JPH03286673A - Picture reader - Google Patents

Abstract

PURPOSE:To read a picture properly by turning a face formed by a line sensor of an image sensor around an axis in parallel with the line sensor. CONSTITUTION:The entire color image sensor 1 is tilted around a G line sensor in the middle of three colors R, G, B. In this case, since the R sensor is parted from a lens 2 by the tilt and the R sensor in the main scanning direction is parted more than the G line sensor and since the B sensor approaches the line 2, the B sensor is made closer. The magnification correction in the main scanning direction is electrically processed, the R sensor applies interleaving and the B sensor applies interpolation to be matched with the G sensor. In this case, in order to eliminate out of focus due to the tilted color image sensor 1, a lens with a sufficiently deep focus depth, e.g. is to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image reading device that optically reads an image on a document, and particularly relates to an image reading device that reads a color document (prior art). As an example of a seed image reading device, there is one shown in FIG. 5, for example. 1A is a plan view of a color image reading device, and FIG. 1B is a diagram showing a schematic configuration thereof.

P in the figure is on the document table glass 100! When the light source 101 irradiates the original P with the placed original to be read, the reflected light is reflected by the mirrors 102, 103, and 104, and is imaged on the image sensor 106 via the lens 105. In this configuration, the entire page of the original P is read by scanning the light source 101 and the mirrors 102, 103, 104 in parallel to the original platen glass 100.

FIG. 6(a) is a diagram showing the configuration of the image sensor;
b) is a schematic drawing of how the image on the document is formed on the light receiving section of the image sensor.

The image sensor 106 has three line sensors 107R, 107G, and 107B arranged in parallel, and these are mounted on the sensor holder 1 so that they form a plane perpendicular to the optical axis.
Supported by 08. Each line sensor 107R
, 107G.

107B, three color light receiving sections 106R, 106G.

106B are lined up at intervals so that a portion that accumulates charges photoelectrically converted by the light receiving portion and a portion that transfers a signal to the output stage are arranged adjacent to the periphery thereof. Therefore, by moving the document P relative to the image sensor 106,
, H, the distance between the light receiving sections is an integral multiple of the width of the light receiving sections.

When there is an interval of m lines between RG and n lines between GB, the G image signal of one line on the document is equivalent to the R image signal by m lines, and the B image signal is equivalent to (m + n) lines. Reads late. In order to correct the temporal phase shift of the image signal caused by the spacing between the line sensors and output the image signals of a certain line for three colors, the R signal processing circuit has (m + n) The line buffer memory for lines is n5 on the G signal processing circuit.
Equipped with 47 minutes of buffer memory.

One of the features of the digital image reading device described above is that read image data can be freely processed. The variable magnification function is one of them, and the common methods are to thin out the data to reduce the size, and to interpolate the data in the main scanning direction and reduce the reading pitch in the sub-scanning direction to enlarge it. be taken in.

(Problems to be Solved by the Invention) However, in the image reading device using the color image sensor 106 configured as described above, the light receiving sections 106R and 106G for each color.

Since the line buffer has an amount corresponding to the interval of 106B, there is a problem that the reading pitch in the sub-scanning direction cannot be made smaller for enlargement. For example, when an attempt is made to enlarge the image twice, the reading pitch becomes 172, and in order to output the image signals of a certain line in all three colors, a line buffer twice as large is required.

The present invention was made in order to solve the problems of the prior art described above, and the light receiving surface of a line sensor in a reading means such as an image sensor is tilted with respect to the optical axis from a normal position perpendicular to the optical axis. It is an object of the present invention to provide an image reading device that enables enlarged reading of an image with a simple configuration without complicating the device configuration by making it possible to switch between positions.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a scanning means for optically scanning an image on a document and outputting optical information, and a scanning means arranged at a distance from each other. a reading means which has a plurality of line sensors arranged in the line sensor, and reads optical information from the scanning means by the line sensor and outputs the reading result as a reading signal; and a correction means for correcting a temporal phase shift of a read signal using a memory, and reads an image based on information corrected by the correction means, wherein a plurality of line sensors of the reading means are provided. It is characterized in that the surface formed by the line sensor can be rotated around an axis parallel to the line sensor.

Further, in a preferred embodiment, the unit scanning amount of the scanning means changes depending on the rotation angle of the surface formed by the line sensor.

