JPH0516622B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an imaging device, and particularly to an imaging device that is capable of both high-speed image scanning and high-resolution scanning.

[Conventional technology] In fields such as OA and FA (Factory Automation), ordinary image scanners scan originals (documents, drawings, etc.) in the form of sheets or books by placing them in a reading space convenient for the machine. In addition, there are cases where an image input device, that is, an imaging device, such as a TV camera, that can capture an image of a subject (hereinafter referred to as a scanned document) located in any space is desired, and moreover, the resolution of a normal TV camera ( Input at a much higher resolution (for example, 2048 pixels x 2048 lines) is often required. In order to realize such a high-resolution imaging device, a method has conventionally been used in which a one-dimensional imaging device is combined with some kind of sub-scanning mechanism system.

FIG. 4 is shown in, for example, Japanese Patent Laid-Open No. 58-69173. 1 is a schematic configuration diagram showing an example of the configuration of such a conventional imaging device, in which 1 is a lens;
is a one-dimensional image sensor, 30 is a linear slide mechanism,
5 is an image memory, 6 is a display device, and 10 is a read document. The operation of this conventional device is as follows.
The lens 1 forms a two-dimensional image of the document 10 to be read on an imaging plane, and the primary imaging element 4 placed on this imaging plane captures an image while being moved in the sub-scanning direction A by a linear slide mechanism to which the element 4 is fixed. Image signals obtained by performing the above steps are sequentially stored in the image memory 5, and a part of the stored contents is displayed as an image on the display device 6.

Further, FIG. 5 is a schematic configuration diagram showing another example of the configuration of a conventional imaging device disclosed in, for example, Japanese Patent Application Laid-Open No. 56-34279.
4 is a one-dimensional image sensor; 5 is an image memory; 6 is a display device;
0 is the original to be read. The operation of this conventional device is as follows. On the optical path where the lens 1 attempts to create a two-dimensional image of the original 10 to be read, there is a polygonal reflecting mirror 40 that rotates at a constant speed. are sequentially imaged on the one-dimensional image sensor 4. An image signal is obtained by sub-scanning by the rotation of the polygonal reflecting mirror 40 and main scanning by the imaging operation of the one-dimensional image sensor 4. The operations of the image memory 5 and the display device 6 are the same as in the example shown in FIG.

[Problem that the invention seeks to solve]

Conventional imaging devices such as those described above have had problems with the scanning speed during imaging and the immediacy and visibility of image content display. For example, in the conventional imaging device described in FIG. is 18 μm, and if the scanning line spacing on the imaging plane in sub-scanning is also equal to this, the maximum scanning speed is 769 lines/second, so it will take at least 2.66 seconds to scan the entire screen (for example, 2048 lines). Become. However, as is well known in televisions, when viewing images on a normal display device 6 such as a CRT that requires refreshing, flickering and other problems occur unless the entire screen is repeated at a rate of about 80 screens/second. Because of this problem, the scanning speed by the linear slide mechanism 30 described above is completely insufficient, and the image signal is temporarily stored in the image memory 5 and then displayed by reading it out at high speed. In addition, in a normal display device 6, the image memory 5 has a large capacity.
Even if you store an image signal of 2048 pixels x 2048 lines,
The entire content cannot be displayed as a list as an image, and displaying the list requires a very expensive high-resolution display device. For this reason, when using a normal display device, it is necessary to divide the stored contents of the image memory 5 into several parts and display them sequentially. In the end, with the conventional imaging device explained in Figure 4, the image being captured can only be observed once every 2.66 seconds, and even then only in sections, and operations such as setting the imaging range and adjusting the focus of the imaging device There was a significant inconvenience.

On the other hand, in the conventional imaging device explained in FIG.
In terms of scanning speed, there is no problem because the polygonal reflecting mirror 40 can be rotated at a sufficiently high speed, but in that case, there is an upper limit to the operating speed of the one-dimensional image sensor 4, so the number of imaging scanning lines is reduced. Images cannot be captured at high resolution. On the other hand, if you want to capture an image with high resolution, you have to reduce the rotational speed of the polygonal reflector 40, and this is because the scanning cycle is too long, as in the imaging device explained in FIG. With this display device, a problem arises in that it is only possible to observe each part.

