JP3048409B2 - Video camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera having a zoom function and an electronic viewfinder.

[0002]

2. Description of the Related Art By using a video camera, it is possible to capture a still image in addition to a moving image. However, the resolution of the video camera is lower than the resolution of the photo camera,
Often, you want to use a photo camera with your video camera. For example, it is conceivable to fix the photo camera to the video camera and operate the shutter of the photo camera while capturing a moving image with the video camera.

In this case, if the image frame of the photo camera is displayed on the electronic view finder of the video camera, the user can recognize the image field of the photo camera with the electronic view finder and can perform the shutter operation properly. .

[0004]

By the way, in a video camera having a zoom function, when the zoom magnification changes, the angle of view of the imaging screen changes. Then, the positional relationship between the imaging screen and the image frame of the photo camera changes according to the change in the angle of view of the imaging screen.

In view of the above, the present invention is intended to accurately recognize the field of view of a photo camera even when the zoom magnification changes.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a video camera having a zoom function and an electronic viewfinder, wherein an image frame display means for displaying an image frame of a photo camera on a screen of the viewfinder, and a zoom magnification. Display size changing means for changing the display size of the imaging screen of the viewfinder according to a change in the angle of view of the imaging screen due to the change of the image, and displaying the imaging screen on the screen of the viewfinder based on the frame of the photo camera. Things.

[0007]

When the zoom magnification is reduced, the angle of view of the imaging screen is increased, and the display size is increased. On the other hand, as the zoom magnification increases, the angle of view of the imaging screen decreases, and the display size decreases. That is, the display size of the imaging screen changes according to the change in the zoom magnification.

[0010] According to the above configuration, the electronic viewfinder displays an image-capturing screen based on the image frame of a photo camera of a fixed size, so that the field of view of the photo camera can be accurately recognized. The user can accurately operate the shutter of the photo camera while looking at the display screen.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. In this example, a video camera and a photo camera are integrally formed.

FIG. 1 is a perspective view showing the overall configuration. In FIG. 1, reference numeral 1 denotes a cabinet. Although not shown, the cabinet 1 contains a video camera unit including an image sensor, a signal processing circuit, and the like, and a photo camera unit including a film loading mechanism, a film driving mechanism, and the like.

Reference numeral 2 denotes an imaging lens of a video camera unit,
Reference numeral 3 denotes an imaging lens of the photo camera unit. That is, the optical systems of the video camera unit and the photo camera unit are configured separately. The focal length f of the imaging lens 2 is 7 mm to 42 m
A 6 × m zoom lens is used. On the other hand, as the imaging lens 3, a fixed focal length lens having a focal length f of 55 mm is used.

In this embodiment, an electronic view finder composed of a small CRT is provided in the cabinet 1.
A screen captured by the video camera unit via the imaging lens 2 is displayed on the RT. 4 is an eyecup. In addition,
There is no finder for directly checking the screen imaged by the photo camera unit via the imaging lens 3.

Reference numerals 5T and 5W denote zoom operation buttons for performing zoom operations in the TELE direction and the WIDE direction, respectively. Reference numeral 6 denotes a recording button for performing an operation of recording an imaged video signal output from the video camera unit on a VTR, and reference numeral 7 denotes a shutter button of the photo camera unit. 8 is a film rewind button.

FIG. 2 shows the configuration of the video camera unit. Image light from a subject is supplied via an imaging lens 2 and an iris 11 to a single-chip CCD solid-state imaging device 12 having complementary color checkerboard color filters.

FIG. 3 is a schematic diagram of the color coding of the image pickup device 12. As shown in FIG. As shown in the figure, field reading is performed. In the A field, charges are mixed in pairs such as A1 and A2, and in the B field, B1 and B2 are mixed.
Charges are mixed in pairs such as 2. Then, from the horizontal shift register Hreg, A1, A in the A field
.., B1, B2,...
The charges are output in the order of.

Here, as shown in FIG. 4, the order of the charges a, b,... Is (Cy +
G), (Ye + Mg),..., (Cy + Mg), (Ye + G),... In the A2 line, and (G + Cy), (Mg + Y) in the B1 line.
e),..., and (Mg +
Cy), (G + Ye),.

The charge output from the image pickup device 12 as described above is supplied to a CDS circuit (correlated double sampling circuit) 13 and is extracted from the CDS circuit 13 as an image pickup signal. By using this CDS circuit 13,
As is well known, reset noise can be reduced.

