JPS6247734A - Coordinate input device - Google Patents

Abstract

PURPOSE:To increase the coordinate input speed by performing the scan by means of a rotary scan mirror only in a specific area around a point indicating tool and then to improve the resolution of the coordinate input by scanning the specific area with high resolution. CONSTITUTION:The 2-dimensional images of a read original 11 and a point indicating tool, i.e., a writing pen 12 which are formed by a lens 1 are reflected by a rotary scan mirror 2 and form next images on a 1-dimensional image pickup element 4. The output picture signal of the element 4 is sampled by a sampling circuit 10 and stored in a picture memory 7. This stored picture signals are displayed on a display device 8 in the form of a picture. A picture processor 9 detects the image of the pen 12 and controls a controller 6 so that the mirror 2 scans a specific area around the pen 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a coordinate input device, and particularly to one that inputs position coordinates of an image or the like into a computer or the like using an imaging device.

[Conventional technology]

Tablets and mice are commonly used as coordinate input devices, but it is necessary to input coordinates only on a special flat surface, or to move a point indicator with a signal cable attached. It is not necessarily good in terms of operability. Another problem is that the function is limited to inputting coordinates, and it is difficult to input existing image data unless an image scanner or the like is prepared as an input device for an imaging device or the like. From this point of view, attempts have been made to use a TV camera to realize a device that functions as both an image scanner and a coordinate input device. It is clear that an imaging device such as a TV camera has the function of an image scanner, and if coordinates can be input by capturing an image of a point pointing device, it is extremely possible to input coordinates without using a special flat table or point pointing device with a cape. It is expected that input operations will be possible in a natural state, and operability will be significantly improved.

Figure 6 is, for example, Journal of the Institute of Electronics and Communication Engineers J 67-D, 1m
6.

1 is a schematic configuration diagram showing the configuration of a coordinate input device using a TV camera published in 1984. In the figure, aυ is the object, for example, a read manuscript (if the purpose is only to input coordinates, there is no need to read the contents written on the manuscript and it may be a blank sheet,
In addition, more generally, it does not need to be a paper surface such as a document or drawing as long as it provides a background that can be identified when the pointing device is imaged, such as the top of a desk. . ), @ is a writing pen as a point pointing tool, ω is a TV camera that simultaneously images the document 0 to be read and the point pointing tool (6), (7) is an image memory that stores the output image signal of the TV camera ω, ( 8) is a display device such as a CRT that displays the stored contents of the image memory (7) as an image, and (9) is a point pointing tool @ that processes the image data stored in the image memory (7).
(6) is an image processing device (
9).

The TV camera ω reads the original αυ at a speed of 80 frames per second.
The entire writing pen (6) is imaged, and the output image signal is stored in the image memory (7). The stored contents of the image memory (7) are displayed on the display device (8) and processed by the image processing device (9). The image processing device (9) is controlled by a controller (6), and when operating as an image scanner, it transfers the contents of the image memory (7) as is to a file memory (not shown), and when operating as a coordinate input device, it transfers the contents of the image memory (7) as is to a file memory (not shown). Image processing is performed to detect the image of the writing pen@ from the image signal. This image processing is performed, for example, by combining the content written on the read manuscript 0υ with a writing pen (6
), spatial filtering such as low-frequency 8-wave filtering, and pattern matching that detects the corresponding image part in the image using a mask pattern selected based on the shape of the pen (6) and lighting conditions, etc. It is a combination of normally known processing methods, and the image processing device (9) is a dedicated device for executing these processes at high speed. and a writing pen (2
) and outputs to the controller (6) the address on the image memory (7) where the image signal corresponding to the specific part such as the tip was stored.

The controller (6) obtains the coordinates of the point indicated by the writing pen (6) by converting this address into coordinates on the read document αυ. The speed of coordinate input by the above image processing (i.e., the number of times coordinate values of a point can be obtained per second) is determined by the imaging speed of the TV camera (8 frames per second) if the operation speed of the image processing device (9) is sufficiently large. If it is not large, it is determined by the image processing speed. If the image of the writing pen (6) can be detected only 15 times per second by image processing,
Controller (6) Controls the image signal in the image memory (7) so that it is updated only once every two frames.

