JPH04100032A - Image inputting device - Google Patents

Abstract

PURPOSE:To shorten fetching time of image according to an image pick up condition by providing a control means varying rotational speed of a rotational drive means according to brightness of image pick up environment. CONSTITUTION:Outputted signals of CCD12 are digitized at an A/D converter 21, and fed to a memory 22 and a control circuit 24. Then, by monitoring this digital data at the control circuit 24, light intensity information of a presently inputted image can be obtained. Based on this light intensity information, if the light intensity is too strong, oscillating frequency of a variable frequency oscillator 19 is controlled to be high, and if it is too weak, the oscillating frequency is controlled to be low by the control circuit 24. That is, if the oscillating frequency of the variable frequency oscillator 19 is set high, rotational speed of a color filter unit 13 is increased, and even when the light intensity to the CCD12 is the same, light receiving time (integration action time) is shortened for each color, and since outputted signal of the CCD12 is made smaller, a darker inputted image can be obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image input device.

[Prior Art] Conventionally, this type of image input device has the following features, as shown in FIG.
A lens 51 is attached to the front of the image input device 50. At the position where the light from the subject 52 forms an image with the lens 51, a solid state image sensor (hereinafter referred to as CCD)
) 53 is provided. Also, its CCD53
A filter unit 54 is arranged on the optical path leading to.

As shown in FIG. 6, this filter unit 54 includes a red filter 55R, a green filter 55G, and a blue filter 55B. The filter unit 54 can selectively arrange the filters 55R, 55G, and 55B on the optical path by rotating around the rotation axis 54C. In addition, this rotating shaft 5
A step motor 57 is attached to 4C. The CCD 53 is connected to a memory 59 via a converter 58 for analog-to-digital conversion of output data. Furthermore, CCD53. Step motor 57.
A control circuit 60 is provided for controlling the memory 59 in an integrated manner.

In the apparatus configured as described above, first, the step motor 57 is rotated to arrange the red filter 55R on the optical path. Then, only the red component of the subject image is formed on the CCD 53.

Next, the CCD 53 receives light for a predetermined time under the control of the control circuit 60, and outputs data of the integral value of the luminance of the light received during that time. This data is converted into digital data by converter 58 and stored in memory 59.

Then, the step motor 57 is intermittently rotated by a predetermined amount, that is, the color filter 55 is rotated every 120 degrees, and the green filter 55G and blue filter 55
B are sequentially arranged on the optical path. Then, the digital data of the green and blue components of the subject image are stored in the memory 59 in the same manner.

On the other hand, instead of the filter unit 54 and step motor 57, as shown in FIG.
Some are covered with R, 62G, and 62B.

[Problems to be Solved by the Invention] However, in the former configuration, the color filter 55R
, 55G, and 55B were rotated intermittently, there was a problem in that it took a long time to capture images.

In addition, in the latter configuration, of all the light input elements of the CCD 61, 1/3 is for red, 1/3 is for green, and 1/3 is for blue, so there is a problem that the resolution is 173. .

The present invention has been made to solve the above problems, and its purpose is to provide an image input device with short image input time and high resolution.

[Means for Solving the Problems] In order to achieve this object, the image input device of the present invention arranges a plurality of optical input elements in the vertical and horizontal directions, and outputs a luminance signal of input light from each optical input element. an imaging means for reading and outputting; a color filter unit having at least two color filters arranged in a predetermined circumference around a rotation axis; and a color filter unit that rotates around the rotation axis to sequentially The apparatus is characterized in that it includes a rotational drive means disposed on the optical path leading to the imaging means, and a control means for varying the rotational speed of the rotational drive means in accordance with the brightness of the imaging environment.

[Function] In the present invention having the above configuration, the imaging means has a plurality of light input elements arranged in the vertical and horizontal directions, and reads and outputs the luminance signal of the input light of each light input element. The color filter unit has color filters of at least two colors arranged on a predetermined circumference around a rotation axis, and is rotated around the rotation axis by a rotation drive means, so that each color filter sequentially captures an image. placed on the optical path leading to the means. Further, the control means varies the rotational speed of the rotation drive means in accordance with the imaging environment so that the brighter the imaging environment is, the faster the rotational speed becomes.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the image input device of this embodiment, and a lens mechanism 11 is attached to the front surface of the image input device 25. As shown in FIG. Further, a CCD 12 is provided behind the lens mechanism 11. The lens mechanism 11 is composed of a plurality of lenses, and by adjusting the position of each lens, it is possible to capture the subject 1 at an arbitrary distance.
A real image of 0 can be formed on the CCD 12.

