JPH09331460A - Image reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently read a color image in simple equipment configuration with high S/N up to high density by eliminating necessity to simultaneously read images with one wavelength while defining a maximum density area of 0 to 3.5 as a detection range. SOLUTION: The absorption density of Cyan color of an image is detected at a peak wavelength λC1 of spectral absorption distribution 94 of cyan coloring matter with a density area of 0 to 2 as the detection range. Next, the absorption density is detected at a wavelength λC2 out of the peak with a density area of 1 to 1.75 as the detection range. Then, when the absorption density detected with the density area of 1 to 1.75 as the detection range is doubled, the absorption density corresponding to the case of detecting it at the peak wavelength λC1 with the density area of 2 to 3.5 as the detection range is obtd. From this absorption density value and an absorption density value detected at the peak wavelength λC1 with the density area of 0 to 2 as the detection range, the density of cyan color of the image is found with a maximum density area of 0 to 3.5 as the detection range. Similarly, the absorption density of Magenta 92 and Yellow 90 is found.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading method, and more particularly to an image reading method for reading an image recorded on a document.

[0002]

2. Description of the Related Art Conventionally, as a light-sensitive material such as a color negative film or a color reversal film used for recording a color image, a blue-sensitive emulsion containing a yellow color-forming dye (coupler) that develops a yellow image, or a magenta color image is used. A structure in which three layers of a green-sensitive emulsion containing a magenta coloring dye (coupler) that develops color and a red-sensitive emulsion containing a cyan coloring dye (coupler) that develops a cyan image are coated on one support. Widely used.

Further, conventionally, as a method of reading a color image recorded on such a light-sensitive material, each color image is irradiated with light having a wavelength having a large absorption by cyan, magenta, and yellow coloring dyes. A method has been used in which the density of each color of a color image is obtained by detecting the amount of transmitted light and calculating the degree of absorption by each color-forming dye.

On the other hand, the spectral absorption characteristics of the above coloring dyes are as follows:
As shown in FIG. 1, it is not flat and has the property of varying depending on the wavelength of light, with the maximum density value being 3.5 at the peak wavelength for each color forming dye.

Therefore, in order to read a color image with good quality by the above method, the density of each color should be 3.0 or more, preferably the maximum density of 3.5, and the high S / N ratio (for example, the minimum). 60 decibels, preferably 70 decibels or more)
I had to ask.

However, conventionally, in order to obtain the density of each color of a color image up to a density of 3.0 or higher with a high S / N ratio, it is necessary to use expensive circuit parts and process the image over time. did not become.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and can efficiently read a color image up to a high density and a high S / N ratio with a simple device configuration. It is an object of the present invention to provide an image reading method that can be performed.

[0008]

FIG. 1 shows the spectral absorption characteristics of each color forming dye in a light-sensitive material such as a color negative film having a layer containing a color forming dye of each color of cyan, magenta and yellow. In this FIG. 1, the curve 9
0 indicates the spectral absorption characteristic of the yellow coloring pigment, curve 92 indicates the spectral absorption characteristic of the magenta coloring pigment, and curve 94 indicates the spectral absorption characteristic of the cyan coloring pigment.

Of these, the spectral absorption characteristics of the yellow coloring dye are shown in FIG. In FIG. 2, the peak wavelength range λ _Y1
, The concentration range is 0-3.5, but if it deviates from the wavelength range λ _{Y1 of} this peak, the concentration range changes like 0-2 or 0-1. Generally, the concentration range is almost similar. It can be regarded as changing.

That is, as shown in FIG. 2, the concentration range is 0 to 1.75 in the wavelength range λ _Y2 and is (1/2) times the concentration range (0 to 3.5) in the wavelength range λ _{Y1. Therefore} , the detected value of the concentration in the wavelength range λ _Y2 for the same image is the wavelength range λ _Y1
It is (1/2) times the detected value of the density at.

Thus, for example, for the concentration range (2 to 3.5) in the wavelength range λ _Y1 , the concentration detected in the concentration range (1 to 1.75) in the wavelength range λ _Y2 is doubled. , You can ask. That is, the density of an image in which a predetermined density range in the peak wavelength range λ _Y1 is set, for example, a density range of 2 to 3.5, is detected in a wavelength range λ _Y2 other than the wavelength range λ _Y1. You can

The above-mentioned density detecting method is not only for detecting the density of an image recorded on a light-sensitive material such as a color negative film having a layer containing coloring dyes of cyan, magenta and yellow, but also for ordinary recording paper and the like. The present invention can also be applied to density detection of an image recorded in.

In order to achieve the above object, the image reading method according to claim 1 is an image reading method for reading an image recorded on an original, which is within the absorption wavelength range of the coloring dyes of the respective colors of the original. The image of the original is read in two or more wavelength ranges that are different for each color in
It is characterized in that the density for each color of the image is obtained based on the reading result in one or more wavelength regions.

The image reading method according to a second aspect is the image reading method according to the first aspect, wherein at least one of the two or more different wavelength ranges is in a wavelength range near the peak and the other is from the peak range. It is characterized in that they are set in different wavelength ranges.