[Problem that the invention seeks to solve]

With the conventional coordinate input device using a TV camera as described above, the TV camera's imaging speed of 807 frames per second is low, so it is only possible to input coordinates of 30 points per second at most.
Compared to normal tablets, the input speed is too slow and the movement of the pointer is restricted, making it difficult to use. Also, the number of scanning lines in one frame of a TV camera is 500.
If the length of the original to be read (b) is 25 mm, the coordinates can only be input with a small resolution of 2 lines/long, which is a problem that greatly limits practical applications.

This invention was made in order to solve such problems, and aims to provide a coordinate input device that has high coordinate input speed and resolution while maintaining good operability of the coordinate input device using an imaging device. shall be.

[Means for solving problems]

The coordinate input device according to the present invention includes a one-dimensional image sensor, a rotating scanning mirror that sequentially sends images of a subject and a spot of water odor on the subject to the one-dimensional image capturing element, and a rotation angle of the rotating scanning mirror. A detector for detecting, a controller that specifies the rotation angle and narrows down the scanning range to a specific area containing the water odor, and an image memory that stores the output image signal of the one-dimensional image sensor in an address corresponding to the rotation angle. and an image processing device that processes the image signal to detect the position coordinates of the spot water odor, and the position of the spot water odor on the subject is determined based on the detection signal. be.

[Effect]

In this invention, since pre-delivery is performed only in a specific area around the finger spotting water odor 9, the coordinate input speed increases. Furthermore, since this specific area is scanned at high resolution, the resolution of coordinate input also becomes high.

〔Example〕

FIG. 1 is a schematic configuration diagram showing a coordinate input device according to an embodiment of the present invention. In the figure, (1) is the lens, (2)
(3) is a rotating scanning mirror that sequentially sends the images of the read original αη and the spot water odor (2) to a one-dimensional imaging device by rotation; (3) is a drive device that drives the rotating scanning mirror; (4)
is a one-dimensional image sensor, (5) is a detector that detects the rotation angle of the rotating scanning mirror, and (6) is a microprocessor that supplies a signal to the drive device (3) specifying the rotation angle that the rotating scanning mirror should take. A controller, (7) is an image memory that stores the output image signal of the one-dimensional image sensor (4), (8) is a display device that displays the stored contents of the image memory as an image, and (9) is the image memory stored in the image memory. An image processing device that processes an image signal to detect the positional coordinates of the water odor, αO is a sub-sampling circuit that reduces the number of pixels in the output image signal from the one-dimensional image sensor (4).

In the coordinate input device configured as described above, the two-dimensional image of the read original αυ and the smeared finger, that is, the writing pen (2), created by the lens (1) is reflected by the rotating scanning mirror (2). The zero-rotation scanning mirror (2) that forms an image on the one-dimensional image sensor (4) receives a digital code or analog voltage that specifies the rotation angle of the rotation scanning mirror, which is generated from the controller (6) to the drive device (3). Since it is tilted to a specified rotation angle by the signal of You can also scan ◇
The detector (5) is a mechanical or optical rotary encoder that detects the current rotation angle of the rotating scanning mirror (2) and outputs a signal, and outputs a signal that indicates the rotation angle specified by the controller (6) and the current rotation angle. The difference between the rotation angle and the rotation angle can be calculated and used for rotation angle control. A primary element (4) driven by an image sensor drive circuit (not shown) performs an imaging operation in synchronization with sub-scanning, and the output image signal is an image after only the necessary portion is selected by a sub-sampling circuit QG. It is stored in a memory (7), and the stored contents are displayed as an image on a display device (8). At the same time, the image memory (
The image signal stored in the writing pen (7) is processed by the image processing device (9) in the same manner as in the conventional device, and by detecting the image of the writing pen (2), the writing pen ( 2), the coordinates of the designated point in the specific area are detected.

The controller (6) determines the position of the writing pen (2) on the read document Qη from this detection signal, and inputs the position coordinates to a computer or the like. Note that the time for inputting coordinates and the time for not inputting coordinates are distinguished by a switch (not shown) attached to a writing pen or the like. Unlike a conventional TV camera, the imaging scanning in this embodiment is characterized in that the scanning target range and scanning resolution can be varied for one read document (b). In this example, the controller (
6) to the boundary of the scanning target range in the read document αN),
After setting the rotation angle of the rotating scanning mirror (2), the controller (6
), a rotation angle designation signal is generated at a constant speed so as to sequentially change the rotation angle minute by minute, and line-sequential scanning is performed.

