JPH03169177A - film image scanner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a film image scanner that optically reads images on a translucent film.

2. Description of the Related Art Conventionally, there have been film image scanners designed to read images on film, one example of which is shown in FIGS. 10 to 12. Reference numeral 50 denotes a slide formed by holding a film 51 around a cardboard frame 52, and as shown in FIG.
It is detachably held by 01. This career 1
00 along the carrier shaft 102, the light beam from the light source 103 is diffused by the diffusion plate 104 and transmitted through the film 5l, and this transmitted light is passed through the lens 105.
By forming an image on the line-type image sensor 106, the image on the film 51 is read. 10 and 11 are perspective views showing the case 107 of the scanner from a different viewing direction, and the case 107 has a recess 10.
Projections 109 and 110 are formed with 8 in between. A carrier lOO, a drive unit (not shown) for driving this carrier 100, a diffusion plate 104, and a light source 103 are housed inside one protrusion 109, and the other protrusion 110
A lens 105 is held therein, and an image sensor 106 is housed therein. Furthermore, a guide groove 1]1 is formed on the wall surface of the protrusion 109 to movably hold the connecting portion of the holder 101 to the carrier 100.

Problems to be Solved by the Invention The case 107 requires a recess 108 in order to attach and detach the slide 50 to the holder 101 in front of the lens 105.
Since the protrusions 109 and 110 are opposed to each other with the recess 108 in between, the case 107 becomes larger. As a result, when the case 107 is incorporated into an electronic device, a large space is required and it is difficult to determine the arrangement. Also, slide 5
0 is inserted and removed from above the case 107, so when an electronic device is installed in the case 107, other devices cannot be installed on top of the electronic device.

Furthermore, since the holder 101 and the lens 105 are exposed to the outside, not only the light rays from the light source 103 that pass through the image but also external light enters the lens 105, and the external light affects the reading accuracy. is easily damaged.

Furthermore, before reading, the light from the lamp 103 is passed through to form an image on the image sensor 106, and shading correction is performed using the output of the image sensor 106 at this time as a reference. Therefore, the slide 50 must be moved in and out each time shading correction is performed, which is cumbersome to operate. Moreover, the time from shading correction to actual reading is left to the user's actions and cannot be specified, and if the time is long, it may be due to changes in the temperature of the lamp 103 and its surroundings. , lamp 103
The amount of light and the sensitivity of the image sensor 106 may change, and the corrected value that should be there may change. Furthermore, before the manufacturer ships the scanner, the manufacturer performs shading correction in advance, writes the correction data to the RAM inside the scanner body, and before reading, reads the correction data from RA~1 and performs the shading correction. However, even in this case, the light intensity of the lamp 103, the sensitivity of the image sensor 106, the reflectance of the mirror in the optical path, etc. may change due to changes over time from the time shading correction is performed until the time of use. , it is not possible to perform high-precision shading correction.

Furthermore, the white image of a general original corresponds to a transparent part of a transparent original such as the film 51, and the light transmittance of this part is reduced by about 50 to 60%. If the gain of the image sensor 106 when this reduced amount of light is incident is set as an output suitable for read data, as described above, the light from the lamp 103 will be received directly during shading correction, so the image sensor 10
6 becomes saturated and the correction standard becomes vague. Conversely, if the gain of the image sensor 106 when receiving the light from the lamp 103 is set to an appropriate value during shading correction, the amount of light will be insufficient during reading, the S/N ratio will decrease, and the gradation accuracy will deteriorate.

Means for Solving the Problems A movable body having a holding portion for removably holding the film is directed toward the back from the film insertion slot on a support body having a film insertion slot formed on the surface into which the film is inserted. Optical reading means is provided on the support body and includes a light source that is movable in a reciprocating manner and is fixed on an optical axis perpendicular to the conveying direction of the movable body, and an image sensor that receives light from the light source. A light transmitting window penetrating through the film is formed at a position on the back side of the film, and a shading correction means that uses the output of the image sensor corresponding to the amount of light of the light source passing through the light transmitting window as a correction standard; output changing means for changing the output.

