JP2511268B2 - Microfilm image reader - Google Patents

Description

The present invention relates to a microfilm image reading apparatus. That is, the image of the microfilm illuminated by the light from the light source is enlarged and projected and exposed on the solid-state imaging device,
The present invention relates to an image reading device.

"Technical background" A CCD (Charge Coupled Device) is typically used as a solid-state imaging device used in such an image reading device. However, the CCD is replaced with a conventional one having a length of about 35 mm, A long product, which is a combination of multiple cables, is being developed recently. By the way, on a microfilm on which an image is imprinted with a resolution much higher than that of a CCD, an original is photographed as an image with a high reduction ratio and various sizes.

Therefore, using a long CCD as described above,
A long CCD that is uniformly magnified to the size of the original document using a projection lens such as a zoom lens, and has an effective reading length that matches the magnified image width, that is, the document width.
Therefore, it is considered effective to read. And
In such a case, the pixel area is large, the sensitivity is high, and sharp reading is possible.

When such a long CCD is used, the reading optical path and the reader optical path for enlarging the image on the screen to confirm the subsequent reading and make various designations are set to the same optical path length. It becomes possible to switch and use. By doing so, the above designation on the screen can be performed more accurately.

"Problems to be Solved by the Invention" By the way, the following problems have been pointed out in the image reading apparatus using such a long CCD.

That is, the illuminance of the screen by the reader light path is
Illuminance of about 300 to 500 lux is required for visual inspection. On the other hand, the long type CCD has high sensitivity and is saturated at exposures of about 30 to 40 lux. As described above, since the required light amount greatly differs between the reader mode and the reading mode, it is necessary to control the light amount by switching the lamp voltage of the light source and the like to appropriate values.
However, particularly when reading an image of microfilm including photographic information such as halftone, it is necessary to drastically reduce the lamp voltage from the voltage set in the reader mode, so that the lamp life of the light source is rapidly deteriorated, There is also a problem that the color temperature fluctuates and the reading is adversely affected.

Even if the light amount control means as described above is additionally provided,
There is also a problem that the configuration is complicated and the operation and control are not easy.

The present invention has been made in view of the above circumstances to solve the above-mentioned problems, and by providing a dimming means in the reading optical path, the solid-state imaging device can be easily and easily provided. Since the light amount is reduced, it is not necessary to additionally provide the above-mentioned light amount control means. Especially, since the image reading density is controlled by accurately sampling and detecting the image density, a more appropriate reading density can be secured. It is an object of the present invention to propose a microfilm image reading device that can take advantage of various advantages such as the above.

[Means for Solving the Problems] In order to achieve the above object, an image reading device for a microfilm of the present invention has a screen and a solid-state image pickup device that outputs an electric signal according to the amount of light emitted. In the image reading device, an image illuminated by a lamp is projected onto the screen and the solid-state image sensor, and a dimming unit that reduces the amount of light from the lamp to an appropriate amount that does not saturate the solid-state image sensor. , Is provided in the optical path between the lamp and the solid-state image sensor. Then, on the screen, the image is projected with the amount of light from the lamp, while on the solid-state imaging device, the image is displayed with the amount of light that is reduced by the dimming device. It is projected. Along with this, based on the signal output from the solid-state image sensor in the state where the lamp is turned on, based on the density detection means for sampling and detecting the image density of the microfilm, and the density detected by the density detection means. , Control means for controlling the image reading density,
Is provided.

"Working" The present invention is constituted by such means, and therefore operates as follows.

In this microfilm image reading device, the image of the microfilm illuminated by the lamp is projected on the screen for confirmation and various designations,
Further, it is projected on the solid-state image pickup device and is used for reading.

At that time, the image on the microfilm is projected as it is on the screen with the light amount from the lamp, whereas on the solid-state image sensor, the light amount from the lamp is reduced by the dimming means as a whole. , The solid-state image sensor is projected with a uniformly reduced amount of light to an appropriate level at which saturation is not achieved. Thus, by interposing the dimming unit, the reading of the image by the solid-state image pickup device can be carried out under an appropriate reading density without being saturated. Further, it is not necessary to extremely reduce the lamp voltage of the light source, and there is no fear of sudden deterioration of the lamp life or fluctuation of the color temperature.