At this time, the size of the scanning target range in the sub-scanning direction corresponds to the range of the rotation angle of the rotating scanning mirror (2), and the scanning resolution corresponds to the minute size of the rotation angle.

FIG. 2 is an explanatory diagram illustrating the imaging operation of the coordinate input device according to an embodiment of the present invention, and FIG. This shows that the target range can be set as the scanning target range, or a part of the specific area υ can be set as the scanning target range. In addition, Fig. 2 (b) and (e) are examples of variable scanning resolution, and Fig. 2 (b) shows a scanning target range that covers the entire scanned document Qυ, with relatively sparse scanning lines. When scanning with a high density, FIG. 2C shows a case where the scanning target range is narrowed down to a specific region Q]) and scanning is performed with a relatively dense scanning line density. In Fig. 2(b), the small step size of the rotation angle is increased to perform high-speed scanning despite the large scanning range, and in Fig. 2(C), the small step size of the rotation angle is reduced to perform a small scan. Scan the target area with high resolution.

Figure 2(d) shows that by high-resolution scanning of the latter small area,
This shows that the specific area (goods) is stored in the image memory (7) as if it were enlarged compared to the former wide-area high-speed scanning. In addition, Fig. 2 (el and (f)) shows the image memory (7).
) is a diagram showing an example of the image signal storage state. The storage address of the 0 image memory (7) is the total number of scanning lines determined from the rotation angle range of the rotating scanning mirror (2) and the minute step size of the rotation angle, and each Each scanning line is associated with the amount of image signal included in the scanning line, that is, the number of pixels per scanning line. Second
Figure (el) is an example of the storage state when the entire read original Qυ is scanned with a larger step size, and 512 lines are stored with each line being 512 pixels. Assuming that the size of the read original aη is 25cIrLX25cm, This corresponds to scanning at a resolution of approximately 2 pixels/ax in both the vertical and horizontal directions, that is, the resolution of the TV right camera. Performs processing to thin out the output image signal of.

The reason for this is that since the one-dimensional image sensor (4) itself has a fixed number of picture elements, the output image signal is appropriately subsampled to obtain an image signal □ with approximately the same resolution in the vertical and horizontal directions. For example, the number of picture elements of the one-dimensional image sensor (4) is 2.
048, in order to obtain an image signal of 512 pixels in one line, one pixel out of every four pixels is selected and stored in the image memory (7). On the other hand, the second figure (g) is an example of the storage state when the specific area (b) is scanned with small rotation angle steps. The ratio of the specific area) to the entire read document αυ is 1 horizontally.
/2 and 1/4 vertically, if this is the scanning target range and the resolution is approximately 5 pixels/six, which is 2.5 times the above, the result will be 640 pixels horizontally x 820 vertical lines as shown in Figure 2). The image signal is stored in an image memory (7). Note that in the figure, the shaded area is the blank area of the memory. At this time, the main scanning direction (
In the horizontal direction), the one-dimensional image sensor (4) is configured to image the entire width 25 cTrL of the document αυ to be read, and the sampling circuit σO captures 5 pixels from 8 pixels of the output image signal of the one-dimensional image sensor (4). In addition, 640 pixels are obtained by subsampling to select 1/2 pixels outside the specific area (goods). Alternatively, adjust the focus of the lens (1) so that the one-dimensional image sensor (4) captures an image of a width of 40 crrL that includes the entire document to be read, and then use the sub-sampling circuit QO to ), 640 pixels may be selected and stored in the image memory (7) by cutting off pixels other than those within the range of the specific area Qυ.
In short, if the entire read document 0η is imaged in a specific area Q with sufficient main scanning resolution, it can be converted to the required resolution by the subsampling circuit αO. The subsampling operation corresponding to the size of the scanning target range and the scanning resolution as described above is performed by the controller (a), the Kerr-dimensional image sensor (4
), and the position and size of the specific area (), the position on the pixel array on the one-dimensional image sensor (4) and the value converted to the ratio of the necessary subsampling μ are subsampled. This is usually done in a well-known manner by applying it as a signal to the circuit head.

