JPS63296470A - Color image reader - Google Patents

Abstract

PURPOSE:To easily and properly execute a correction conforming to the kind of the color negative film of a reading image by using a color filter for a shading correction. CONSTITUTION:Storing means 106-108 to respectively store an output decomposed to the three primary colors of R.G.B. when a color filter is projected and image-formed and arithmetic means 105 and 111 to calculate an output read from the storing means, a correcting coefficient conformed to the kind of a color negative film and an output to read the image of a color negative film original are equipped. Thus, an output value from the R.G.B. color decomposing sensor of the color filter is conformed to the kind of the negative film, calculated and corrected and the output value of the R.G.B. color decomposing sensor of the image to be read can be properly corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image reading device, and is particularly intended to improve the image quality of a copied image when reading an image from a color negative film.

[Prior Art] Color negative film has a brownish color even when unexposed, and the subject image develops color on it. Conventionally, in a color image reading device, the color of the above-mentioned unexposed color negative film is determined from the output values of a color separation sensor for the three primary colors R (red), G (green), and B (blue) corresponding to the projected image to be read. In order to eliminate this, there was a device that was configured to project an unexposed area of a color negative film of the same type as the image to be read, store the output values of this R, G, and 8 color separation sensor, and perform calculations and corrections. .

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, (1) in addition to the image to be read, it is necessary to prepare at least one unexposed portion of the same type of color negative film.

(2) If an unexposed portion of the same color negative film as the color negative film of the read image is used for a long period of time and projection is repeated, the color will fade, making it impossible to obtain proper correction data.

There was a drawback.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a color image reading device that can eliminate the above-mentioned conventional drawbacks and easily and correctly correct the read image in accordance with the type of color negative film.

[Means for Solving the Problems] In order to achieve such an object, the present invention includes a color image reading device equipped with a color filter,
When this color filter is projected, the R, G, and 8-color separation sensor output values are the R, G of the unexposed portion of the color negative film of the same type as the image to be read.

Multiply the coefficient corresponding to each film type so that it is equal to the 8-color separation sensor output value, and use that value as the R of the image to be read.
It is used to correct the output values of the GB color separation sensor.

That is, in the present invention, a color negative film original is projected and a formed image is scanned, and an R (red) image is scanned.

When an image is formed by projecting a color filter on a color image reading device that separates and reads the three primary colors of G (green) and B (blue), converts them into R, G, and B digital data, and outputs them. storage means for storing the output separated into the three primary colors of R, G, and B over one scanning line, the output read from the storage means, the correction coefficient according to the type of color negative film, and the image of the color negative film original. It is characterized by comprising a calculation means for calculating the read output.

[Function] According to the present invention, the output values from the R, G, and B color separation sensors of the color filter can be calculated and calibrated according to the type of negative film, and the output values of the RG8 color separation sensor of the image to be read can be calibrated. Output values can be corrected correctly.

[Example code] The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Further, FIG. 2 is an arrangement diagram showing an example of a three primary color R, G, B color separation filter.

In FIG. 1, 101 is a CCD line sensor for image input, and as shown in FIG. 2, three primary colors R, G, and eight color separation filters are applied to each pixel and arranged in a line.

102.102R, 102G and 102B are sample and hold circuits, 103R, 103G and 103[1 are A/D converters, 104R, 104G and 104B are selectors, 105 is a multiplier, 106.107 and 108
is line memory.

109 is a logarithmic conversion table circuit 110 is a color processing circuit;
11 is an MPU.

Image signals manually input from the CCD line sensor 101 are sent to sample and hold circuits 102j02R, 102G and 1.
02B, A/D converter 103Rj03G and 103
The color B is separated into the three primary colors R, G, and B and converted into digital signals for each, resulting in a time series signal for one line.

Line memories 106 to lO8 are CCD line sensors 10
In order to correct for the sensitivity variations in 1 and the light intensity unevenness of the document illumination light source, one line of R,
Each of G and B data (hereinafter referred to as shading data) is stored for each pixel, and is constituted by a RAM (hereinafter referred to as shading RAM).