Furthermore, in applications in OA and FA, it is not only necessary to always input an image of the entire read document, but also to identify areas of interest within the entire read document (hereinafter referred to as regions of interest) and scan them at high resolution. It is often advantageous if possible. However, in the conventional imaging apparatus as shown in FIG. 4, the scanning period is long and the image is displayed only in sections, so identifying the region of interest is difficult to operate and requires a lot of effort. Furthermore, the access time required to move the scanning range to the region of interest after identification cannot be ignored. On the other hand, in the conventional imaging device as shown in FIG. 5, if the multifaceted mirror 40 is rotated at high speed, the region of interest can be easily specified, but conversely, the region of interest cannot be read with high resolution. In addition, since the polygonal reflecting mirror 40 generally has a large mass,
By rapidly reducing the rotation speed from a high-speed rotation state,
It is difficult to control the region of interest to be scanned at high resolution, and it is not suitable for scanning an original to be read with variable scanning range and resolution.

This invention was made to solve this problem, and it is possible to scan a read document at high speed and immediately view the entire document, and also to identify a region of interest in the read document. It is an object of the present invention to provide an imaging device that can easily perform input at high resolution.

[Means for solving problems]

An imaging device according to the present invention includes a one-dimensional imaging device,
A rotating scanning mirror that rotates to sequentially send images of a subject to the one-dimensional image sensor; a drive device that drives this rotating scanning mirror; a detector that detects the rotational angle of the rotating scanning mirror; an image memory that stores the output image signal of the one-dimensional image sensor;
A display device that displays the image signal stored in this image memory, on the image displayed on this display device,
a position indicating means for outputting a position signal for specifying a scanning target range; and a position indicating means for instructing a rotation angle of the rotary scanning mirror to the drive device based on the position signal, specifying the scanning range and determining a rotation step size. It is equipped with a controller that allows you to change the resolution.

[Effect]

In this invention, by using a rotating scanning mirror, a detector that detects the rotation angle of the rotating scanning mirror, and a controller, it is possible to quickly access any sub-scanning position on the document to be read as long as it is within the scannable range. Moreover, line-sequential scanning is also possible by controlling the rotation angle of the rotary scanning mirror to be changed minutely in steps by a controller. This can also be used to scan line-by-line at a relatively high speed and display the scanned document instantly and at a glance to identify the region of interest, and to input the identified region of interest at high resolution. scanning can be easily realized by the controller.

〔Example〕

FIG. 1 is a schematic configuration diagram showing an imaging apparatus according to an embodiment of the present invention, and the same reference numerals as in FIGS. 4 and 5 indicate the same or corresponding parts. 2 is a one-dimensional image sensor 4 which rotates an image of a subject 10 (a document to be read).
It is a rotating scanning mirror and a galvanometer mirror.
Reference numeral 3 denotes a driving device for driving the rotating scanning mirror 2; 7, a rotation angle detector for detecting the rotation angle of the rotating scanning mirror 2; and 8, a signal indicating the rotation angle of the rotating scanning mirror 2 is given to the driving device 3 to perform scanning. A controller that specifies the range and varies the resolution by changing the step size of rotation; 6 a display device that displays the image signal stored in the image memory 5; 9 a controller that scans the image displayed on the display device 6; A position pointing device, in this case a light pen, outputs a position signal specifying the target range.
Reference numeral 11 denotes a sub-sampling circuit that reduces the number of pixels of the output image signal of the one-dimensional image sensor 4 so that it has a predetermined resolution and stores it in the image memory 5.

In the imaging device configured as described above, a two-dimensional image of the original to be read 10 created by the lens 1 is reflected by the rotating scanning mirror 2 and captured by the one-dimensional image sensor 4.
image on top. The rotating scanning mirror 2 is tilted to a specified rotational angle in response to a digital code or analog voltage signal that specifies the rotational angle of the rotating scanning mirror, which is generated from the controller 8 to the drive device 3.
An arbitrary position on the read document 10 can be imaged on the image sensor 4, and this can also be used for sub-scanning to perform line-sequential scanning. The rotation angle detector 7 is a mechanical or optical rotary encoder that detects the current rotation angle of the rotating scanning mirror 2 and outputs a signal to determine the difference between the rotation angle specified by the controller 8 and the current rotation angle. Be able to calculate the difference. The one-dimensional image sensor 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 stored in the image memory 5, and the stored contents are displayed as an image. displayed on the device 6.