Furthermore, what should be added to the description of the imaging operation in FIG. 2 is the high speed of scanning using the rotating scanning mirror (2), especially the high speed when changing the scanning target range. Rotating scanning mirror (2)
is lightweight and the controller (6) is controlled by the drive device (3).
Since the rotation angle specified by can be reached accurately at high speed and by being equipped with a detector (5), it is possible to access any scanning target range in a short time, and also,
It is possible to execute very small rotation angle steps for line-sequential scanning at high speed, and it is easy to achieve a scanning speed higher than the scanning speed of a TV camera of 512 lines per second x 80 lines per second. ) and image processing devices (9)
The operating speed of will give an upper limit to the scanning speed.

Furthermore, it should be noted that even when scanning at high resolution, if the range to be scanned is appropriately limited, it is possible to scan the entire read document Q at a higher speed than when scanning at a resolution comparable to that of a TV camera. In the example given in Figure 2, a one-dimensional image sensor (4
) is the same, scanning the entire document (b) requires 512 lines of sub-scanning, whereas scanning of a specific area (]) requires 820 lines of sub-scanning. If 9) can be processed in real time, a frame rate of 1.6 times, that is, a coordinate input speed can be realized, and the resolution will be 2.5 times as high.

From the above explanation, it has been made clear that the coordinate input device of the above embodiment can perform high-speed scanning with respect to the scanned document Ql) by varying the scanning target range and scanning resolution. Due to this property, it goes without saying that by using a TV camera as an image scanner in the same way as a conventional coordinate input device using a TV camera, better performance can be obtained than that using a TV camera. It can realize more obvious advantages as a coordinate input device.

FIG. 3 is an explanatory diagram of the operation of a coordinate input device performed by an embodiment of the present invention having the configuration shown in FIG.

Here, for the sake of simplicity, we will first explain the case where no drawing is performed on the read document α with the writing pen @. In that case, the writing pen (2
) is detected, and point coordinates are input once in each frame. In FIG. 3(a), the read original (
2) In the process of moving the writing pen (to) with respect to Dot (
2) coordinates are input, and the point (to) is entered in the previous frame.
Assume that the coordinates of are input. At this time, the controller (6) calculates the moving direction of the writing pen 4 from between the points to the point (to), and sets the scanning target range in the next frame in that direction. That is, the position of the specific area 0υ is determined so as to sufficiently include the coordinates predicted to be detected in the next frame if the writing pen @ continues to move, and is set as the scanning target range. The simplest method for predicting the position is to set a specific area 0η so as to sufficiently include positions symmetrical to point (A). The size of the specific area and the predicted relative position to the next position of the writing pen (2) should be determined based on the magnitude of change in the moving direction and moving speed of the writing pen (6). Here, it is assumed that a specific area 0η of the size of the vertical and horizontal signatures of the read document is simply set centered on the point (to) the position of the writing pen in the immediately previous frame. When the coordinates of point ■ are input through scanning and image processing of the specific area 0η set in this way, the scanning target range for the next frame is further changed by changing the point (b) as shown in Figure 3 (b). The point 2, which is the position of the next writing pen (6), is detected.

In this way, the position of the specific area to be scanned next is determined according to the position of the writing pen (6) obtained by scanning the specific area once and image processing.
2) Coordinates are input in such a way as to track. Second
As can be easily inferred from the explanation of the figure, if the size of the specific area and the scanning resolution within it are appropriate, the reading document a
υIt is possible to input coordinates faster and with higher resolution than by repeatedly scanning the entire area. In this case, the rotating scanning mirror (2) changes the range of rotation angles for scanning one after another according to the rotation angle designation signal output by the controller (6), while changing the minute step size of the same rotation angle. The subsampling circuit αG
In accordance with a signal indicating the range of the specific region and the subsampling ratio output by the controller (6), pixels outside the region are truncated and subsampling μ is performed.

Processing within the image processing device (9) is similar to that of conventional devices.

FIG. 4 is a flow chart showing an outline of the operation of the controller (6) according to an embodiment of the present invention as described above.

The controller (6) rotates the rotating scanning mirror (
2) Set the range of rotation angle to be taken and the step size of the rotation angle. corresponding to the starting edge of the range) and ending angle (corresponding to the starting edge of the range)
Corresponding to the end of the scan target range) and set the step size. In addition, regarding the step, the ratio of sub-sampling to sub-sampling circuit 00 and the image memory (7)
A signal indicating the effective range of the signal to be stored in the image memory (7) is outputted, and in a further step, a signal indicating the update frequency or timing of the image signal to be stored in the image memory (7) is outputted.