An image reading method according to a third aspect is an image reading method for reading an image recorded on a photosensitive material having layers each containing a coloring dye of each color of cyan, magenta and yellow. The density of each color of the image in the wavelength range near the peak in the spectral absorption distribution of the dye is detected as a detection range in the first density range of a predetermined density value or less, and in the wavelength range deviated from the peak of the image. The density of each color is detected as a detection range of a second density range corresponding to the density range of the predetermined density value or more, and the detection result for each color and the second density range of which the detection range is the first density range.
The density for each color of the image is obtained based on the detection result for each color in which the density range is as the detection range.

The image reading method according to claim 4 is the image reading method according to claim 2 or 3, wherein a wavelength range deviated from the peak in the spectral absorption distribution of one color-developing dye is the other color-developing color. It is characterized in that it is set outside the spectral absorption distribution range of the dye.

According to the image reading method of the fifth aspect,
The image reading method according to any one of claims 1 to 4, wherein the original document releases or diffuses at least a photosensitive silver halide, a binder, and a diffusible dye imagewise on a support. It is characterized in that it is composed of a photosensitive material containing at least three types of photosensitive layers that include a coloring material having a function and have different photosensitive wavelength regions and different hues after development of the coloring material.

Further, in the image reading method according to claim 6,
The image reading method according to any one of claims 1 to 4, wherein the original contains at least a photosensitive silver halide, a binder, and a dye-donating coupler on a support, and the photosensitive wavelength region thereof is included. And a dye formed from the dye-providing coupler, which is composed of a light-sensitive material having at least three types of light-sensitive layers having different hues.

In the image reading method according to the first aspect of the present invention, first, the image of the original is read in two or more wavelength ranges that are different for each color within the absorption wavelength range of the coloring dye of each color of the original.
Specifically, as in the invention according to claim 2, for example, as shown in FIG.
The image of the original is read in the wavelength range λ _C1 near the peak and in the wavelength range λ _C2 deviated from the peak in the absorption wavelength range of the cyan color-developing dye as shown in FIG.

Similarly, for other colors, the image of the original is read in the wavelength range λ _M1 near the peak and the wavelength range λ _M2 deviated from the peak in the absorption wavelength range of the magenta coloring dye shown in FIG. , The image of the original is read in the wavelength range λ _Y1 near the peak and in the wavelength range λ _Y2 deviated from the peak in the absorption wavelength range of the yellow coloring dye.

By the way, as described above, in the spectral absorption characteristics of the color-developing dye, if the wavelength shifts from the peak wavelength range, the density range changes like 0 to 2 or 0 to 1, but generally the density range is almost similar. Since it can be considered that it changes with the above, the reading result when the image of the original is read in two or more wavelength ranges (two wavelength ranges in the above example) different for each color as described above is the maximum density range in the peak wavelength range. It can be converted into a reading result of 0 to 3.5. That is, the density for each color of the image can be accurately obtained based on the reading results in the above two or more wavelength ranges converted into the reading results in the maximum density range 0 to 3.5.

According to the image reading method of the present invention, it is necessary to read the image (obtain the densities of the respective colors of the image) with the maximum density range 0 to 3.5 at a time in one wavelength range as in the conventional case. Since it is not necessary, it is not necessary to read the image over time using expensive and special circuit parts, and the image can be read efficiently with a simple device configuration.

According to the image reading method of claim 1,
It is not always necessary to include a wavelength range near the peak as two or more wavelength ranges that differ for each color.

However, as in the second aspect of the present invention, the maximum density range 0 to 3.5 is obtained by including the wavelength range near the peak where the density variation is large as the two or more wavelength ranges different for each color. It is possible to obtain a reading result in a density range equal to or close to, and the reading accuracy is improved.

In connection with the image reading method according to claim 1, more specifically, 2 for each color as described in claim 3.
An image reading method of reading a color image by obtaining the density in one wavelength range may be adopted.

First, the densities of the respective colors of the image are detected in the wavelength range near the peak in the spectral absorption distribution of the color forming dye, with the first density range below the predetermined density value (for example, density range 0 to 2) as the detection range. In addition, the density of each color of the image in the wavelength range deviated from the peak is detected with the second density range (for example, the density range 1 to 1.75) corresponding to the density range of the predetermined density value or more as the detection range. .

Then, the detection result (density) for each color of the image in the wavelength range deviated from the peak is converted into the detection result in the wavelength range near the peak. For example, the detection result in the concentration range (1 to 1.75) as the second concentration range is doubled to obtain the detection result in the concentration range (2 to 3.5) in the wavelength range near the peak.

Further, based on the converted detection result for each color and the detection result for each color with the detected first density range as the detection range, the density of the image with the maximum density range for each color as the detection range. Can be asked.

