JPH0442692A - Color still picture input device - Google Patents

Abstract

PURPOSE:To use components for each system in common by using a vertical frequency detection means so as to detect a frequency of a vertical synchronizing signal sent from a video signal processing section to a monochroic solid-state image pickup element and using a frequency division means so as to set a frequency division ratio of a frequency division ratio drive pulse generating section in response to the detected frequency. CONSTITUTION:The above device is provided with a drive pulse generating section 14a formed with a frequency division ratio typed generating section, a vertical frequency detection means 20 detecting a frequency of a vertical synchronizing signal in a control signal sent to a monochroic solid-state image pickup element 4 from a video signal processing section 18, and a frequency division ratio setting means 22 setting a frequency division ratio of the frequency division ratio variable drive pulse generating section 14a in response to the detected frequency. That is, since the frequency division ratio of the drive pulse generating section 14a is set in response to the detected frequency, even when the processing system of the video signal is revised, the rotating phase of a stepping motor, that is, a three-color filter 6 is always synchronized with the vertical synchronizing signal after the revision. Thus, the crystal oscillator and the drive pulse generating section 14a (frequency divider) are used in common without any modification.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention captures a color still image of a document or the like using a monochrome solid-state image sensor and three-color filters, and captures the three-color images obtained for each color filter. The present invention relates to a color still image input device that generates a color video signal by superimposing two video signals.

<Prior Art> FIG. 2 shows a conventional example of a device that uses a monochrome solid-state image sensor and a three-color filter to input a video signal of a color still image.

In the figure, 2 is a photographing lens, 4 is a monochrome solid-state image sensor (CCD), 6 is a three-color filter, 8 is a stepping motor, 10 is a photointerrupter, I2 is a crystal oscillator, 14 is a drive pulse generator, and 16 is a motor driver,
18 is a video signal processing section.

A photographic lens 2 and a monochrome solid-state image sensor 4 are arranged facing each other, and a three-color filter 6 is interposed between them. This 3
As shown in FIG. 3, the color filter 6 has R (red), G (
120' for each of the three primary colors: green) and B (blue).
A red filter 6a, a green filter 6b, and a blue filter 6c having a central angle of . A red filter 6a and a blue filter 6 in this three-color filter 6
A slit 6d is formed at the boundary with C to indicate the initial phase. The photointerrupter 10 detects this slit 6d and outputs a reset signal to the drive pulse generator 14.

The drive pulse generator 14 is configured as a frequency divider that divides the frequency of the reference clock CLK input from the crystal oscillator 12 and outputs the frequency-divided signal to the motor driver 16 as the drive pulse signal S1. This frequency divider has a fixed frequency division ratio.

The motor driver 16 generates a drive signal S2 based on the drive pulse signal Sl from the drive pulse generator 14, and uses this drive signal S2 to drive the stepping motor 8.
is configured to drive.

The video signal processing unit 18 generates a horizontal synchronization signal, a horizontal synchronization signal, and other necessary control signals S based on the reference clock CLK input from the crystal oscillator 12.

This control signal S is sent to the monochrome solid-state image sensor 4.
By transmitting the signal to the monochrome solid-state image sensor 4, the monochrome solid-state image sensor 4 is horizontally scanned and vertically scanned, and the video signal S4 from the monochrome solid-state image sensor 4 obtained as a result of the scanning is captured.

Due to the rotation of the stepping motor 8, the video signal S4 is captured when the red filter 6a of the three-color filter 6 is facing the monochrome solid-state image sensor 4, and the video signal S is captured when the green filter 6b is facing the monochrome solid-state image sensor 4. □6> is captured, and when the blue filter 6c is facing the video signal S44. is taken in. Video signals 341R+Sa+ of these three colors. , 5ats+ (hereinafter,
(simply represented by 34) is captured one frame at a time.

The video signal processing unit 18 then superimposes these three color video signals S4 to generate a color video signal.