And these are the simple structure of the dimming means,
Reliable and easy to achieve.

In particular, by controlling the image reading density based on the image density sampled and detected through such a solid-state image sensor, a more appropriate reading density can be secured. That is, under the condition that the amount of light to the solid-state image sensor is reduced by the dimming means as described above,
Since sampling and detection are performed, the image density is always accurately detected without any change in color temperature. Then, in accordance with the image density detected in this way, for example, by setting the lamp voltage to an appropriate value and controlling the output voltage of the image signal read by the solid-state image sensor, A proper reading density can be secured.

[Examples] The present invention will be described in detail below based on the examples shown in the drawings.

First, an example of a microfilm image reading device will be outlined with reference to FIGS. 1 and 2.

FIG. 1 is a side view of the optical system, and FIG. 2 is a perspective view of the same.

The light from the exposure lamp 1, which is a light source, is reflected by the reflection mirror 2, condensed by the movable condenser lens 3, directed upward by the reflection mirror 4, and further condensed by the fixed condenser lens 5. Then, the light from these illuminating devices illuminates the image of the microfilm M held horizontally between the carrier glasses 6 from below and passes through it, and reaches the projection lens 7. Therefore, the image on the microfilm M is magnified and projected by the projection lens 7, which is a magnifying lens, up to, for example, the size of the original document before the projection.

First, in the reader mode, the reader optical path X is formed as shown by the alternate long and short dash line in the figure. That is, the image from the projection lens 7 is bent by the first scanning mirror 8 stopped at the home position A, the swing mirror 9 at the leader position, the fixed leader mirror 10 and the like, and the screen 11 arranged on the upper front part of the main body. It is enlarged and projected.
Then, by checking the image projected on the screen 11, an operation panel (not shown) provided in the central portion of the front surface of the main body is operated, and setting input such as designation of the next various read information is performed. Here, the read information means photographic information such as the type, read density, range, position, etc. of the microfilm concerned, whether it is binary information in black and white, information concerning enlargement or composition, and the like.

 The leader mode is like this.

Next, in the reading mode, the reading optical path Y is formed as shown by the solid line in the figure. That is, the swing mirror 9 swings upward from the above-mentioned leader position to the retracted position indicated by the chain double-dashed line in FIG.
Evacuate to the outside.

After that, first, preliminary scanning is performed. That is, the first
The scanning mirror 8 and the second scanning mirror 12 integrally arranged to face the first scanning mirror 8 at right angles to each other,
Reading preparation position B on the left side of the drawing from each home position A
The pre-scanning is performed in conjunction with the scanning table 13 along with. During this preliminary scanning, the image from the projection lens 7 is bent by the first scanning mirror 8 and the second scanning mirror 12 and projected on the CCD 14 which is a solid-state image pickup device, so that its image density is CCD.
Sampling is measured by 14. Then, the measured density data is input from the CCD 14 to a control unit (not shown) such as a microcomputer for analysis and data processing, and a control signal for setting the lamp voltage to an appropriate value corresponding to the image density. Are output to the exposure lamp 1 via the drive circuit.

In the illustrated example, the control unit such as the microcomputer described above functions as the concentration detection unit and the control unit in this way.

Further, in addition to or instead of such lamp voltage control, output voltage control of the image signal read by the CCD 14 may be performed. That is, the control unit according to the above may set the threshold value of the reference voltage of the A / D converter in correspondence with the image density.

In the above example, only about half of the image of the image is measured centering on the home position A, but in order to sample and measure the image density of the entire image, a reading end position D and a reading start position C, which will be described later, are set. If the preliminary scanning is performed in step 1, more accurate density data can be obtained.

 The prescan is performed in this way.

Now, then, the first operation mirror 8 and the second scanning mirror 12
Is reversely moved from the reading preparation position B toward the reading start position C, which is slightly closer to the home position A, due to the reverse rotation of the motor. This movement is a preliminary operation to ensure the rising of the scanning speed during image scanning, and the vibration that occurs due to the reversal of the scanning direction does not adversely affect the subsequent reading. Be seen.

