JP3632921B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that reads an image recorded on a color film as electronic information.
[0002]
[Prior art]
FIG. 3 shows a conventional image reading apparatus of this type.
[0003]
As shown in FIG. 3, the conventional image reading apparatus 10 includes a halogen lamp 2, a dimming filter (including an ND filter) F (Fp for positive film and Fn for negative film), a film feeding device 3, and a lens 4. A beam splitter 12 on which a cold mirror 11 is formed, a first CCD line sensor 13, and a second CCD line sensor 14.
[0004]
The light from the halogen lamp 2 passes through the film P mounted on the film feeding device 3 through the dimming filter Fn or Fp, and is accompanied by image information on the film P (hereinafter referred to as “image light”). After passing through the lens 4, the cold mirror 11 provided on the beam splitter 12 distributes the light to the first CCD line sensor 13 for visible light and the second CCD line sensor 14 for infrared light and irradiates the image on the film P. Is converted to electronic data.
[0005]
The first CCD line sensor 13 is a color three-color CCD line sensor for visible light, and three CCD line sensors having spectral sensitivities corresponding to the colors of blue light, green light, and red light are arranged in parallel. The second CCD line sensor 14 is composed of a CCD line sensor for infrared light. The second CCD line sensor 14 may use one of the three CCD line sensors of the color three-color CCD line sensor for infrared light.
[0006]
When reading the image on the film P, the CCD line sensors 13 and 14 internally perform main scanning by electronic scanning, while the film feeding device 3 displaces the film P in the sub scanning direction to perform sub scanning. Reading the entire image.
[0007]
The electronic data obtained by the image reading apparatus 10 is taken into a memory and used in various modes such as being used as exposure data for photographic paper or being hard-copied by a printer.
[0008]
The cold mirror 11 is formed by laminating a high refractive index layer and a low refractive index layer on a transparent substrate to form an infrared ray transmitting film. As shown in FIG. 4, the cold mirror 11 normally transmits light having a wavelength of 800 nm or more. , And has a characteristic of reflecting light having a wavelength of less than 800 nm. In the image reading apparatus 10, the cold mirror 11 and each sensor are arranged so that visible light is distributed to the first CCD line sensor 13 and infrared light is distributed to the second CCD line sensor 14.
[0009]
Here, since the infrared light passes through the dye forming the image on the film P, but does not pass through the scratches and dust existing on the film P, the second CCD line sensor 14 obtains image data relating only to the scratches and dust. be able to.
[0010]
Then, by performing image processing between data including scratches and dust due to visible light obtained by the first CCD line sensor 13 and data including only scratches and dust due to infrared light obtained by the second CCD line sensor 14, Image defects caused by them can be removed.
[0011]
[Problems to be solved by the invention]
Here, the transmission wavelength characteristics of the negative positive film and the positive film used for reading by the image reading apparatus 10 are as shown in FIG. 5 (negative film) and FIG. 6 (positive film).
[0012]
As can be seen from these figures, there is a wavelength band that does not contribute to the composition of the color of the image between the wavelength bands of blue light, green light, red light, and infrared light. When the CCD line sensors 13 and 14 are irradiated, the color reproducibility of the image is deteriorated.
[0013]
Therefore, in the image reading apparatus 10, a dimming filter F that transmits light in the transmission wavelength bands of blue light, green light, red light, and infrared light is inserted between the lamp 2 and the film P, and unnecessary light is generated. Irradiation to each CCD line sensor is prevented.
[0014]
Here, comparing FIG. 5 with FIG. 6, it can be seen that the transmission wavelength bands of the red light and the negative film do not match.
[0015]
That is, the negative film has a transmission wavelength band of red light of 650 to 750 nm, whereas the positive film has a transmission wavelength band of red light of 630 to 750 nm, which includes the transmission wavelength band of the negative film. Distributed to the side.
[0016]
Therefore, it is necessary to set the red light transmission wavelength band of the light control filter F to 650 to 750 nm when reading a negative film image and to 630 to 750 nm when reading an image on a positive film.
[0017]
When the positive film dimming filter Fp is used to read a negative film image, light in the range of 630 to 650 nm is irradiated to the CCD line sensor 13 as noise, and the color reproducibility of the image is lowered.
[0018]
In addition, when a negative film dimming filter Fn is used for reading an image on a positive film, light in a range of 630 to 650 nm including necessary information is not irradiated to the CCD line sensor 13, and in this case as well, Color reproducibility decreases.