In normal line-sequential scanning, the controller 8 sets the rotation angle of the rotary scanning mirror 2 at the boundary of the scanning target range in the document 10 to be read, and then the controller 8 sets the rotation angle to be changed stepwise by minute amounts. This is possible by generating a rotation angle designation signal at a high speed. At this time, the size of the scanning target range in the sub-scanning direction corresponds to the rotation angle range of the rotary scanning mirror 2, and the scanning resolution corresponds to the minute step size of the rotation angle. Furthermore, the storage address in the image memory 5 is determined by the total number of scanning lines determined from the rotation angle range and minute step size of the rotation angle, and the amount of image signals included in each scanning line, that is, the number of images per scanning line. It is associated with a scanning line. As a result, if the minute step size of the rotation angle is increased, relatively high-speed scanning is performed and a low-resolution image signal is stored in the image memory 5, and conversely, if the minute step size of the rotation angle is decreased, scanning is performed at a relatively high speed. Although the required time is longer, a high-resolution image signal is stored in the image memory 5, and the resolution can be made variable.

In addition, the rotating scanning line 2 is lightweight and can reach the rotational angle specified by the controller 8 at high speed by the rotating scanning mirror driving device 3, so that access to any scanning target range can be made in a short time. , the time it takes each time to return to the initial boundary of the scanned area in order to repeatedly scan the scanned area is also small. Therefore, scanning in which the scanning target range is variable can be easily realized.

FIG. 2 is a flowchart showing an outline of the operation of the controller 8 according to an embodiment of the present invention.
The operating modes can be roughly divided into two modes: scanning and region of interest specification, and can be switched by a switch or the like (not shown) (step (51)). In the scanning mode, the controller 8 moves the rotating scanning mirror 2 in steps (52) and (53) corresponding to the scanning target range of the original 10 to be read.
Set the rotation angle range and step size that should be taken. For example, when scanning the entire document 10 to be read at high speed or when scanning a region of interest with high resolution, different starting angles, ending angles, and step sizes of rotation are set. Also, in step (54),
A signal indicating the subsampling ratio and the effective range of the signal to be stored in the image memory 5 is output to the subsampling circuit 11. After the above settings have been made, first, in step (55), the starting angle corresponding to the starting end of the scanning target range is set as the target value of the rotation angle that the rotating scanning mirror 2 should take, and in step (56), the target angle is set. A signal specifying this is given to the drive device 3. As a result, the rotating scanning mirror 2 rotates to obtain the target rotation angle, so in step (57), the current rotation angle, which is the output of the rotation angle detector 7, is input, and in step (58), this is determined as the target angle. The rotation angle designation signal is output until it is confirmed that they match. If the current angle matches the target angle, it is checked in step (59) whether it matches the terminal angle corresponding to the end of the scanning target range. If they do not match, step (60) sets the next target angle by adding the step size to the current angle, and returns to step 56. By repeating this, the range to be scanned is sequentially scanned from the start end to the end end at a predetermined step size. Note that the step size itself is not necessarily constant during scanning, and the step size of the rotation angle is changed in order to make the rotation of the rotating scanning mirror 2 scan the document 10 with a constant step size. There are cases where it is necessary to change the angle in small increments according to the absolute value of the angle. In such a case, the controller 8 stores the step size of the rotation angle as a table, or performs a calculation, and sets the next target angle using the stored value or calculated value in step (60). This method will be used.

If it is found in step (59) that the current angle has reached the terminal angle, step (55) is executed if the operation mode is such that scanning is repeated in step (61).
Returning to , a similar scan is performed again from the starting angle, and if the operation mode is not a repeat scan mode, the scan is terminated. The part surrounded by the broken line in the figure is the rotating scanning mirror 2.
This corresponds to the operation of accessing the scanning position using this part, and it is also possible to perform a random access operation using this part.

In the region specifying operation mode, the controller 8 inputs two coordinate values specifying the scanning range from the position indicator 9 in step (62), and determines the rotational scanning range of the rotating scanning mirror 2 from these coordinate values in step (63). Calculate the starting and ending angles.

