JPH09214813A - Focus information display device for video camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To electrically display the focus information of a video signal in the form of a split image on a view finder corresponding to out-of-focus quantity. SOLUTION: When displaying the focus information of a subject in the form of the split image on a view finder 34 corresponding to out-of-focus quantity δin the case of shooting an object using the video camera, that focus information is not optically displayed by using two critical prisms and an imaging device for focus detection or the like as a conventional case but the rear starting position of video data of the subject stored in a VIDEO RAM 32 are controlled by a split image data control circuit 33 corresponding to the out-of-focus quantity δ so that the information can be electrically processed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus information of a video camera for electrically displaying a focus information of a subject image on a viewfinder as a split image when a subject is photographed by using the video camera. The present invention relates to a display device.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 5-48028 discloses a technique in which focus information of a subject image is displayed on a viewfinder as a split image when a subject is photographed by using a video camera. .

FIG. 4 is a diagram showing a state in which the focus information of a subject image is displayed as a split image on the viewfinder by using the focus information display method of a television camera or the like in the conventional example. Shows the focus state,
(B) shows a non-focused state.

As shown in FIG. 4, a method of displaying the focus information of a subject image in a split image according to the amount of defocus on the viewfinder using the conventional focus information display method of a television camera or the like, Tokkyo 5-48
It is disclosed in Japanese Laid-Open Patent Publication No. 028, and will be briefly described here.

In the focus information display method for a television camera or the like, which is disclosed in Japanese Patent Publication No. 5-48028, a part of a subject image projected on the image pickup device for photographing by the photographing optical system is used as light of the photographing optical system. For exit pupil division, which is composed of two critical angle prisms whose inclination surfaces are opposite to each other so that the light flux from the first region and the second region with the axis as a boundary can be mainly divided. Through the optical member, the image is output from the image pickup device by projecting it onto the image pickup device for focus detection which is placed on or near the plane that is substantially conjugate with the image pickup device for the image pickup optical system. Color display on the viewfinder monitor and single-color display of the image output from the focus detection image sensor as a split image that shifts laterally when out of focus depending on the focus state by synthesizing the screen on a part of the monitor. It is characterized. If necessary, refer to Japanese Patent Publication No. 5-48028.

That is, as shown in FIGS. 4 (A) and 4 (B),
At a substantially central portion in the viewfinder 100, the first and second split image frames 1 divided into upper and lower parts by a dividing line S are provided.
00a and 100b are set. And FIG.
When the photographed subject image is in the focused state as shown in (A), the first and second split image frames 100
The subject images are vertically aligned in a and 100b. On the other hand, when the photographed subject image is in a non-focus state as shown in FIG. 4B, the subject images are vertically displaced in the horizontal direction in the first and second split image frames 100a and 100b. At this time, the lateral shift amount changes according to the focus shift amount.

[0007]

By the way, in the above-mentioned conventional focus information display method for a television camera or the like, as shown in FIGS. Since the split image is displayed on the first and second split image frames 100a and 100b in the inside according to the defocus amount, the subject image can be taken while confirming the in-focus state and non-focus state of the subject image. , First and second split image frames 10
When the subject image is displayed as a split image on 0a and 100b, it is optically displayed by using two critical angle prisms and an image sensor for focus detection, so that the configuration is complicated and the cost of parts is high. There are problems such as being expensive.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an image of a subject is formed on an image pickup device by an image pickup lens, a zoom lens, a focus lens of a video camera and the like. In a focus information display device for a video camera, which displays focus information of a subject image on a viewfinder as a split image according to the amount of defocus, a video signal of the subject image output from the image sensor is A / D converted. VIDEO RAM for storing the D conversion circuit and the image data of the subject image digitally output from the A / D conversion circuit in a large rectangular frame of rows × columns.
In the VIDEO RAM, a small rectangular frame which is smaller in size in the vertical and horizontal directions than the large rectangular frame is set, and the small rectangular frame is divided into two by dividing lines to set first and second split image frames. The VI of the split image data for the first and second split image frames is relatively displaced via the dividing line according to the defocus amount.
A split image data control circuit for controlling the read start position of the video data of the subject image stored in the DEO RAM and the split image data for the first and second split image frames read from the VIDEO RAM are displayed. A focus information display device for a video camera, comprising a viewfinder.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a focus information display device for a video camera according to the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a block diagram showing a focus information display device of a video camera according to the present invention, and FIG. 2 is a diagram for explaining an operation of creating split image data using the VIDEO RAM shown in FIG. Yes, (A) is V
FIG. 3 shows a state in the IDE RAM, FIG. 3B shows a state in which split image data is created, and FIG. 3 shows a focus information display device for a video camera according to the present invention.
It is the figure which showed the state which displayed the focus information of a to-be-photographed image by the split image on the viewfinder, (A) shows the front focus shift state which the focus shifted to the front, (B) shows the focus point which the focus matched. The state is shown, and (C) shows the state where the focus is shifted backward and the focus is defocused.

