JPH08234306A - Microfilm reader - Google Patents

Abstract

PURPOSE: To display an image of high quality never inferior to a screen- projected image in a microfilm reader for reading the image by an image sensor and displaying it on a display device such as CRT. CONSTITUTION: This device has a multi-valuing processing means for multi- valuing the image signal which is read and outputted by an image sensor 96 into a multi-value of binary or more, and a display means for displaying the multi-valued signal by multi-valued density gradation. The display device used here is a one capable of multi-valued density gradation display, and a CRT 12 is used therefor. The background area of the image displayed on the display device is not pure white as a binarized image, but gray. Thus, when the multi- valued image is edge-emphasized, only the dark image side in contact with the edge (boundary) of the image is desirably emphasized without emphasizing the background side in contact with the edge.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A microfilm reader 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.

In this case, the image signal read by the image sensor is binarized by dithering or the like and digitally processed. It is also considered to display an image on a display device such as a CRT or a liquid crystal plate by using the binarized image signal.

[0004]

However, when displaying a binarized image on a CRT, there is a problem in that the image quality changes greatly depending on the setting of the binarization threshold value, especially the image quality of halftone density deteriorates. Occurs.

Further, when areas having different density levels are mixed in the image, if a certain threshold value is used for binarization, some areas cannot be read. In order to read this image with good reproducibility, it is necessary to set the binarization threshold value separately for each area having different density levels, which complicates the configuration.

On the other hand, a microfilm image enlarged and projected on a screen is characterized in that a high-quality image can be faithfully reproduced on the screen even if the image has a halftone density. If a binary image is displayed, it is impossible to obtain such a high quality display.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and displays a high quality image which is not inferior to a screen projected image even though it is read by an image sensor and displayed on a display device such as a CRT. It is an object of the present invention to provide a microfilm reader that can be used.

[0008]

According to the present invention, an object of the present invention is to provide a microfilm reader which reads an image on a microfilm with an image sensor, processes the read image signal and displays the image signal.
The present invention is achieved by a microfilm reader characterized by comprising multi-value processing means for performing multi-value processing equal to or more than a value and display means for displaying the multi-valued signal in multi-value density gradation.

The display device used here is capable of multi-value density gradation display, and a CRT or the like is used. Also, the background area of the image displayed on this display device is not gray like a binarized image but gray. Therefore, when edge enhancement is performed on a multi-valued image, it is desirable to enhance only the dark image side in contact with the edge (boundary) of the image and not enhance the background side in contact with the edge. This is because if the edge enhancement is performed on the background side, a blank frame that enters the gray background side is generated along the peripheral edge of the image, and the image quality deteriorates.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing a use state of the present invention, FIG. 2 is a perspective view showing the inside of a scanner used in this embodiment, FIG. 3 is a side view showing the arrangement of essential parts, and FIG. 5 is a perspective view showing a line sensor driving unit, FIG. 5 is a block diagram showing a simplified control system, FIG. 6 is an overall operation flowchart, FIG. 7 is a flowchart showing an operation example of multi-valued image processing, and FIG. 8 is edge enhancement. FIG. 9 is a conceptual explanatory diagram of processing, and FIG. 9 is an explanatory diagram of edge enhancement processing.

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 capable of multi-value gradation display such as CRT, 14 is a keyboard, and these are mounted on a desk 16. 18 is this desk 1
A scanner stored under 6 and a printer 20 placed beside the desk 16.

The scanner 18 has a cartridge insertion port 22 on the upper front surface thereof, and the cartridge 2 inserted therein.
4 (see FIGS. 2 and 3)
Read the image. The read image is the computer body 10
Predetermined image processing is performed by the internal CPU or the like. In this image processing, the image is binarized by, for example, dithering, and multi-valued processing in which the image is multi-valued to a density level of 2 ⁸ = 256 gradations and displayed on the display device 12 in multi-valued density gradations. Binarization processing is included.

The binarized output is output to the printer 20, the magneto-optical disk, an external processing device, or the like. The multi-valued process and the binarized process may be performed simultaneously in parallel, but the images may be separately read by the scanner 18 and processed separately. Normally, only the multi-valued process may be performed to display the image on the display device 12, and the binarized process may be additionally performed only when print output is required.

