JPH08279924A - Device and method for inputting picture - Google Patents

Abstract

PURPOSE: To provide a picture input device capable of preventing a display picture from being disturbed even when phase synchronism with an external synchronizing signal(ESS) can not be executed. CONSTITUTION: In the picture input device, a system control part 13 monitors an ESS input detection signal detected by an input detection part 9, and when the input of an ESS is detected, a picture signal inputted from an image pickup device 3 is processed by a clock controlled in accordance with the ESS and the processed signal is outputted from a VIDEO output terminal 17. When a phase control signal outputted from a phase comparing part 8 excludes a prescribed voltage range based upon the ESS and an internal synchronizing signal(ISS) even when the input of the ESS is detected, the control part 13 switches a switch SW to the side of a reference voltage generating part to supply reference voltage to a VCO part. Thereby the picture input device processes an image pickup signal inputted from the device 3 by a clock controlled by internal reference voltage and outputs the processed signal from the terminal 17. Then the control part 13 displays a message that the image pickup signal can not be synchronizied with the ESS inputted from a GL signal input terminal 16 on a condition display part 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device for outputting an input image of a document placed on a document placement surface to a display section.

[0002]

2. Description of the Related Art Conventionally, a so-called GL (Generato) which outputs an image signal in synchronization with an external synchronization signal in phase.
An image input device having an r-Lock) function is known. FIG. 4 is a block diagram showing the configuration of a conventional image input device having a GL function. The operation of the GL function will be described. The phase comparison unit 108 compares the phases of the internal synchronization signal generated by the signal generation unit 107 and the external synchronization signal input from the GL signal input terminal 116, and the phase difference between these two synchronization signals is output as a phase control signal. Generator 107
Is output to

The signal generator 107 increases or decreases the original oscillation clock frequency based on the phase control signal, and outputs the internal synchronization signal generated from the original oscillation clock to the phase comparator 108 again.

By repeating the above operation, the phase difference between the external synchronizing signal and the internal synchronizing signal converges, and the image signal phase-synchronized with the external synchronizing signal is output from the video (VIDEO) output terminal 117.

[0005]

However, the above-mentioned conventional example has the following problems. That is, since the original oscillation clock frequency of the signal generator 107 is limited to a predetermined variable range, if the phase difference between the internal synchronization signal and the external synchronization signal exceeds this variable range, the phase synchronization does not converge, There is a problem that the image signal output from the VIDEO output terminal 117 is disturbed.

Further, when the external synchronization is not possible, the user has to cancel the input of the external synchronization signal, and there is a problem that the operation is troublesome.

Furthermore, if an external synchronizing signal is input and the display image is disturbed, the external synchronizing cannot be performed and the display image is disturbed. Or, although the external synchronizing is possible but the synchronizing range of the display device is exceeded, the image is disturbed. There was a problem that it was not possible to distinguish whether it was disturbed.

Therefore, it is an object of the present invention to provide an image input device in which a display image is not disturbed even when phase synchronization with an external synchronizing signal cannot be performed.

[0009]

In order to achieve the above object, an image input device according to claim 1 of the present invention is an image input device for processing an input image signal according to a synchronization signal and outputting the processed image signal to a display unit. In the device, external synchronization signal input means for inputting an external synchronization signal, phase comparison means for comparing the phases of the input external synchronization signal and internal synchronization signal, and the external synchronization signal and the internal portion according to the comparison. A phase synchronization control means for performing phase synchronization with a synchronization signal, a synchronization detection means for detecting that the phase synchronization does not match, and a phase synchronization cancellation means for canceling the phase synchronization when the phase synchronization is detected.

In the image input device according to a second aspect, in the image input device according to the first aspect, the phase comparison means outputs a voltage control signal according to the comparison of the phases, and the synchronization detection means outputs the voltage control signal. The detection is performed by comparing the voltage control signal with a predetermined voltage.

The image input device according to claim 3 is the image input device according to claim 1.
In the image input device according to the present invention, a display means is provided, and the synchronization detection means displays on the display means that the phase synchronization does not match.