In the above, for example, when a device for detecting the density by quantizing the predetermined density range with 12 bits is used, the wavelength range λ
_C2 quantized with 12 bits concentration range 1 to 1.75 as detection range, assuming that the concentration range 0-2 in the wavelength range lambda _C1 and quantized with 12 bits as the detection range, the density of each color of the image, This means that the maximum density range 0 to 3.5 was quantized and quantized with 13 bits, and the maximum wavelength range 0 to 3.5 was set as the detection range in the peak wavelength range λ _C1 as before.
The density can be obtained with higher accuracy than the case where the density is obtained by quantizing with 2 bits.

As described above, the maximum density range 0 to 3.5 is divided into a plurality of parts, and the density of each color is obtained in the divided small detection range. Therefore, an image can be accurately formed with high resolution (that is, with a high S / N ratio). Can be read.

Here, in order to decompose the densities of 0 to 3.5 with 12 bits, the highest density portion is 3.5 and (3.5
X (1-1 / 4096)) is required to be electrolyzed, which corresponds to D = 3.5 for the peak level (concentration 0) of "0.00031623", D = (3.
"0.00031685" corresponding to 5 x (1-1 / 4096)
Means that we need to decompose between the signals of
An accuracy of "0.00000062" is required.

On the other hand, in order to decompose the densities 1 to 1.75 with 12 bits, D is applied to the peak level (density 1).
= 0.17783 corresponding to = 1.75, D = (1.75-
"0.17790" corresponding to (1.75-1) / 4096)
It is only necessary to be able to resolve between the signals of, and the accuracy of "0.000075" is sufficient.

That is, the circuit accuracy is reduced by about 120 times. As described above, in the image reading method according to the third aspect, the densities of the respective colors of the image in the wavelength range near the peak where the amount of density change is large correspond to the low-medium density range requiring high gradation resolution. Since the first concentration range is detected as the detection range, it is possible to accurately detect in the low to middle concentration range.

On the other hand, in the second density range corresponding to the density range equal to or higher than the predetermined density value, the density is detected in the wavelength range deviating from the peak, so that the detected density range is shifted to the middle density range. . Therefore, it is not necessary to use expensive and special circuit components for detection, and the concentration can be detected efficiently with a simple device configuration.

In the invention described in claim 2 or 3, the maximum value D ₁ of the concentration value in the wavelength region near the peak in the spectral absorption distribution and the concentration value in the wavelength region deviated from the peak The larger the deviation from the maximum value D ₂ is, the higher the concentration range can be shifted to and detected in the lower concentration range. Therefore, the concentration can be detected efficiently with a simple device configuration. Specifically, the maximum value D ₁ and the maximum value D
It is desirable to deviate from ₂ by 0.5 or more. Further, when the maximum value D ₁ and the maximum value D ₂ are deviated from each other by 1 or more, the above effect is further enhanced.

Further, in the invention described in claim 1 or 3, the spectral absorption distribution of each color forming dye of the document on which the image is recorded has a peak wavelength range (for example, wavelength range λ _{Y1 in} FIG. 2).
Although it was considered that the density range would change in a similar manner when deviated from the deviation, depending on the document, the density range may not necessarily change in a similar manner when deviated from the peak wavelength range.

For such an original, information on the spectral absorption characteristics as shown in the diagram of FIG. 1 is stored in advance in a lookup table (LUT) or the like, and the information on the spectral absorption characteristics is referred to. The concentration in the wavelength range of the peak as described above can be converted into the detection result.

By the way, as shown in FIG. 1, in the spectral absorption characteristics of cyan, magenta, and yellow coloring dyes in the light-sensitive material, wavelength regions absorbed by a plurality of coloring dyes (wavelength regions Q1 and Q2 in FIG. 1). Exists. When obtaining the density of one color forming dye in this wavelength range, it is necessary to make a correction so as to exclude the amount absorbed by another color forming dye which is not the target color forming dye.

Therefore, as in the invention described in claim 4, by setting the wavelength range deviated from the peak in the spectral absorption distribution of one coloring dye to be outside the spectral absorption distribution range of the other coloring dye, As described above, it is not necessary to perform correction so as to remove the amount absorbed by another color-forming dye that is not the target color-forming dye, and the processing load can be reduced and the processing can be performed efficiently.

By the way, in the above-mentioned original, as described in claim 5, at least a photosensitive silver halide, a binder, and a coloring material having a function of releasing or diffusing a diffusible dye in an image form are provided on a support. The photosensitive material may include at least three types of photosensitive layers having different photosensitive wavelength regions and different hues after development processing of the color material.

When the photothermographic material containing a colorant as described above (hereinafter referred to as a colorant-containing photothermographic material) is used, for example, the image is exposed to the colorant-containing photothermographic material, The exposed color material-containing photothermographic material and the processing member having a layer containing at least a mordant on the support are superposed, and the superposed color material-containing photothermographic material and the processing member are heated and heated. By removing a part or all of the diffusible dye emitted from the photothermographic material containing a colorant,
An image of at least three colors can be formed on the color material-containing photothermographic material.