The scanner 18 has a vertically long casing 28, and a supply reel driving unit 30 is provided above the front 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 behind the gap between the reel driving portions 30 and 32, that is, on the back side as 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 which 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 portion housed in a space 38 between the reel driving portions 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 section 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 rotary 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 this 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. When the changeover switch 110 is connected to the B side and a main scan is performed, the output of the line sensor 66 is read and predetermined image processing is performed. The image processing unit 118 first multi-values the image signal output from the line sensor 96 to display an image on the display device 12 including a CRT with multi-value density gradation. This processing is performed by the multi-value quantization processing means 118A in FIG.

Further, the image processing means 118 binarizes the image signal of the line sensor 96 when print output or a memory for a magneto-optical disk is required.
It is binarized in 18B. This binarization process can be performed using, for example, a known dither matrix. In this binarizing process, the scanner 18 is operated to read an image only when a binarized output is required. In the image processing means 118, in addition to the multi-valued processing and the binarized processing, for example, edge enhancement, image inversion, image enlargement / reduction,
Well-known processing such as spatial filtering processing, trimming, masking, black and white reversal 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. After this preliminary scanning, the image is read in multi-value gradation and is displayed on the CRT display device 12. A main scan is carried out for displaying the gradation of the value (step 210). The line sensor 96 reads the image again, and the output is the image processing means 11.
The multivalued processing means 118A of 8 performs multivalued processing (step 212).

In this multi-value quantization process (step 212),
As shown in FIG. 7A, edge enhancement processing (step 2
14), enlargement / reduction processing (step 216), trimming processing (step 218), black-and-white inversion, and the like, and appropriate processing is additionally performed. The edge enhancement processing performed here has a configuration unique to multi-value gradation display as described below.

FIG. 8A shows the edge enhancement processing that has been widely performed in the past, and FIG. 8B shows the processing in this embodiment. The solid line in FIG. The change in (D) and the broken line indicate the change in density (D) after the edge enhancement processing. As described above, in the conventional processing, the boundary (edge) where the density suddenly changes is sandwiched, and the both sides are emphasized. In a binary gradation image,
Since the density D ₁ of the background area in the image is white and the density D ₂ of the image is black, the image becomes clear if the edges on the image side are emphasized in black and the edges on the background side are emphasized in white across the boundary. .

However, in multi-value gradation image display, the background density D ₁₁ becomes gray (light color) instead of white. For this reason, if the edge on the background side is emphasized in white by sandwiching the boundary, the white edge appears along the edge of the image, and the image quality deteriorates.
In view of this, in the present embodiment, only the edge on the image side is emphasized to be deeper than the image density D ₂₂ by sandwiching the boundary, and the edge on the background side is not emphasized.

The edge emphasis processing having such characteristics is
It is obtained by performing the density conversion shown in FIG. This conversion can be performed by converting the density A _{0 of the} central pixel shown in FIG. 7B using the characteristic formula shown in FIG. In this conversion, if the central pixel density A ₀ is darker than the surrounding pixel densities A _{1 to} A ₈ , it is sufficiently dark (density A ₀₀ ), and if it is opposite, the density A ₀ is hardly changed. In FIG. 9C, the coefficients K ₁ and K ₂ are constants.

In the enlargement / reduction processing (step 216),
The image is enlarged / reduced to the magnification designated by the keyboard 14 and displayed on the CRT display device 12, or the magnification is automatically changed so that the designated area is fitted to the display area of the CRT display device 12. In the trimming process (step 218), the black frame appearing around the image is automatically erased, or the area designated by the keyboard 14 is erased. After performing various processes in this way, the multi-valued gradation image becomes CR.
Display on the T display device 12 in multi-value gradation (step 22).
0).

When the CRT display device 12 is viewed and the image needs to be printed out, stored in a magneto-optical disk, or transferred to another image processing device, the image reading by binary gradation is performed by the keyboard 14. From (step 222). At this time, the scanner 18 performs the main scan again (step 224) and performs the binarization process (step 226).

In addition to this processing, it goes without saying that various processing such as enlarging / reducing processing, trimming processing, and black / white inversion may be performed. For example, in the enlargement / reduction processing, the magnification can be automatically set by presetting the paper size to be printed out.

FIG. 10 is a diagram showing the concept of automatic setting of the magnification. By manually setting the dimensions of the print paper 150, the CRT 100 obtains a magnification suitable for outputting the output image area 152 to this print paper 150. The image signal binarized in this manner is output to the printer 20 and printed out (step 228). The result is also stored in an external memory device such as a magneto-optical disk or output to another image processing device.

The main scan (steps 210 and 22)
After 4) is finished and the image signal is stored in the CPU 100, the next frame can be immediately searched. At this time, it is desirable to return the tilt correction to the original state after finishing the main scan (step 230 in FIG. 6). In this way, the tilt is returned to the original state. If the scanning range of the line sensor 96, that is, the reading range is greatly tilted in the opposite direction with respect to the film frame, 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.