An image input method according to a fourth aspect is the image input method of processing an input image signal according to a synchronization signal and outputting the processed image signal to a display unit, by inputting an external synchronization signal,
The phases of the input external synchronization signal and the internal synchronization signal are compared, the external synchronization signal and the internal synchronization signal are phase-synchronized according to the comparison, and it is detected that the phase synchronization does not match, When it is detected, the phase synchronization is released.

[0013]

In the image input device according to the first aspect of the present invention, when the input image signal is processed according to the synchronizing signal and is output to the display unit, the external synchronizing signal is input by the external synchronizing signal inputting means, Phase comparison means compares the phases of the input external synchronization signal and internal synchronization signal, and phase synchronization control means performs phase synchronization between the external synchronization signal and the internal synchronization signal according to the comparison to detect synchronization. The means detects that the phase synchronization does not match, and the phase synchronization canceling means cancels the phase synchronization when detected.

[0014]

EXAMPLES Next, examples of the image input apparatus of the present invention will be described. FIG. 1 is a block diagram showing the arrangement of the image input apparatus according to the embodiment. In the figure, reference numeral 1 denotes a lens unit including a zoom lens group and a focus lens group that collect light from a subject (not shown).

Reference numeral 2 is an iris portion for controlling the amount of light from the lens portion 1, and 3 is an image pickup device including a CCD (solid-state image pickup element) for photoelectrically converting light from a subject and outputting an electric signal. Reference numeral 4 denotes a zoom control unit including a motor for controlling the position of the zoom lens group of the lens unit 1 according to a control signal from the camera control unit 5, and reference numeral 5 denotes a focus lens of the lens unit 1 according to a control signal from the camera control unit 12. The focus control device 6 is composed of a motor for controlling the position of the group, and 6 is an iris drive unit composed of a motor for controlling the opening area of the iris part 2 according to a control signal from the camera controller 12.

Reference numeral 7 denotes a synchronizing signal for driving the image pickup device 3, a synchronizing signal for giving a signal processing timing to the pre-signal processing section 10, a synchronizing signal for giving a signal processing timing to the signal processing section 11, and a phase for the phase comparing section 8. Is a signal generator that outputs an internal synchronization signal for comparing Signal generator 7
Is a VCO (voltage controlled oscillator) that controls the original oscillation clock frequency for generating the synchronization signal and the internal synchronization signal by the phase control signal from the phase signal switching unit 18, and switches the oscillation of the original oscillation clock by the control signal from the system control unit 13. ), A counter logic IC, and a frequency divider.

Reference numeral 8 compares the phases of the external synchronizing signal input from the GL signal input terminal 16 and the internal synchronizing signal output from the signal generator 7, converts the phase difference into a voltage, and outputs the phase signal as a phase control signal. It is a phase comparison unit that outputs to the switching unit 18. 9 detects the input level of the external synchronizing signal or the period of the synchronizing signal input from the GL signal input terminal 16,
The input detection unit includes an OP amplifier and a sync detector that output a detection signal to the system control unit 13 when an external synchronization signal is input.

Reference numeral 10 denotes an IC or the like which performs processing such as noise removal and level correction on the image signal output from the image pickup device 3 in accordance with the synchronization signal output from the signal generation unit 7 and outputs it as a normal image signal. Is a pre-signal processing unit.

Reference numeral 11 is a modulator and mixer circuit for mixing the image signal output from the pre-signal processing unit 10 and the synchronization signal output from the signal generation unit 7 and converting the image signal into a standard image signal such as NTSC or PAL. , A signal processing unit including a video amplifier and the like.

Reference numeral 12 controls a lens unit 1 and an iris unit 2 via a zoom control unit 4, a focus control unit 5 and an iris drive unit 6 in accordance with a control signal from a system control unit 13 to form an image on an image pickup device 3. It is a camera control unit including an arithmetic device for controlling an image.