Further, as described in claim 6, the above-mentioned manuscript contains at least a photosensitive silver halide, a binder, and a dye-donor coupler on a support, and the light-sensitive wavelength region thereof and the dye-donor coupler. It can be composed of a light-sensitive material having at least three types of light-sensitive layers having different hues of the dye formed from.

Photothermographic material containing a coupler as described above (hereinafter referred to as coupler-containing photothermographic material)
In the case of using, for example, an image is exposed on the coupler-containing photothermographic material, and the coupler-containing photothermographic material is heated by superposing the exposed coupler-containing photothermographic material and the coupler-containing photothermographic material. By superimposing a heat-development processing member used for forming an image on the light-sensitive material and heating the combined coupler-containing heat-development light-sensitive material and heat-development processing member, a dye-donating coupler is used. At least three color images can be formed on the coupler-containing photothermographic material.

By the way, FIG. 8B shows the density-exposure amount characteristics of the above color material-containing photothermographic material and coupler-containing photothermographic material. The density-exposure amount characteristic of FIG. 8 (B) is similar to the density-exposure amount characteristic of the conventional negative film shown in FIG.
The concentration due to the remaining unexposed silver halide crystals and the concentration due to silver generated by exposure or light emission are superposed. That is, since the density range is considerably wider than that of the conventional negative film, it is necessary to read high density with good accuracy.

When reading an image recorded on such a color material-containing photothermographic material and a coupler-containing photothermographic material, as in the image reading method of the present invention, the density range of each object is adjusted at a plurality of wavelengths. Set and read the image.

FIG. 9 shows cyan, magenta, and cyan in a photothermographic material containing a color material or a photothermographic material containing a coupler.
The spectral absorption characteristics of each yellow coloring dye are shown. The density in this spectral absorption characteristic is composed of three elements, that is, the density due to the remaining unexposed silver halide crystals, the density due to silver generated by exposure or light emission, and the density due to the coloring dye. Is almost constant regardless of wavelength. In the spectral absorption characteristics of the cyan, magenta, and yellow coloring dyes, the wavelengths λ _C1 and λ _C2 are for cyan, the wavelengths λ _M1 and λ _M2 are for magenta, and the wavelength λ is for yellow. _It suffices to read _Y1 and wavelength λ _Y2 respectively.

Accordingly, when the image recorded on the color material-containing photothermographic material according to claim 5 or the coupler-containing photothermographic material according to claim 6 is read, the image reading method of the present invention is applied. Thus, it is possible to read a wide range of density, particularly high density with good accuracy. That is, the effect of improving the image reading accuracy according to the present invention is remarkable.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, referring to the drawings, an example in which an image (frame image) recorded on each frame of a developed film is read by an image reading method of the present invention as an embodiment of the present invention explain. First, the configuration of the image reading apparatus 10 that executes the image reading method of the present invention will be described with reference to FIGS. 3 and 4.

As shown in FIG. 3, in the image reading device 10, one frame image of the film N set at a predetermined reading position is read along a predetermined main scanning direction (direction of arrow U in FIG. 3). An optical scanning unit 38 that scans the beam is installed.

As shown in FIG. 4, the optical scanning unit 38 includes a semiconductor laser 258C as a light source for detecting the density of a cyan coloring dye, a semiconductor laser 258M as a light source for detecting the density of a magenta coloring dye, and a yellow coloring. A semiconductor laser 258Y is arranged as a light source for detecting the dye concentration.

These semiconductor lasers 258C, 258M,
A control unit 100 for controlling the wavelength and the light intensity of the light beam emitted from each semiconductor laser is connected to each of the 258Y. The control unit 100 includes a microcomputer (not shown), and executes a control routine for frame image reading processing, which will be described later.

On the other hand, these semiconductor lasers 258C, 25
8M, 258Y, each semiconductor laser 25
8C, 258M, and 258Y are provided with collimator lenses 260 for converting the light beams emitted from the diffused light beams into parallel light beams, respectively. Collimator lens 2
Each light beam that has become a parallel light beam at 60 enters a reflection mirror 262 via a cylindrical lens group 263 and a light amount adjustment filter 261, is reflected by the reflection mirror 262, and is reflected by a reflection surface 268 of a polygon mirror 264 which is a polygon mirror.
Focus on top. Note that the cylindrical lens 263 has a role of shaping the light beam in the sub-scanning direction.

The polygon mirror 264 is connected to the reflecting surface 2.
68, and rotates at high speed around a shaft 266 by a driving force from a motor (not shown).
(Rotation) to continuously change and deflect the angle of incidence of the light beam on each reflection surface 268. That is, the polygon mirror 264 deflects the respective light beams and scans them along the main scanning direction (direction of arrow U in FIG. 3).

In the traveling direction of the light beam deflected by the polygon mirror 264, the optical point is optically moved so that the image formation point on the film N in FIG. 3 by the deflected light beam moves at a constant speed along the main scanning direction. Fθ lens system 27
0 is set. The fθ lens system 270 is composed of lenses 271, 273 and 275.

