JPS6329471B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is configured such that an optical image formed on an image sensor moves on the image sensor, and the path of image information converted by the image sensor is changed along with the movement. The present invention relates to an image information reading device that obtains a resolution higher than the resolution of an image determined by the number of light receiving sections formed on an image sensor by switching the number of light receiving sections formed on an image sensor. Generally CCD (Charge
When using a solid-state image sensor (one form of photoelectric conversion element, hereinafter referred to as an image sensor) such as a Coupled Device (coupled device) and a facsimile device, image reading is the first step.
Proceed as shown in the figure.

That is, FIG. 1 shows a perspective view, and when a document 1 is illuminated with an illumination light source 2, an image (not shown) recorded on the document 1 is formed on an image sensor 4 by a lens system 3. At this time, if the number of individual light-receiving parts (hereinafter referred to as the number of bits) of the image sensor is N, and the width of the document is Dmm, then the resolution R during reading is R=N/D lines on the surface of the document. /mm.

For example, if the width D of the document is 215.9 mm and the number of bits N is 1024, the resolution R is 4.74 lines/mm.
becomes. If high resolution is required in facsimile, R=8 lines/mm or more is required. The number of bits at this time is N=1728 bits or more.

If even higher resolution is required, R = 12 lines/mm.
The number of bits at this time is N=2591 bits or more. In this way, in order to obtain a high-resolution image, an image sensor with a correspondingly large number of bits is required. However, as the number of bits increases, the price of the image sensor increases rapidly.
In many cases, a plurality of image sensors with a small number of bits (that is, inexpensive) are used side by side.

FIG. 2 shows a plan view when image information is read using two image sensors, and half of the image information recorded on the document passes through lens systems 3 and 3', corresponding to each half. The image is formed onto the image sensor 4, 4'. It is also possible to use three or more image sensors in a similar manner. However, with the above method, it is necessary to align the electrical characteristics of multiple image sensors, adjust the setting positions, and match the seams of the images, so these new problems must be solved. Must be.

The image information reading device of the present invention solves the above-mentioned problems, and is advantageous in that it can obtain resolution greater than a given number of bits using one inexpensive image sensor with a small number of bits. This is what I did.

The present invention will be explained below with reference to the drawings.

FIG. 3 shows a plan view of an image sensor used in the image information reading device of the present invention.
It is constructed by arranging ...... vertically and horizontally (including diagonally).

At this time, the relationship between the width a of the light receiving section 6a and the pitch p between adjacent light receiving sections is set to a/p1/2 (actually, a/p<1 is also effective).

Next, in explaining the embodiment of the present invention, the configuration and operation of the conventional example will be explained using FIG.

FIG. 4 shows a plan view of a conventional example improved to read image information using the image sensor 5 shown in FIG. When the original 7 (subject) is illuminated with an illumination light source 8 such as a fluorescent lamp, an image (not shown) recorded on the original 7 is formed on the image sensor 5 by the lens system 9 (optical system). image is formed on the image sensor). The image sensor 5 is vibrated in a direction substantially perpendicular to the optical axis 9a by a vibrating means 10 composed of, for example, a piezo element.

In FIG. 3, for example, if the image sensor 5 is moved by p/2 in the direction of the arrow 11, the light receiving parts 6a, 6b
The positions of ...... are indicated by broken lines 6'a, 6'b...
move to the respective positions. At this time, since the image formed on the image sensor does not move, the light receiving section 6a,
6b...... are two points (6a and 6'a,
The image information (electrical signals) at 6b and 6'b......) are output respectively.

Therefore, when the image pickup device 5 has N bits (N light receiving sections), it is possible to obtain an output of 2N bits, thereby doubling the resolution. 5A to 5D are signal waveform diagrams showing the processing procedure of image information output from the light receiving sections 6a, 6b (FIG. 3). The light receiving sections 6a, 6b as described above...
The output signals of are represented by signals 13a, 13b, . . . in the signal 13 of FIG. 5b, respectively.
In addition, 6'a, 6'b... of the light receiving sections 6a, 6b...
. . are represented by signals 14a, 14b, . . . in signal 14 of FIG. 5c, respectively. Therefore, the signal 15 formed by the sum of the signals 13 and 14 has an output of 2N bits. Signal 12 is generated by a clock pulse generator 16 shown in FIG.
a, 13b......, 14a, 14b...... are controlled and synchronized.