In the focus information display device 1 for a video camera according to the present invention shown in FIG. 1, a photographing lens 3 for photographing a subject H is provided in a lens barrel 2 and an optical axis K of the lens barrel 2 is used for photographing. Along with the zoom lens 4 for changing the size of the subject image while adjusting the image frame of the subject H, an intermediate lens 5, an iris (aperture) 6 for adjusting the light amount at the time of shooting, and shooting The focus lens 7 that sometimes moves in the direction of the arrow along the optical axis K of the lens barrel 2 to adjust the focus of the subject image, and the subject image photographed via the above-mentioned photographing optical systems 3 to 7 are optically. The image pickup device 8 that forms an image and photoelectrically converts the subject image is arranged in the order described above.

Here, the zoom lens 4 movable in the optical axis direction is connected to a zoom motor 11 using a stepping motor via a gear portion 10. The zoom motor 11 is pulse-driven by a zoom control circuit 12. Has been done. On the other hand, a focus lens 7 that is movable in the optical axis direction
Is connected to a focus motor 21 using a stepping motor via a gear unit 20, and the focus motor 21 is pulse-driven by an autofocus control circuit 22.

During shooting, the focus lens 7 that cooperates with the movement of the zoom lens 4 adjusts the focus of the subject image according to the subject distance by a well-known hill-climbing servo. At this time, autofocus control is performed. Circuit 2
From 2, the defocus amount δ due to the hill climbing servo is output. The defocus amount δ is output with a variation value of ± in a front defocus state in which the focus is deviated forward with respect to the in-focus state and in a rear defocus state in which the focus is deviated rearward. The defocus amount δ output from the autofocus control circuit 22 is supplied to a split image data control circuit 33 described later.

The image signal of the subject image photoelectrically converted by the image pickup device 8 is sent to the autofocus control circuit 22 and the A / D conversion circuit 31 via the image signal processing circuit 30, and is not shown. It is also sent to the well-known VTR (video tape recorder) side.

In the A / D conversion circuit 31, the video signal of the subject image photoelectrically converted by the image pickup device 8 is A / D converted into digital video data to be converted into the VIDEO RAM 32.
Has been sent to. Further, the VIDEO RAM 32 is configured by using a well-known digital memory, and the video data of the subject image passing through the A / D converter 31 is shown in FIG.
It is temporarily digitally stored in a large rectangular frame 32a of horizontal rows × vertical rows as shown in FIG.

Here, components and operations for electrically displaying the focus information of the subject image, which is the main part of the present invention, in a split image on the viewfinder 34, which will be described later, in accordance with the defocus amount δ. A description will be given in combination with FIG.

First, the split image data control circuit 33 has a function of electrically displaying a subject image as a split image on the viewfinder 34, which will be described later, in accordance with the defocus amount δ. That is, FIG.
Large rectangular frame 32 of VIDEO RAM 32 shown in FIG.
A small rectangular frame 32b with the vertical and horizontal directions slightly smaller than a
Is set in the VIDEO RAM 32, and the small small rectangular frame 32b is bisected diagonally by one dividing line S to divide the first and second split image frames 32b ₁ and 32b ₂
Is set. At this time, the first and second split image frames 32b ₁ and 32b _{2 which} divide the small rectangular frame 32b of the VIDEO RAM 32 into _two are the viewfinder 3 described later.
4th 1st, 2nd split image frames 34a, 34b
(Fig. 3) is also supported.

Further, the split image data control circuit 33 includes the first and second split image frames 32b ₁ and 3b.
VIDEO RA so that the split image data for 2b ₂ is relatively displaced via the dividing line S in accordance with the defocus amount δ output from the autofocus control circuit 22.
The read start position (cutout start position) of the video data of the subject image digitally stored in the large rectangular frame 32a of M32 is controlled.

Here, in FIG. 2A, for example, on the upper side of the first split image frame 32b ₁ on the left side in the figure, the image data of the subject image in the horizontal direction is formed along the line in the frame 32b ₁ until it intersects with the dividing line S. Is read out, and thereafter, on the side of the second split image frame 32b ₂ on the right side of the drawing, the dividing line S is extended to the large rectangular frame 32a and the extended dividing line S
The image data of the subject image is read out laterally along a line outside the second split image frame 32b ₂ from a position that is diagonally upwardly displaced by a defocus amount δ along. Then, in the same manner as above, the dividing line S is formed along the line in the first split image frame 32b ₁ at approximately the center of the first and second split image frames 32b ₁ and 32b _2.
The image data of the subject image is read out in the lateral direction until the second split image frame 32b ₂ is moved from a position shifted obliquely upward along the dividing line S by the defocus amount δ.
The video data of the subject image is read out in the horizontal direction along the line inside.

As described above, based on the control command of the split image data control circuit 33, the VIDEO RAM
When the image data of the subject image is sequentially read out in 32 in the above procedure, the first and second split image frames 32b ₁ and 32b
The split image data to b ₂ is read out as shown in FIG. 2 (B), and this state is immediately shown in FIG.
As shown in (C), the data is transferred to the first and second split image frames 34a and 34b of the viewfinder 34.

