JP2002171388A - Image reader and storage medium with controlling procedure stored thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely decide a shading correction coefficient by each pixel in the case of reading an image on an original monochromatically or with color by using a plurality of monochromatic line sensors. SOLUTION: A 3-line CCD line sensor 5 consists of three CCD line sensors. Whenever the three CCD line sensors read respectively one line, the maximum value of image data outputted in order is obtained. Based on the obtained maximum value of the image data, the white balance of the sensor 5 is obtained. Next, an exposure time for obtaining the white balance is obtained and also the shading correction coefficient of each pixel is obtained from the exposure time and the full range of an A/D converter 7.

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 an original such as a photographic film with light to optically read an image on the original in black and white or color, and stores a control procedure of the image reading apparatus. It relates to a storage medium. In particular, according to the present invention, when an image on a document is read in black and white or color using a plurality of black and white line sensors, the white balance and the shading correction coefficient are accurately determined for each image color, and The present invention relates to an image reading device suitable for reading with high image quality, and a storage medium for storing a control procedure of the image reading device.

[0002]

2. Description of the Related Art As a prior art, there is an illumination switching type image reading apparatus using a single monochrome CCD line sensor. Specifically, the light source sequentially switches the emission colors in the order of red (R), green (G), and blue (B), and the R color, G
Lights of color and B are sequentially illuminated. Subsequently, the single monochrome CCD line sensor reads an R line image signal using the R color illumination light, a G line image signal read using the G color illumination light, and a B color illumination light. , And sequentially outputs the B-line image signals read by using, and obtains a one-line color image read signal in the main scanning direction.

In the image switching apparatus of the illumination switching type using the single monochrome CCD line sensor, when reading an image, there is a difference depending on the transfer characteristic of the optical system. Further, the monochrome CCD line sensor also has sensitivity unevenness depending on the pixel position. Therefore, distortion occurs in both the light amount distribution of the light incident from the document and the light amount distribution indicated by the signal generated by the image reading device. For this reason, if the light amount distribution is not corrected, for example, a phenomenon occurs in which the light amount is large in the central portion of the image and small in the peripheral portion compared to the original.

[0004] In order to eliminate such distortion of the light amount distribution caused by the characteristics of the apparatus, the image reading apparatus has conventionally been provided with a shading correction function. The conventional shading correction includes a memory that previously stores a large number of shading correction coefficients determined for each emission color of the light source and for each pixel on the imaging surface according to the characteristics of the device. At the time of shooting, a predetermined control device reads one shading correction coefficient from the memory according to the main scanning position,
The image data output by the imaging device is multiplied by the shading correction coefficient to obtain image data subjected to shading correction. Each time the main scanning position changes, the shading correction coefficient read from the memory changes.

Needless to say, even in an image reading apparatus using monochromatic light using a single monochrome CCD line sensor,
The shading correction is performed similarly. recent years,
An image reading apparatus using a plurality of monochrome CCD line sensors is being developed. Therefore, a technique for accurately performing shading correction in an image reading apparatus using a plurality of monochrome CCD line sensors is desired.

[0006]

SUMMARY OF THE INVENTION A conventional single black and white CC
In an image reading apparatus using a D line sensor, a shading correction coefficient is calculated for each pixel of a single monochrome CCD line sensor for each color or for the single color only when monochromatic light is used. However, in an image reading apparatus using a plurality of monochrome CCD line sensors, when the method of obtaining the shading correction coefficient of the image reading apparatus using the single monochrome CCD line sensor is executed, the following problems occur.

That is, a shading correction coefficient for each pixel of an image reading apparatus using a plurality of monochrome CCD line sensors by using each pixel output of one monochrome CCD line sensor among a plurality of monochrome CCD line sensors. Is obtained, only the shading correction coefficient of the one monochrome CCD line sensor can be accurately obtained. However, since the pixel outputs of the other monochrome CCD line sensors are not taken into account, the shading correction coefficients of the other monochrome CCD line sensors cannot be accurately obtained.

For this reason, the amount of light incident on a plurality of monochrome CCD line sensors from a subject is different from the other monochrome CCD line sensors.
When the saturation level of the line sensor is exceeded, electric charges overflow into the registers of adjacent pixels, and a phenomenon (blooming) of disturbing the image occurs. If the level of the electric signal output by the other monochrome CCD line sensor exceeds the saturation level of a signal processing circuit such as an A / D converter, the digital image data before shading correction does not change, and the input light amount and The relationship with the level of the image data becomes non-linear.

For such non-linear image data,
Even if the shading correction processing is performed, a correct correction result cannot be obtained. A first object of the present invention is to provide an image reading apparatus using a plurality of monochrome CCD line sensors, in which the main scanning scan data at the white balance determination position is the maximum among the image data of all line pixels in each color for illumination. The value is determined, and the exposure time of white balance is determined based on the maximum value. Another object of the present invention is to provide an image reading apparatus capable of accurately obtaining a shading coefficient of each pixel of each line based on the white balance exposure time.

