JP2515398B2 - Imaging device with electronic telephoto function - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image pickup apparatus with an electronic telephoto function, such as a camera-integrated video tape recorder, in which a circuit for processing an electric signal that has been photoelectrically converted has an image enlarging function. .

<Prior Art> A camera-integrated video tape recorder (hereinafter abbreviated as VTR) as shown in, for example, FIG. 4 is conventionally known as an image pickup apparatus with an electronic telephoto function of this type. This camera-integrated VTR has a zoom lens 21 driven by a motor, and the movement of the zoom lens 21 on the tele side by forward / reverse rotation of the motor.
The zoom switch 23 provided on the grip 22 for switching to the wide side and the electronic telephoto switch provided on the side of the main body
It has 24. Then, when the cameraman presses the electronic telephoto switch 24 while looking into the subject with the electronic viewfinder 25 on the upper part of the main body, it is captured by the image sensor (not shown) through the zoom lens 21 as shown in FIG. 5 (a). The electric signal of the subject O is processed by a signal processing circuit (not shown), recorded in a built-in VTR, and stored in the electronic viewfinder 25 at a predetermined magnification (area ratio 4 times) as shown in FIG. 5 (b). Is enlarged and displayed.

<Problems to be Solved by the Invention> However, since the conventional camera-integrated VTR has a structure in which the cameraman manually pushes the electronic telephoto switch 24 while looking into the electronic viewfinder 25, it is easy to make a mistake and the zoom switch 23 There is a drawback that if the electronic telephoto switch 24 is mistakenly pressed while the is set to the wide side, the resolution is deteriorated and an image that is hard to see is recorded. Also, if you take your eyes off the electronic viewfinder 25 to confirm the position of the electronic telephoto switch 24, image shake will occur, and the number of switches will increase, impairing the operability which is a great advantage of this type of VTR. There's a problem.

Therefore, an object of the present invention is to detect an image shake by detecting the telephoto side moving end of the zoom lens and the closing of the zoom switch to the telephoto side and automatically operating the signal processing circuit based on the detection result. Another object of the present invention is to provide an image pickup apparatus with an electronic telephoto function which can improve the operability by reducing the number of switches by eliminating the recording of unsightly images due to the deterioration of resolution.

<Means for Solving the Problems> In order to achieve the above-mentioned object, an electronic telephoto imaging device of the present invention includes a zoom lens driven by a motor and a zoom lens movement by a forward and reverse rotation of the motor on the tele side. A zoom switch for switching to the wide side, an image pickup means for converting the image information captured by the zoom lens into an electric signal, and a signal processing circuit having an electronic telephoto function for processing the electric signal into a video signal and enlarging a standard image. When a tele-side detection sensor that detects that the zoom lens is at the tele-side moving end and a tele-side on signal that indicates that the zoom switch is switched to the tele side are input, the tele-side sensor is provided. When the detection signal from the edge detection sensor is continuously input for a predetermined time or more, the signal processing circuit outputs a control signal for operating the electronic telephoto operation. It is characterized by having a sub-telephoto switching control circuit.

<Operation> When the zoom switch is switched to the tele side, a tele-side ON signal is output from the zoom switch to the electronic telephoto switching control circuit, and the motor rotates, for example, in the forward direction to move the zoom lens to the tele side. When the zoom lens reaches the telephoto side movement end (the position of the maximum focal length of the zoom lens), the telephoto end detection sensor continuously outputs a detection signal to the electronic telephoto switching control circuit. The electronic telescopic switching control circuit is a signal processing that processes an electric signal from the image pickup means into a video signal when the detection signal from the tele side end detection sensor is continuously input for a predetermined time or more when the tele side ON signal is input. A control signal for operating the signal processing circuit in the electronic telephoto operation is output to the circuit. Then, the signal processing circuit enlarges the standard image to a predetermined magnification and outputs it as a video signal to a built-in VTR or an external device. Therefore, if the zoom switch is set to the wide side or if the zoom lens does not stop at the tele end for more than a predetermined time when the zoom switch is set to the tele side, the signal processing circuit does not operate in the electronic telephoto mode. The resolution does not deteriorate due to the electronic telephoto operation on the wide side.

<Examples> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

FIG. 1 is a block diagram showing a camera-integrated VTR which is an embodiment of the present invention, wherein 1 is a zoom lens driven by a motor 2 via a gear, 3 is a positive lens of the motor 2 via a motor drive circuit 4, Reverse movement of zoom lens 1
3a, a zoom switch for switching to the wide side 3b, 5 a tele-side end detection sensor for detecting the tele-side moving end of the zoom lens 1 (position of the maximum focal length of the zoom lens), 6 is image information captured by the zoom lens 1 Is an image pickup device that converts a signal into an electric signal.

