection circuit 6a and the contour correction signal DTL shown in FIG. By these series of operations,
Outside the focus area, a signal obtained by multiplying the input image signal V by the first coefficient α to the contour correction original signal is added, and the added image is displayed. In the focus area, as shown in FIG. 3C, a signal obtained by multiplying the offset correction level X by a second coefficient β is added to the offset level X, and the added image is displayed.

According to the present embodiment, the offset level X is multiplied by the second coefficient β in the focus area P0 as shown in FIG. 4B with respect to the original picture shown in FIG. Only the contour correction signal DTL is displayed on the display device. As described above, the cameraman can visually recognize only the contour correction signal of the subject to obtain the just focus on the display device 12. Further, by arbitrarily adjusting the values of the offset level X and the coefficient β, the cameraman himself can easily recognize the contour correction signal DTL in the focus area on the display device 12 in any subject image.

Although not described in the present embodiment, by displaying a frame signal indicating the set focus area on the VF, the burden on the cameraman can be further reduced.

(Embodiment 2) Next, an image pickup apparatus according to Embodiment 2 will be described as the second aspect of the present invention. This imaging apparatus includes a selection circuit 5, a first multiplier 9a, a second multiplier 9b, in addition to a focus area setting circuit 2, a contour correction signal generation circuit 3, and a display device 12 similar to those in the first embodiment. First adder 11a, second adder 11
b, memory 13, and R / W control circuit 14.

The focus area setting circuit 2 sets a focus area indicating an in-focus range of an arbitrary size on the display device 12 at an arbitrary position in the display area, and a focus area signal FA indicating whether or not the focus area is attained. Is a circuit that outputs.
The contour correction signal generation circuit 3 is a circuit that generates a contour correction original signal from the input video signal V.

The multiplier 9a is a circuit for adjusting the gain by inputting the contour correction original signal of the contour correction signal generating circuit 3 as a multiplicand and multiplying it by a first coefficient α. The adder 11a is a circuit that adds the output of the multiplier 9a and the input video signal V. The memory 13 is a memory for storing an original contour correction signal output from the contour correction signal generation circuit.

When the focus area signal FA indicates the in-focus range, the R / W control circuit 14 generates a write control signal group W for writing the contour correction original signal into the memory 13 and, at the same time, generates a write control signal group W for displaying the contour correction signal. Is a circuit for generating a read control signal group R for reading out the contour correction original signal from the memory 13 at an arbitrary position in FIG. R / W control circuit 1
Reference numeral 4 also generates a switching control signal for switching and outputting the video signal to the display device 12 based on the focus area signal FA.

The multiplier 9b is a circuit for adjusting the gain by inputting the contour correction original signal read from the memory 13 as a multiplicand and multiplying it by a second coefficient β. The adder 11b is a circuit that adds the output of the multiplier 9b and an arbitrary offset level X. The selection circuit 5 is an adder 1
1a and the output signal of the adder 11b,
Switching and outputting based on the switching control signal SEL,
This is a circuit that outputs the switched video signal to the display device 12.

The operation of the imaging apparatus configured as described above will be described. When the input video signal V is input, the contour correction signal generation circuit 3 generates a contour correction original signal. Since the contour correction signal generating circuit 3 is constituted by a high-pass filter, any frequency band can be selected as a boost frequency. The contour correction original signal obtained by the photographer selecting a desired boost frequency is given to the multiplier 9a as a multiplicand. The multiplier 9a adds a first coefficient α to the multiplicand.
, The gain of the contour correction original signal is adjusted. The adder 11a is provided with an input video signal input V and a multiplier 9a.
And outputs the addition result to one of the selection circuits 5.

As shown in FIG. 2, the focus area setting circuit 2 sets a focus area of an arbitrary size at an arbitrary position in the vertical and horizontal directions of the input video signal V on the screen. The focus area signal FA indicating whether or not this area is generated by the logical product of the horizontal gate pulse shown in FIG. 2A and the vertical gate pulse shown in FIG. 2B. Therefore, the logic level of the focus area signal FA5 becomes High inside the focus area, and the logic level becomes Low outside the focus area.
Such a focus area setting is performed for a subject intended by the cameraman, that is, a subject portion for which it is desired to obtain just focus.

Next, when the focus area signal FA indicates the inside of the focus area, the contour correction original signal generated by the contour correction signal generation circuit 3 is stored in the memory 13. When the focus area signal FA indicates the inside of the focus area, the R / W control circuit 14 generates a write control signal group W that matches the specifications of the memory 13. The write control signal group W includes a chip select signal, a write address bus signal, a write enable signal,
This signal indicates a write clock. The contour correction original signal stored in the memory 13 is read by the read control signal group R of the R / W control circuit 14 and displayed at an arbitrary position on the display device 12. In the case of a general memory, the read control signal group R is a signal indicating a chip select signal, a read address bus signal, a read enable signal, and a read clock.