Reference numeral 13 is a system control including an arithmetic unit for performing system control of the entire apparatus, a program, a memory and the like. Reference numeral 14 is an operation panel composed of a switch operated by a user, a variable resistor and the like.
Reference numeral 15 is a status display unit including an LCD, an LED and the like for displaying the operating status to the user. Reference numeral 16 is a GL signal input terminal for inputting an external synchronizing signal for synchronizing an image between the image input device and an external device. Reference numeral 17 is a VIDEO output terminal for connecting the image signal output from the signal processing unit 11 to a monitor or the like.

A phase signal switching unit 18 compares the voltage levels of the phase control signals output from the phase comparison unit 8 and outputs a detection signal to the system control unit 13 when the voltage levels are out of a predetermined voltage range. The phase signal switching unit 18 switches between the phase control signal from the phase comparison unit 8 and the reference voltage signal generated internally by the control signal of the system control unit 13 and outputs the signal to the signal generation unit 7.

FIG. 2 is a block diagram showing the configurations of the signal generator 7 and the phase signal switcher 18. In the figure, 20
Reference numeral 1 denotes a VCO unit that generates a reference clock when generating a synchronization signal. The oscillation frequency of the clock can be changed by the phase control signal output from the phase signal switching unit 18. The VCO unit 201 is a crystal oscillator that oscillates according to the control signal from the system control unit 13 regardless of the phase control signal,
It consists of a variable voltage diode.

Reference numeral 202 denotes a counter, a frequency divider or the like for generating a synchronization signal necessary for the image pickup device 3, the pre-signal processing unit 10, the signal processing unit 11 and the phase comparison unit 8 based on the clock output from the VCO unit 201. It is a synchronization signal generator configured.

A switch 203 switches the output signal to the signal generator 7 between the phase control signal from the phase comparator 8 and the reference voltage from the reference voltage generator 205 in response to the switching signal from the system controller 13. SW) switching unit.

Reference numeral 204 compares the voltage levels of the phase control signals output from the phase comparison section 8 and outputs a detection signal to the system control section 13 when the voltage levels deviate from the predetermined voltage range.
This is a voltage comparison unit composed of an amplifier and the like.

Reference numeral 205 is composed of an OP amplifier, a resistor and the like which, when the phase control signal from the phase comparator 8 exceeds a predetermined range, generates a reference voltage to be output to the signal generator 7 instead of the phase control signal. It is a reference voltage generator.

The operation of the image input device having the above configuration will be described. FIG. 3 is a flowchart showing an operation sequence when an external synchronization signal is input. First, as an initial state, the SW switching unit 203 switches to output the phase control signal from the phase comparison unit 8 to the signal generation unit 7 (step S301).

The system control unit 13 monitors the input detection signal of the external synchronization signal from the input detection unit 9 (step S3).
02). When the input of the external synchronization signal is not detected, the system control unit 13 switches the clock oscillation of the VCO unit 201 to the free-run state irrelevant to the phase control signal, so that the image input device receives the internally generated clock from the imaging device 3. The input image signal is processed and output from the VIDEO output terminal 17 (step S303).

On the other hand, when the input of the external synchronizing signal is detected in step S302, the phase comparison signal output from the phase comparison section 8 is compared by the voltage comparison section 204 (step S302).
304), if the voltage level of the phase control signal is out of the predetermined range, the process proceeds to step S305, and if it is within the predetermined range, the phases of the external synchronization signal and the internal synchronization signal generated by the synchronization signal generation unit 202 When it is determined that the synchronization is or is being synchronized, this routine is ended. As a result, the image input device processes the image signal input from the image pickup device 3 with the clock controlled according to the external synchronization signal, and outputs the processed image signal from the VIDEO output terminal 17.

When the phase control signal is out of the predetermined voltage range in step S305, the system controller 13 switches the switch SW.
203 is switched to the reference voltage generation unit 205 side to supply the reference voltage to the VCO unit 201. As a result, the image input device processes the image pickup signal input from the image pickup device 3 with the clock controlled by the internal reference voltage, and outputs the image pickup signal from the VIDEO output terminal 17.