By the way, in order to specify the region of interest in the read document 10 as the scan target range, a position indicating means is required to indicate the boundary of the scan target range on the read document 10 or on the image displayed on the display device 6. be. In the embodiment shown in FIG. 1, a display device 6 and a light pen 9 are used as the position indicating means. The operation of the apparatus in this case will be explained below with reference to FIG.

FIG. 3 is an explanatory diagram illustrating the operation of an imaging device according to an embodiment of the present invention, and FIG.
An image displayed on the display device 6 via the image memory 5 is shown. In this scanning, as shown in FIG. 3b, the minute step size of the rotation angle of the rotary scanning mirror 2 is set to be large, and the speed at which the rotation angle designation signal is generated from the controller 8 is set as high as possible for imaging by the image sensor 4. do. If this scanning could be repeated at high speed without flickering, it would be possible to input the image signal directly to the display device 6 and display it without going through the image memory 5, but it is not so fast. However, it is sufficient to have a scanning speed that allows instantaneous movement of the document 10 to be read within the imaging range and adjustment of the focus. It can be observed in Note that this display image is of course a low-resolution image that can be displayed on a normal display device, and the contents of the read document 10 may not be completely legible, but there is no problem in indicating the position of the region of interest. Therefore, on this display image, the light pen 9
It is easy to specify the region of interest 23 by indicating the two diagonal points 21 and 22 of the region of interest. The positions of the diagonal points 21 and 22 are associated with the positions on the original to be read 10 by the controller 8, and further converted into the rotation angle of the rotary scanning mirror 2 corresponding to the scanning target range from the ratio to the entire original to be read 10. .

Following the above operations, the controller 8 specifies the rotation angle of the rotary scanning mirror 2 and sets the upper and lower ends of the region of interest 23 as the boundaries of the scanning target range, as shown in FIG.
As shown in the figure, the region of interest is scanned at high resolution, the image signal is stored in the image memory 5, and the stored contents are further transferred to a data memory or file memory (not shown) to complete the input. This region of interest is scanned only once by reducing the minute step size of the rotation angle. Through this scanning, the region of interest can be input with a higher resolution than during high-speed scanning, as shown in FIG. 3d.

FIGS. 3e and 3f show examples of the storage state of image signals in the image memory 5 during the high-speed scanning and high-resolution scanning, respectively. During high-speed scanning, the entire document 10 to be read is scanned in 512 lines, and the stored contents are stored in the image memory 5 in units of 512 addresses corresponding to 512 pixels per line. By reading out the image, the image is displayed on the display device 6 as an image. Note that the number of pixels in one line is originally determined by the number of pixels possessed by the one-dimensional image sensor 4, and if an image sensor 4 with 2048 pixels is used, 2048 pixels will be output as an image signal in one line, but high-speed scanning Sometimes, it is often sufficient to have a resolution in the main scanning direction that is approximately equal to the resolution in the sub-scanning direction. The sub-sampling circuit 11 shown in FIG. 1 thins out the pixels in the image signal in such a case, thereby reducing the number of pixels in one line to an appropriate amount. In the example of FIG. 3e, the image sensor 4
By subsampling the output 2048 pixels at a rate of 1 in 4 pixels, 512 pixels are stored in the image memory 5.
I remember it. In this case, assuming that the area of interest 23 has a size of 15/512 vertically and 25/64 horizontally compared to the entire document to be read, the area of interest itself is 200 pixels x 60 pixels.
This means that the line is being scanned.

If the sub-scanning resolution is quadrupled during high-resolution scanning, the region of interest 23 will be scanned with 240 scanning lines, and the corresponding number of horizontal pixels will be 800, as shown in Figure 3(f). However, the data is not stored neatly in units of 512 addresses, but two units are allocated to one line and stored. This resolution corresponds to the case where all 2048 pixels of the image sensor 4 are used to image the horizontal direction of the original 10 to be read, so the subsampling circuit 11 does not thin out the image by taking one pixel out of every few pixels. By cutting off pixels corresponding to parts other than the region of interest in the signal, only 800 pixels within the region of interest are transmitted to the image memory 5. A signal indicating the position of a pixel falling within the area in this line and a signal indicating the necessary thinning rate are sent to the controller 8.
is applied to the sub-sampling circuit 11, which receives this signal and performs the above operation in a generally known manner. This allows the third
In FIG. , a storage method is used in which the divisions between lines are regular.