A cylindrical lens 269 and a cylindrical mirror 272 are sequentially installed in the traveling direction of the light beam transmitted through the fθ lens system 270, and the reflection mirror 274 is disposed in the traveling direction of the light beam reflected by the cylindrical mirror 272. Is installed. The reflection mirror 274 is inclined at a predetermined angle so that the light beam reflected on the surface is reflected substantially vertically downward.

On the side of the reflection mirror 274, the SOS (Star
t Of Scan) A mirror 277 is provided, and the light beam reflected by the polygon mirror 264 is irradiated first. The SOS mirror 277 reflects an initially irradiated light beam (a light beam corresponding to the vicinity of the main scanning start point) and enters the SOS sensor 276. The SOS sensor 276 is connected to the SOS mirror 27
When a light beam is incident from the light source 7, a predetermined signal is output, and the output signal is input to the control unit 100 and the control unit 10
0 indicates SOS.

As shown in FIG. 3, the reading position of the film N is provided in the emission direction of the light beam from the optical scanning unit 38. The film N is transported by a transport roller (not shown) in a sub-scanning direction perpendicular to the main scanning direction of the arrow U (front side of the paper surface of FIG. 3). The transport operation of this film N is
It is controlled by the control unit 100.

A CCD line sensor 12 is installed below the reading position of the film N, and the CCD line sensor 12 detects the light amount of the transmitted light which is emitted from the optical scanning unit 38 and transmitted through the frame image of the film N. To do. The output ends of the CCD line sensor 12 are connected to the amplifiers 14 and 16, respectively, and the output ends of the amplifiers 14 and 16 are
It is connected to the multiplexer 18. The output terminal of the multiplexer 18 is an analog-digital converter (hereinafter referred to as A /
A digital signal output from the A / D converter 20 is input to the control unit 100.

That is, after the analog signal corresponding to the amount of transmitted light detected by the CCD line sensor 12 is amplified by the amplifier 14 or the amplifier 16, it is converted into a digital signal by the A / D converter 20 and input to the controller 100. To be done.

By the way, since the light beam emitted from the light scanning unit 38 is scanned in the main scanning direction and the film N is conveyed in the sub scanning direction, the frame image of the film N is scanned by the light beam. Will be.

As described above, the CCD line sensor 12 detects the amount of light transmitted through the frame image, so that the control unit 100 can obtain the absorption density of the light beam by the frame image.

For example, by irradiating a coma image with a light beam having a peak wavelength in the spectral absorption distribution of the cyan coloring dye, the light beam is absorbed by the cyan coloring dye in accordance with the cyan color density at the irradiation point of the coma image, The amount of light that is not absorbed is detected by the CCD line sensor 12. That is, according to the amount of light detected by the CCD line sensor 12 (the amount of light that has not been absorbed),
The control unit 100 can determine the absorption density of the cyan color-developing dye at the irradiation point, and further can determine the cyan color density at the irradiation point of the frame image by the absorption density.

Further, the control unit 100 can similarly obtain the absorption densities of the magenta and yellow colors at the irradiation point of the frame image, and the colors of the irradiation point are determined based on the absorption densities of the three colors at the irradiation point. You can ask. Then, by scanning the entire frame image and obtaining the color of each pixel based on the absorption densities of the three colors as described above,
The frame image can be read.

As shown in FIG. 3, the control unit 100 has a magnetic disk device 102 for storing the absorption densities of the three colors obtained as described above, and an operator starts / stops various processes. An operation unit 103 including a keyboard, buttons, and the like (not shown) for issuing operation instructions such as is connected.

Next, the operation of the present embodiment will be described. After the operator sets the head of the target film N at a predetermined position and then instructs the start of the frame image reading process by the operation unit 103, the control unit 100 starts executing the control routine shown in FIG.

At step 122 in FIG. 5, the film N is conveyed and driven, and the polygon 264 in the optical scanning unit 38 is rotationally driven. As a result, the film N is conveyed in the sub-scanning direction (front side of the paper surface of FIG. 3). In the next step 124, it is monitored whether or not the first frame of the film N reaches the reading position. When the first frame reaches the reading position, the process proceeds to step 126 to stop the transport of the film N, and Position the frame at the reading position.

At the next step 128, a subroutine (see FIG. 6) for reading the cyan color component of the image recorded on the first frame thus positioned is executed. In step 152 of FIG. 6, a light source (here, a semiconductor laser 258
C) is set to the peak wavelength λ _C1 in the spectral absorption distribution of the cyan coloring dye in FIG. 1, and in the next step 154, the semiconductor laser 258C irradiates the frame image of the film N with light of the peak wavelength λ _C1. To do. This peak wavelength λ
The light of _C1 is deflected by the rotating polygon 264 to be scanned in the main scanning direction indicated by the arrow U in FIG.

In step 154, the film N is conveyed at a predetermined speed in the sub scanning direction. As a result, the frame image of the first frame thus positioned is scanned with the light having the peak wavelength λ _C1 .