FIG. 6 shows a signal processing circuit suitable for the present invention for carrying out the above-mentioned signal processing. (The arrow indicates the direction in which the signal is traveling). The clock pulse generator 16 outputs the signal 12 shown in FIG. 5a, and the driver 17 controlled by the signal outputs the signals 13a and 13b shown in FIG. 5b from the image sensor 5.
...... is output.

On the other hand, the analog signal controlled by signal 12
Shift register driver 18 (hereinafter referred to as ASRD1)
8) is the analog shift register 19
(hereinafter referred to as ASR 19) controls the timing of signals stored in the ASR 19. Therefore, the signals 13a, 13b outputted from the image sensor are switched to the switch 2.
0 and is input to the ASR 19 bit by bit (in synchronization with signal 12). The storage capacity of the ASR 19 is set when the image sensor 5 has N bits (N-1).

After outputting the Nth bit signal from the image sensor 5, the switch 20 (route switching means) is switched in this state, and the signals after the N+1st bit [signals 14a, 14b shown in FIG. 5c] are Image sensor 5
The signal is input to the adder circuit 21 via the switch 20. The switch 20 is the vibration means 10 shown in FIG.
(in FIG. 7 of the present invention, in synchronization with the means for moving the optical image), for example, in FIG.
a, 6'b... (or when the optical image moves to produce an effect equivalent to this), the output signal of the image sensor 5 (Fig. 6) is ASR1.
The signal is switched to be output from the 9 side to the adder circuit 21 side.

When the Nth bit signal is output from the image sensor 5, the first bit signal is output from the ASR 19, and after being delayed by 1/2 clock by the analog delay 22, the first bit signal is sent to the adder circuit 21. [Signal 13a in FIG. 5b] is input. Next, the N+1st bit signal [signal 14 in FIG.
a] is input to the adder circuit 21 with a delay of 1/2 clock from the first bit signal. Next, the second bit signal (signal 13b in FIG. 5b) that has passed through the analog delay 22 is further delayed by 1/2 clock from the N+1st bit signal and then sent to the adder circuit 22.
is input.

In this way, the input signal is sent to the adder circuit 21.
is added. Therefore, the output signal of the adder circuit is represented by signal 15 in FIG. 5d. In addition, the vibration means 1
0 is preferably an intermittent movement so that the image does not move while the image sensor 5 is accumulating charge (the same applies to the means for moving the optical image in FIG. 7 of the present invention).

Further, the vibration means 1 with the a/p as a/p1/3
If the image pickup device 5 connected to 0 is stopped at three positions (for example, V
It is also possible to obtain three times the resolution (this can be achieved by applying a voltage such that = 0, V ₁ , 2V ₁ ).

In Figure 3, the pitch p of the light receiving section is p≒10μm.
~20 .mu.m, so in order to obtain n times higher resolution, it is sufficient to stop at each displacement point of P/n, 2/np, . . . n-1/np. For example, when n=2, the amount of displacement (in the case of FIG. 4, the amplitude of the image sensor 5) is 5 μm to 10 μm.

First, if the glass block 27 is placed approximately perpendicular to the optical axis 26a and then rotated by an angle △θ (rad), the amount of movement △S of the optical image is △S.
= dg cos△θ [tan△θ−tan {sin ^-1 (sin△θ/ng)}
] becomes. Here, dg is the thickness of the glass block,
ng is the refractive index of the glass block.

In the above equation, for example, if ng=1.5 and dg=5 mm, when Δθ=3×10 ⁻³ to 6×10 ⁻³ rad (10′ to 20′), ΔS=5 μm to 10 μm. Note that aberrations caused by movement of the optical image can be ignored.

