JPH08163328A - Microfilm scanner - Google Patents

Abstract

PURPOSE: To make an entire scanner small by arranging a projection lens between a film and an image forming face and reading an image while a line sensor is moved in parallel and rotated on the image forming face thereby making the size of an optical system small. CONSTITUTION: In the preliminary scanning, a scan control means 108 throws a changeover switch 110 to the position of A, a lamp 54 is lighted and a frame image is magnified by a projection lens and projected to a moving base 80. The base 80 is driven by a motor 88 so that a line sensor 96 is moved from one side of the entire projected image to the other side. The sensor 96 reads a projected image on an image forming face for that time. A CPU 100 uses a black frame detection means 112 to obtain a black frame included in the projected image and a tilt detection means 114 obtains a tilt of an image based on the black frame to allow a motor 76 to drive the rotary frame 68 so as to set a tilt to be zero. After the preliminary scanning, the switch 110 is turned to the position of B, and main scanning is conducted. The sensor 96 reads an image again and its output is processed by an image processing means 118 and outputted to a printer 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microfilm scanner for reading a microfilm image by using a line sensor.

[0002]

2. Description of the Related Art A microfilm scanner has been proposed in which an image on a microfilm is read using an image sensor such as a line sensor. By thus reading the image with the image sensor, it is easy to perform image processing as a digital image signal and output it to a printer, store it in a magneto-optical disk, etc., or transfer it to another image processing device. Become.

As such an apparatus, a projection image of a film is greatly enlarged and projected on a screen by using a reflecting mirror, and C
Some CD line sensors read this magnified image.

In this case, if the image taken on the microfilm is tilted, the tilted image is also projected on the screen. Therefore, the operator reads the image with the line sensor after correcting the inclination of the image while looking at the screen.
The correction of the inclination of the image is performed by interposing an image rotation prism in the optical system and rotating the prism by a servo motor.

[0005]

2. Description of the Related Art As described above, in the conventional apparatus, since the projected image is enlarged by using a plurality of reflecting mirrors, there is a problem that the apparatus becomes large. The image rotation prism can also secure a storage space with such a large optical system, but when the optical system is made smaller, the storage space cannot be secured, and it is difficult to downsize the device. There are problems such as

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can correct the inclination of an image without using an image rotating prism, and is suitable for downsizing the entire apparatus, especially for downsizing the optical system. It is intended to provide a microscanner.

[0007]

According to the present invention, the object is to form a projected image on an image forming plane parallel to the microfilm in a microfilm scanner for reading an image of the microfilm contained in a cartridge by using a line sensor. A projection lens having a fixed focus disposed between the microfilm and the image plane and a fixed frame to which the projection lens is attached are rotatably held around an axis parallel to the optical axis of the projection lens. A rotating frame; a line sensor attached to the rotating frame to move in parallel on the image plane to read a projected image; a tilt detecting means for detecting a tilt of the projected image read by the line sensor; A microfilm scanner, comprising: a tilt correction control unit that corrects by rotating the rotating frame. It is achieved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing a usage state of the present invention, FIG. 2 is a perspective view showing the inside of this embodiment, FIG. 3 is a side view showing the arrangement of essential parts, and FIG. FIG. 5 is a perspective view showing the drive unit, FIG. 5 is a block diagram showing a simplified control system, and FIG. 6 is an operation flow chart.

In FIG. 1, reference numeral 10 is a computer main body, which has a built-in CPU and the like. Reference numeral 12 is a display device such as a CRT, 14 is a keyboard, and these are mounted on a desk 16. Reference numeral 18 is a scanner housed under the desk 16, and 20 is a printer placed beside the desk 16. The scanner 18 has a cartridge insertion port 22 on the upper front surface thereof, and reads an image on the microfilm 26 contained in the cartridge 24 (see FIGS. 2 and 3) inserted therein. The read image is subjected to predetermined image processing by the CPU or the like in the computer main body 10 and then displayed on the display device 12 or printed out on the printer 20,
It is stored in a magneto-optical disk or the like, or transferred to an external processing device.