Further, 7 is a signal processing circuit having an electric telephoto function for processing the electric signal into a video signal V and enlarging a standard image, and 8 is a timing for supplying various timing pulses necessary for the image pickup device 6 and the signal processing circuit 7. A pulse generating circuit 9 is a detection signal S ₂ = “L” from the tele-side end detection sensor when a tele-side ON signal S ₁ = “L” indicating that the tele side 3a of the zoom switch 3 is ON is input. Is continuously input for a predetermined time or longer, the timing pulse generating circuit 8 outputs a control signal S ₃ = “H” for operating the signal processing circuit 7 by electronic telephoto.
It is an electronic telephoto switching control circuit that outputs via.

The telephoto end detection sensor 5 is made of a mechanical contact type or an optical type such as a reflection type photointerrupter, and detects the telephoto side movement end of the zoom lens 1 and outputs a detection signal S ₂ = “L”. To do. The zoom switch 3 does not turn on the tele side 3a and the wide side 3b at the same time, and when the tele side 3a is turned on, outputs the tele side ON signal S ₁ = “L”. The blocks other than the telephoto end detection sensor 5 and the electronic telephoto switching control circuit 9 are the same as those provided in the conventional example shown in FIG.

FIG. 2 is a detailed block diagram showing a configuration example of the electronic telephoto switching control circuit 9. The control circuit 9 receives a logical sum of the tele-side ON signal S ₁ and the detection signal S ₂ and inverts it, and the output of this NOR gate as a trigger signal at the input terminal A, and the output signal is "L". Time constant Tm
The power supply voltage Vcc is applied to the T ₂ terminal through the capacitor C and the resistor R that determine the voltage, and the monostable multivibrator 12 to which Vcc is applied to the input terminal and ▲ ▼, and the output of this monostable multivibrator 12 are input as a clock. The output of the NOR gate 11 is received by the terminal CK, the input terminal D and the clear terminal ▲ ▼ are received, Vcc is applied to the input terminal ▲ ▼, and the control signal S ₃ is output from the output terminal Q to the timing pulse generating circuit 8. It is composed of a D-flip-flop 13. The time constant Tm is Tm ≈ 0.72 x C x R (seconds)
Becomes

The operation of the camera-integrated VTR having the above structure will be described below with reference to FIG. 3 centering on the electronic telephoto switching control circuit 9 of FIG.

First, at time t ₀ , the tele-side zoom switch 3a is not pressed, and the tele-side ON signal S ₁ is at "H" level as shown in FIG. 3 (a). Next, the zoom switch
When 3a is pushed down at time t ₁ , the NOR gate of control circuit 9
The "L" level tele-side ON signal S ₁ is output to one of the input terminals of the zoom lens 11 (see FIG. 3 (a)), and the motor 2 is rotated in the forward direction via the motor drive circuit 4 to allow the zoom lens to rotate. 1 starts moving to the tele side. And the zoom lens 1
When it reaches the tele-side moving end at time t ₂ , the tele-side end detection sensor 5 detects it and outputs the "L" level detection signal S ₂ to the other input of the NOR gate 11 as shown in FIG. 3 (b). Output to the terminal. The NOR gate 11, which has received the "L" level signal at both input terminals, outputs a signal changing from "L" to "H" as shown in FIG. 3 (c) to the terminals A and D- of the monostable multivibrator 12.
Output to the terminal D of the flip-flop 13. The multivibrator 12 is triggered on the rising edge of the above signal,
The output is inverted from normal "H" to "L" level as shown in FIG. 3 (d).

When the time constant Tm elapses and the time t ₃ elapses, the multivibrator 12 which has inverted the output causes its output to rise to the normal “H” level, and this signal becomes the clock input terminal of the D-flip-flop 13. Join CK. At this time, the tele-side ON signal S ₁ and the detection signal S ₂ are still "L".
If it is a level, NOR gate 11 is generated at the rising edge of the above signal.
The "H" level output is latched through the input terminal D to the D- flip-flop 13, the output terminal Q of the third diagram as shown in (e) "H" level of the control signal S ₃ is a timing pulse generating circuit 8 (See FIG. 1). Then, the signal processing circuit 7 is caused to perform an electronic telephoto operation by the timing pulse generation circuit 8 which receives the control signal S ₃ , and the standard image of FIG. The video signal V as described above is output.