The selector 104 sends the digital signals from the A/D converters 103R, 103G, and 103B to the multiplier 105 when they are image signals, and to the line memories 106 to 108 when they are shading data signals to the A/D converter 103R.
, 103G and 103B. The switching signal for this purpose is supplied from the MPU III, and the CCD
Data for one line of the line sensor 101 is written.

The multiplier 105 performs calculations between the image signal and the shading data, and corrects the output fluctuation of the image signal in the CCO main scanning direction and corrects the R, G, and B white balance. The logarithmic conversion table circuit i09 logarithmically converts the image signal corrected by the multiplier 105 described above and converts it into density signals Y (yellow), 1M (magenta), and C (cyan). The color processing circuit 11.0 performs masking correction, inking, and IJC on the Y, M, and C signals output from the logarithmic conversion table circuit 109.
Well-known color processing such as R is applied to generate Y, M, C and (black) signals to an image output device such as a laser printer.

MPlllll can directly access the shading RAM of the line memories 108 to 108,
The algorithm described later is executed to correct the shading data.

FIG. 3 is a layout diagram showing the configuration of an example of color image reading.

In FIG. 3, reference numeral 301 denotes a glass plate for placing an original on which a reflected original image is usually placed.

302 is a focusing rod lens array (for example, 5elfo
c'lens array), and a CCD that captures the original image, which will be described later.
An image is formed on a photoelectric conversion element array such as an array. 30
3 is an infrared light filter that blocks unnecessary infrared light.

304 is the CCD array mentioned above.

A projector lamp 305 illuminates a transparent original such as a negative film or a color filter. Reference numeral 306 is a transparent original, which is a color film, color filter, etc. to be read. A color correction filter 307 corrects color balance. Reference numeral 308 denotes a lens, which forms an image of the original onto the original table glass 301 . 309 is a mirror for bending the optical path, 310 is a Fresnel lens, and lens 3
The light beam diverging from 08 is bent and converted into a parallel light beam. 311 and 312 are convergent rod lens arrays 3;
02, infrared light filter 303 and CCD array 304
This shows the moving position of the CCD unit consisting of.

Actually, the shading data is imported as follows. That is, a color filter is set on the transparent original 306, the lamp 305 is turned on, the color filter is projected onto the original platen glass 301, and the CCD unit that is normally at the position 311 is moved to the position 312.
Data for one line of the line sensor consisting of the CD array 304 is stored in the line memories 106 to 106 in the embodiment shown in the first figure.
108.

FIG. 4 is a layout diagram showing the configuration of another embodiment for color image reading.

In FIG. 4, 401 is a projector lamp that illuminates a transparent original. A transparent original 402 is a color negative film, a color filter, or the like to be read. 403
is a color correction filter that corrects color balance.

, 404 is a focusing rod lens array, which forms an image on the CCD array 406.

405 is an infrared light cut filter.

In the embodiment shown in FIG. 4, shading data is captured by directly imaging the color filter of a transparent original 402 illuminated by a projector lamp 401 onto a CCD array 406 by a focusing rod lens array 404, and The shading data is read in the line memories 106 to 108 in the first illustrated embodiment.

The above-mentioned shading data is read by MP[1111, and correction is performed for each type of film.

FIG. 5 is a characteristic diagram showing the conversion of a read signal into a normalized signal.

In general, the gradation recording characteristics of a color negative film are as follows: -logT= A + RlogE ・= Where E is the amount of light incident on the film and T is the transmittance after development processing.
It is expressed by the relational expression (1). Here, A and R are positive constants determined by the color negative film used. This relational expression (1) applies to the linear region of each characteristic curve in the first quadrant shown in FIG.