(Function) According to the present invention, the angle of the light-receiving surface of the line sensor with respect to the optical axis can be adjusted according to the reading pitch in the sub-scanning direction by making the surfaces of the plurality of line sensors rotatable. It is possible to read images without increasing memory for correcting the temporal phase shift of read signals between line sensors.

(Example) The present invention will be explained below based on illustrated embodiments.

FIGS. 1A and 1B are diagrams showing a schematic configuration of an image reading section of an image reading apparatus according to a first embodiment of the present invention. In the figure, 1 is a color image sensor provided in the image reading section, IR, IG, and 1B are color image sensors 1.
The light receiving portions of the plurality of line sensors are arranged at 1111 distances from each other. 2 is a lens for forming an image of optical information from an optical scanning section (not shown here) on the color image sensor 1; 3 is a sensor holder that holds the color image sensor 1; The sensor holder 3 is rotatably supported by the main body about a fulcrum 3a corresponding to a line G, which is a center line of the color image sensor l. Reference numeral 4 denotes a spring that urges one end of the sensor holder 3 in a counterclockwise direction, and normally the other end of the sensor holder 3 is stopped against a stopper 6 by the force of this spring 4.

Reference numeral 5 denotes a blade linked to the sensor holder 3, and by energizing it, the tip link 5a is moved, and the sensor holder 3 is rotated 60 degrees clockwise about the fulcrum 3a.

FIG. 2 is a block diagram showing the electrical configuration of the image reading device of this embodiment.

In the figure, 21R, 21G, and 21B receive image information from each line sensor of the color image sensor 1,
This is a magnifying device that augments this. 22R, 22G, 22B
is each booster 21R.

This is an A/D converter that converts analog signals from 21G and 21B into digital signals.

23R and 23G are line buffers for correcting the temporal phase shift of the read signal read by the line sensor. 24 is an image processing circuit which receives the outputs of the line buffers 23R and 23G and performs color correction calculations, binarization processing, etc., and supplies R2O and H image signal outputs. 25
is a CPU that controls the image processing circuit 24, the motor drive circuit 26, and the solenoid drive circuit 28. The motor drive circuit 26 outputs a drive signal to drive the motor 27,
This motor 27 rotates at a frequency according to the drive signal.

The solenoid drive circuit 28 drives the flywheel 5, and the ROM 30 is a memory that stores control commands to the CPU 25.

Next, the operation of the image reading device according to this embodiment is illustrated in FIG.
), (b) to FIG. 3.

The image data of each color read by the color image sensor l is sent to magnifiers 21R and 21G, respectively.

After being sent to 21B and amplified, the A/D converter 22
It is converted into a digital image signal by R, 22G, and 22B. Light receiving parts IR and IG of each color of color image sensor 1
, IB are lined up at intervals, so the image of a certain line on the manuscript is as shown in Figure 1 (a), G is m lines for H, B is (m+n) lines for H. be taken and read. Therefore, in order to match the phase before one image value number is input to the image processing circuit 24, the rear stage of the A/D converter 22R is used for (m+n) lines, and the rear stage of the A/D converter 22G is used for n lines. Buffer memory 23
0 image processing circuit 24, which is provided with R and 23G, and is output in accordance with the B signal read last (see Figure 83).
The image signal after color correction calculations, binarization processing, etc. is output.

Normally, the color image sensor 1 is located at the position shown in FIG. 1(a), and the plane 1a forming the three color light receiving portions IR, IG, and IB is perpendicular to the optical axis. In this state, it is possible to perform same-size reading and reduced reading by thinning out.

When the enlargement mode is set, the phosphorus noid 5 is energized under the control of the CPU 25, and the color image sensor 1 is tilted at 60 degrees with respect to the optical axis.At this time, as shown in FIG.
The interval between the lines that the color line sensor reads on the document is half of normal. At the same time, motor 2 is controlled by the CPU 25.
The feed pitch of the scanning system is halved by reducing the number of drive pulses in 7, etc., and the reading pitch is 1/2 that of the original magnification.
The spacing between RG and GB is mtin and n, respectively.
Since it is a line, it is possible to double the enlarged reading using the same amount of buffer memory as in normal times. By performing thinning on this, it is also possible to enlarge the image by a factor of 1 or more but less than 2 times.

In this embodiment, the color image sensor 1 is entirely tilted with respect to the G line sensor, which is in the middle of the three colors. At this time, by tilting, the R sensor moves away from the lens, so the main scanning direction is more enlarged than the G sensor, and the BC
It becomes smaller as it gets closer to Yones. Magnification correction in the main scanning direction can be processed electrically, and R can be thinned out and B can be interpolated to match G.