Timing pulses required by the image pickup device 12 and the CDS circuit 13 are supplied from a timing generator 14. The timing generator 14 has 8
fsc (fsc is the color subcarrier frequency) reference clock CK0
, And horizontal and vertical synchronization signals HD and VD are supplied from the synchronization generator 16. On the other hand, synchronization generator 1
6 is a clock CK of 4 fsc from the timing generator 14.
1 is supplied.

An image signal output from the CDS circuit 13 is supplied to a level detection circuit 17, and an output signal of the detection circuit 17 is supplied to an iris driver 18. And
The iris of the iris 11 is automatically controlled by the iris driver 18.

Here, a process for obtaining a luminance signal Y and a chroma signal (color difference signal) from the image pickup signal output from the CDS circuit 13 will be described.

The luminance signal Y is obtained by adding adjacent signals. In FIG. 4, a + b, b +
An added signal of c, c + d, d + e,... is sequentially formed.

For example, the A1 line is approximated by the following equation. Here, Cy = B + G, Ye = R + G, Mg
= B + R.

Y = {(Cy + G) + (Ye + Mg)) × 1/2 = (2B + 3G + 2R) × 1/2 Further, the A2 line is approximated by the following equation.

Y = {(Cy + Mg) + (Ye + G))} × 1/2 = (2B + 3G + 2R) × 1/2 Other lines of the A field and lines of the B field are similarly approximated.

The chroma signal is obtained by subtracting adjacent signals.

For example, the A1 line is approximated by the following equation.

R−Y = (Ye + Mg) − (Cy + G) = (2R−G) Further, the A2 line is approximated by the following equation.

-(B−Y) = (Ye + G) − (Cy−Mg) = − (2B−G) The other lines in the A field and the lines in the B field are similarly processed with the red difference signals RY and RY. The blue difference signal-(BY) is obtained alternately in a line-sequential manner.

Returning to FIG. 2, the imaging signal output from the CDS circuit 13 is supplied to a low-pass filter 20 constituting a luminance processing unit via an AGC circuit 19. The low-pass filter 20 performs an addition process (averaging) of adjacent signals. Therefore, this low-pass filter 2
From 0, a luminance signal Y is output.

The image signal output from the AGC circuit 19 is supplied to sample and hold circuits 21 and 22 constituting a chroma processing unit. Sample and hold circuit 21,
Sampling pulses SHP1 and SHP2 (illustrated by E and F in FIGS. 5 and 6) are supplied from the timing generator 14 to 22.

From the sample and hold circuit 21, (Cy
+ G) or (Cy + Mg) continuous signal S1 is output and supplied to the subtractor 23 (shown in FIGS. 5B and 6B). From the sample and hold circuit 22, (Ye + M
g) or a continuous signal S2 of (Ye + G) is output and supplied to the subtractor 23 (shown in FIGS. 5C and 6C).

In the subtractor 23, the signal S1 is subtracted from the signal S2. Therefore, the subtractor 23 outputs the red difference signal RY and the blue difference signal-(BY), respectively, in a line-sequential manner (illustrated in FIGS. 5D and 6D).

The color difference signal output from the subtractor 23 is supplied to the fixed terminal b of the direct changeover switch 24 and the fixed terminal a of the changeover switch 25 and has a delay time of one horizontal period. The signal is supplied to the fixed terminal on the a side of the changeover switch 24 and the fixed terminal on the b side of the changeover switch 25 via 26.

Switching of the changeover switches 24 and 25 is controlled by the controller 27. That is, one horizontal period during which the red difference signal RY is output from the subtractor 23 is b.
, While one horizontal period during which the blue difference signal-(BY) is output is connected to the a side. The controller 27 is supplied with the synchronization signals HD and VD from the synchronization generator 16 as reference synchronization signals, and is also supplied with a clock CK1 from the timing generator 14.

Since the changeover switches 24 and 25 are switched as described above, the changeover switch 24 outputs the red color difference signal RY in each horizontal period, and the changeover switch 25 outputs the blue color difference signal − ( BY) is output.

The luminance signal Y output from the low-pass filter 20 and the color difference signals (RY) and-(BY) output from the changeover switches 24 and 25 are supplied to an encoder 28. The encoder 28 is supplied with a composite synchronization signal SYNC, a blanking signal BLK, a burst flag signal BF, and a color subcarrier signal SC from the synchronization generator 16.