Since the present invention has the CRT display device 12, it is possible to use the display device 12 to display various information necessary for retrieval. For example, the feed amount of the microfilm 26 can be displayed. Figure 11
Shows an example of the display. Since the CPU 100 has the search control means 102 as described above, it is possible to know the feed amount of the microfilm 26. So CPU1
The film feed amount display means 154 is added to 00,
It may be displayed on the CRT display device 12.

For example, the supply side reel 15 is displayed on the CRT display screen.
6 and the take-up reel 158 are displayed, the film winding diameter corresponding to the film feed amount is calculated, and each reel 15
6, 158 can be displayed so as to change the film winding diameter. In addition, scale 1 that moves according to the feed amount
You may display 60. 11A shows the initial stage of film feeding, and FIG. 11B shows the middle of film feeding.

Further, in the above-mentioned embodiment, the photographed image of the microfilm is read by the line sensor 96, but a two-dimensional image sensor may be used. Further, the image sensor may be closely attached to the microfilm and read. If the present invention is applied to an apparatus for reading an image including a halftone density gradation or an image with a gray background, such as another photographic film, an X-ray X-ray photographic film, instead of the microfilm, the same effect as the present invention can be obtained. Is obtained.

In the above embodiment, after the preliminary scan (step 202 in FIG. 6), the main scan for reading multi-value gradation (step 210) and the main scan for reading binary gradation (step 224). And are done separately. However, the preliminary scan is not essential to the present invention. It is also possible to perform the two main scans only once.
For example, multi-value and binarization can be performed in parallel,
The multi-valued image information may be stored in a memory, and the contents may be read out and binarized. Further, the present invention is not limited to the reading of a black and white image, and it is needless to say that the present invention can be directly applied to a color image by separating it into color components by a color filter.

In general, many microfilms are negative films, but in this case, when they are projected on the screen, black and white appear on the screen in reversed black and white, which is difficult to see. On the other hand, according to the present invention, by electrically processing the image signal in the image processing means 118, black and white can be easily inverted, and the image of the negative film can be displayed on the CRT display device 12 as a positive image that is easy to see. It will be possible.

In the case of a microfilm, the arrangement of the light source section 52 and the projection lens 66 is usually opposite to that of this embodiment,
When the microfilm used in such a conventional apparatus is used in the present 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.

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.

[0052]

As described above, the invention according to claim 1 reads a microfilm image as an image of multi-value density gradation by an image sensor, and can display the multi-value density gradation such as CRT. Therefore, the gray background of the film and the image of halftone density can be displayed with high image quality, and the resolution of the image is improved. Therefore, an excellent image that is not inferior to the image projected on the screen can be output to a display device such as a CRT.

According to the second aspect of the present invention, when the edge emphasis processing is performed, the boundary (edge) of the image is sandwiched to emphasize the image side darkly, while the gray background side is not emphasized white. Therefore, the image quality does not deteriorate when the background is gray.

[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.

[Figure 6] Overall operation flow chart

FIG. 7 is a flowchart showing an operation example of multi-valued image processing.

FIG. 8 is a conceptual explanatory diagram of edge enhancement processing.

FIG. 9 is an explanatory diagram of edge enhancement processing.

FIG. 10 is a conceptual diagram of automatic magnification setting at the time of print output.

FIG. 11 is a diagram showing a display example of a film feed amount.

[Explanation of symbols]

 10 Computer Main Body 12 Display Device (CRT) 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 96 CCD Line Sensor 100 CPU 118 Image processing means 118A Multi-value conversion processing means 118B Binarization processing means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soji Oono 1005 Kozono, Ayase City, Kanagawa Prefecture Fuji Micrographix Co., Ltd. (72) Inventor Takao Yoshida 1005 Kozono, Ayase City, Kanagawa Prefecture Fuji Micrologix Co., Ltd. Within

Claims (2)

[Claims] 1. A microfilm reader for reading an image of a microfilm with an image sensor, processing the read image signal and displaying the image signal, and a multi-valued multi-value processing of the image signal read and output by the image sensor. A microfilm reader comprising a binarization processing unit and a display unit for displaying the multilevel signal in multilevel density gradation. 2. The microfilm reader according to claim 1, further comprising edge enhancing means for strongly enhancing the edge of the output of the multi-value quantization means on the high density side and weakly enhancing the edge on the light density side.