JPH03169174A - Image scanner for film - Google Patents

Abstract

PURPOSE:To exactly correct magnification just before starting read by providing a magnification correcting means to define the output of an image sensor as a correction reference corresponding to a range for the light of a light source to pass through a light transmission window. CONSTITUTION:A film inserted from a film inserting port 4 is held by a movable body and in such a process, since the light transmitted form a light source 18 through the film is received by an image sensor 21, the image of the film can be read. When the movable body 14 is moved and the magnification is corrected with the output of the image sensor 14 as the correction reference corresponding to an area for the light of the light source 18 to pass a light transmission window 36, the magnification can be always exactly corrected just before starting reading based on the real position of an optics or the image sensor. Thus, the magnification can be always exactly corrected just before starting read.

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 it with a cardboard frame 52. As shown in FIG.
It is detachably held by 01. This career 1
00 along the carrier shaft 102, the light rays from the light source 103 are diffused by the diffusion plate 104 and transmitted through the film 51, 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.
8 in between. Projections 109 and 110 are formed.

A carrier 100, a drive unit (not shown) for driving the carrier 100, a diffusion plate 104, and a light source 103 are housed inside one protrusion 109, and the other protrusion 11
0, a lens 105 is held and an image sensor 106 is housed. Furthermore, a guide groove 111 is formed on the wall surface of the protrusion 109 to movably hold the connecting portion of the holder 10l 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 5o to the holder 101 in front of the lens 105,
Since the protrusions l09 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 the case 107 is incorporated into an electronic device, other devices cannot be installed on top of the electronic device.

Furthermore, since the holder IOI 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. Easy to damage.

Also, when the device is downsized, the optical path length becomes shorter, so
Although variations in the imaging magnification due to variations in the positions of the film 5l, lens 105, and image sensor 106 increase,
Since there are limits to determining these positions accurately,
The magnification accuracy is worse than that of general image scanners for reading originals.

Means for Solving the Problem A movable body having a holding part for removably holding the film is reciprocated from the film insertion opening toward the back of a support body having a film insertion opening formed on its surface into which the film is inserted. Optical reading means is provided on the support body and includes a light source fixed on an optical axis orthogonal to the conveying direction of the movable body and an image sensor that receives light from the light source, and at least one of the movable body A light transmitting window is formed at a position on the back side of the film on both sides, and a magnification correction means is provided which uses the output of the image sensor corresponding to the range through which the light from the light source passes through the light transmitting window as a correction reference.

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 can be read by receiving the light transmitted through the film from the light source with an image sensor. Since the insertion opening is formed on the surface of the support, it is possible to insert and remove the film using a large external space.This makes it possible to reduce the space inside the film insertion opening, and the system It can be placed in a small space when incorporated into an electronic device as an optical reader, and all the 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 reduced. can be removed.

Furthermore, by correcting the magnification based on the image sensor output corresponding to the area where the light source light passes through the light transmission window when the movable object moves, reading is always started based on the actual optical system and image sensor position. It is possible to accurately perform magnification correction immediately before the

Embodiment An embodiment of the present invention will be explained based on 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. In the figure, 1 is a support body, and this support body 1 consists of a base 2 whose front and upper 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 joining these base 2, front panel 3, and cover 5 together. A carrier frame 7 is fixed to the bottom surface of the base 2 by a plurality of screws 8, and support parts 10 for supporting a carrier shaft 9 are formed on both sides of the carrier frame 7.
The fixing member 11 that presses the carrier shaft 9 is screwed 1
It is attached by 2.

A conveyance means 13 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 l4 which is a movable body slidably held on the carrier shaft 9, a step motor 15, a gear 17 connected to the step motor l5 via a deceleration mechanism 16, and a carrier l4. 1
A rack (
(not shown). The step motor 15, the speed reduction mechanism l6, and the galley l7 are attached to one side of the carrier frame 7. Furthermore, a lamp (fluorescent lamp) 18 that is a light source
An optical reading means 22 having a mirror 19, a converging lens 20, and an image sensor 21 is provided. lamp 1
8 and mirror l9 are arranged on the optical axis perpendicular to the conveying direction of the carrier 14, and the converging lens 20 and the image sensor 2
1 is arranged on the optical axis which is refracted at a right angle by the mirror 19. The opto frame 23 is attached to the carrier frame 7 so that its position can be freely adjusted in the optical axis direction.
A converging lens 20 is attached so as to be adjustable in position, an image sensor 21 is attached to the carrier frame 7 via a mounting plate 24, and a 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 14 is formed with a U-shaped receiving part 27 that supports three sides of the frame 52 of the slide 5o, and the receiving part 27 is provided with a U-shaped receiving part 27 on both sides of the frame 52. A pressing member 28 is provided for pressing the slide 50, and the receiving portion 27 and the pressing member 28 serve as a holding portion for detachably holding the slide 50. 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 14 by a screw 29;
It consists of leaf springs 3l fixed on both sides of this leaf spring 30. The leaf spring 31 is formed of a material thinner than the plate thickness of the leaf spring 30, and includes an elastic part 32 that is curved in a U shape, and is folded back from one end of the elastic part 32 to press the frame 52 over a certain length. a pressing surface 33 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 52, and a horizontally elongated light beam located on the back side of these slide detection holes 35. A transparent window 36 is featured.

Next, FIG. 8 shows an electronic circuit. The CPU 37 includes a ROM 38 in which a program is written, a RAM 39 that stores variable data, an inverter circuit 40 that drives the lamp 18, a motor control circuit 4l that drives the step motor 15, and a motor control circuit 4l that drives 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 2l and are also connected to the CPU 37. The output side of the I/F circuit 48 is connected to the host computer.

In this configuration, the slide 50 is inserted through the film insertion opening 4, supported by the receiving portion 27 of the carrier 14, and pressed by the leaf spring 3l 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. limit switch 4
2 is OFF, the step motor 15 is reversely rotated to return the carrier 14 to the film insertion slot 4 side. As shown in FIG. 1, the light from the lamp l8 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. Based on the output of the image sensor 2l at this time, the step In step 4, shading correction and magnification correction are performed. This step 4 is a shading correction means and a magnification correction means. During this time, the carrier 14 moves forward away from the film insertion slot 4, so the light from the lamp l8 passes through the edge of the light transmitting window 36, and immediately after this, the light from the lamp l8 reaches the mirror 19. is shielded from light by the carrier 14. At this moment, the output of the image sensor 21 changes from H to L, and the step counter is set to 0 based on this change.

The carrier 14 continues to advance forward and enters the slide detection hole 3.
5 passes under the lamp 18. At this time carrier 14
The suitability of insertion of the slide 50 is detected. That is, as shown in FIG. 3, if the light from the lamp I8 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 is transmitted through the slide 50, it is detected by the output of the image sensor 21 that the slide 50 has been inserted at an angle.

In this case, the detection signal causes the step motor l5 to
is reversed and returns carrier l4. If the left and right slide detection holes 35 are closed by the frame 52 of the slide 50, the output of the image sensor 21 is maintained at L, so it is determined that the slide insertion is appropriate, and the time when the count of the carrier counter reaches a certain value is reached. Start reading the image on film 5. That is, step 10 in the flowchart of FIG. 9 is a reading start time setting means for setting the reading start time. At this time, the count number of the step counter is determined at the time when the output of the image sensor 2l 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. Furthermore, when the reading is finished when the count number of the step counter reaches a certain value, the lamp 18 is turned off.
Set it to FF, reverse the step motor l5, and move the carrier 1.
4 interferes with the actuator of the limit switch 42 and returns the carrier 14 until it is turned ON. In this case, the light transmission window 36 for shading correction and magnification correction
Since the reading start time is set based on the point in time when the carrier 14 blocks the light passing through the carrier 14, it is not necessary to accurately determine the return position of the carrier 14.Therefore, the limit switch 42 prevents the carrier 14 from overrunning. It is only necessary to use the limit switch 42 with a rough hysteresis characteristic, and there is no need to strictly determine its mounting position.Thereby, costs can be reduced.

As described above, since the film inlet 4 is formed on the front surface of the support 1, the slide 50 can be inserted and removed using the large external space, and thereby the inner side of the film inlet 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 14
By arranging the lamp 18 and the mirror 19 to face each other with the transport direction of 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.