In the encoder 28, as is well known, a synchronizing signal SYNC is added to the luminance signal Y, and a quadrature two-phase modulation is applied to the color difference signal to form a carrier color signal C, and a color burst signal is added. . And
The luminance signal Y and the carrier chrominance signal C are added to form an NTSC color video signal, for example. Thus, the color video signal SCV output from the encoder 28 is led out to the output terminal 29.

The encoder 28 outputs a black-and-white video signal SV (a luminance signal Y to which a synchronization signal SYNC is added), and the black-and-white video signal SV is supplied to an electronic viewfinder 30. Then, an imaging screen is displayed on a small CRT constituting the electronic viewfinder 30.

The zoom magnification of the imaging lens 2 is adjusted by a zoom driver 41. FIG. 7 shows a specific configuration of the zoom driver 41. In the figure, reference numeral 411 denotes a lens constituting the imaging lens 2;
This is for adjusting the zoom magnification. This lens 4
The zoom magnification is adjusted by moving the position 11 back and forth by rotational driving. For example, by rotating to the T side, it is adjusted in the TELE direction, and by rotating to the W side, it is adjusted in the WIDE direction.

The rotation of the lens 411 is performed by a DC motor 412. One end and the other end of the motor 412 are connected to output terminals q1 and q2 of the zoom driver 413, respectively. The input terminals p1 and p2 of the zoom driver unit 413 are respectively connected to the zoom operation switch 4
2 are connected to the fixed terminals on the T and W sides.

In this case, when a high-level "H" signal is supplied to the terminal p1, a current flows through the motor 412 in the direction from the terminal q1 to the terminal q2 (shown by a solid line), and the lens 411 rotates in the T direction. Driven. Conversely, when a high-level "H" signal is supplied to the terminal p2, the terminal q2
, A current flows to the motor 412 in the direction of the terminal q1 (shown by a broken line), and the lens 411 is driven to rotate in the W direction. When a high-level "H" signal is not supplied to either of the terminals p1 and p2, no current flows through the motor 412, the lens 411 is not driven to rotate in any direction, and the position is maintained. Is done.

The movable terminal of the zoom operation switch 42 is connected to a power supply terminal. Operation button 5 of cabinet 1 described above
When pressing T and 5W, the zoom operation switch 42 is connected to the T side and the W side, respectively. Zoom operation switch 4
When 2 is connected to the T side and the W side, a high-level "H" signal is supplied to terminals p1 and p2 of the zoom driver unit 413, respectively, and zoom adjustment is performed in the TELE direction and the WIDE direction.

As shown in FIG. 2, a variable resistor 44 constituting a potentiometer is disposed at a position where the lens 411 of the imaging lens 2 is mounted. The movable element position of the variable resistor 44 is configured to be shifted by the rotation of the lens 411, and a voltage corresponding to the zoom magnification is obtained on the movable element, and this voltage is supplied to the controller 27 as a detection signal SD. As shown in FIG. 8, the detection signal SD is, for example, W
The voltage becomes 1 V at the IDE end (f = 7 mm), and the TELE end (f
= 42 mm) and set to 4V.

In this example, the picture frame 30 of the photo camera is placed on the screen 301 of the small CRT of the viewfinder 30.
2 are arranged in close contact with each other (see FIG. 1).
5).

Then, an imaging screen 304 is displayed based on the image frame 302 of the photo camera. in this case,
Since the angle of view of the imaging screen changes according to the zoom magnification, and thus the field of view changes, the display size of the imaging screen 304 changes according to the change in the zoom magnification. In order to change the display size, it is necessary to determine the ratio between the field of the photo camera and the field of the imaging screen.

Here, the angle of view will be described with reference to FIG. The angle of view θ can be obtained from the imaging surface size T and the f value (focal length) as shown in Expression 1. Note that FIG.
, T 'is the field of view, and L is the object distance.

[0047]

[Number 1] θ = 2tan ^-1 T / 2f imaging lens 2 is six times zoom lens of f = 7mm~42mm. When the imaging element 12 is a 1/3 inch, the horizontal size ZH of the imaging surface is 4.9 mm, the vertical size ZV is 3.69 mm, and the diagonal size ZD is 6.13 mm (see FIG. 10). ).