[0019]
Accordingly, in order not to deteriorate the color reproducibility of the image, it is necessary to selectively switch between the two types of dimming filters Fn and Fp according to the type of film. However, the dimming filters Fn and Fp have spectral characteristics. However, since high accuracy is required, it is expensive, and since a switching mechanism is also required, there is a problem that the manufacturing cost of the apparatus becomes high.
[0020]
The present invention solves the above-described conventional problems, and can perform image reading that can prevent a decrease in color reproducibility due to a difference in transmission wavelength characteristics of red light between a negative film and a positive film without switching a light control filter. An object is to provide an apparatus.
[0021]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a light source that emits at least light corresponding to a wavelength of a transmission wavelength band of a positive film having a transmission wavelength band of red light of 630 to 750 nm, a spectroscopic unit, and a first imaging device And an image reading device that irradiates each imaging device with the image light obtained by irradiating the film with the light of the light source via the spectroscopic means. transmission wavelength band of the red light to light having a wavelength less than the lower limit of the transparent over the wavelength range of the negative film is 650~750nm the first imaging device, the light of the lower limit or more wavelengths of said transmission wavelength band in the second imaging device is irradiated by distributing each case of reading an image of a negative film, while using only data obtained by the second imaging device for red light, when reading an image of a positive film, the red light Nitsu Te is characterized by using in addition processing the data obtained by both the imaging device.
[0022]
The wavelength band of the red light irradiated on the film by the image reading apparatus having the above configuration corresponds to the wavelength of the transmission wavelength band of the red light of the positive film. On the other hand, the red light transmission wavelength band of the negative film to be read is the same on the long wavelength side of the positive film red light transmission wavelength band, but on the short wavelength side the positive film red light transmission wavelength band is It spreads to the wavelength band side below the lower limit of the transmission wavelength band of the red light of the negative film.
[0023]
Therefore, when reading an image of a negative film, the red light applied to the spectroscopic means includes unnecessary light on the wavelength band side below the lower limit of the transmission wavelength band of the red light of the negative film. Since the light having a wavelength less than the lower limit of the transmission wavelength band of the red light of the negative film is distributed to the first imaging device and the light having a wavelength not less than the lower limit of the transmission wavelength band is distributed to the second imaging device, the first film is irradiated. The two imaging devices are irradiated only with light having a wavelength band necessary for constructing an image.
[0024]
On the other hand, when reading an image on a positive film, light in the red light wavelength band of image light does not contain light of an unnecessary wavelength, but the lower limit wavelength of the red light transmission wavelength band of the negative film is delimited by the spectroscopic means. In other words, the first imaging device and the second imaging device are allocated.
[0025]
That is, both of the imaging devices are separately irradiated with red light having a wavelength less than the lower limit wavelength and red light having a wavelength equal to or more than the lower limit wavelength. If the data obtained by these imaging devices are added, Complete data about red light can be obtained.
[0026]
In the present invention, as a light source that emits light corresponding to at least the wavelength of the transmission wavelength band of the positive film, a light source that emits white light such as a halogen lamp, and at least light having a wavelength of the transmission wavelength band of the positive film. In addition, a combination of filters having high transmittance, or a light source itself having a property of emitting light of at least the wavelength band can be used.
[0027]
Here, the transmission wavelength band of the red light of the negative film is 650 to 750 nm. Therefore, the lower limit of the red light transmission wavelength band of the negative film is 650 nm. That is, the light wavelength of less than 650nm in the spectroscopic means first imaging device, good results are obtained with respect to the color reproducibility by wavelength to the second imaging device to irradiate each of the above light 650nm.
[0028]
As described above, according to the image reading apparatus of the present invention, by changing the characteristics of the spectroscopic means, the filters of the negative film and the positive film are provided, and the red color of both films can be switched without selectively switching them. A decrease in color reproducibility due to a difference in light transmission wavelength characteristics can be prevented.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an image reading apparatus according to the present invention will be described below in detail with reference to the drawings.
[0030]
FIG. 1 is a diagram schematically showing an overall configuration of an image reading apparatus 1 according to an embodiment of the present invention.
[0031]
An image reading apparatus 10 according to the present embodiment includes a halogen lamp 2 and a positive film dimming filter Fp constituting a light source, a beam splitter 6 as a spectroscopic unit, a first CCD line sensor 7 as a first imaging device, and a second imaging device. The second CCD line sensor 8 is provided.