Then, as shown in FIGS. 3A to 3C, in the first and second split image frames 34a and 34b of the viewfinder 34, VI depending on the defocus amount δ.
The subject image is electrically displayed as a split image corresponding to the split image data read in the first and second split image frames 32b ₁ and 32b ₂ in the DEORAM 32. That is, FIG. 3A shows a front focus shift state in which the focus is shifted to the front, and the second split image frame 34a on the left side of the drawing shows the second focus image frame on the right side of the drawing.
The split image frame 34b is displaced to the left. Further, FIG. 3B shows a focused state in which the focus is matched, and the first split image frame 34a on the left side in the drawing and the second split image frame 34b on the right side in the drawing match without shifting. Further, FIG. 3C shows a rear focus defocused state in which the focus is shifted rearward, and the first split image frame 34a on the left side in the figure shifts leftward with respect to the second split image frame 34b on the right side in the figure. There is.

As described above, according to the present invention, when the focus information of the subject image is displayed on the viewfinder 34 as a split image according to the defocus amount δ when the subject H is photographed by using the video camera, the conventional method is used. Without optically displaying using the two critical angle prisms and the focus detection image pickup device, the read start position of the video data of the subject image stored in the VIDEO RAM 32 is split according to the defocus amount δ. Since it can be electrically processed by being controlled by the image data control circuit 33, the configuration can be simplified and the cost of parts of the device 1 can be reduced, and the focus state display operation of the device 1 can be performed reliably and reliably. Therefore, the photographer can look through the viewfinder 34 to visually confirm whether or not the subject image is in focus.

In the embodiment, the first and second split image frames 32b ₁ and 32b ₂ are stored in the VIDEO RAM 32.
When setting, the small rectangular frame 32 of the VIDEO RAM 32
Although b is set to be divided into two in the diagonal direction by the dividing line S, it is not limited to this and may be divided into upper and lower parts as in the conventional example shown in FIG. It is only necessary to read the image data of the subject image within the large rectangular frame 32a of the VIDEO RAM 32 so that the split image data to the first and second split image frames are shifted to the left and right by δ.

Further, the VIDEO RAM provided in the embodiment
It is also possible to share 32 with a VIDEO RAM for setting the cut-out position of the image data of the subject image during camera shake correction.

[0025]

According to the focus information display device for a video camera according to the present invention described in detail above, when the subject is photographed by the video camera, the focus information of the subject image is displayed on the viewfinder according to the amount of defocus. When displaying a split image, the read start position of the image data of the subject image stored in the VIDEO RAM is displayed without optically displaying it using two critical angle prisms and an image sensor for focus detection as in the prior art. Can be electrically processed by controlling the split image data control circuit 33 according to the amount of defocus, so that the configuration can be simplified and the cost of parts of the device can be reduced, and the focus state display operation of the device can be performed with high reliability. Since it can be performed reliably, the photographer can look through the viewfinder and visually check whether or not the subject image is in focus. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a focus information display device of a video camera according to the present invention.

2A and 2B are views for explaining the operation of creating split image data using the VIDEO RAM shown in FIG. 1, where FIG. 2A shows a state in the VIDEO RAM and FIG. 2B shows split image data. It is a figure showing the created state.

FIG. 3 is a diagram showing a state in which the focus information of a subject image is displayed as a split image on a viewfinder by using the focus information display device of the video camera according to the present invention. FIG. A front defocused state that is deviated is shown, and (B) shows a focused state where the focus is matched,
(C) shows a state where the focus is deviated to the rear and then defocused.

FIG. 4 is a diagram showing a state in which focus information of a subject image is displayed as a split image on a viewfinder by using a focus information display method of a television camera or the like in a conventional example, and FIG. And (B) shows the out-of-focus state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Focus information display device of video camera, 3 ... Photographing lens, 4 ... Zoom lens, 7 ... Focus lens, 8 ... Imaging element, 30 ... Video signal processing circuit, 31 ... A / D conversion circuit, 32 ... VIDEO RAM, 32a ... Large rectangular frame, 3
2b ... Small rectangular frame, 32b ₁ , 32b ₂ ... First and second split image frame, 33 ... Split image data control circuit, 34 ... Viewfinder, 34a, 34b ... First and second split image frame, H ... Subject , S ... Dividing line, δ ... Defocus amount.

Claims (1)

[Claims] Claims: 1. A subject is imaged on an image sensor by an image pickup lens, a zoom lens, a focus lens of a video camera, and the focus information of the formed image of the subject is split image on a viewfinder according to the amount of defocus. In a focus information display device for a video camera, the video signal of the subject image output from the image sensor is
A / D conversion circuit for D conversion, and V for storing video data of a subject image digitally output from the A / D conversion circuit in a large rectangular frame of rows × columns.
In the VIDEO RAM, a small rectangular frame that is smaller in the vertical and horizontal directions than the large rectangular frame in the VIDEO RAM is set, and the small rectangular frame is divided into two by dividing lines to set first and second split image frames. At the same time, the split image data to the first and second split image frames may be relatively shifted via the dividing line according to the defocus amount.
A split image data control circuit for controlling the read start position of the video data of the subject image stored in the O RAM, and the split image data for the first and second split image frames read from the VIDEO RAM. A focus information display device for a video camera, comprising: a viewfinder.