After the above settings have been made, first set the starting angle in step ((to) as the target value of the rotation angle that the rotating scanning mirror (2) should take, and then send a signal specifying the target angle in step (e!5). to the drive unit (3), which causes the rotating scanning mirror (2) to
rotates to take the target rotation angle, so input the output of the detector (5) to know the current rotation angle step by step, and repeat the same rotation until the step confirms that this matches the target angle. Outputs the angle specification signal. If the current angle matches the target angle, it is checked in step 4 whether it has reached the final angle. If the terminal angle has not been reached, in step 4, add the rotation nutep size to the current angle, set this as the next target angle, and return to step (trowel).Step (
(g) By repeating step 71, the scan target range is scanned from the beginning to the end with a predetermined step size.

Step (If it is found that the current angle has reached the terminal angle, the controller (6) sends the image processing device (9) to the detection position (address on the image memory) of the image of the finger water odor (2).
is received, and the position on the read document, that is, the coordinates of the designated point, is calculated from the address on the image memory using information such as the scanning target range and step size. This means that one coordinate input has been obtained. If the coordinate input state continues in step (3), the process advances to scanning for the next coordinate input, and if the coordinate input state is not in the coordinate input state, the coordinate input ends.

In order to input the next coordinates, take step - and separate the image captured by the previous scan (previous frame) and the image captured by the current scan (current frame), and place the detected spot on the water odor@ The moving direction of the point finger water odor @ is calculated from the coordinate position of , and based on this, the next scanning target range is determined in step σ, and the next scanning is started in a stepwise manner.

As can be seen from the above explanation, the part surrounded by the broken line in FIG. 4 (from step ■ to step width (to)) corresponds to the operation of accessing the scanning position using the rotating scanning mirror (2).
Further, the portion surrounded by the dashed line (from step 2 to step 4) corresponds to the line sequential scanning operation using the rotating scanning mirror (2). It is also possible to perform a random access operation using the access operation, or to perform trace scanning using line sequential scanning.

In the above description, it should be noted that the rotation step size is not necessarily constant even during −-way scanning. This scans the original Qυ
A rotating scanning mirror (2
) may need to be changed minutely in accordance with the absolute value of the rotation angle. In such a case, the controller (6) may store changes in the step size of the rotation angle as a table, or
Alternatively, the step size may be calculated from the absolute value of the rotation angle, and the next target angle may be set using the stored value or the total 'X value in step 4.

Further, FIG. 6 is an explanatory diagram of the coordinate input operation in the coordinate input device according to an embodiment of the present invention, but unlike the case in FIG. I will explain about it.

In this case as well, the method for setting the position of the specific area is the same as in Figure 3, but since the drawn content and the writing pen (2) are imaged at the same time, the image processing device ( 9), the symbols attached to points and specific areas are the same as in Figure 3, but the image of the writing pen @ (hatched area) and the drawing content ( The solid line part in the trajectory of the tip of the writing pen) is imaged, and in the specific area 0υ, the drawing content up to point (b) and the image of the writing pen f
411 (the image signal of this frame is designated as A) is obtained, and in the specific area (2), the drawing contents up to the gift and the image of the writing pen (b) (the image signal of this frame is designated as B) are obtained.

From image signal A and image signal B, perform a logical operation to obtain A - B (logical product of the inverted image of A and B. Here, A and B are assumed to be binary logical value signals). If executed circuitically, the drawing contents up to the previous frame and the writing pen @
The images of are canceled out, and only the newly drawn content from point (b) to point ■ and the image of the writing pen in the new frame remain, as shown in Figure 5(b), and the new drawn content is Image of a thin line (from dot (b) to dot ■) and writing pen i42
can be easily separated by spatial filtering that eliminates thin lines, so the coordinates of the point indicated by the tip of the writing pen are detected and input from the frame imaged by the specific area μs by image processing similar to conventional methods. It turns out.

In the example shown in Fig. 6, in order to perform a logical operation between two frames, it is necessary to know the corresponding parts in the image signal of the two frames. Since we know the image memory (7
), it is easy to correlate and calculate the image signals of successive frames.