Then, the first scanning mirror 8 and the second scanning mirror 12 are interlocked with each other along the scanning table 13 from the reading start position C to the reading end position D on the right side in the drawing from the home position A. Image scanning is performed. Due to this reading and scanning, the image from the projection lens 7 is bent by the first scanning mirror 8 and the second scanning mirror 12, and the CCD 14 is subjected to scanning projection exposure.

The reading start position C is associated with the alignment line of the projection image provided on the screen 11. Further, the reading end position D, that is, the reading scanning amount is designated by the selection button on the operation panel for each image, that is, for each original, and the motor of the driving mechanism for the first scanning mirror 8 and the second scanning mirror 12 (not shown) is set by the corresponding timer. ) Is set by controlling the rotation amount. That is, for example, if the illustrated read end position D is for an A4 horizontal size original, the read end position for A4 vertical size is set further to the right in the figure than the illustrated read end position D. Then, the timer value of the timer is selected corresponding to the size of each original.

The image signal read by the CCD 14 and photoelectrically converted as described above is output via the sample hold and amplifier circuits, the A / D converter, and the comparator, and is input to the optical disk storage device, the laser printer, and the like.

 The read mode is like this.

When the reading mode is completed in this manner, the reader mode is restored again. That is, the first scanning mirror 8 and the second scanning mirror 12 are returned from the reading end position D to the home position A by the reverse rotation of their motors. The speed of this return operation is set to about half of the speed of the above-mentioned reading scan, so that accurate pulse counting to the motor can be performed, and the first scanning mirror 8 and the second scanning mirror 8
There is little inertial traveling of the scanning mirror 12, and home position A
The positioning is surely stopped.

Further, in this way, the first scanning mirror 8 and the second scanning mirror 12
When is returned to the home position A, the swing mirror 9 is swung downward from the retracted position to the leader position again.

In the figure, S is a sensor, and this sensor S is for detecting flicker when the exposure lamp 1 which is a light source is lit, and based on the detection, the flicker correction process is performed on the exposure lamp 1. . Further, P in the figure is a light shielding plate that partitions the inside of the apparatus main body.

The image reading apparatus is roughly as described above. Next, the swing mechanism of the swing mirror 9 will be described with reference to FIG.

As shown in FIG. 3 (1), the swing mirror 9
The holding portion 15 for holding the is rotatably attached to the apparatus main body by a horizontal turning shaft 16 provided at the base end portion.
This holding portion 15 is a cam follower projecting from a shaft 17.
The cam follower 18 is in contact with the cam 19. Therefore, the swing mirror 9 can swing between the leader position indicated by the solid line in the figure and the retracted position indicated by the chain double-dashed line in the figure by the rotation of the cam 19 via the cam follower 18 and the holding portion 15, and at both positions. Are positioned.

Next, as shown in FIGS. 3 (2) and 3 (3), the cam
A control plate 21 is fixed to a cam shaft 20 that connects 19 to its drive motor (not shown). The detection protrusion 22 provided on the control plate 21 is connected to the first switch SW1, the second switch SW2, and the second switch SW2. The rotation of the cam 19 that interlocks with the control plate 21, that is, the position of the swing mirror 9 is detected by monitoring with the 3 switch SW3. That is, when the swing mirror 9 is at the leader position, the first and second switches SW1 and SW2 are turned off by the detection protrusions 22 as shown in (2), while when the swing mirror 9 is at the retracted position, (3) 1st, 2nd, 3rd switch SW1, SW2, SW
All of the three are set to be turned off by the detection protrusion 22. Based on such position detection of the swing mirror 9, driving of the drive motor for the cam 19 and scanning of the first scanning mirror 8 and the second scanning mirror 12 are controlled.

The swing mechanism of the swing mirror 9 is as described above.

 Next, the dimming means 23 will be described.

In the reading optical path Y, a dimming means 23 having a light dimming property.
Is intervening.

As a first example of the light reducing means 23, in FIG.
4 The one in which a neutral density filter is provided immediately before is shown. The dimming means 23 of the illustrated first example cuts off external light that has entered the inside of the device through a gap in the exterior of the device main body,
It is possible to prevent the CCD 14 from being adversely affected. Therefore, it is not necessary to form the exterior of the apparatus body into a strict dark box shape, and there is an advantage in that it is excellent in terms of configuration and cost.