The system control unit 13 displays a G on the status display unit 15.
The fact that the external synchronizing signal input from the L signal input terminal 16 could not be synchronized is displayed (step S306) to notify the user.

As described above, according to the image input apparatus of the present embodiment, even if the external synchronizing signal cannot be phase-synchronized, the internal reference voltage is used to control the oscillation frequency of the clock to disturb the image. Can be prevented.

When the external synchronizing signal cannot be synchronized, the user can easily judge whether the image input device is operating in the external synchronizing mode by displaying the fact to the user.

[0035]

According to the image input device of the first aspect of the present invention, when the input image signal is processed according to the synchronizing signal and is output to the display unit, the external synchronizing signal is input by the external synchronizing signal input means. And comparing the phases of the external synchronization signal and the internal synchronization signal, which are input by the phase comparison means,
The phase synchronization control means performs phase synchronization between the external synchronization signal and the internal synchronization signal according to the comparison, the synchronization detection means detects that the phase synchronization does not match, and the phase synchronization release means detects the phase synchronization. In this case, since the phase synchronization is released, the disturbance of the image signal can be eliminated by not performing the phase synchronization when the phase synchronization is lost.

According to the image input device of the second aspect, the phase comparison means outputs the voltage control signal according to the phase comparison, and the synchronization detection means outputs the voltage control signal and the predetermined voltage. The phase synchronization can be detected by using the voltage control signal.

According to the image input apparatus of the third aspect, the display means is provided, and the synchronization detecting means displays on the display means that the phase synchronization does not match, so that the user can easily know the operation state. be able to.

According to the image input device of the fourth aspect, in the image input method of processing the input image signal according to the synchronization signal and outputting the processed image signal to the display unit, the external synchronization signal is input and the input external signal is input. When the phases of the synchronization signal and the internal synchronization signal are compared, the external synchronization signal and the internal synchronization signal are phase-synchronized in accordance with the comparison, and it is detected that the phase synchronization does not match Since the above-mentioned phase synchronization is released, the disturbance of the image signal can be eliminated by not performing the phase synchronization when the phase synchronization is lost.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of an image input device according to an embodiment.

FIG. 2 is a block diagram showing configurations of a signal generator 7 and a phase signal switcher 18.

FIG. 3 is a flowchart showing an operation sequence when an external synchronization signal is input.

FIG. 4 is a block diagram showing a configuration of a conventional image input device having a GL function.

[Explanation of symbols]

 3 Imaging Device 7 Signal Generation Section 8 Phase Comparison Section 9 Input Detection Section 11 Signal Processing Section 13 System Control Section 16 GL Signal Input Terminal 17 VIDEO Output Terminal 18 Phase Signal Switching Section

Claims (4)

[Claims] 1. An image input device for processing an input image signal according to a synchronization signal and outputting the processed image signal to a display unit, an external synchronization signal input means for inputting an external synchronization signal, the input external synchronization signal and an internal portion. Phase comparison means for comparing phases with a synchronization signal, phase synchronization control means for performing phase synchronization between the external synchronization signal and the internal synchronization signal according to the comparison, and synchronization for detecting that the phase synchronization does not match An image input device comprising: detection means; and phase synchronization cancellation means for canceling the phase synchronization when the detection means is detected. 2. The phase comparing means outputs a voltage control signal according to the phase comparison, and the synchronization detecting means detects the voltage control signal by comparing the output voltage control signal with a predetermined voltage. The image input device according to claim 1. 3. The image input device according to claim 1, further comprising display means, wherein the synchronization detection means displays on the display means that the phase synchronization is not correct. 4. An image input method for processing an input image signal according to a synchronization signal and outputting the processed image signal to a display unit, by inputting an external synchronization signal and determining a phase between the input external synchronization signal and internal synchronization signal. Comparing, the external synchronization signal and the internal synchronization signal are phase-synchronized according to the comparison, it is detected that the phase synchronization does not match, and the phase synchronization is released when the phase synchronization is detected. Image input method.