The film inserted through the film insertion slot is held and transported by a movable body, and during this transport process, the image on the film can be read by receiving the light transmitted through the film from the light source with an image sensor. Since the insertion slot is formed on the surface of the support, it is possible to insert and remove the film using the large external space, which makes it possible to reduce the space inside the film insertion slot. When integrated into electronic equipment as a system, it can be placed in a small space, all components of the optical reading means can be hidden and protected inside the support, and the influence of external light on reading accuracy can be removed.

Furthermore, when the movable body moves, the output of the image sensor corresponding to the light intensity of the light source passing through the light transmission window can be used as a correction standard to correct the shading. Shading correction can always be performed accurately just before the start of reading based on various conditions such as image sensor sensitivity and image sensor sensitivity, and furthermore, the output changing means can equalize the output of the image sensor during shading correction and during reading. As a result, shading correction can be performed correctly and a high SN ratio can be obtained during reading.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 9. Regarding the slide 50, the same reference numerals as in the conventional example will be used, and the explanation will be omitted. FIG. 5 is an exploded perspective view, and in the figure, l is a support body, and this support body 1 consists of a base 2 whose front and top surfaces are open, and a front panel 3 that covers the front surface of this base 2. 3 has a film insertion opening 4 formed therein. A cover 5 covers both sides and the top surface of the base 2. A casing 6 is formed by connecting the base 2, front panel 3, and cover 5. A carrier frame 7 is fixed to the bottom surface of the base 2 by a plurality of screws 8, and on both sides of the carrier frame 7, support parts 10 for supporting a carrier shaft 9 are formed.
The fixing member l1 that presses the carrier shaft 9 is screwed l1.
It is attached by 2.

A conveyance means l3 is provided for conveying the slide 50 toward the back of the film insertion opening 4 in a reciprocating manner. This conveying means 13 includes a carrier 14 which is a movable body slidably held by the carrier shaft 9, a step motor l5, a gal l7 connected to this step motor 15 via a deceleration mechanism l6, and a carrier. 1
It consists of a rack (not shown) formed on the negative side of 4 and meshed with gal 17. Step motor l5 and reduction mechanism 1
6 and the gear 17 are attached to one side of the carrier frame 7. Furthermore, an optical reading means 22 having a lamp (fluorescent lamp) 18 as a light source, a mirror 19, a converging lens 20, and an image sensor 21 is provided. lamp 18
and mirror 19 are arranged on the optical axis perpendicular to the conveyance direction of carrier 14, and convergent lens 20 and image sensor 21
are arranged on the optical axis which is refracted at right angles by the mirror 19. The converging lens 2o is attached to the optical frame 23, which is attached to the carrier frame 7 so as to be adjustable in position in the optical axis direction, and the image sensor 21 is attached to the carrier frame 7 via the mounting plate 24.
The lamp 18 is attached to the carrier frame 7 via a lamp holder 25. 26 is a printed wiring board attached to the carrier frame 7.

Further, as shown in FIG. 6, the carrier l4 has a U-shaped receiving part 27 that supports the three sides of the frame 52 of the slide 50, and the receiving part 27 has a U-shaped receiving part 27 for supporting the three sides of the frame 52 of the slide 50. A pressing member 28 that presses both sides is provided, and these receiving portions 27 and pressing members 28 serve as a holding portion that holds the slide 50 in a detachable manner. The length B of the receiving portion 27 in the depth direction is set to be shorter than the length A of the frame 52. Further, the pressing member 28 includes a leaf spring 30 attached to the carrier l4 by a screw 29,
It consists of leaf springs 3l fixed on both sides of this leaf spring 30. The leaf spring 31 is made of a material thinner than the plate thickness of the leaf spring 3o, and includes an elastic part 32 that curves into a U-shape, and an elastic part 32 that is folded back from one end to press the frame 52 over a certain length. and an inclined surface 3 that slopes upward at an angle of approximately 45 degrees from the tip of the pressing surface 33.
4. Further, the carrier 14 has a pair of left and right slide detection holes 35 formed in a portion of the receiving portion 27 that supports the front edge of the frame S2, and a horizontally long light beam located at the back side of these slide detection holes 35. A transmission window 36 is formed.