The scanner 18 has a vertically long casing 28, and a supply reel driving unit 30 is provided above the front portion of the casing 28.
A take-up reel drive unit 32 is arranged below the front portion. The supply-side reel drive unit 30 has a cartridge insertion port 2
When the cartridge 24 is inserted into the cartridge 2,
4 is automatically moved to engage the reel 24A with the rotating shaft. Further, the leading end of the film 26 is pulled out and fed downward, and is guided to the take-up reel 32A of the take-up side reel drive unit 32.

As shown in FIGS. 2 and 3, the film 26 passes through the rear side of the gap between the reel driving units 30 and 32, that is, the rear side when viewed from the front of the housing 28. 34, 34 in FIG.
Reference numerals 36 and 36 denote guide rollers for the film 26. Therefore, a space 38 is formed between this gap and the front panel 28A of the housing 28, and the light source unit 52 described later is housed therein.

The take-up reel drive section 32 has a drive belt 40 that travels in contact with the reel 32A as shown in FIG. This drive belt 40 is a guide roller 4
2, 44, the drive roller 46, the encoder 48, and the tension roller 50, and the drive roller 46 drives the film in the film winding direction (arrow direction).

Reference numeral 52 is a light source unit housed in a space 38 between the reel driving units 30 and 32, and a lamp 54,
It has a reflecting mirror 56, a condenser lens 58, an appropriate filter, and the like. In FIG. 2, 60 is a power supply circuit section, and 62 is a power control circuit section such as a motor.

Next, the line sensor driving unit 64 will be described.
The line sensor driving unit 64 is integrated with the projection lens 66. That is, as shown in FIGS. 3 and 4, the frame (rotating frame) 68 of the line sensor driving unit 64 is integrally formed with a tubular portion 70 that holds the projection lens 66.
The projection lens 66 held by the cylindrical portion 70 has a fixed focus and a magnification of about 2 times. The tubular portion 70 is rotatably held by a frame (fixed frame) 72 fixed to the housing 28. Here, the cylindrical portion 70 is the optical axis 7 perpendicular to the film 26.
Rotate around 4.

A cylindrical portion 70 of the rotating frame 68 and a pulley 76 of a servo motor 76 mounted on a fixed frame 72.
A belt 78 is wound around A. The rotating frame 68 is rotatable around the optical axis 74 by the rotation of the motor 76.

As shown in FIG. 4, a movable base 80 is attached to the rotary frame 68 on the surface opposite to the cylindrical portion 70. That is, the movable base 80 includes a pair of guide rods 82, 82.
Slidably held by the optical axis 74 near the opening of the tube 70.
It is possible to reciprocate in the direction orthogonal to. Rotating frame 68
Parallel to the reciprocating direction of the movable base 80, the pulleys 84, 84
A belt 86 wound around the movable base 80 is fixed to the belt 86. The rotation of the servo motor 88 is transmitted to the one pulley 84 via the belt 90. As a result, the movable base 80 can be reciprocated on the plane orthogonal to the optical axis 74 by rotating the servo motor 88 in the forward and reverse directions.

The movable base 80 has guide rods 82, 82.
The long window is formed in the direction orthogonal to the direction, that is, in the direction orthogonal to the reciprocating direction of the movable table 80. The center of the long window 92 in the length direction is located on the optical axis 74. A printed wiring board 94 is fixed to the rear surface of the movable table 80, that is, the surface opposite to the tubular portion 70 so as to be orthogonal to the optical axis 74.

A CCD line sensor 96 facing the long window 92 is fixed to the substrate 94 (FIG. 3). A preamplifier that amplifies the output of the line sensor 96 is also mounted on the substrate 94. CCD line sensor 9
It goes without saying that the light receiving surface of 6 coincides with the image forming surface of the projection image of the projection lens 66.

CPU built in the computer body 10
100 has various functions as shown in FIG. Although these functions are formed by software, they are shown as blocks in FIG. 5 for convenience. Search control means 1
Reference numeral 02 detects a target frame by using a search blip (not shown) attached to the film 26 in advance. That is, the blip sensor 10 placed close to the traveling path of the film 26
The output of 4 is counted, while the reel drive unit 3 on the winding side
The second motor 106 and the motor (not shown) of the supply side reel drive unit 30 are controlled to obtain a target frame.