Furthermore, there is a risk that the color image sensor l may go out of focus by tilting it, but the following countermeasures can be considered.

(1) Use a lens with a sufficiently deep depth of focus.

(2) In lens design, chromatic aberration is used to set the focal length of the sensor whose distance from the lens changes to be between two positions.

(3) Move the color sensor that is less likely to be affected even if the image is out of focus. For example, in a system that separates colors with an RGB filter and prints with YMC ink, the sensor for G, which is the complementary color of M, which is the most blurry, is placed at the center of rotation.

FIG. 4 shows a second embodiment of the invention. Components that are the same as those in the first embodiment described above are given the same reference numerals.

In this embodiment, a pulse motor is used as the driving source for the rotation of the color image sensor 1, and 7 in the figure is a gear attached to the rotation center 3a of the sensor holder 3, and the rotation of the pulse motor 8 is driven by a motor. It is transmitted to this via bow 9. The tilt of the image sensor 1 can be changed by changing the number of pulses given to the pulse motor 8.

On the other hand, the scanning system uses a pulse motor as the drive source, which makes it easy to switch the feed pitch.For example, if it takes 5 pulses to feed one line during normal reading, then 4 pulses, 3 pulses: When ... is given, the feed amount becomes 0.8 times, 0, 6 times, etc. of the normal amount, and the sub-scanning magnification becomes the reciprocal of that, 1.25 times, 1.33 times. By determining the number of pulses given to the pulse motor so that the tilt angle of the color image sensor l corresponds to this,
Various enlargement ratios can be set without thinning. These controls are performed by storing the relationship between the tilt angle of the color image sensor l and the number of pulses in advance in the ROM 30, and
This can be done by the PU25.

As described above, according to the image reading device of this embodiment, enlarged reading in the sub-scanning direction can be performed without increasing the capacity of the buffer memory.

In addition, in the above embodiment, a color image sensor that combines three reduced RGB line sensors was described, but the number of line sensors is not limited to three, and multiple line sensors are arranged in parallel, and their outputs are aligned in phase. The present invention can be applied to any type of device that uses a memory or the like.

In addition, since there is a limit to the chip size of a 1-size CCD image sensor, regardless of whether it is black and white or color, there is a method in which N number of chips are arranged in a staggered manner and the deviation in the reading position is corrected using memory. There is something like that.

The present invention can also be applied to devices using such sensors.

(Effects of the Invention) The present invention has the above-described configuration and operation, and by making the surfaces of the plurality of line sensors rotatable, the image on the document can be read regardless of the reading magnification. Images can be read appropriately without increasing memory capacity for correcting temporal phase shifts of signals.

[Brief explanation of the drawing]

1(a) and 1(b) are diagrams showing a schematic configuration of an image reading section of an image reading device according to a first embodiment of the present invention, and FIG.
The figure is a block diagram showing the electrical configuration of the image reading device of the first embodiment, FIG. 3 is a diagram showing the data storage state of the line buffer in the image reading device of the first embodiment, and FIG. 4 is the invention of the present invention. FIGS. 5(a) and 5(b) are a plan view and a diagram showing a schematic configuration of a conventional color image reading device, and FIG.
Figure (a Mc) is a vertical diagram of the image sensor of a conventional color image reading device, and Figure 6 (b) is a diagram schematically depicting how an image on a document is formed on the image sensor. It is. Explanation of symbols 1...Color image sensor 2...Lens 3...Sensor holder 4...
Spring 5... Solenoid 6... Stopper
7...Gear 8...Pulse motor

Claims (2)

[Claims] (1) It has a scanning means that optically scans an image on a document and outputs optical information, and a plurality of line sensors arranged apart from each other, and the line sensors detect the optical information from the scanning means. a reading means for outputting a reading result as a reading signal; and a correcting means for correcting, using a memory, a temporal phase shift of the read signals between the line sensors caused by the spacing at which the plurality of line sensors are arranged; An image reading device that reads an image based on information corrected by a means, characterized in that a surface formed by a plurality of line sensors of the reading means is rotatable about an axis parallel to the line sensors. image reading device. (2) The image reading device according to claim 1, wherein the unit scanning amount of the scanning means changes depending on the rotation angle of the surface formed by the line sensor.