For this reason, the horizontal, vertical and diagonal angles of view θZH, θZV, θW at the WIDE end (f = 7 mm)
θZD is 38.6 °, 29.5 °, and 47.3 °, respectively.
Becomes On the other hand, the horizontal, vertical, and diagonal angles of view θZH, θZV, θZD at the TELE end (f = 42 mm)
Are 6.7 °, 5.0 °, and 8.3 °, respectively.

The imaging lens 3 is a fixed focal length lens of f = 55 mm. When the film is 35 mm, the horizontal size PH of the imaging surface is 36 mm, the vertical size PV is 24 mm, and the diagonal size PD is 43.3.
mm (see FIG. 11).

Therefore, the angles of view θPH, θPV, θPD in the horizontal, vertical, and diagonal directions are 36.2 °, 2
4.6 ° and 43.0 °.

From the above, the relationship between the angles of view of the imaging lens 2 as a zoom lens and the imaging lens 3 as a fixed focus lens is as shown in Table 1.

[0052]

[Table 1]

Next, the field ratio between the imaging screen and the photo camera will be described. From FIG. 9, the field of view T 'can be obtained as shown in Expression 2.

[0054]

T '= 2Ltan θ / 2 Assuming that the object distance L between the imaging lens 2 of the video camera unit and the imaging lens 3 of the photo camera unit is equal, the field ratio changes depending on the angle of view θ.

Here, the horizontal and vertical angles of view θZH and θZV of the imaging screen are shown in Table 1, so that the horizontal and vertical fields of view T′ZH and T′ZV at the WIDE end are each 0. 7L and 0.53L, while the horizontal and vertical fields of view T'ZH and T'ZV at the TELE end are 0.12L and 0.09L, respectively.

The angles of view θZH and θZV of the imaging screen other than the WIDE end and the TELE end can be obtained as shown in Expression 3 based on the detection signal SD.

[0057]

Equation 3 θZH = 38.6 ° − (38.6 ° −6.7 °) (SD-1) / 3 θZV = 29.5 ° − (29.5 ° −5.0 °) (SD− 1) / 3 The angles of view θZH and θZV obtained by the equation
By substituting into θ, the field of view T′ZH, T′ZV can be obtained.

Further, since the horizontal and vertical angles of view θPH and θPV of the photo camera are shown in Table 1, the horizontal and vertical fields of view T′PH and T′PV are 0.65 L, respectively.
0.44 L.

From the above, the relationship between the field of view of the imaging screen and the field of view of the photo camera is as shown in Table 2. FIG. 12 shows the horizontal field relationship, and FIG. 13 shows the vertical field relationship.

[0060]

[Table 2]

The horizontal and vertical field ratios T'ZH
/ T'PH, T'ZV / T'PV are as shown in Table 3.

[0062]

[Table 3]

It should be noted that the field of view T 'can also be determined from FIG.

[0064]

T ′ = L × T / f The focal length f can be obtained as shown in Expression 5 based on the detection signal SD.

[0065]

F = 7 mm + (42 mm−7 mm) (SD−1) / 3 The focal length f obtained by the equation (5) is substituted into the equation (4). By substituting the direction size ZV, the horizontal and vertical fields of view T'ZH and T'ZV can be obtained.

Returning to FIG. 2, the controller 27 changes the image-capturing screen 304 displayed on the small-sized CRT screen 301 of the viewfinder 30 to the horizontal and vertical field ratios T'ZH / T'PH, T '. Size data Ds for forming a display size corresponding to ZV / T'PV is formed.

FIG. 14 is a flowchart showing the output processing of the size data in the controller 27. First, the focal length f is calculated from the detection signal SD using Expression 5 (Step 61).

Next, the focal length f is substituted into Equation 4 and the horizontal size ZH and the vertical size ZV of the imaging surface are substituted into T in Equation 4 to obtain the horizontal and vertical images of the imaging screen. The boundaries T'ZH and T'ZV are calculated (step 62).

Next, the field ratios T'ZH / T'PH and T'ZV / T 'in the horizontal and vertical directions of the imaging screen and the photo camera are used by using the fields T'ZH and T'ZV. The PV is calculated (step 63).

Then, the field ratio T'ZH / T'PH, T '
The size data Ds is output according to ZV / T'PV (step 64). The size data Ds is data for controlling the horizontal and vertical deflection angles of the viewfinder 30 on the small CRT.