The outline correction original signal thus read is input to the multiplier 9b. The multiplier 9b adjusts the gain of the contour correction original signal by the second coefficient β, and
1b. The adder 11b adds the output of the multiplier 9b to an arbitrary offset level X, and supplies the addition result to the other of the selection circuits 5 as the contour correction signal DTL. Selection circuit 5
Switches between the output of the adder 11a and the contour correction signal DTL by the switching signal SEL from the R / W control circuit 13, and supplies the output to the display device 12. This switching signal SE
L is output in synchronization with the read control signal group R of the memory 13 and is used to display an outline correction signal in the focus area at an arbitrary position on the display device 12. Thus, a so-called picture-in-picture (Pin)
The operation of P) is realized. Through a series of these operations, the cameraman can visually recognize the image of the entire subject and the contour correction signal of the subject at the same time while confirming the subject on which just focus is to be obtained on the display device 12.
For this reason, focus adjustment becomes easy.

FIG. 6 shows an example of a display screen of the display device 12 when such an operation is realized. When the area shown by the dotted line is set as the focus area P0 with respect to the image of the subject shown in FIG. 6A, the image displayed by PinP is shifted to the right in the viewfinder as shown in the DTL portion of FIG. The outline is highlighted at the bottom. In the first and second embodiments, the value of the coefficient α and the value of the coefficient β can be arbitrarily set by the user of the imaging apparatus.

[0028]

As described above, according to the present invention, it is possible to eliminate the conventional difficulty in visually recognizing the contour correction signal at the time of focusing, and to reduce the luminance difference between the subject and the background when the subject has low luminance. Even when there are few, you can clearly observe only the contour correction signal of the subject that you want to obtain just focus,
The effect of remarkably reducing the load on the focusing operation of the cameraman can be obtained.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an imaging device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of a focus area setting circuit according to the first and second embodiments of the present invention.

FIG. 3 is a signal waveform diagram illustrating an operation in a focus area according to the first embodiment.

FIG. 4 is an explanatory diagram showing an operation of a display screen in the first embodiment.

FIG. 5 is a functional block diagram of an imaging device according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an operation of a display screen according to the second embodiment.

[Explanation of symbols]

 2 focus area setting circuit 3 contour correction signal generation circuit 6, 6a, 6b selection circuit 9, 9a, 9b multiplier 11, 11a, 11b adder 12 display device 13 memory 14 R / W control circuit V input video signal X offset level FA focus area signal SEL switching signal DTL contour correction signal W write control signal group R read control signal group α first coefficient β second coefficient

Claims (2)

[Claims] 1. A viewfinder for displaying a captured image of a subject, and a focus area for designating a focus range for the subject at an arbitrary position of the image displayed on the viewfinder. A focus area setting circuit that outputs a focus area signal indicating whether or not the image is in a range; a contour correction signal generating circuit that obtains a contour correction original signal of the subject from an input video signal; First to switch and output based on area signal
A second selection circuit that switches the first coefficient value or the second coefficient value based on the focus area signal and outputs the switched coefficient value; and a selection circuit output from the contour correction generation circuit. A multiplier for multiplying the contour correction original signal by the coefficient value selected by the second selection circuit to obtain a gain-adjusted contour correction signal; an output of the first selection circuit and an output from the multiplier And an adder for adding the added contour correction signal and outputting the added video signal to the viewfinder. 2. A viewfinder for displaying a captured image of a subject, and a focus area for designating a focus range for the subject at an arbitrary position of the image displayed on the viewfinder. A focus area setting circuit that outputs a focus area signal indicating whether or not the image is in a range; a contour correction signal generating circuit that obtains a contour correction original signal of the subject from an input video signal; and a contour correction source output from the contour correction generating circuit. A first multiplier for inputting a signal as a multiplicand and performing gain adjustment by multiplying by a first coefficient; a first adder for adding an output of the first multiplier and the input video signal; A memory for storing a contour correction original signal output from the contour correction signal generation circuit; and a contour correction when the focus area signal indicates a focusing range. Generating a write control signal group for writing an original signal to the memory; generating a read control signal group for reading the contour correction original signal from the memory at an arbitrary position in a display area of the viewfinder; An R / W control circuit for generating a switching control signal for switching and outputting a video signal to the viewfinder based on a focus area signal; and inputting the contour correction original signal read from the memory as a multiplicand; A second multiplier that performs gain adjustment by multiplying by a second coefficient; a second adder that adds an output of the second multiplier to an arbitrary offset level; and a first adder And the output signal of the second adder are input, switched and output based on the selection circuit control signal, and the switched video signal is Imaging apparatus characterized by comprising a selection circuit for outputting the over finder, a.