A color filter unit 13 is provided between the lens mechanism 11 and the CCD 12. This color filter unit 13 has a disk shape as shown in FIG.
Green filter 14G.

Blue filters 14B are arranged at regular intervals.

This color filter unit 13 is rotatable around a rotation shaft 13C provided in the center, and each color filter 14R, 14G, 14B is rotated to the lens mechanism 1 according to the rotation.
They can be sequentially inserted into the optical path between CCD 1 and CCD 12. Note that this rotating shaft 13C is connected to the output shaft of the step motor 17.

The optical path is surrounded by a black light shielding wall (not shown), and a magnet 15 for detecting rotational speed is provided between the red filter 14R and the blue filter 14B. A Hall IC (integrated circuit) 16 is provided at a position where the magnet 15 crosses when the color filter unit 13 rotates due to the rotation of the step motor 17. In this Hall IC 16, the magnet 15 is a Hall IC.
A pulse is generated every time 16 is crossed. Note that this pulse train is hereinafter referred to as a speed signal.

Further, one output terminal of the variable frequency oscillator 19 is connected to the CC
They are respectively connected to a D driver 20 and an analog-to-digital converter (hereinafter referred to as an A/D converter). The CCD driver 20 drives the CCD 12 based on the frequency from the output terminal. Further, the A/D converter 21 similarly performs an analog-to-digital conversion operation based on the frequency from the output terminal. Furthermore, the output terminal is also connected to a write clock terminal of the memory 22.

In addition, the output terminal of the oscillator 23 that oscillates at a constant frequency is
It is connected to the read clock terminal of the memory 22. Then, data is written to the memory 22 in synchronization with the frequency of the write clock terminal, data is read out from the memory 22 in synchronization with the frequency of the read clock terminal,
The signal is sent to an external device via the output terminal. Memory 2 like this
2 is configured to be capable of writing and reading at different speeds. For example, the representative one at the moment is T.
TMs4 manufactured by ex5as Instruments
c1050, 1060 memory, etc.

Further, a control circuit 24 is provided to collectively manage each of the components, and is connected to the control circuit 24 so that the conversion output result of the A/D converter 21 can be monitored. Further, the control circuit 24 can obtain light intensity information of the image currently being input by monitoring the digital data.

Then, based on this light intensity information, the control circuit 24 sets the oscillation frequency of the variable frequency oscillator 19 to be high when the light intensity is excessive, and to lower the oscillation frequency when the light intensity is too weak. Control.

A variable frequency oscillator 19 whose oscillation frequency can be varied
The other output terminal of the step motor driver 18
The step motor driver 18 rotates the step motor 17 at a speed corresponding to the frequency output from the variable frequency oscillator 19. That is, the rotation speed of the color filter unit 13 is controlled by a variable frequency oscillator 19 that is varied by a control circuit 24 based on the imaging environment (light intensity information).

Next, the solid state image sensor will be explained.

FIG. 3 shows a light input pixel 12a of the CCD 12 in the present invention.
FIG. 2 is an enlarged view showing an arrangement of several tens of optical input pixels arranged at equal intervals in the vertical direction and the horizontal direction. The optical information of the subject 10 imaged on these light input pixels 12a as described above is converted into electrical information as will be described later.

Further, FIG. 4 shows typical photoelectric conversion characteristics of a solid state image sensor such as a CCD. As is clear from Fig. 4, solid-state imaging devices such as CCDs can obtain a signal current that is directly proportional to the intensity (brightness) of input light (hereinafter, this region is referred to as a linear region). It exhibits saturation characteristics with respect to light (hereinafter, this region will be referred to as an overflow region). Since this output current is per unit time, the actual output current is the total (integral) value of the light receiving time of the CCD or the like.

Next, the step motor 17, ie, the color filter unit 13. CCD12. The synchronous operation of the A/D converter 21 and memory 22 will be explained.

As is clear from FIG. 1, the output terminals of the variable frequency oscillator 19 are commonly connected to the CCD 12. It is connected to an A/D converter 21 and a memory 22. Therefore, the higher the frequency of the variable frequency oscillator 19, the faster the color filter unit 13 rotates. At the same time, the following operations occur in synchronization with this frequency.

(1) The data retrieval cycle from the CCD 12 becomes shorter.

(2) The conversion speed of the A/D converter 21 increases.

(3) The memory 22 increases the data write speed from the A/D converter 21 according to the frequency applied to its write terminal.

Conversely, if the frequency becomes low, the operation (1)
, (2), (3) and the opposite actions occur. In this way, these three members 12, 21 and 22 simultaneously and simultaneously change their operating speeds (rotational speeds in the case of the color filter unit 13) based on the synchronization that is centrally controlled by the frequency. Move it up and down.