The light having the peak wavelength λ _C1 for scanning the frame image of the first frame was absorbed by the layer containing the cyan coloring dye of the film N and not absorbed by the amount of light corresponding to the cyan color density of the frame image. The minute light amount is detected by the CCD line sensor 12. In the next step 156, the density range 0 to 2 as a predetermined low density range is quantized as a detection range with a predetermined bit (12 bits as an example),
The cyan color density is obtained based on the detected value of the amount of transmitted light of the frame image by the CCD line sensor 12.

The cyan color density based on the detected value of the transmitted light amount of the frame image is executed for the entire frame image (step 158). When the reading (detection of cyan color density) in the density range of 0 to 2 is completed for the entire frame image, the process proceeds to step 160.
The conveyance of the film N is stopped, and the film N is returned to the leading position of the frame (here, the first frame).

In the next step 162, the wavelength of the light source (here, the semiconductor laser 258C) is set to the wavelength λ _C2 deviated from the peak in the spectral characteristic of the cyan coloring dye in FIG. 1, and in the next step 164, the semiconductor laser 258C is used. Light of the above wavelength λ _C2 is irradiated toward the frame image of the film N, and scanning is performed in the main scanning direction indicated by an arrow U in FIG. Also,
In step 164, the film N is conveyed at a predetermined speed in the sub scanning direction. As a result, the frame image of the first frame is scanned with the light of wavelength λ _C2 .

The light of the above wavelength λ _C2 for scanning the frame image of the first frame was absorbed by the layer containing the cyan coloring dye of the film N and not absorbed by the amount of light corresponding to the cyan color density of the frame image. CCD line sensor 1
Detected by 2. In the next step 166, the density range 1 to 1.75 as a predetermined high density range is quantized as a detection range with a predetermined bit (12 bits as an example), and the CCD line sensor 12 detects the transmitted light amount of the frame image. Determine the cyan color density based on the value.

The cyan color density based on the detection value of the transmitted light amount of the frame image is executed for the entire frame image (step 168). When the reading (cyan color density detection) with the density range 1 to 1.75 as the detection range is completed for the entire frame image, step 170
Then, the film N is stopped to be returned to the leading position of the frame (here, the first frame).

Then, in the next step 172, the detection result of the cyan color density with the detection range of 1 to 1.75 in the entire frame image is doubled to set the density range of 2 to 3.5 as the detection range. Converted to the cyan color density. Further, the density of the target color component (here, the cyan color component) in each pixel of the frame image is obtained based on the converted cyan color density and the detection result of the cyan color density with the density range 0 to 2 as the detection range. . The density of the cyan color component was obtained by dividing the density range 0 to 3.5 into two as described above and quantizing each density range with 12 bits, so that the density range 0 to 3. This is equivalent to quantizing 5 with 13 bits and accurately obtaining the density of the cyan color component with high resolution.

Further, in step 172, the density of the target color component (here, the cyan color component) in each pixel of the obtained frame image is stored in the magnetic disk device 102,
The process returns to the main routine of FIG.

In the next step 130 in FIG. 5, the same reading process as above is executed for the magenta color component,
The density of the magenta color component in each pixel of the frame image obtained as the processing result is stored in the magnetic disk device 102. In the next step 132, the reading process similar to the above is executed for the yellow color component, and the density of the yellow color component in each pixel of the frame image obtained as the processing result is stored in the magnetic disk device 102.

By the processing of steps 128 to 132, the densities of the respective color components of cyan, magenta and yellow in each pixel of the first frame image can be obtained and stored in the magnetic disk device 102.

At the next step 134, it is judged whether or not the reading process is completed for all the frames of the film N, and the process proceeds to step 136 until the reading process is completed for all the frames, and the next frame is changed. The film N is conveyed and driven to be positioned at the reading position, and then step 12
Return to 4.

Thereafter, the frames of the film N are set one by one at the reading position, and the reading process for each color component in steps 128 to 132 is executed for the frame image. As a result, the reading result for each color component of each frame image of the film N, that is, the density information (digital data) of each color component of cyan, magenta, and yellow in each pixel of the frame image is stored in the magnetic disk device 102. Go.

When the reading process is completed for all the frames, an affirmative decision is made in step 134 and the control routine is ended.

By the above reading process, each frame image of the film N is read for each color component, and the reading result is stored in the magnetic disk device 102. By reading the density information of each color component in each pixel of the frame image from the magnetic disk device 102, and reproducing and superimposing the three-color component density of each pixel of the frame image based on the information,
The frame image of the original film N can be accurately reproduced.

According to the present embodiment described above, since it is not necessary to read the frame image with the maximum density range 0 to 3.5 as the detection range at a time, it takes time to read using expensive and special circuit parts. There is no need, and frame images can be efficiently read with a simple device configuration.

Further, as in the conventional case, light having a peak wavelength of one color-developing dye (for example, the peak wavelength λ _C1 of the cyan color-developing dye) is quantized in 12 bits with the entire density range of 0 to 3.5 as the detection range, and the density is quantized. In this embodiment, the density is determined by dividing the density range 0 to 3.5 as described above by using each density range as the detection range and quantizing the same with 12 bits to obtain the density. It is possible to accurately obtain the density.