Reference numeral 108 denotes a scan control means, which activates the line sensor drive section 64 when the target frame enters a predetermined position in the projection range including the optical axis 74. That is, the motor 88
Is operated to move the line sensor 66 in parallel on the image plane of the image to read the projected image. During this scan, the lamp 54 of the light source unit 52 is turned on.

Reference numeral 110 denotes a changeover switch, which is connected to the A side in FIG. 5 in the first preliminary scan and is changed to the B side in the second main scan. Reference numeral 112 denotes a black frame detecting means, which detects the black frame by reading the image signal obtained by the scan of the line sensor 66 when the changeover switch 110 is connected to the A side.

The black frame is a portion around the original, that is, a portion that appears on the outer periphery of the original image at the time of printing. Various black frame detection algorithms have been proposed. For example, when scanning a document into a document from a black frame, black pixels of a certain number or more change into continuous white pixels, so that the boundary between the black frame and the document can be detected.

When the black frame is detected in this way, the tilt detecting means 114 then finds the tilt of the image of the document. The tilt correction means 116 drives the motor 76 to correct this tilt. As a result, the entire line sensor driving unit 64 rotates and makes the line sensor 66 parallel to one side of the projected image.

Reference numeral 118 denotes an image processing means, which reads the output of the line sensor 66 and performs a predetermined image processing when the changeover switch 110 is connected to the B side and a main scan is performed. For example, processing such as image enhancement, image inversion, image enlargement / reduction, spatial filtering processing, trimming, and masking is performed.

Next, the operation of this embodiment will be described. When the cartridge 24 is inserted into the cartridge insertion port 22 and loaded into the supply-side reel drive unit 30, the leading end of the film 26 is pulled out downward. Then, the leading end of the film 26 is guided by the guide rollers 34, 34, 36, 36 and the like, and is guided to the winding side reel drive unit 32. The beginning of the film 26 is sandwiched between the reel 32A and the drive belt 40 and wound around the reel 32A.

A search blip is attached to the film 26 in advance, and this blip is detected by the blip sensor 104 (FIG. 5) such as a phototransistor while the film 26 is running (step 200 in FIG. 6). The search target frame is identified by counting the blips in the search means 102. When the target frame arrives, this frame is positioned within the projection range (frame) including the optical axis 74, and the feeding of the film 26 is stopped. Then, the image reading of this frame starts.

Since this first image reading is a preliminary one for obtaining the inclination of the image, it is called a preliminary scan (step 202). In this preliminary scan, the scan control means 108 first turns on the changeover switch 110 to the A side and turns on the lamp 54 of the light source unit 52. Then, the image of the frame is magnified approximately twice by the projection lens 66, and the movable table 80 is moved.
Projected on.

The movable base 80 is driven by a motor 88 so that the line sensor 96 moves in the entire projection range of the projected image from one direction to the other. During this time, the line sensor 96 reads the projection image on the image plane. In this way, while the scan (preliminary scan) by the line sensor 96 is performed,
The output of the line sensor 96 is amplified by the preamplifier on the board and sent to the computer main body 10.

In the CPU 100, the black frame detecting means 112 obtains the black frame of the document included in the projected image (step 204). Then, the inclination detecting means 114 obtains the inclination of the image by the black frame (step 206). This inclination can be obtained by detecting a black frame that is the periphery of the image of the document. When the tilt of the image is calculated,
The rotary frame 68 is rotated by the servo motor 88 to make the inclination zero. That is, the line sensor 9 is provided on one side of the black frame.
6 are aligned in the longitudinal direction (step 208).

The above scanning operation is a preliminary operation for matching the inclinations of the image and the line sensor 96, and the main scanning for reading the original image is performed after this preliminary scanning (step 210). Line sensor 96
Reads the image again, this output is image-processed by the image processing means 118 (step 212), and the result is printed out to the printer 120 (step 214). The result is also stored in an external memory device such as a magneto-optical disk or output to another image processing device.

When a large number of frames are continuously searched, the next frame can be searched immediately after the main scan is completed and the image signal is stored in the CPU 100. At this time, it is desirable to return the tilt correction to the original state after finishing the main scan (step 21 in FIG. 6).
6). In this way, the inclination is returned to the original state. If the scanning range of the line sensor 66, that is, the reading range is largely inclined in the opposite direction with respect to the frame of the film, the image deviates from this scanning range and the black frame is correctly corrected. This is because a state that cannot be detected may occur.