[0032]
The image reading apparatus 10 of the present embodiment further forms a film feeding device 3 that performs mechanical scanning with the film P mounted thereon, and forms an image on the film P on the first CCD line sensor 7 and the second CCD line sensor 8. A lens 4 is provided.
[0033]
The dimming filter Fp for positive film is a filter that transmits only blue light, green light, red light, and infrared light corresponding to the wavelength of the transmission wavelength band of the positive film. The film P is selectively irradiated with only light in the wavelength band of.
[0034]
The first CCD line sensor 7 is a color three-color CCD line sensor, and CCD line sensors having spectral sensitivities corresponding to blue light, green light, and red light are arranged in parallel and integrated.
[0035]
The second CCD line sensor 8 is composed of a CCD line sensor having spectral sensitivity corresponding to infrared light and red light, and these are integrated and arranged in parallel.
[0036]
The cold mirror 8 reflects light having a wavelength lower than 650 nm, which is the lower limit wavelength of the red light transmission wavelength band of the negative film, irradiates the first CCD line sensor 7, and transmits light having a wavelength of 650 nm or more to the second CCD line sensor 8. Irradiate.
[0037]
That is, light having a wavelength of less than 650 nm among blue light, green light, and red light is distributed to the first CCD line sensor 7, and light having a wavelength of 650 nm or more of red light is distributed to the second CCD line sensor 8. Irradiated.
[0038]
In reading the image on the film, the CCD line sensors 7 and 8 internally perform main scanning by electronic scanning, while the film feeding device 3 displaces the film P in the sub scanning direction to perform sub scanning. Reading the whole.
[0039]
When reading the image of the negative film with the image reading apparatus 1 of the present embodiment, the light having a wavelength of 650 nm or more, which is the red image light of the negative film, is irradiated to the second CCD line sensor 8 and simultaneously less than 650 nm which is unnecessary. Although the light is irradiated to the first CCD line sensor 7, only the data obtained by the second CCD line sensor 8 is used for red light in the subsequent data processing, so that the color reproducibility is not affected.
[0040]
In addition, when reading the image of the positive film, the wavelength band of the red light transmitted through the positive film is 630 to 750 nm. Therefore, the light having a wavelength of less than 650 nm among the red light is transmitted to the first CCD line sensor 7. However, in this case, the data from each sensor is added and processed as one piece of data relating to red light.
[0041]
As described above, according to the present embodiment, as the dimming filter F, only the dimming filter Fp that transmits only light corresponding to the wavelength of the transmission wavelength band of the positive film is used. Can be read with excellent color reproducibility.
[0042]
In addition, since the second CCD line sensor 8 is provided with a CCD line sensor having a spectral sensitivity corresponding to the wavelength of infrared light, image data relating only to scratches and dust caused by infrared light can be acquired. An image free from defects due to scratches and dust can be obtained by performing arithmetic processing with image data using visible light.
[0043]
【The invention's effect】
As described above, according to the image reading apparatus of the present invention, the image light is distributed and irradiated to the first CCD line sensor and the second CCD line sensor by the spectroscopic means with a specific wavelength as a boundary, and thus the dimming filter of the dimming filter is used. Without switching, it is possible to prevent a decrease in color reproducibility due to a difference in transmission wavelength characteristics of red light between a negative film and a positive film.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention.
FIG. 2 is a graph showing spectral transmittance characteristics of a cold mirror according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of a conventional image reading apparatus.
FIG. 4 is a graph showing spectral transmittance characteristics of a cold mirror of a conventional image reading apparatus.
FIG. 5 is a graph showing the spectral transmittance characteristics of a negative film.
FIG. 6 is a graph showing the spectral transmittance characteristics of a positive film.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image reader 2 Halogen lamp 6 Beam splitter 7 1st CCD line sensor 8 2nd CCD line sensor P Film

Claims (1)

A light source that emits at least light corresponding to a wavelength of a transmission wavelength band of a positive film having a transmission wavelength band of red light of 630 to 750 nm, a spectroscopic unit, a first imaging device, and a second imaging device, In the image reading device that irradiates each imaging device with the image light obtained by irradiating the film with the light of
The spectroscopic means, a light with a wavelength less than the lower limit of the transparent over the wavelength band of the negative film transmission wavelength band of the red light is 650~750nm the first imaging device, the lower limit of the transmission wavelength band in the second imaging device The light of the above wavelengths is distributed and irradiated ,
When reading a negative film image, only the data obtained by the second imaging device is used for red light,
An image reading apparatus characterized in that when reading an image on a positive film, the red light is used after adding data obtained by both imaging devices.

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