Further, in the present embodiment, as is clear from the diagram of FIG. 1, the wavelength λ _C2 deviated from the peak in the spectral absorption characteristic of the cyan color-developing dye is set to the magenta and yellow color-developing dyes other than the cyan color-developing dye. The wavelength is set outside the spectral absorption distribution range of. Similarly, for wavelengths λ _{M2 that} deviate from the peak in the spectral absorption characteristics of magenta coloring dye and wavelengths λ _Y2 that deviate from the peak in the spectral absorption characteristics of yellow coloring dye, wavelengths outside the spectral absorption distribution range of other coloring dyes It is set. As a result, it is not necessary to correct the amount of light absorbed by the other coloring pigment other than the target coloring pigment, and the reading processing load can be reduced and the reading processing can be performed efficiently.

As means for changing the wavelength from the wavelength λ _C1 to the wavelength λ _C2 in this embodiment, the temperature of the semiconductor laser may be changed, or separate semiconductor lasers having different wavelengths (not shown) are provided for each of the three colors. May be. That is, a total of 6 laser beams each having a wavelength λ _C1, a laser beam having a wavelength λ _C2, a laser beam having a wavelength λ _M1, a laser beam having a wavelength λ _M2, a laser beam having a wavelength λ _{Y1, and} a laser beam having a wavelength λ _Y2 are emitted. A semiconductor laser of a table may be provided.

Alternatively, a white light source and six filters may be provided, and white light may be decomposed by each filter to obtain light of six wavelengths.

Depending on the light-sensitive material, it may be difficult to set the wavelength deviated from the peak in the spectral absorption characteristic of one color forming dye to a wavelength outside the spectral absorption distribution range of another color forming dye. In such a case, the information on the spectral absorption characteristics as shown in the diagram of FIG. 1 is stored in advance in a look-up table (LUT) or the like, and the information on the spectral absorption characteristics is referred to. It suffices to obtain a rate at which light is absorbed by another color-forming dye that is not a color-forming dye, and perform a correction such as subtracting the ratio.

Further, the photosensitive material such as the film N deteriorates with the passage of time, and the semiconductor lasers 258C, 2C of the optical scanning unit 38, 2
Since the performances of 58M and 258Y are also deteriorated, the spectral absorption characteristics of light having a peak wavelength and the spectral absorption characteristics of light having a wavelength deviated from the peak in the image reading device 10 are corrected before or periodically. Is desirable.

For example, using a reference negative film on which reference patterns of cyan, magenta, and yellow having predetermined densities are recorded, a low density region is detected by light having a peak wavelength with respect to the reference pattern of each color. As the range, the high-concentration region is detected with light having a wavelength deviated from the peak, the absorption concentration is detected, respectively, and the spectral absorption characteristics with light having a peak wavelength and light having a wavelength deviated from the peak are detected based on the detection result. The spectral absorption characteristics of may be corrected.

In the above correction, if the detection range for the light of the peak wavelength and the detection range for the light of the wavelength deviated from the peak are overlapped, it is more accurate in the overlapped range. It is desirable because it can be corrected.

By the way, in the above-mentioned embodiment, each coloring pigment is used.
At the peak wavelength in the spectral absorption distribution of
The maximum concentration range (0 to 3.5) by 2
An example of reading processing by dividing is shown, but three or more wavelengths are used.
The reading process is performed by dividing the maximum density range into many by the light of
May be. For example, the spectrum of the yellow coloring dye shown in FIG.
In characteristics, peak wavelength λ_Y1The low concentration range (0 to
1.5) is the wavelength λ deviated from the peak_Y2Light in the medium concentration range
(1.5 to 2.5) is a wavelength λ deviated from the peak _Y3Light of
The high concentration range (2.5-3.5) is the detection range.
Then, the reading process may be performed.

Further, in the above-mentioned embodiment, the reading process for each frame image recorded on the film N as a color negative film has been described, but the image reading method of the present invention uses the cyan, magenta and yellow colors. The present invention can also be applied to reading processing of images recorded on other photosensitive materials such as a reversal film as a photosensitive material having a layer containing a color forming dye, or a recording sheet.

Further, the present invention can be applied not only to the field of photography but also to various fields of reading a high density image in which the spectral characteristic is not flat.

By the way, the film N contains at least a photosensitive silver halide, a binder, and a coloring material having a function of releasing or diffusing a diffusible dye in an image form on a support, and the photosensitive wavelength region and the color A photosensitive material (color material-containing photothermographic material) having at least three types of photosensitive layers having different hues after development processing of the material can be used.

Further, as the film N, at least a photosensitive silver halide, a binder, and a dye-donating coupler are contained on a support, and the light-sensitive wavelength region thereof and the hue of the dye formed from the dye-donating coupler are mutually A photosensitive material having at least three different photosensitive layers (coupler-containing photothermographic material) can also be used.