In order to generate an accurate color video signal, it is necessary to capture exactly one frame of each of the RG and B video signals S4. Therefore, each of the R, G, and H color filters 6a, 6b, and 6c, while constantly rotating, faces the monochrome solid-state image sensor 4 for two periods of the vertical scanning period of the monochrome solid-state image sensor 4. It is necessary to continue to do so. Further, it is necessary to adjust the timing so that switching between color filters to be reset is performed within the vertical retrace period. That is, the control signal 32 (vertical synchronization signal) given from the video signal processing unit 18 to the monochrome solid-state image sensor 4 and the rotational phase of the three-color filter 6 must be accurately synchronized. In order to achieve this synchronization, The oscillation frequency of the crystal oscillator 12 is accurately determined based on the frequency of the vertical synchronization signal of the video signal processing section 18.

Note that by resetting the frequency divider in the drive pulse generating section 14 at the timing when the slint rod d in the three-color filter 6 is detected by the photo-ink converter 10, the initial phase of each rotation of the three-color filter 6 can be adjusted each time. It's matching.

<Problems to be Solved by the Invention> However, the frequency of the vertical synchronization signal of the monochrome solid-state image sensor 4 is different between the NTSC system and the PAL system.
It is also different from the computer method. Furthermore, the number of horizontal lines also differs depending on the method. For this reason, in the past, in addition to changing the video signal processing unit depending on the video signal processing method, multiple types of crystal oscillators with different frequencies and multiple types of drive pulse generators with different frequency division ratios (
frequency divider) had to be prepared separately.

The present invention was devised in view of these circumstances, and allows the crystal oscillator and drive pulse generator (frequency divider) to be shared without changing when changing the video signal processing method. The purpose is to do so.

<Means for Solving the Problems> In order to achieve the above object, the present invention has the following configuration.

That is, the color still image input device of the present invention includes a drive pulse generator that divides the frequency of a reference clock of a crystal oscillator to generate a drive pulse signal, and a motor driver that controls a stepping motor based on the drive pulse signal. , a three-color filter rotated by the stepping motor, a monochrome solid-state image sensor that captures a still image through the three-color filter, and a scanning device for the monochrome solid-state image sensor based on a reference clock of the crystal oscillator. In a color still image input device, the drive pulse generating section is frequency-divided, and a video signal processing section that generates a control signal and inputs video signals of each color from a monochrome solid-state image sensor and synthesizes them into a color video signal. vertical frequency detection means for detecting the frequency of a vertical synchronization signal in a control signal sent from the video signal processing section to the monochrome solid-state image pickup device; The present invention is characterized by comprising a frequency division ratio setting means for setting a frequency division ratio of the variable drive pulse generating section.

<Effect> The effects of the above configuration of the present invention are as follows.

The structure is such that the frequency of the vertical synchronization signal is detected and the frequency division ratio of the drive pulse generator is set according to the detected frequency, so even when changing the video signal processing method, the stepping motor, that is, the three-color filter This means that the rotational phase of is always correctly synchronized with the changed vertical synchronization signal.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram of a color still image input device according to an embodiment.

A three-color filter 6 interposed between the photographing lens 2 and the monochrome solid-state image sensor 4 and connected to the stepping motor 8 is a red filter 6a as in the conventional example (FIG. 3).
, a green filter 6b and a blue filter 6c, and a filter 1-6d exhibiting an initial phase is formed between one adjacent color filter. The reference clock CLK from the crystal oscillator 12 is supplied to the frequency division ratio variable drive pulse generator 14.
a and the video signal processing section 18.

The variable division ratio drive pulse generator 14a outputs a drive pulse signal S generated by dividing the reference clock CLK by a predetermined frequency division ratio to the motor driver 16, and the motor driver 16 outputs the drive pulse signal S to the motor driver 16.

A drive signal S2 generated based on this is sent to the stepping motor 8.