Next, FIG. 8 shows an electronic circuit. The CPU 37 includes a ROM 38 in which a program is written, a RAM 39 for storing variable data, an inverter circuit 40 for driving the lamp 18, a motor control circuit 41 for driving the step motor 15, and a memory for controlling the film insertion slot 4. A limit switch 42 located nearby to detect the return operation of the carrier 14 and a sensor drive circuit 43 that drives the image sensor 21 are connected. Also, amplifier 4
4, an A/D converter 45, an image processing circuit 46, a RAM 47 for temporarily storing read data, and an I/F circuit 4.
8 are sequentially connected to the output side of the image sensor 21 and are also connected to the CPU 37. The output side of the I/F circuit 48 is connected to the host computer.

In such #It, the slide 50 is inserted from the film insertion 04, supported by the receiving portion 27 of the carrier 14, and pressed by the leaf spring 31 of the pressing member 28. The reading operation will be explained below with reference to the flowchart shown in FIG. When the power is turned on or a scan command is received, the lamp 18 is turned on after confirming that the limit switch 42 is turned on. When the limit switch 42 is OFF, the step motor 15 is reversed to return the carrier 14 to the film insertion slot 4 side. 1st
As shown in the figure, the light from the lamp 18 passes through the light transmission window 36, is reflected by the mirror 19, and is focused on the image sensor 21 by the converging lens 20.
Using the output as a reference, in step 4, shading correction and magnification correction are performed. This step 4 is a shading correction means. During this time, the carrier 4 moves forward away from the film insertion slot 4, so the light from the lamp 18 passes through the edge of the light transmitting window 36, and immediately after this, the light from the lamp 18 travels to the mirror 19, as shown in FIG. The light is blocked by the carrier 14. At this moment, the output of the image sensor 2l changes from H to L, and the step counter is set to O based on this change. carrier l4
The slide detection hole 35 continues to move forward until the slide detection hole 35 reaches the ramp 1.
Pass under 8. At this time, the suitability of insertion of the slide 50 into the carrier l4 is detected. That is, as shown in FIG. 3, if the light from the lamp l8 passes through both the left and right slide detection holes 35, the slide 50 is detected as not inserted by the output of the image sensor 21, and only one of the slide detection holes 35 is inserted. If the light from the lamp 18 passes through,
The slide 5o is detected as having been inserted at an angle based on the output of the image sensor 2l. In this case, the detection signal causes the step motor 15 to rotate in reverse to return the carrier l4. If the left and right slide detection holes 35 are blocked by the frame 52 of the slide 50, the image sensor 21
Since the output of is maintained at L, it is determined that slide insertion is appropriate, and reading of the image on the film 5l is started when the count of the carrier counter reaches a certain value.

That is, step 1 in the flowchart of FIG.
0 is a reading start time setting means for setting the reading start time. The count number of the step counter at this time is determined at the time when the output of the image sensor 21 changes from H to L when the edge of the light transmission window 36 passes the optical axis of the lamp 18 in step 6 (in step 7, the count number of the step counter is
The reference point is the point in time when the value was set. moreover,
When the reading is completed when the count number of the step counter reaches a certain value, the lamp 18 is turned off, and the step motor 15 is reversed until the carrier 14 interferes with the actuator of the limit switch 42 and turns on.
Carrier 14 is restored. In this case, since the reading start time is set based on the point in time when the light passing through the light transmission window 36 for shading correction and magnification correction is blocked by the carrier 14, it is not necessary to accurately determine the return position of the carrier 14. . Therefore, the limit switch 42 only has to serve to prevent the carrier l4 from overrunning, and the limit switch 42 has a rough hysteresis characteristic.
2, and there is no need to strictly determine its mounting position.