Note that in the description of the above embodiment, the one-dimensional image sensor 4
Although specific numerical values have been given for the number of picture elements, the sizes of the read original 10 and the region of interest 23, and the size of the image memory 5, etc., it goes without saying that these numerical values are not limited to the above-mentioned specific examples and can be generalized.

Further, in the above embodiment, the light pen 9 for indicating the position on the image displayed on the display device 6 was used as a position indicating means for specifying the region of interest 23. The original to be read 10 is placed on the tablet and a point on the original to be read is indicated with the stylus pen of the tablet. (However, it is assumed that the scanning target range and the tablet coordinates are associated in advance.) Instructions may be given on the document to be read, and the specific device for specifying the position may be a mouse, joystick, etc. Of course, various devices can be used.

Furthermore, in the above embodiment, when scanning the region of interest 23, a case has been described in which the entire document 10 to be read is imaged in the horizontal direction using all the pixels of the image sensor 4. The resolution of the lens 1 is not limited to the resolution of
It goes without saying that scanning with higher resolution is possible by adjusting the focus, etc. of the image. Furthermore, it is easy to understand that, in general, if the image memory 5 has a sufficient capacity, scanning can be performed with the scanning resolution being independently variable for the scanning target range set in the read document 10.

Similarly, in the above embodiment, the subsampling circuit 11 thins out the output image signal of the image sensor 4 so as to obtain a resolution in the main scanning direction that is approximately equivalent to the subscanning resolution for scanning the original 10 to be read or the region of interest 23. The case where the number of pixels is reduced by truncation or truncation has been explained, but this is a process performed to keep the storage capacity of the image memory 5 small. If display on the display device 6 is possible by subsampling or the like, it is not necessary. Further, even when subsampling is performed, it is not necessary to reduce the number of pixels to a degree corresponding to the sub-scanning resolution, and the degree of subsampling can be made independent within the capacity of the image memory 5.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a one-dimensional imaging device, a rotating scanning mirror that rotates to sequentially send images of a subject to the one-dimensional imaging device, a drive device that drives the rotating scanning mirror, and a rotating scanning mirror that rotates the rotating scanning mirror. a detector that detects the angle; an image memory that stores the output image signal of the one-dimensional image sensor at an address corresponding to the rotation angle; a display device that displays the image signal stored in the image memory; and a display device that displays the image signal stored in the image memory. a position indicating means for outputting a position signal for specifying a scanning target range on the scanned image; and a position indicating means for outputting a position signal for specifying a scanning target range; Since the imaging device is configured with a controller that changes resolution by changing the step size of rotation, it is possible to obtain an apparatus capable of both high-speed scanning and high-resolution scanning.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an imaging device according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of a controller according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram illustrating the operation of an imaging device according to an embodiment of the present invention, and FIGS. 4 and 5 are schematic configuration diagrams each showing a conventional imaging device. DESCRIPTION OF SYMBOLS 1... Lens, 2... Rotating scanning mirror, 3... Drive device, 4... One-dimensional image sensor, 5... Image memory, 6... Display device, 7... Rotation angle detector, 8...
...Controller, 9...Light pen, 10...Reading document, 11...Subsampling circuit. In addition,
In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A one-dimensional image sensor, a rotating scanning mirror that rotates to sequentially send images of a subject to the one-dimensional imaging device, a drive device that drives this rotating scanning mirror, and detecting a rotation angle of the rotating scanning mirror. a detector, an image memory that stores the output image signal of the one-dimensional image sensor at an address corresponding to the rotation angle, a display device that displays the image signal stored in the image memory, and an image displayed on the display device. a position indicating means for outputting a position signal for specifying a scanning target range; and a position indicating means for specifying a rotation angle of the rotating scanning mirror to the drive device based on the position signal, specifying the scanning range, and determining the rotation step size. An imaging device equipped with a controller that changes the resolution by changing the resolution. 2. An imaging device according to claim 1, comprising a sub-sampling circuit, which reduces the number of pixels of an output image signal of a one-dimensional imaging device to a predetermined resolution and stores the resulting signal in an image memory.