The video signal processing unit 18 generates a control signal S including a vertical synchronization signal based on the reference clock CLK and sends it to the monochrome solid-state image sensor 4, and also outputs one frame of each color captured by the monochrome solid-state image sensor 4. minute video signal s
4 and synthesizes them to generate a color video signal.

When the photo ink converter 1o detects the slit 6d, it sends a recent signal to the frequency division ratio variable drive pulse generator 14a to match the initial phase of each rotation of the three-color filter 6. There is.

The above configuration is similar to the conventional example except that the drive pulse generator 14a has a variable frequency division ratio.

Furthermore, the difference from the conventional example is that the control signal S sent from the video signal processing section 18 to the monochrome solid-state image sensor 4 includes a vertical frequency detection means 2o that detects the frequency fv of the vertical synchronization signal, and Detection means 2o
The present invention is characterized in that it includes a frequency division ratio setting means 22 that sets the frequency division ratio in the frequency division ratio variable drive pulse generation section 14a in accordance with the detected frequency f of the vertical synchronization signal.

As a result of the above configuration, the video signal processing method is N.
Regardless of whether it is changed to the TSC method, PAL method or computer method, the frequency division ratio variable drive pulse generator 1
The frequency of the drive pulse signal S2 output from 4a to the motor driver 16 is synchronized with the frequency of the vertical synchronization signal (detection frequency fv) of each method, and the rotation phase of the stepping motor 8, that is, the three-color filter 6, is Correct synchronization can also be achieved with vertical synchronization signals.

Therefore, regardless of changes in the video signal processing method,
There is no need to change the crystal oscillator 12 and the drive pulse generator 14a (variable frequency division ratio type), and as a result of being able to share these, manufacturing costs can be reduced.

Note that the vertical frequency detection means 20 and the frequency division ratio setting means 2
2 may be a hardware configuration using an IC circuit or a software configuration using a microcomputer. Further, as the three-color filter 6, instead of R, G, and B, three-color filters of Y (yellow), M (magenta), and C (cyan) may be used.

<Effect of the invention> According to the present invention, the following effects are achieved.

The vertical frequency detection means detects the frequency of the vertical synchronization signal sent from the video signal processing section to the monochrome solid-state image sensor, and the frequency division ratio setting means sets the frequency division ratio of the frequency division ratio variable drive pulse generation section to the detected frequency. Since the configuration is configured so that settings can be made accordingly, even if the video signal processing method is different, the 3
The rotational phase of the color filter can always be correctly synchronized with the changed vertical synchronization signal.

Therefore, depending on the method, multiple types of crystal oscillators with different frequencies and multiple types of drive pulse generators with different frequency division ratios (
There is no need to separately prepare separate frequency dividers, and these parts can be shared for each system, reducing manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color still image input device according to an embodiment of the present invention. FIG. 2 is a block diagram of a conventional color still image input device. FIG. 3 is a schematic diagram of a three-color filter common to the embodiment and the conventional example.

Claims (1)

[Claims] (1) A drive pulse generator that divides the reference clock of a crystal oscillator to generate a drive pulse signal, a motor driver that controls a stepping motor based on this drive pulse signal, and a motor driver that is rotated by the stepping motor.
a color filter, a monochrome solid-state image sensor that captures a still image through the three-color filter, and a monochrome solid-state image sensor that generates a scanning control signal for the monochrome solid-state image sensor based on the reference clock of the crystal oscillator; In a color still image input device comprising a video signal processing section that inputs video signals of each color from an image sensor and synthesizes them into a color video signal, the driving pulse generating section is configured to have a variable division ratio, and the driving pulse generating section is configured to have a variable division ratio. vertical frequency detection means for detecting the frequency of a vertical synchronization signal in a control signal sent from the video signal processing unit to the monochrome solid-state image sensor;
A color still image input device comprising a frequency division ratio setting means for setting a frequency division ratio of the frequency division ratio variable drive pulse generation section according to the detected frequency.