In the explanation of the embodiments so far, we have taken as an example the case where the shape of a writing pen is detected by the image processing device (9), but the watery smell of the finger (2) is detected by the image processing device. Any object may be used as long as it can be separated and identified from the image signal. For example, using a thin cross-shaped object, an image processing device can detect the intersection of the crosses, or a light-emitting element such as an LED is attached to one pen tip, and the image processing device can detect high-luminance peaks in the image signal. A device that can detect color and input color to the one-dimensional image sensor (4) (
For example, by using a one-dimensional image sensor (such as a color filter) and using a pen-shaped point indicator of a different color from the original to be read, the color can be identified by an image processing device, thereby detecting the odor of point water. Of course, it is possible to input coordinates.

In addition, in the explanation of the above embodiment, the setting of the size and position of the specific area to be moved was explained using a specific example to track the smell of water, but these are not limited to the exemplified size and setting method. Needless to say, it can be selected appropriately depending on the way the finger is moved. Further, in the above embodiment, the subsampling circuit αO is the image memory (7
) was used to reduce the amount of image signals stored in
If the image memory itself has a sufficiently large storage capacity and the necessary sub-sample processing and high-speed processing are executed at the display and image processing stages, the Of course, the sub-sampling circuit QO for reducing the number of pixels becomes unnecessary. Further, the coordinate input device according to the present invention can also be used as a normal image scanner, and has the effect of providing a device that also functions as a coordinate input device.

〔Effect of the invention〕

As described above, the coordinate input device according to the present invention includes a one-dimensional image sensor, a rotating scanning mirror that rotates to sequentially send images of a subject and a point of water odor on the subject to the one-dimensional image sensor;
A detector that detects the rotation angle of this rotating scanning mirror, a controller that specifies the rotation angle and narrows down the scanning range to a specific area containing the water odor, and an address corresponding to the rotation angle of the one-dimensional image sensor. an image memory for storing output image signals;
The present invention also includes an image processing device that processes the image signal to detect the positional coordinates of the point pointing tool, and the position of the point finger water odor on the subject is determined based on this detection signal, which is different from the conventional method. Compared to a coordinate input device using a TV camera, this has the effect of providing a device that can input coordinates at high speed and with high resolution.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a coordinate input device according to an embodiment of the invention, FIG. 2 is an explanatory diagram showing an imaging operation in the coordinate input device according to an embodiment of the invention, and FIG. An explanatory diagram showing the coordinate input operation in the coordinate input device according to the embodiment, FIG. 4 is a flowchart showing the operation of the controller according to the embodiment of the present invention, and FIG. 5 shows the coordinate input operation of the coordinate input device according to the embodiment of the present invention. An explanatory diagram showing image processing for input operation, and FIG. 6 are schematic configuration diagrams showing a conventional coordinate input device. In the figure, (1) is a lens, (2) is a rotating scanning mirror, and (3) is a rotating scanning mirror.
) is a drive device, (4) is a one-dimensional image sensor, (5) is a detector, (6 is a controller, (7) is an image memory, (8) is a
) is a display device, (9) is an image processing device, αO is a subsampling circuit, aη is a read document, and (2) is a writing pen. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A one-dimensional image sensor, a rotating scanning mirror that rotates to sequentially send images of a subject and a pointing device on the subject to the one-dimensional imaging device, a detector that detects the rotation angle of this rotating scanning mirror, and the rotation of the rotating scanning mirror. A controller that specifies a corner and narrows down the scanning range to a specific area including the point indicator, an image memory that stores the output image signal of the one-dimensional image sensor at an address corresponding to the rotation angle, and a controller that processes the image signal. A coordinate input device comprising: an image processing device that detects the positional coordinates of the point pointing tool, and the position of the point pointing tool on the subject is determined based on the detection signal. (2) The coordinate input device according to claim 1, wherein the controller has a function of determining a specific area to be scanned next according to the position of the pointing tool and tracking the movement of the pointing tool. (3) The coordinate input device according to claim 1 or 2, wherein the controller changes the resolution by changing the step size of rotation of the rotating scanning mirror. (4) Any one of claims 1 to 3, comprising a sub-sampling circuit, which reduces the number of pixels of an output image signal of a one-dimensional image sensor to a predetermined resolution and stores the resulting signal in an image memory. Coordinate input device as described.