This makes it possible to reduce costs.

As described above, since the film insertion opening 4 is formed on the front surface of the support body 1, the slide 50 can be inserted and removed using the wide external space, and thereby the inside of the film insertion opening 4 can be inserted and removed. It becomes possible to reduce the space, and when it is incorporated into electronic equipment as a system, it can be placed in a small space. Furthermore, carrier l4
By arranging the lamp 18 and the mirror l9 to face each other with the conveyance direction in between, and by making the dimension B in the depth direction of the receiving portion 27 of the carrier l4 shorter than the length A of the frame 52 of the slide 50, the carrier 14 The moving distance and the depth dimension of the support body 1 can be effectively shortened. Furthermore, since the film insertion slot 4 is formed on the front surface of the casing 6, when this casing 6 is incorporated into an electronic device, other electronic devices or other objects can be placed on the top surface of the electronic device. Therefore, a narrow installation space can be used effectively.

Furthermore, all the components of the optical reading means 22 can be hidden and protected inside the support 1, and the influence of external light on reading accuracy can be eliminated.

Furthermore, since the leaf spring 30 of the pressing member 28 is made of a thick material, the pressing force of the slide 50 can be increased. In addition, leaf springs 3l formed of a thin material are fixed on both sides of the leaf spring 30, and these leaf springs 31 have a U-shaped elastic part 32 and a flat pressing surface 33. , the entire pressing surface 33 can be brought into close contact with the frame 52 by bending the elastic portion 32. Thereby, the slide 50 can be held securely even though the depth dimension B of the receiving portion 27 is difficult. Further, since the inclined surface 34 is formed at the tip of the leaf spring 31, the slide 50 can be easily inserted into the carrier 14, and the tip edge of the frame 52 can be prevented from bending or breaking.

Next, shading correction will be explained.

Even if the film 5l is transparent, it reduces the amount of light from the lamp 18 by about 50 to 60%. Image sensor 2 at this time
If the gain of l is set to an appropriate value, the output of the image sensor 21 will be saturated because the amount of light from the lamp 18 passing through the transmission window 36 will be high during shading correction, making the correction standard ambiguous. For this reason, during shading correction, the output of the image sensor 21 is reduced by approximately 50 to 60% of the time of reading, and the output of the image sensor 21 is returned to 100% during reading.

Moreover, shading correction can be performed using the output of the image sensor 21 corresponding to the amount of light of the lamp l8 passing through the light transmission window 36 as a correction reference when the carrier 14 is moved.
As a result, the amount of light from the lamp 18 and the amount of light from the mirror 1 at that time are determined.
Under various conditions such as the reflectance of the image sensor 9 and the sensitivity of the image sensor 21, shading correction can always be performed accurately just before the start of reading. Although not shown, lowering the output of the image sensor 21 during shading correction is performed by an output changing means. Specifically, it is means for changing the accumulation time of the image sensor 21 or changing the amplification factor of the output of the image sensor 21.

Note that the operation is easy because shading correction and reading can be performed successively by simply attaching the slide 50 to the carrier 14 from the film insertion slot 4 once for reading.

Next, determination of the magnification correction coefficient will be explained.

The width of the light from the lamp l8 is the width of the light transmission window 36 of the carrier 14.
In order to correspond to the length in the width direction, as shown in Fig. 7,
The output distribution of the image sensor 22 is a semicircular distribution that is high at the center and gradually decreases toward both ends. here,
Since the width of the light transmission window 36 and the imaging magnification of the optical system are known, the number of pixels that should exist between the output from the boundary line between L and H to the boundary line between H and L at both ends of the image sensor 2l is known. can be calculated as follows. That is, if the width of the light transmission window 36 is W, the imaging magnification of the optical system is B, and the pixel pitch of the image sensor 21 is d, the number of pixels to be obtained is WX
B/d. However, since there is a limit to adjusting the accuracy of the imaging magnification of the optical system, a difference occurs between the actual number of pixels and the calculated number of pixels.