Then, the telephoto side zoom switch 3a is turned off at time t _4, the detection signal S ₂ of the telephoto side end detecting sensor 5 but still "L" level, the telephoto side on signal S ₁ is the "H" level Then, the output of the NOR gate 11 becomes "L" level. This “L” level output is also input to the clear terminal ▲ ▼ together with the input terminal D of the D-flip-flop 13, and as a result, the control signal from the output terminal Q of the D-flip-flop 13 is input.
S ₃ changes to the “L” level that does not allow electronic telephoto operation (3rd
(FIGS. (A)-(e)), the image returns from the enlarged FIG. 5 (b) to that of the standard FIG. 5 (a). It should be noted that at time t ₄ , the telephoto side 3a of the zoom switch 3 is turned off and the wide side 3b is turned on and pressed, and the motor 2 is rotated in the reverse direction to zoom the zoom lens 1
Even when is moved to the opposite wide side, the detection signal S _{2 of the} telephoto end detection sensor 5 changes to “H” and the telephoto ON signal S ₁ changes to “H”, and the output of the NOR gate 11 changes to “H”. It changes to L ",
Similarly to the above, the control signal S ₃ becomes “L” which is the non-operation of the electronic telephoto.

On the other hand, at time t ₅ , the tele-side moving end of the zoom lens 1 is detected as at time t ₂ and the NOR gate is detected.
When the output of 11 changes to “H” and the output of the monostable multivibrator 12 changes to “L”, the tele side 3a of the zoom lens 3 is turned off at time t ₆ before time t ₇ corresponding to the time constant Tm. if, D- since the D input terminal when the clock is input to the flip-flop 13 which is already "L" level, the control signal S ₃ of the "H" level from the output terminal Q is not output, the image 5 ( The standard shown in a) remains.

Thus, according to the above embodiment, the zoom switch 3
When the tele side 3a is off or the wide side 3b is on or the tele side 3a of the zoom switch 3 is on, the zoom lens 1
Is not stopped for a predetermined time Tm or more at the tele-side moving end (5), the signal processing circuit 7 does not perform the electronic telephoto operation, so that the resolution does not deteriorate due to the electronic telescopic operation on the wide side unlike the conventional case, and the VTR Good recording can be performed. If electronic telephoto is not required at the telephoto side moving end, the telephoto side 3a of the zoom switch may be turned off, and the signal processing circuit 7 can be automatically operated by the electronic telephoto switching control circuit 9. It is not necessary to remove the eye from the electronic viewfinder 25 and press the switch as in the case of manual operation, and image blur does not occur. Further, an electronic telephoto switch is not required, which is advantageous in terms of design and manufacturing cost, and the operability can be significantly improved.

Needless to say, the present invention is not limited to the illustrated embodiment.

<Effects of the Invention> As is apparent from the above description, in the electronic telephoto imaging device of the present invention, the tele-side end detection sensor detects that the zoom lens driven by the motor is at the tele-side moving end. , The detection signal from the tele-side end detection sensor at the time of input of a tele-side on signal indicating that the zoom switch for switching the movement of the zoom lens to the tele-side or the wide-side by the forward or reverse rotation of the motor is switched to the tele-side. Is continuously input for a predetermined time or longer, a control signal is output from the electronic telephoto switching control circuit to automatically operate the electronic telephoto operation of the signal processing circuit that processes the photoelectrically converted electric signal into a video signal. Therefore, the resolution does not deteriorate due to the electronic telephoto operation on the wide side as in the past, and you can remove the eye from the electronic viewfinder and press the electronic telephoto switch. There is no need for image blurring, good recording is possible, and a reduction in the number of switches makes the configuration simple and inexpensive,
In addition, the operability of the device can be significantly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a camera-integrated VTR as an embodiment of the present invention, FIG. 2 is a detailed block diagram of the electronic telephoto switching control circuit of FIG. 1, and FIG. 2 is a diagram showing the operation timing of the control circuit of FIG. 2, FIG. 4 is a diagram showing a conventional camera-integrated VTR, and FIG. 5 is a diagram showing images during standard and electronic telephoto photography. 1 ... Zoom lens, 2 ... Motor, 3 ... Zoom switch,
3a ... Tele side, 3b ... Wide side, 5 ... Tele side end detection sensor,
6 ... Image sensor, 7 ... Signal processing circuit, 9 ... Electronic telephoto switching control circuit, S ₁ ... Tele side ON signal, S ₂ ... Detection signal, S ₃ ... Control signal.

Claims (1)

(57) [Claims] 1. A zoom lens driven by a motor, a zoom switch for switching the movement of the zoom lens by moving the motor forward and backward to a telephoto side and a wide side, and image information captured by the zoom lens is converted into an electric signal. Imaging means,
In an image pickup apparatus with an electronic telephoto function, which is provided with a signal processing circuit having an electronic telephoto function for processing the electric signal into a video signal and enlarging a standard image, a telephoto side for detecting that the zoom lens is at a telephoto side moving end. When the end detection sensor and the tele-side ON signal indicating that the zoom switch is switched to the tele side are input, when the detection signal from the tele-side end detection sensor is continuously input for a predetermined time or more, the signal processing is performed. An image pickup apparatus with an electronic telephoto function, comprising an electronic telephoto switching control circuit for outputting a control signal for operating the electronic telephoto to the circuit.