Color negative film has an orange color even in an unexposed state, and the density varies depending on the type of film. Therefore, even for the same subject, depending on the image film, the transmission density characteristic curve 5 corresponds to Hafilm ■ and ■.
It is not uniform like 0F and 502.

Now, when an original image is read by a CCD array on a negative film photographed with proper exposure, the signal output from the CCD array is, for example, the light beam B of the projector lamp 305 and the film transmittance in the example shown in the third figure. It is proportional to the product of T. That is, if C is a constant, D=CTB (2). This is because the density of the unexposed part of the film (hereinafter referred to as base film) differs depending on the type of film, so even for the same subject, from the characteristics shown in the second quadrant of Figure 5, for example, for the above films ■ and ■, respectively, D, = CT, B and D2 = CT2B, obtaining different CCD array output signals, and D2.

Therefore, shading correction is performed to correct this. Next, this will be explained in detail. The film transmittance of the base film is T. Then, this CCD array output. From equation (2), Do = CToB - (3).

Therefore, the CCD array reads the base film.
Set the array output Do to 255 (8 bits),
The CCD array output signal of the read image is the CCD array output signal of the base film. When normalized by , the corrected signal Sc (hereinafter referred to as the normalized luminance signal) becomes . This relational expression (4) is expressed by characteristics 504 and 505 shown in the third quadrant of FIG.

In this embodiment, for example, instead of a base film having a different spectral distribution from the characteristic curve 601 shown in FIG.
A color filter with a spectral distribution of 0.02 is used. Let the transmittance of this color filter be Tr, and use it as described in (3) above.
Corresponding to the formula, the color filter CCD array output signal DF = CTF'B...
・It can be expressed as (5).

This varies depending on the film of the read image, =
(Tr/To) x (CToB) =C+Do
”” (6) Substituting this into equation (4) yields. For example, in the embodiment shown in the first figure, after manually calculating the constant CI for each type of film, the calculation of equation (7) is executed by the microprocessor (MPII) 11, thereby achieving shading correction equivalent to that of the base film. becomes possible.

[Effects of the Invention] As is clear from the above, according to the present invention, by using a color filter for shading correction, (1) a base film (unexposed part of the film) is prepared separately from the image film to be copied; This eliminates the need for color negative film copying.

(2) Even with repeated projections, there is no effect of discoloration due to unexposed areas of the film, and appropriate data for shading correction can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. Figure 4 is a layout diagram showing the configuration of another example of color image reading, Figure 5 is a characteristic diagram showing the conversion of the read signal to a normalized signal, and Figure 6 is the spectral distribution of the color negative film and shading color filter. FIG. 3 is a characteristic diagram showing an example. 101.304.406...-CCO line sensor (array), 102.102R, 102G, 102B... Zumble hold circuit, 103R, 103G, 103B... A/D converter, 1
048,. 104G, 104B...Selector, 105
... Multiplier, 106.107,108... Line memory, 109.
... Logarithmic conversion table circuit, 110 ... Color processing circuit, 111 ... MPU. 301... Original plate glass, 302.404... Focusing rod lens array, 30
3.405...Infrared light cut filter, 305.40
1... Lamp, 306.402... Transparent original, 307.403... Color correction filter, 308... Lens, 309... Mirror, 310... Fresnel lens. He shows his ingenuity in pronunciation and profanity of the signal that he reads and listens to.1
1 Potato Raw Drawing Figure 5 Color Negative Film b' Paralysis Eating Power - Fino's evening course) View 4νr's Ike) Request I'M, l Engineering Drawing Figure 6

Claims (1)

[Claims] 1) The image formed by projecting a color negative film original is scanned, separated into three primary colors of R (red), G (green), and B (blue) and read. In a color image reading device that converts and outputs G and B digital data, it stores the output separated into the three primary colors of R, G, and B over one scanning line when a color filter is projected to form an image. and a calculation means for calculating an output read from the storage means, a correction coefficient according to the type of the color negative film, and an output obtained by reading the image of the color negative film original. Color image reading device.