In the case of microfilm, the light source unit 5 is usually used.
Since the arrangement of 2 and the projection lens 66 is the reverse of that of this embodiment, when the microfilm used in such a conventional apparatus is used in this embodiment, the projected image is turned over. In this case, it suffices to electrically convert into a correct image by image processing, and such processing is easy.

In the above embodiment, the line sensor driver 64
Although the central axis of rotation of is matched with the optical axis 74, these may not be matched. Normally, since the image of the original is imprinted on one side in the projection range, the image of the original is out of the scanning range of the line sensor by displacing the rotation center axis of the line sensor drive unit 64 on the one side. It is possible to reduce the risk. 7 to 9 explain the principle.

FIG. 7 corresponds to the embodiment described with reference to FIGS. 3 and 4, and shows a case where the scan range S is rotated around the optical axis 74. In this figure, S ₀ is the scan range for the film 26 when the tilt correction for the film 26 is not performed. S ₁ is a scan range rotated about the optical axis 74 counterclockwise by about 20 °.

Frame 2 of the original document photographed on the film 26 now
If 6A is tilted counterclockwise by about 20 °, the line sensor driver 64 is rotated by the same angle based on the detected black frame, and the scan range S ₀ is changed to S ₁ . At this time, the area near the corner of the original scan range S ₀ may deviate from the new scan range S ₁ . In FIG. 7, the shaded portion within the range ΔABC of the frame 26A is the unreadable range. As the amount of tilt correction increases, the unreadable range increases. In the figure, 26B is a blip, which is detected by the blip sensor 104 (FIG. 5).

FIG. 8 shows the center D of the left side of the scan range S _0.
The case where the scan range S ₀ is rotated counterclockwise around is shown. S ₂ is the new scan range. Other conditions are the same as in the case of FIG. Generally, the frame 26A is imprinted on one side of the projection range,
The center D of rotation is placed on the side closer to 6A. Since the center of rotation approaches the top 26A in this manner, the top of the top 26A
A does not fall out of the scan range after the tilt correction.

FIG. 9 shows a case where one half of the film 26 is photographed sequentially in the length direction of the film 26.
As such an imaging method, there are a duo method and a duplex method. In the duo system, the film is divided into A and B channels, each of which has a width of 1/2, and one frame is sequentially shot on each side of the A channel. After the A channel is shot, the B channel is shot in reverse order. It will be done. In the duplex method, the front side and the back side of an original are photographed at the same time so that they are adjacent to each other in the film width direction.

When the frame 26C (FIG. 9) is photographed within the half width of the film as in these systems, the frame 26C
The interval L (FIG. 9) between C and the scan range S ₀ becomes smaller. Therefore, the rotation center for tilt correction is the scan range S _0.
It is desirable that the point E is displaced from the center D of the side near the frame 26C by a distance X toward the frame 26C. This distance X should be determined in consideration of the maximum angle of inclination correction, the interval L, and the position of the top 26C. In FIG. 9, S ₃ is the scan range after tilt correction.

Next, an embodiment in which the center (D or E) of inclination correction is decentered from the optical axis 74 in this way will be described with reference to FIGS. FIG. 10 is a side view in which a part of this embodiment is shown in section, and FIG. 11 is a front view of the substrate 94 and the line sensor 96 in FIG. In FIGS. 10 and 11, the portions corresponding to those in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will not be repeated.

10 and 11, the fixed frame 72A
An inner cylinder portion 72B is provided in the center of the projection, and the center (rotation center) 72C of the inner cylinder portion 72B is eccentric with respect to the optical axis 74 of the projection lens 66. Further, an outer cylinder portion 70A, which is held outside the inner cylinder portion 72B via a radial bearing 68B and a thrust bearing 68C, is formed on the rotary frame 68A. The outer cylinder portion 70A is provided with a motor 76 via a belt 78.
Is rotated by.

In this rotating frame 68A, 37 pins 70B (only one is shown) are provided on the outer peripheral surface of the outer cylinder portion 68B so as to project in the radial direction at equal intervals, and these pins 70B are interposed via bearings 70C. It is held down by the holding ring 70D.
As a result, the outer cylinder portion 70A and the rotating frame 68A are held on the fixed frame 72A side.