Therefore, the actual number of pixels is determined by performing magnification correction by signal processing such as linear interpolation and determining a correction coefficient.

In the embodiment described above, the film 51 is held around the frame 52, but the film 51 may be directly mounted on the carrier l4.

Alternatively, a belt may be used as the movable body that holds and conveys the slide 50, and a holding portion that holds the slide 50 may be provided on this belt.

Effects of the Invention As described above, the present invention provides a support body having a film insertion opening formed on its surface, and a movable body having a holding portion for removably holding a film, which can freely reciprocate from the film insertion opening toward the back. an optical reading means having a light source fixed on an optical axis perpendicular to the conveyance direction of the movable body and an image sensor that receives light from the light source is provided on the support body, A shading correction means that forms a penetrating light transmission window at a position on the back side, and uses an output of the image sensor corresponding to the amount of light of the light source passing through the light transmission window as a correction reference, and an output that changes the output of the image sensor. By providing a changing means, the film inserted from the film insertion slot is held and transported by a movable body, and during this transport process, the image on the film is read by receiving the light transmitted through the film from the light source with an image sensor. In addition, since the film insertion slot is formed on the surface of the support, it is possible to insert and remove the film using a large external space, thereby reducing the space inside the film insertion slot. It becomes possible to
When incorporated into electronic equipment as a system, it can be placed in a small space, and all the components of the optical reading means can be hidden and protected inside the support.
Furthermore, the influence of external light on reading accuracy can be removed, and shading correction can be performed using the output of the image sensor corresponding to the amount of light from the light source passing through the light transmission window as a correction standard when the movable body moves. As a result, shading correction can always be performed accurately just before the start of reading based on various conditions such as the light intensity of the light source, the reflectance of the optical system, and the sensitivity of the image sensor at that time. This makes it possible to equalize the output of the image sensor during shading correction and during reading, thereby making it possible to correctly perform shading correction, obtain a high S/N ratio during reading, and improve gradation accuracy.

[Brief explanation of the drawing]

1 to 9 show an embodiment of the present invention,
FIG. 1 is a longitudinal side view showing the state of shading correction and magnification correction, FIG. 2 is a longitudinal side view showing the state of detecting the reading start position, FIG. 3 is a longitudinal side view showing the state of slide insertion detection, and FIG. Figure 4 is a perspective view showing the exterior, Figure 5 is an exploded perspective view showing the internal structure, Figure 6 is an exploded perspective view showing an enlarged view of the slide holding structure, and Figure 7 corresponds to the width of the light transmission window. A graph showing the output distribution of the image sensor, FIG. 8 is a block diagram showing the electronic circuit, FIG. 9 is a flowchart showing the reading operation, and FIGS. 10 to 12 show conventional examples. Fig. 11 is a perspective view showing the external appearance, and Fig. 12 is an exploded perspective view showing the internal structure. 1...Support body, 4...Film insertion slot, 14...Movable body, 18... Light source, 2l... Image sensor, 2
2... Optical reading means, 27.28... Holding section, 36
...Light transmission window, 5l...film

Claims (1)

[Claims] A support body having a film insertion opening formed on its surface into which the film is inserted, and a holding part that holds the film removably, and is attached to the support body so as to be reciprocatingly movable toward the back from the film insertion opening. a movable body, an optical reading means having a light source fixed on an optical axis perpendicular to the conveying direction of the movable body, and an image sensor that receives light from the light source; a light transmission window penetrated at a position of , shading correction means that uses the output of the image sensor as a correction reference corresponding to the amount of light of the light source passing through the light transmission window, and output change means that changes the output of the image sensor. A film image scanner characterized by: