JP2000261614A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read images with satisfactory image quality and to enhance flexibility in design of miniaturization of an image reader by generating light producing no unevenness among colors, when a light emitting element with less generating heat and a high color temperature such as an LED is used for a light source. SOLUTION: An LED 64 with a broad bandwidth spectrum is used for a light emitting element. In a relative luminous intensity characteristic where the maximum intensity is set at 1.0, the maximum luminous intensity of the spectrum is in a B wavelength band. The minimum luminous intensity, however, is in an R wavelength band and with relative intensity of 0.46. Thus, the ratio Max: Min is 10:4.6 and then a set value 10:1 applicable to a white light source is clearly seen as being fully ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for irradiating a film on which an image is recorded with light from a light emitting element, and receiving the transmitted or reflected light by a photoelectric conversion element and reading the image.

[0002]

2. Description of the Related Art In recent years, a frame image recorded on a photographic film is photoelectrically read by a reading sensor such as a CCD, and image processing such as enlargement / reduction and various corrections is performed on digital image data obtained by the reading. In addition, a technique is known in which an image is formed on a recording material using a laser beam modulated based on digital image data that has been subjected to image processing.

As described above, in the technique of digitally reading a frame image using a reading sensor such as a CCD, the frame image is preliminarily read (so-called pre-scan) and the density of the frame image is read in order to realize accurate image reading. Reading conditions (for example, the amount of light applied to a frame image and CC
D, etc.), and the frame image is read again under the determined reading conditions (so-called fine scan).

In the above-described image reading system, a halogen lamp, which has been widely used for printing exposure and the like, is conventionally used as a light source. However, this halogen lamp generates a large amount of heat, and therefore, the luminous efficiency is low. Unfortunately, the increase in reading speed was limited.

That is, a halogen lamp is most suitable as a light source for directly printing on a photographic paper through a negative film as in the case of printing exposure. However, as described above, a CCD (usually for each of the three primary colors) is used. In a system that reads an image with a line CCD in which filters are attached so as to be sensitive to light, since the color temperature is low, the light amount of a short wavelength (B (blue) system in terms of color) is low, and the SN of the read image is low. Deteriorates. For these reasons, the halogen lamp has a problem in high-speed reading.

Further, a lamp having a high color temperature (for example, a xenon lamp, a metal halide lamp, etc.) has a problem that discharge noise occurs and reading cannot be performed with good image quality.

For this reason, it has been proposed to apply an LED as a light source. LEDs usually have a specific color (blue,
(Green, red), these are collectively arranged to form a white light source. LEDs generate less heat,
Since the color temperature is high, it is suitable as a light source for an image reading system.

On the other hand, the line CCD on the reading side is provided with a color filter for each line, and each line CCD detects the density (light amount) of each color.

[0009]

However, in the configuration of the prior art described above, a plurality of LEDs that emit light of each color are collectively arranged to constitute a white light source. However, depending on this arrangement, color unevenness may occur. is there. Therefore, multiple LEs
It is necessary to suppress color unevenness by increasing the number of D, or to arrange a light diffusing plate or the like on the output side, so that light cannot be used effectively. Further, it is conceivable to irradiate the film separately for each color, but in any case, the number of components is increased, which hinders miniaturization of the apparatus.

The present invention takes the above facts into consideration, and as a light source,
When using a light-emitting element such as an LED that emits less heat and has a high color temperature, it can generate uniform light between colors, read images with good image quality, and reduce the size of the device. It is an object of the present invention to obtain an image reading apparatus which can increase the degree of freedom of the design.

[0011]

According to a first aspect of the present invention, a film on which an image is recorded is irradiated with light from a light emitting element, and the transmitted or reflected light is received by a photoelectric conversion element.
An image reading apparatus for reading an image, wherein the light emitting element has an emission wavelength range of 400 nm to 500 nm, 500 n
It is characterized in that the ratio between the maximum value and the minimum value of the maximum emission intensity in each wavelength band of m to 600 nm and 600 nm to 700 nm is within 10: 1. Here, the intensity is not a measured light amount represented by a lumen or the like,
Refers to the amount of radiation expressed in watts or the like.

According to the first aspect of the present invention, the emission wavelength range of the light emitting element is B (blue), G (green), R
It is preferable that the light emission intensity has no unevenness through the wavelength of (red). However, it is difficult to obtain the above light emission intensity in the LED and LD. So, BG
R from 400 nm to 5 according to the emission wavelength band of each color of R
Two of the maximum emission intensities in the three wavelength bands of 00 nm, 500 nm to 600 nm, and 600 nm to 700 nm, the maximum value and the minimum value, are selected, and when these are compared, the intensity ratio is 10: 1. Set to within. This setting is performed, for example, by setting L for each color of RGB.
When the ED is used, the ratio of the emission peak intensity of each color can be kept within 10: 1 by adjusting the intensity of each color or by dimming with an optical means such as a filter.

In a system in which a film image is read and subjected to image processing and printed, the S / N at the time of reading is
Must be balanced between the colors, and as a result of an experiment, it has been found that good results can be obtained if the intensity ratio of the three colors of the reading illumination light source is within 10: 1.

As described above, by defining the intensity distribution of the light emitting element, it is possible to eliminate color unevenness, to provide a light source close to a white light source such as a halogen lamp, and to obtain a characteristic of the light emitting element such as low heat generation and low heat generation. High color temperature can be maintained.

As such a light emitting element, an LED having a wide spectrum band may be used.

According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, a plurality of the light emitting elements are arranged in a line in the width direction of the film to form a light emitting element group. A scanning-type image reading apparatus that reads an image while transporting the film while irradiating the film with the light.

According to the second aspect of the present invention, since the image reading apparatus is a scanning type image reading apparatus, it is preferable that the light from the light emitting element is irradiated on the film surface in a narrow line shape. For this purpose, divergent light output from the light emitting element is used as condensed light (or parallel light), and light from the light emitting element is effectively used. In this case, if a diffuser plate or the like is used, light cannot be effectively used. Therefore, if light-emitting elements that emit light for each color are simply assembled, color unevenness may occur. However, by defining the relative ratio of the intensity peak of each color as described in the claim light,
The above-mentioned color unevenness does not occur.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the optical guide means for guiding most of the divergent light output from the light emitting element to a required area on the film is provided. Have more.

According to the third aspect of the present invention, a light guide path, a lens, or the like is disposed as a guide optical system in a space between the light emitting element and the film, and most of the light output from the light emitting element is directed onto the film surface. By guiding, the light from the light emitting element can be used effectively.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the read pixels of the photoelectric conversion element are arranged in three rows along the width direction of the film. They are arranged, and are separated into colors corresponding to the peak wavelengths of the divided wavelength bands for each column and photoelectrically converted.

According to the fourth aspect of the present invention, since the intensity peak of the light from the light emitting element is determined as in the first aspect, a so-called three-line CCD is used similarly to a white light source such as a halogen lamp. Thus, it is possible to receive a color (for example, RGB) in a different wavelength range for each line.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the light from the light emitting element has an optical axis incident substantially perpendicular to the film surface. And an auxiliary light source having an optical axis inclined by a predetermined angle with respect to the optical axis of the light emitting element.

According to the fifth aspect of the invention, when light from the light emitting element is to be used effectively, condensed light or parallel light is naturally irradiated onto the film surface. In this case, if there is a scratch on the film surface, the light is refracted by the scratch and unevenness in the amount of light is likely to occur. For this reason,
By disposing an auxiliary light source having an optical axis inclined at a predetermined angle with respect to the optical axis of the light emitting element (perpendicular to the film surface), if the flaw is found, the light emitting element is refracted by the flaw. Instead of the light from the light source, a portion having a small light amount can be supplemented, and the irradiation light amount on the film surface can be stabilized (substantially uniform).

[0024]

1 and 2 show a schematic configuration of a digital lab system 10 according to the present embodiment.

As shown in FIG. 1, the digital lab system 10 includes a line CCD scanner 14, an image processing unit 16, a laser printer unit 18, and a processor unit 20. The processing unit 16 is integrated as the input unit 26 shown in FIG.
Are integrated as an output unit 28 shown in FIG.

The line CCD scanner 14 is for reading a frame image recorded on a photographic film such as a negative film or a reversal film.
5 size photographic film, 110 size photographic film, and photographic film with a transparent magnetic layer (24
0 size photographic film: so-called APS film), 12
Frame images of photographic film of size 0 and size 220 (Brownie size) can be read. The line CCD scanner 14 reads the above-mentioned frame image to be read by the line CCD 30, performs A / D conversion in the A / D converter 32, and outputs image data to the image processing unit 16.

In this embodiment, a digital lab system 10 in which a 135-size photographic film 22 is used will be described.

The image processing section 16 stores image data (scanned image data) output from the line CCD scanner 14.
Is input, and image data obtained by photographing with the digital camera 34 or the like, a document (for example, a reflection document, etc.)
Data obtained by reading the image data with a scanner 36 (flat bed type), image data generated by another computer and recorded in a floppy disk drive 38, MO drive or CD drive 40, and received via a modem 42 The communication image data and the like (hereinafter, these are collectively referred to as file image data) can be input from the outside.

The image processing section 16 stores the input image data in the image memory 44, and stores a color gradation processing section 46, a hypertone processing section 48, and a hyper sharpness processing section 50.
Image processing such as various corrections and the like, and outputs the image data to the laser printer unit 18 as recording image data. Further, the image processing unit 16 outputs the image data subjected to the image processing to an external device as an image file (for example, outputs the image data to a storage medium such as an FD, an MO, a CD, or to another information processing device via a communication line). Transmission, etc.).

The laser printer section 18 has R, G, and B laser light sources 52, and controls a laser driver 54 to record image data (temporarily stored in an image memory 56) input from the image processing section 16. Is applied to the photographic printing paper, and scanning exposure (in the present embodiment, mainly the polygon mirror 58 and the fθ lens 60) is performed.
An image is recorded on the photographic paper 62 by an optical system using the same. Further, the processor unit 20 includes a laser printer unit 18.
The photographic paper 62 on which an image has been recorded by scanning exposure is subjected to color development, bleach-fixing, washing, and drying.
Thus, an image is formed on the printing paper.

(Configuration of Line CCD Scanner) Next, the configuration of the line CCD scanner 14 will be described. FIG. 3 shows a schematic configuration of an optical system of the line CCD scanner 14. This optical system includes a plurality of LED chips 64 (hereinafter collectively referred to as an LED chip group 64), and includes a light source 66 for irradiating the photographic film 22 with light.

The LED chip groups 64 are arranged on the aluminum substrate 65 in one to two rows (two rows in the present embodiment) along the width direction of the photographic film 22.

The LED chip 64 has a broadband spectrum L
It is ED and emits white light. FIG. 4 shows a relative intensity distribution characteristic diagram of a wavelength band of the LED chip applied in the present embodiment. As can be seen from FIG.
The chip 64 has a predetermined strength in all of the BGRs. Further, the wavelength band is set from 400 nm to 500 nm.
B band, 500 nm to 600 nm G band, 6 band
When divided into the R band from 00 nm to 700 nm,
The maximum intensity and the minimum intensity are selected from these three bands, and if these ratios are within 10: 1, it can be applied as a white light source. As shown in FIG. 4, the maximum intensity Max is 1.0 in the B band, and the minimum intensity Min is 0.46 in the R band.
It has become. Therefore, Max: Min = 10: 4.
6, which is within 10: 1.

Each LED chip group 64 has a transparent protective film 6
7 to protect the light emitting surface from scratches and the like.

On the light emitting side of the LED chip group 64, a light guide member 80 as optical guiding means is provided. One end face of the light guide path member 80 is close to the LED chip group 64, and has a structure in which almost all light output as divergent light from the LED chip group 64 is incident on the light guide path member 80.

The light guide path member 80 has a rectangular parallelepiped shape in which the film transport direction is narrow, and the other end face is close to the photographic film 22. Therefore, most of the light output from the LED chip group 64 can be applied as light for image reading.

On the side opposite to the light source 66 across the photographic film 22 positioned and transported by the negative carrier 74,
Along the optical axis of each of the LED chip groups 64R, 64G, and 64B, a lens unit 76 for forming light transmitted through the frame image and a 3-line CCD 30 are sequentially arranged.

The three-line CCD 30 has a plurality of pixels for detecting light arranged in the width direction of the photographic film 22.
This is provided in three lines in the film transport direction. 3
The line CCD 30 is provided with a filter for receiving light of different wavelengths (RGB) for each line.

The light transmitted through the photographic film 22 is transmitted through a lens unit 76 (for example, a SELFOC lens).
An image is formed on the pixels of the line CCD 30.

Here, a function of accumulating electric charges (one-dimensionally) according to the light received sequentially from the pixel on one end side to the pixel on the other end side of each line is provided, and the photographic film is conveyed. Together with this, the frame image (two-dimensional) can be electrically read.

The operation of this embodiment will be described below.

An operator inserts the photographic film 22 into the film carrier 74 and operates the keyboard 1 of the image processing section 16.
When the start of frame image reading is instructed by 6K, the transport of the photographic film 22 is started in the film carrier 74.
By this transport, a pre-scan is performed. That is, while the photographic film 22 is transported at a relatively high speed, the line CCD scanner 14 reads not only image frames but also various data outside the image recording area of the photographic film 22. The scanned image is
It is displayed on the monitor 16M.

At this time, the size of the frame image is recognized, and, for example, in the case of a panoramic size frame image, the plain portions unique to the panoramic size image (both ends in the width direction of the photographic film) are shielded.

Next, the reading conditions at the time of fine scanning are set for each frame image based on the prescan result of each frame image, and the reading conditions at the time of fine scanning are set based on the prescan result. It is set every time.

When the setting of the reading conditions at the time of the fine scan for all frame images is completed, the photographic film 22 is set.
Is conveyed in the direction opposite to the prescan, and a fine scan of each frame image is executed.

At this time, since the photographic film 22 is being conveyed in the direction opposite to that in the pre-scan, the fine scan is executed sequentially from the last frame to the first frame.
The transport speed of the fine scan is set lower than that of the pre-scan, and the reading resolution is accordingly increased. In addition, at the time of pre-scanning, the image state (for example, captured image aspect ratio, under, normal, over,
Since the shooting state such as super-over and the presence / absence of flash shooting are recognized, it is possible to read under appropriate reading conditions.

Here, the line CC in the present embodiment
The light source unit 66 applied to the D scanner 14 is not a halogen lamp or a xenon lamp that has been widely applied in the past.
The LED chip group 64 is applied.

The LED chip group 64 is arranged at a high density substantially linearly along the width direction of the photographic film 22.

The light emitted by the LED chip group 64 loses most of the light from the LED chip group 64 to the photographic film 22 by the light guide path member 80 and only in the area of the surface of the photographic film 22 which is close to the necessary minimum. Can be irradiated.

The light transmitted through the photographic film 22 is condensed by the lens unit 76 and received by the pixels of each line of the three-line CCD 30. In the three-line CCD 30, a filter for separately receiving RGB light is attached to each line, and as a result, it is possible to obtain a light amount for each of three colors corresponding to an image for each line.

As described above, the LED chip group 64 is connected to the light source 6
By applying as 6, the characteristics of the LED such as high color temperature and low light amount of short wavelength are sufficiently exhibited, the SN of the read image is good, and high-speed reading is possible. That is, it is more suitable as a light source for reading an image than another light source such as a halogen lamp.

However, a drawback of the LED chip 64 was uneven color. However, in this embodiment, since the intensity peak relative ratio for each color wavelength is kept within 10: 1,
It is possible to eliminate color unevenness and eliminate insufficient light quantity.
That is, as shown in FIG. 4, in the emission relative intensity characteristic where the maximum intensity is 1.0, the maximum intensity is in the B band. On the other hand, the minimum intensity is in the R band, and its relative intensity is 0.46. Thereby, Max: Mi
It can be seen that n is 10: 4.6, which sufficiently secures a set value of 10: 1 applicable as a white light source.

In this embodiment, the LED 64 having a wide band spectrum is used as the light emitting element.
You may use the LED which emits each color of B. At this time, the intensity of each color is dimmed by electric control such as current control, or dimmed by an optical member such as a filter, or the intensity is adjusted by the number of LEDs. The ratio between the maximum intensity and the minimum intensity needs to be within 10: 1.

In this embodiment, an LED is used as a light emitting element, but a semiconductor laser LD may be used.