As described above, the density-exposure amount characteristics (see FIG. 8B) of the above two kinds of photosensitive materials have a considerably wide density range as compared with the conventional negative film.
It is necessary to read high concentrations with good accuracy. Therefore, when reading an image recorded on these photosensitive materials,
In the spectral absorption characteristics of each of the cyan, magenta, and yellow coloring dyes shown in, the wavelength λ _C1 and the wavelength λ _C2 for the cyan color, the wavelength λ _M1 and the wavelength λ _M2 for the magenta color,
For yellow color, the wavelength λ _Y1 and the wavelength λ _Y2 are controlled to be read.

As a result, a wide range of densities, particularly high densities, can be read with good accuracy, and the effect of improving the image reading accuracy according to the present embodiment is remarkable.

In the above embodiment, an example of a light-sensitive material in which silver halide and developed silver remain is shown. However, even when reading after removing one or both of them by a treatment such as bleaching, good high density is obtained. It can be read with excellent image quality.

[0099]

As described above, according to the present invention,
Since it is not necessary to read the image (obtain the density of each color of the image) with the maximum density range 0 to 3.5 at one wavelength range at a time, it takes time to use the image with expensive and special circuit parts. The effect that the image can be efficiently read with a simple device configuration is eliminated.

Further, by dividing the maximum density range 0 to 3.5 into a plurality of parts and determining the density of each color in the divided small detection range, the resolution is high and the accuracy is high (that is, the S / N ratio is high).
The effect that the image can be read is also obtained.

In particular, according to the invention described in claim 4, it is not necessary to make a correction so as to remove the amount absorbed by another color-forming dye which is not the target color-forming dye, and the processing load is reduced and the process is efficiently performed. The effect that can be performed is obtained.

When the image recorded on the color material-containing photothermographic material according to claim 5 or the coupler-containing photothermographic material according to claim 6 is read, the image reading method of the present invention is applied. In addition, it is possible to obtain the effect that the density in a wide range, especially the high density can be read with good accuracy. In this case, the effect of improving the image reading accuracy according to the present invention is remarkable.

[Brief description of drawings]

FIG. 1 is a diagram showing spectral absorption characteristics of cyan, magenta, and yellow coloring dyes.

FIG. 2 is a diagram showing that the density range changes in a similar manner in the spectral absorption characteristics of the yellow coloring dye.

FIG. 3 is a block diagram showing a schematic configuration of an image reading apparatus according to the present embodiment.

FIG. 4 is a schematic configuration diagram of an optical scanning unit.

FIG. 5 is a flow chart showing a control routine of a negative film frame image reading process executed by a control unit.

FIG. 6 is a flowchart showing a subroutine of reading processing of each color component.

FIG. 7 is a diagram showing an example of density region division when the reading process is performed by dividing the maximum density region into three by light of three wavelengths.

FIG. 8A is a graph showing density-exposure amount characteristics of a conventional negative film, and FIG. 8B shows density-exposure amount characteristics of a color material-containing photothermographic material or a coupler-containing photothermographic material. It is a graph.

FIG. 9 is a diagram showing spectral absorption characteristics of cyan, magenta, and yellow coloring dyes in a color material-containing photothermographic material or a coupler-containing photothermographic material.

[Explanation of symbols]

 10 image reading device 12 CCD line sensor 38 optical scanning unit 100 control unit N film (photosensitive material)

Claims (6)

[Claims] 1. An image reading method for reading an image recorded on a document, wherein the image of the document is read in two or more wavelength regions different for each color within an absorption wavelength region of a coloring dye of each color of the document, An image reading method, wherein the density of each color of the image is obtained based on the reading result in two or more different wavelength bands for each color. 2. The method according to claim 1, wherein at least one of the two or more different wavelength ranges is set to a wavelength range near the peak and the other is set to a wavelength range deviated from the peak. Image reading method. 3. An image reading method for reading an image recorded on a light-sensitive material having layers each containing a coloring dye of each color of cyan, magenta and yellow, wherein the wavelength near the peak in the spectral absorption distribution of the coloring dye. The density for each color of the image in the region
And the density for each color of the image in the wavelength range deviated from the peak, and the second density range corresponding to the density range of the predetermined density value or more is detected as the detection range. Determining the density of each color of the image based on the detection result of each color having the first density range as the detection range and the detection result of each color having the second density range as the detection range. Characteristic image reading method. 4. The wavelength range deviated from the peak in the spectral absorption distribution of one coloring dye is set outside the spectral absorption distribution range of another coloring dye. The image reading method described in. 5. The original includes, on a support, at least a photosensitive silver halide, a binder, and a coloring material having a function of releasing or diffusing a diffusible dye in an image form, and the photosensitive wavelength region and the coloring material. 5. The image reading method according to claim 1, wherein the image reading method is composed of a photosensitive material having at least three types of photosensitive layers having different hues after the development processing. 6. The original contains at least a photosensitive silver halide, a binder, and a dye-donor coupler on a support, and the light-sensitive wavelength region thereof and the hues of dyes formed from the dye-donor coupler are mutually different. The image reading method according to any one of claims 1 to 4, wherein the image reading method is composed of a photosensitive material having at least three different types of photosensitive layers.