FIG. 7a shows a perspective view of an embodiment of the present invention in which image signals are read using the image pickup device 5 shown in FIG. 3, and shows a structure without a movable part.

The original 7 is alternately illuminated with monochromatic light of different wavelengths (for example, red and blue) from illumination light sources 29a and 29b. (Wavelength switching means is involved).

An image (not shown) recorded on the original 7 is captured by a lens system 30 and a chromatic dispersion prism 31 (hereinafter referred to as prism 3).
(denoted as 1), the image is formed on the image sensor 5.

The prism 31 includes a low dispersion glass 31a (for example, LaK, etc.) and a high dispersion glass 31, as shown in FIG. 7b.
b (for example, 5F, etc.). Here, the aberration of the lens system 30 needs to be corrected in advance in consideration of the presence of the prism 31. The amount of light incident on the prism 31 is refracted varies depending on the wavelength (that is, color) of the light, and the shorter the wavelength (for example, blue), the more the light is refracted.

That is, when the original 7 is illuminated with red light by the illumination light source 29a, one point recorded on the original 7
The information of Po travels from the optical path 32 to the optical path 32a (Fig. 7b) by the prism 31, and then the information of the original 7
When the document 7 is illuminated with blue light by the illumination light source 29b, the information of one point Po recorded on the document 7 is transmitted by the prism 31 from the optical path 32 to the optical path 32b (FIG. 7b). Therefore, the image on the image sensor 5 can be moved as described above.

The amount of movement △S at this time is △S=P/2. What is necessary is to set the angle of the color dispersion.

In this embodiment, it is preferable that the document 7 records image information consisting of white and black.

However, the present invention can be sufficiently applied to general multicolor originals by appropriately selecting the colors of the illumination light sources 29a and 29b.

Further, in FIG. 7, another lens system can be inserted between the prism 31 and the image pickup device 5 to make the incident light on the prism 31 affocal.

In this way, if the signal processing circuit shown in FIG. 6 is used in the configuration shown in FIG. 7, it is possible to obtain a resolution higher than the number of bits using an image element with a small number of bits, as explained in FIG. 4. I can do things.

Furthermore, there are no moving parts, no high-voltage power source is required to drive the electric polarizing element, etc., and a high-resolution signal can be obtained with an extremely simple configuration. The movement of the optical image on the image sensor is a linear reciprocating motion (1
Although the above-mentioned movement has been described as a movement (two-dimensional), for example, the movement can also be a movement (two-dimensional) that combines movement in the left-right direction and the up-down direction. In addition, the subject is not only recorded on a flat surface such as a manuscript;
In some cases, it is also possible to form an optical image of an object, scenery, etc. on an image sensor to improve resolution.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional image reading device, FIG. 2 is a plan view of an image reading device using two image sensors, and FIG. 3 is a plan view of an image sensor used in the image reading device of the present invention. 4 is a plan view showing a conventional image reading device for explaining the principle of the present invention, FIG. 5 a to d are signal waveform diagrams, and FIG. 6 is a signal processing circuit suitable for the present invention. Block diagram, No. 7
FIG. 7a is a plan view showing a first embodiment of the present invention, and FIG. 7b is a plan view showing a color separation prism. In the figure, 5...imaging device, 6a to 6c...
Light receiving unit, 7... Original, 10... Vibration means, 8, 2
9a, 29b...Illumination light source, 9, 30...Lens system, 16...Clock pulse generator, 17...Driver, 18...Analog shift register driver, 19...Analog shift register, 20...
Switch, 21...addition circuit, 22...analog delay, 31...prism.

Claims (1)

[Scope of Claims] 1. Refraction means included in an optical system that forms an optical image of a subject and refracts the optical path of the optical image; An imaging means comprising an array of a plurality of light receiving sections for photoelectrically converting the optical image; A control means for periodically forming optical images at a plurality of positions shifted by a small width with respect to a pitch P between the light receiving parts by periodically changing the wavelength of the light incident on the refracting means; An image information reading device comprising a synthesizing means for synthesizing photoelectrically converted image information at the plurality of imaging positions.