Further, in this embodiment, the light source 66 is set to L
ED chip group 64, the optical axis of which is
2 (see FIG. 5), but because the light from the LED chip 64 is collected by the light guide path member 80, the light is close to being parallel to the optical axis. It has a great effect (scattering of light due to the scratch) on the formed scratch. Therefore, as shown in FIG. 6, auxiliary light sources 82 are provided on the upstream and downstream sides of the light source 66 in the film transport direction so that the optical axis is inclined by a predetermined angle with respect to the optical axis of the light source 66 by the light guide path member 84. Light from the auxiliary light source 82 may be guided to the photographic film 22. The auxiliary light source 82 is capable of supplying light to an insufficient light amount area instead of light that is scattered by a scratch and cannot be used as an irradiation light source of the photographic film 22, and provides stable light regardless of the presence or absence of a scratch. 22.

In this embodiment, the photographic film 2
Although the target is a transmission film as in the case of No. 2, the present invention can be applied to reading of a reflection original.

In this embodiment, the LED chip constituting the LED chip group 64 has a general structure in which the light emitting chip is embedded in a rectangular resin block. And a reflection type LED chip in which the chip is arranged at the condensing position on the parabolic surface may be used. In this case, the light emitted from the chip is reflected by the reflector and output as substantially parallel light,
It is suitable for a configuration in which an image is read with color separation.

Although the selfoc lens 76 is used as the lens unit 76, a general disc-shaped convex lens or concave lens may be used. However, the diameter is preferably relatively large in consideration of chromatic aberration and the like.

Further, three lines CC as photoelectric conversion elements
Although D30 is used, another photoelectric conversion element such as a MOS may be applied.

[0060]

As described above, in the image reading apparatus according to the present invention, when a light emitting element such as an LED having a small heat generation at the time of light emission and a high color temperature is used as a light source, there is no unevenness between colors. It has an excellent effect that light can be generated, an image can be read with good image quality, and the degree of freedom in designing a compact device can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a digital laboratory system according to an embodiment of the present invention.

FIG. 2 is an external view of a digital laboratory system.

FIG. 3 is a perspective view showing a schematic configuration of an optical system of the line CCD scanner.

FIG. 4 shows a broadband spectrum L applied to the present embodiment.
FIG. 4 is a graph showing a wavelength-relative emission intensity characteristic of an ED.

FIG. 5 is a front view of the line CCD scanner according to the embodiment;

FIG. 6 is a front view of a line CCD scanner according to a modification.

[Explanation of symbols]

 Reference Signs List 10 digital laboratory system 14 line CCD scanner 22 photographic film 30 line CCD (photoelectric conversion element) 64 LED chip group (light emitting element group) 66 light source 76 lens unit 80 light guide path member (optical guide means) 82 auxiliary light source

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C072 AA01 CA05 DA09 EA05 NA01 QA06 VA03 WA04 5F041 AA11 DA13 DA20 DA41 DB07 EE11 FF13

Claims (5)

[Claims] 1. An image reading apparatus for reading an image by irradiating a film on which an image is recorded with light from a light emitting element and receiving the transmitted or reflected light by a photoelectric conversion element and reading the image. 400 nm to 500 in the wavelength range
nm, 500 nm to 600 nm, 600 nm to 70
An image reading apparatus, wherein the ratio between the maximum value and the minimum value of the maximum emission intensity in each wavelength band of 0 nm is within 10: 1. 2. The image reading apparatus according to claim 1, wherein a plurality of the light emitting elements are arranged in a line in a width direction of the film to form a light emitting element group, and the film is irradiated with linear light. An image reading apparatus that reads an image while transporting the film in a state in which the image is read. 3. The image reading apparatus according to claim 1, further comprising an optical guiding means for guiding most of the divergent light output from said light emitting element to a required area on said film. 4. The read pixels of the photoelectric conversion element are arranged in three rows along the width direction of the film, and each row performs photoelectric conversion with maximum sensitivity in each of the divided three wavelength bands. The image reading apparatus according to claim 1, wherein: 5. An auxiliary light source having an optical axis that is incident on the film surface substantially perpendicularly to the light from the light emitting element and having an optical axis inclined at a predetermined angle with respect to the optical axis of the light emitting element. The image reading device according to claim 1.