The size data Ds output from the controller 27 is supplied to the viewfinder 30. The display size in the horizontal and vertical directions of the imaging screen 304 is equal to the size indicated by the field ratios T'ZH / T'PH and T'ZV / T'PV based on the image frame 302 of the photo camera. Is controlled so that

In this case, the display size in the vertical direction is changed by, for example, changing the amplitude of the sawtooth wave signal by a vertical drive circuit.
It is controlled by changing the amplitude of the current flowing through the vertical deflection coil. On the other hand, the display size in the horizontal direction is controlled by changing the capacitance of the resonance capacitor of the horizontal output circuit and changing the amplitude of the current flowing through the horizontal deflection coil.

Although the detailed description is omitted, when the horizontal and vertical deflection angles are reduced, the scanning time of the electron beam of the CRT is not changed, the scanning width is shortened, and the energy on the phosphor screen is increased. It is configured to lower and protect the phosphor screen.

FIG. 16 shows a viewfinder 30 with a small C
An RT screen 301 is shown, and an image screen 304 has a display size corresponding to a zoom magnification for an image frame 302 of a photo camera of a fixed size.

As described above, in the present embodiment, the screen 301 of the small CRT of the viewfinder 30 has an image pickup screen 304 based on the image frame 302 of the photo camera of a fixed size.
Is displayed, so that the field of view of the photo camera can be accurately recognized even if the zoom magnification changes. Therefore,
The shutter operation of the photo camera can be accurately performed while looking at the display screen of the viewfinder 30.

In the above embodiment, the video camera and the photo camera are integrated, but the invention is similarly applied to a type in which a separate photo camera is fixed to the video camera. be able to. in this case,
For example, there is provided means for inputting data of the field of view T'PH, T'PV of the photo camera (data of the angle of view θPH, θPV or data of the focal length f and the image pickup plane size PH, PV) to the controller 27. Thus, any type of photo camera can be handled.

In the above-described embodiment, the picture frame 302 of the photo camera is displayed by placing the glass plate 303 in close contact with the screen 301 of the CRT. The image frame 302 can also be directly drawn.

[0078]

According to the present invention, since the imaging screen is displayed on the electronic viewfinder based on the image frame of a photo camera of a fixed size, the field of view of the photo camera can be accurately determined even when the zoom magnification changes. The user can accurately operate the shutter of the photo camera while looking at the display screen of the electronic viewfinder.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an embodiment.

FIG. 2 is a diagram illustrating a configuration of a video camera unit.

FIG. 3 is a schematic diagram of color coding.

FIG. 4 is a diagram illustrating an output of a horizontal output register.

FIG. 5 is a diagram for explaining color signal processing.

FIG. 6 is a diagram for explaining color signal processing.

FIG. 7 is a diagram illustrating a configuration of a zoom driver.

FIG. 8 is a diagram illustrating a relationship between a zoom angle of view and a detection signal.

FIG. 9 is a diagram for explaining how to obtain an angle of view.

FIG. 10 is a diagram illustrating the size of an imaging surface of a 1/3 inch CCD solid-state imaging device.

FIG. 11 is a diagram showing the size of an imaging surface of a 35 mm film.

FIG. 12 is a view (horizontal direction) of an imaging screen and a photo camera.
FIG.

FIG. 13 is a view (vertical direction) of an imaging screen and a photo camera.
FIG.

FIG. 14 is a flowchart illustrating an output processing operation of size data.

FIG. 15 is a view showing a glass plate for frame display.

FIG. 16 is a diagram showing a display screen of an electronic viewfinder.

[Explanation of symbols]

 Reference Signs List 1 cabinet 2, 3 imaging lens 4 eye cup 5T, 5W zoom operation button 6 recording button 7 shutter button 12 CCD solid-state imaging device 14 timing generator 16 synchronization generator 20 low-pass filter 21, 22 sample hold circuit 23 subtractor 24, 25 Changeover switch 26 Delay circuit 27 Controller 28 Encoder 29 Output terminal 30 Electronic viewfinder 41 Zoom driver 42 Zoom operation switch 44 Variable resistor 301 CRT screen 302 Photo camera frame 303 Glass frame for frame frame display 304 Imaging screen

Claims (1)

(57) [Claims] 1. A video camera having a zoom function and an electronic viewfinder, wherein: an image frame display means for displaying an image frame of a photo camera on a screen of the viewfinder; Display size changing means for changing the display size of the imaging screen of the viewfinder according to a change in angle, wherein an imaging screen is displayed on the screen of the viewfinder based on the image frame of the photo camera. Video camera.