Further, 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. Additionally, plate springs 31 made of a thin plate material are fixed to both sides of the plate spring 30, and these plate springs 31 have a U-shaped elastic portion 32 and a flat pressing surface 33. Therefore, 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 short. Furthermore, since an inclined surface 34 is formed at the tip of the leaf spring 31, the carrier l4
The slide 50 can be easily inserted into the frame 52, and the leading edge of the frame 52 can be prevented from bending or breaking.

Next, shading correction will be explained.

Even though the film 51 is transparent, it reduces the amount of light from the lamp 18 by about 50-60%. Image sensor 2l at this time
If the gain is set to an appropriate value, the output of the image sensor 21 will be saturated because the amount of light from the lamp l8 passing through the transmission window 36 will be high during shading correction, making the correction standard ambiguous.

For this reason, when performing shading correction, the lamp 1
8 is reduced to about 50-60% of the reading time. As a result, during shading correction, it is possible to obtain a high output from the image sensor 21 without saturation and perform correct correction, and also during reading, the image sensor 21
1, it is possible to obtain a high output and read the image on the film 5l with a high signal-to-noise ratio and high gradation accuracy. Of course, the light intensity of the lamp 18 is kept constant,
The same objective can be achieved even if the gain of the image sensor 21 during shading correction is reduced by approximately 50 to 60% during reading. In particular, shading correction can be performed using the output of the image sensor 21 corresponding to the amount of light from the lamp 18 passing through the light transmission window 36 as a correction reference when the carrier l4 moves, and thereby the lamp l8 at that time
Based on various conditions such as the amount of light, the reflectance of mirror 9, and the sensitivity of image sensor 21, shading correction can always be performed accurately just before the start of reading. Furthermore, the operation is easy because shading correction and reading can be performed continuously by simply mounting the slide 50 from the film insertion slot 4 to the carrier 14 once for reading.

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

The width of the light from the lamp 18 is the width of the light transmitting 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 21 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 21 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, based on the optical system such as the lamp 18, the mirror l9, the lens 20, and the actual position of the image sensor 2l, the image sensor 2l outputs a signal corresponding to the area of light passing through the light transmission window 36, and this output The actual number of pixels is determined by performing magnification correction by signal processing such as linear interpolation based on the signals at both ends of the area and determining a correction coefficient. Thereby, it is possible to perform apparently accurate magnification correction.

Note that the same purpose can also be achieved by forming a pair of left and right light transmitting windows by holes or notches only on both sides of the carrier l4, and blocking the light from the lamps 18 between these light transmitting windows. can do.

In the embodiment described above, the film 51 is held around the frame 52, but the film 5l may be directly attached to the carrier 14.

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 structure in which a movable body having a holding portion for removably holding a film is movable back and forth from the film insertion port toward the back of a support body having a film insertion port formed on the surface thereof. An optical reading means is provided on the support body, and includes 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; By forming a light transmission window at a position on the back side of the film in the part, and providing a magnification correction means that uses the output of the image sensor corresponding to the range through which the light from the light source passes through the light transmission window as a correction reference, 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 can be read by receiving the light transmitted through the film from the light source with an image sensor. Since the opening is formed on the surface of the support, the film can be inserted and removed using the large external space.
This makes it possible to reduce the space inside the film insertion slot, allowing the system to be installed in a small space when incorporated into electronic equipment, and furthermore, all the components of the optical reading means can be hidden inside the support. Furthermore, the influence of external light on reading accuracy can be removed, and the output of the image sensor corresponding to the area where the light from the light source passes through the light transmission window when the movable object moves is used as a correction standard. By correcting the magnification, it is possible to always accurately correct the magnification immediately before starting reading based on the actual position of the optical system and image sensor.

[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 detecting slide insertion; 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. 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;
FIG. 12 is an exploded perspective view showing the internal structure. 1... Support body, 4... Film insertion slot, 14...
Movable body, l8... light source, 2l... image sensor,
22... Optical reading means, 27.28... Holding section, 3
6...Light transmission window, 5l...Film-3 Figure 3

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; It is characterized by comprising a light transmission window penetrated to a position on the back side of the film, and a magnification correction means that uses the output of the image sensor corresponding to the range through which the light from the light source passes through the light transmission window as a correction reference. Image scanner for film.