Further, the light reduction means 23 is not limited to the first example shown in the figure, and for example, as shown by a broken line in FIG. 1, a portion between the first scanning mirror 8 and the second scanning mirror 12 is shown in FIG. Therefore, a neutral density filter may be provided at a position where the reading optical path Y intersects. In the second example, there is an advantage that the width of the neutral density filter can be reduced. Thirdly, dimming means
23 may be constituted by subjecting the second scanning mirror 12 to a light reduction treatment such as a coating treatment. Fourthly, as shown in FIG. 4, the protective glass 24 of the CCD 14 is subjected to the same light reduction treatment. You may comprise by. The dimming means 23 of the first, second, third and fourth examples may be used in combination.

Further, FIG. 5 shows a light-reducing means 23 which is appropriately associated with the long CCD 14. That is, the long CCD 14 is a plurality of long CCDs, for example, five CCDs 14 ₁ , 14 ₂ , 1 due to the relationship of wafers.
A combination of 4 ₃ , 14 ₄ and 14 ₅ is used. In such a long CCD 14, the difference in sensitivity between the CCDs 14 ₁ , 14 ₂ , 14 ₃ , 14 ₄ and 14 _{5 of} each channel
Variations inevitably occur. This difference in sensitivity has been made uniform by electrical adjustment of the amplifier circuit, but delicate adjustment and accurate uniformity of sensitivity have not been achieved yet.

Therefore, in FIG. 5, an attenuating filter is provided as the attenuating means 23 immediately before the CCD 14, and the attenuating means 23 is provided for each of the CCDs 14 ₁ , 14 ₂ , 14 ₃ , 14, ₄ 14, 14 ₅ of each channel. Individual light extinction and transmittance 23 ₁ , 23 ₂ , 23 ₃ , 23 ₄ , 23 ₅ corresponding to sensitivity,
A spliced configuration is shown. High CCD ₁₄₁ sensitivity in this manner, 14 _2, 14 _3, 14 _4, 14 about _5, higher extinction device of dimming of 23 _1, 23 _2, 23 _3, 23 _4, 23 _5, be made to correspond to Therefore, there is an advantage that the sensitivity of the entire long CCD 14 can be surely made uniform.

 The dimming means 23 has such a configuration.

The microfilm image reading device according to the present invention is
It is as explained above.

 Next, the operation and the like will be described.

FIG. 6 is a flowchart showing an example of the control, and the operation and the like will be described below also with reference to FIG.

When the reading start key of the operation panel is turned on and the reading start output is made in step, the mode is switched from the reader mode in which various initial inputs are made by the reader optical path X to the reading mode in which the reading optical path Y is formed. .

Then, in a first step, the exposure lamp 1 is set to a predetermined lamp voltage for AE and is lit with a constant light quantity lower than that in the reader mode. In addition, the swing mirror 9 swings from the leader position to the retracted position.

Then, the first scanning mirror 8 and the second scanning mirror 12 perform preliminary scanning from their home position A toward the read preparation position B. Then, in a step, it is determined whether or not the first scanning mirror 8 and the second scanning mirror 12 are in the photometric area between the home position A and the reading start position C corresponding to the reading preparation position B. To be done.

If it is within the photometric area, in step S14, the CCD 14 performs sampling photometry of the image density, and the density data is input to a microcomputer or the like.

When the first scanning mirror 8 and the second scanning mirror 12 pass through the photometric area, that is, when the scanning start position C is reached, the process proceeds to step S11,
The density data input from CCD14 is analyzed and processed.

Based on the result, in step, a control signal is output to the exposure lamp 1 and the lamp voltage is set to an appropriate value corresponding to the image density. As described above, the output voltage control of the image signal read by the CCD 14 may be performed in combination with or instead of the lamp voltage control.

After that, the flow advances to step, and it is judged whether or not the first scanning mirror 8 and the second scanning mirror 12 are at respective reading start positions C. That is, the first scanning mirror 8, the second
When the scanning mirror 12 is inverted through each read preparation position B and reaches the read start position C, the reading is started in steps. Then, in step, reading scanning is performed until the reading end position D, and the image is read and output by the CCD 14.