Moreover, such operation speed control is performed based on the following principle.

As mentioned above, the light from the subject 10 is sequentially transmitted to the CCD for each color according to the rotation of the lens mechanism 11 and the color filter unit 13.
12. At this time, the output signal of the CCD 12 follows the characteristics and light reception time as shown in FIG. The output signal of the CCD 12 is digitized by an A/D converter 21 and sent to a memory 22 and a control circuit 24.

By monitoring this digital data in the control circuit 24, light intensity information of the image currently being input can be obtained. Based on this light intensity information, the control circuit 24:
When the light intensity is excessive, the oscillation frequency of the variable frequency oscillator 19 is controlled to be high, and when the light intensity is too weak, the oscillation frequency is controlled to be low. That is, by increasing the oscillation frequency of the variable frequency oscillator 19, the rotation speed of the color filter unit 13 increases, and the CCD
Even if the light intensity to 12 is the same, the light reception time for each color (
Since the integration time (integration time) becomes shorter and the output signal of the CCD 12 becomes smaller, a darker input image is obtained. Furthermore, if the intensity is too weak, the oscillation frequency is lowered to perform the complete opposite control, and the output signal of the CCD 12 becomes larger, resulting in a brighter input image. Here, CCD1
How much to reduce the output signal of 2 is determined by, for example, CC
When D12 is operating in the overflow region,
The output signal of the CCD 12 may be reduced by operating in a linear region (see FIG. 4). Conversely, CC
How much to increase the output signal of D12 is determined by CCD1.
CCD 12 so that the maximum value of digital data obtained by converting the output signal of 2 by A/D converter 21 becomes a predetermined value.
All you have to do is increase the output signal.

Note that the rotation speed of the color filter unit 13 is detected as follows.
This is done based on the result of counting the aforementioned speed signal by the control circuit 24.

The excessive light intensity state refers to, for example, the operating state of the CCD 12 in the overflow region, and the operating state in the weak light region refers to, for example, the MSB bit of the A/D converter 21 being OFF over the entire screen. This refers to the case where

As detailed above, the CCD 12 and the A/D converter 21
The memory 22 changes its operating speed according to the rotational speed of the color filter unit 13.
The image written to the color filter unit 13
It is clear that this is true regardless of the rotation speed.

As described above, in the present invention, since the color filter unit 13 is rotated at high speed in a bright environment, image input can be completed in a short time. Further, each light input element 12a of the CCD 12 is not divided for each color as in the prior art shown in FIG. It is clear from the explanation.

Finally, reading from the memory 22 will be explained.

As mentioned above, data read from the memory 22 at a constant speed is connected to an external device via the output terminal. Generally, the output signal sent to the outside is converted into an analog signal by a digital-to-analog converter (not shown) and sent to a display monitor (not shown). The frequency of the oscillator 23 is often determined based on this monitor system (NTSC, PAL, etc.).

The present invention is not limited to the embodiments detailed above, and modifications can be made without departing from the spirit thereof.

[Effects of the Invention] As is clear from the detailed description above, according to the image input device of the present invention, it is possible to shorten the image capture time depending on the imaging conditions, and the resolution is also high. It has excellent effects.

[Brief explanation of drawings]

1 to 4 show embodiments embodying the present invention. FIG. 1 is a diagram showing the device configuration of the embodiment of the present invention, FIG. 2 is a diagram showing a color filter unit, and FIG. FIG. 3 is a diagram showing the arrangement of optical input elements of the solid-state image sensor, FIG. 4 is a diagram showing the photoelectric conversion characteristics of the solid-state image sensor, and FIGS. 5 to 7 are diagrams explaining the conventional technology. , FIG. 5 is a diagram showing the configuration of the prior art, FIG. 6 is a diagram showing a color filter unit of the prior art, and FIG. 7 is a diagram showing another configuration of the prior art. 12: Solid state image sensor 13: Color filter unit 14R: Red filter 14G Nigeleen filter 14B Nibble filter 16: Hall IC 17: Step motor 19: Variable frequency oscillator 21: A/D converter 22: Memory 24: Control circuit

Claims (1)

[Claims] 1. Imaging means for arranging a plurality of light input elements in the vertical and horizontal directions and reading and outputting the luminance signal of the input light of each light input element; and a predetermined circumference centered on the rotation axis. a color filter unit having at least two color filters arranged in a shape; a rotation driving means for rotating the color filter unit around the rotation axis and sequentially disposing the color filter unit on an optical path leading to the imaging means; and rotation thereof. An image input device comprising: a control means for varying the rotational speed of the drive means according to the brightness of an imaging environment.