A motor 88A for scanning the line sensor 96 is attached to the upper part of the rotary frame 68A, and its rotation is via the belt 88B to the intermediate pulley 8A.
8C, and is further transmitted to another intermediate pulley 88E by the belt 88D. The rotation of the motor 88A is decelerated by the intermediate pulleys 88B and 88D to reciprocate the belt 86A to which the movable base 80 is fixed. In FIG. 11, S ₀₀ indicates the scan range of the line sensor 96.

According to this embodiment, rotation of the motor 76 causes the rotary frame 68A to move to the outer cylinder portion 70A and the inner cylinder portion 7.
Rotate around the center 72C of 2B. As a result, the center of tilt correction can be decentered from the optical axis 74 as described with reference to FIGS.

Although the projection lens 66 is shown in a state of being separated from the film 26 in FIG. 3, the tip of the projection lens is extended to the film side and slidably abuts on a transparent glass plate for positioning the film. You may leave it. By doing so, the relative positioning accuracy of the film and the projection lens is improved. Since this projection lens is held by the rotary frame 68 of the line sensor driving unit, the relative positioning accuracy of the film, the projection lens, and the line sensor traveling surface can be increased. Therefore, it is possible to read an image with high accuracy even if a projection lens having a fixed focus and a low magnification is used.

[0045]

As described above, according to the first aspect of the present invention, the projection lens is arranged between the film and the image forming plane parallel to the film, and the line sensor is moved in parallel on the image forming plane to read the image. The inclination of the projected image is corrected by rotating the scan range of the line sensor. Therefore, the optical system can be downsized without using a reflecting mirror or an image rotation prism, and the downsizing of the entire apparatus can be achieved.

The rotary frame for holding the line sensor may be rotated around the optical axis of the optical system (projection lens), but the position of the frame is deviated to a predetermined one side within the projection range. If so, it is desirable to deviate the center of the rotating frame to this deviation side. By doing so, it is possible to prevent the frame image from deviating from the scan range of the line sensor during tilt correction (claim 2).

[Brief description of drawings]

FIG. 1 is a diagram showing a usage state of an embodiment of the present invention.

FIG. 2 is a perspective perspective view of this embodiment.

FIG. 3 is a side view of the same main part.

FIG. 4 is a perspective view showing a line sensor driving unit.

FIG. 5 is a block diagram showing a control system.

[Fig. 6] Flow chart of operation

FIG. 7 is an explanatory diagram of tilt correction.

FIG. 8 is an explanatory diagram of tilt correction.

FIG. 9 is an explanatory diagram of tilt correction.

FIG. 10 is a side view of another embodiment.

FIG. 11 is a front view of the same.

[Explanation of symbols]

 10 Computer Main Body 12 Display Device 18 Scanner 20 Printer 22 Cartridge Insertion Port 24 Cartridge 26 Micro Film 30 Supply Side Reel Drive Unit 32 Winding Side Reel Drive Unit 52 Light Source Unit 64 Line Sensor Drive Unit 66 Projection Lens 68, 68A Rotating Frame 72, 72A Fixed frame 72C Rotation center 74 Optical axis 80 Movable stand 92 Long window 94 Substrate 96 CCD line sensor 100 CPU 114 Tilt detection means 116 Tilt correction control means

Claims (2)

[Claims] 1. A microfilm scanner for reading an image of a microfilm by using a line sensor, wherein a projection image is arranged between the microfilm and the image plane so as to form an image on the image plane parallel to the microfilm. A fixed focus projection lens provided, a rotary frame rotatably held on a fixed frame to which the projection lens is mounted about an axis parallel to the optical axis of the projection lens, and the imaging attached to the rotary frame. A line sensor that moves in parallel on a plane to read a projection image, a tilt detection unit that detects a tilt of the projection image read by the line sensor, and a tilt correction control that corrects the found tilt by rotating the rotary frame. A microfilm scanner comprising: 2. The microfilm scanner according to claim 1, wherein the rotary frame is rotatable about an axis that is parallel to the optical axis of the projection lens and that is displaced toward the position where the original image in the film projection range is located.