That is, the image on the microfilm M is sequentially projected and exposed on the CCD 14 by the formed read optical path Y, read, and the photoelectrically converted image signal is output to an optical disk, a laser printer, or the like.

Here, the amount of light to the CCD 14 depends on the intervening dimming means 2
Since it is properly lowered by 3, the reading with the CCD 14 can be performed under the proper reading density.
Therefore, depending on the image density, for example, when an image of a halftone micro film M that is a halftone is read,
There is no need to reduce the lamp voltage of the exposure lamp 1 to an extremely high level, and thus there is no possibility of a sudden deterioration in the life of the exposure lamp 1 and adverse effects on the reading of the CCD 14 due to variations in color temperature. Then, these are surely and easily realized by the simple structure of the light reducing means 23.

After that, the flow proceeds to step, sets the lamp voltage of the exposure lamp 1 to that for the reader mode, and ends.

 The above is the description of the operation and the like.

"Effects of the Invention" The image reading device of the microfilm according to the present invention is
As described above, the light amount to the solid-state image pickup device is appropriately reduced by interposing the dimming unit in the reading optical path. Therefore, an appropriate reading density is secured, there is no abrupt deterioration of the lamp life of the light source, there is no adverse effect on the reading due to the variation of the color temperature of the illumination light, and these are easily realized with a simple configuration. There are some remarkable and significant effects such as elimination of problems that hinder practical application.

And, in particular, the light reduction means is interposed in the reading optical path, and according to the image density detected by sampling,
By carrying out the control of the image reading density, such as the control of the lamp voltage and the control of the output voltage of the image signal from the solid-state image pickup device, the following effects are exhibited.
That is, under the condition that the light amount to the solid-state image sensor is reduced by the light attenuating means until these controls become possible, the light amount of the image, etc. of the image is calculated based on the image density accurately sampled and detected without color temperature change. Since the control is performed, a more appropriate reading density can be secured. When reading from an image of a halftone halftone microfilm, it is preferable to set the maximum light amount of the lamp so as to correspond to the saturation level of the solid-state image sensor.

[Brief description of drawings]

FIG. 1 is a side view of an optical system of an embodiment of a microfilm image reading apparatus according to the present invention. FIG. 2 is a perspective view of the same. FIG. 3 shows the swing mechanism of the swing mirror, FIG. 1 (1) is a side view, and FIG. 3 (2) is an explanatory view showing the relationship between the control plate and the switch when the swing mirror is at the leader position, FIG. 3C is an explanatory diagram showing the relationship between the control plate and the switch when the swing mirror is at the retracted position. FIG. 4 is a front view showing a CCD and its protective glass. FIG. 5 is a perspective view showing an example in which a long CCD is appropriately made to correspond to a light reducing means. FIG. 6 is a flowchart showing the control of the above embodiment. 1 ... exposure lamp (light source) 11 ... screen 14 ... CCD (solid-state image sensor) 23 ... dimming means M ... microfilm X ... leader optical path Y ... reading optical path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Ito 2-30 Azuchi-cho, Higashi-ku, Osaka-shi, Osaka, Osaka International Building Minolta Camera Co., Ltd. (56) Reference JP-A-61-222361 (JP, A) Kaisho 62-25563 (JP, A)

Claims (1)

(57) [Claims] 1. A micro having a screen and a solid-state image sensor for outputting an electric signal according to the amount of light emitted, and projecting an image illuminated by a lamp onto the screen and the solid-state image sensor. In the image reading apparatus for film, a dimming unit that reduces the amount of light from the lamp to an appropriate amount of light that does not saturate the solid-state image sensor is provided in the optical path between the lamp and the solid-state image sensor. The image is projected on the screen with the amount of light from the lamp, while the solid-state image sensor has the amount of light from the lamp entirely reduced by the dimming unit. Is projected, and the image density of the microfilm is sampled based on the signal output from the solid-state image sensor with the lamp lit. And concentration detection means for ring detection, based on the concentration detected by the concentration detection means, further comprising a control means for controlling the read density of the image, the image reading apparatus of the microfilm, characterized in.