A second object of the present invention is to enable a maximum value of the image data to be obtained, to enable the white balance to be determined, and to accurately obtain the shading correction coefficient. It is an object of the present invention to provide a storage medium for storing a control procedure of an image reading apparatus that enables an optimal exposure time to be determined.

[0011]

According to a first aspect of the present invention, there is provided an image reading apparatus comprising: an illuminating means for illuminating an original; a sub-scanning stage for mounting the original and moving in the sub-scanning direction; A main scan showing the received light intensity of each of the plurality of pixels, which is constituted by providing two or more line sensors for receiving light by the pixels on the same chip, or configured to output the same line sensor by a plurality of taps Imaging means for outputting a plurality of analog image data in each direction for each line sensor; driving means for driving the sub-scanning stage in the sub-scanning direction; and sequential output from two or more line sensors provided in the imaging means. A / D conversion is performed on two or more series of analog image data to obtain digital image data, and the maximum value of the digital line image data in all the series is obtained. And having a value detection unit.

According to the first aspect of the invention, the image data maximum value detecting means converts a plurality of analog image data output from two or more line sensors into digital image data by one scan in the main scanning direction. Converted,
The maximum value can be obtained from the plurality of converted digital image data. The image reading device according to claim 2 is the image reading device according to claim 1, wherein the illuminating unit includes:
One or more colors are sequentially emitted at each preset initial exposure time, and the imaging means receives reflected light of a reference white plate provided on the sub-scanning stage or light transmitted through a transparent window, and receives two lights. The image data indicating the light receiving intensity of each of the pixels of the line sensor is output, and the image data maximum value searching means obtains a white balance based on the maximum value of each color of the digital image data. And

According to the second aspect of the present invention, the image data maximum value searching means can determine the white balance based on the maximum value of each color of the digital image data. In the image reading apparatus according to a third aspect, in the image reading apparatus according to the second aspect, the white balance detecting unit divides a full range of the A / D conversion output by a maximum value of the digital image data, and obtains the result by dividing. The exposure time for obtaining a white balance is determined by multiplying the initial exposure time by the calculated exposure time.

According to the third aspect of the present invention, an exposure time for obtaining a white balance can be determined. According to a fourth aspect of the present invention, in the image reading apparatus of the third aspect, a shading correction coefficient Snm of each pixel of two or more line sensors (n is a line sensor number, m is a pixel number, and both are positive integers) Is obtained by dividing each of the A / D-converted image data by the maximum value in all the lines, and this shading correction coefficient is calculated for each color.

According to the present invention, the shading correction coefficient Snm of each pixel of two or more line sensors can be accurately obtained for each color. A storage medium for storing a control procedure of the image reading apparatus according to claim 5, an illuminating unit for illuminating a document, a sub-scanning stage mounted on the document and moving in a sub-scanning direction, and a plurality of light beams from the document. Two or more line sensors for receiving light by pixels are provided on the same chip, or the same line sensor is configured to be output by a plurality of taps, and a main scanning direction indicating light receiving intensity of each of the plurality of pixels Imaging means for outputting a plurality of analog image data for each line sensor, driving means for driving the sub-scanning stage in the sub-scanning direction, and two or more line sensors provided in the imaging means sequentially output from the two or more line sensors. A / D conversion of two or more series of analog image data
Converting the digital image data to obtain the maximum value of the digital line image data in all the series, the image data having a maximum value detection means for storing a control procedure of the image reading device, wherein the control procedure, The illuminating means sequentially emits one or more colors at each preset initial exposure time, and the imaging means receives the reflected light of the reference white plate provided on the sub-scanning stage or the light transmitted through the transparent window, Outputting image data indicating the received light intensity of each of the pixels of the two or more line sensors, and wherein the image data maximum value searching means obtains a white balance based on the maximum value of each color of the digital pixel data. It is characterized by.

According to the fifth aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading apparatus according to the first aspect. A storage medium for storing a control procedure of the image reading apparatus according to claim 6 is a storage medium for storing a control procedure of the image reading apparatus according to claim 5, wherein the control procedure is such that the white balance detection unit is configured to execute the A The full range of the / D conversion output is divided by the maximum value of the digital image data, and a value obtained by the division is multiplied by the initial exposure time to determine an exposure time for obtaining a white balance.

According to the invention described in claim 6, it is possible to provide a storage medium for storing a control procedure for the image reading device described in claim 2. A storage medium storing a control procedure of the image reading apparatus according to claim 7 is a storage medium storing a control procedure of the image reading apparatus according to claim 6, wherein the control procedure is performed for each pixel of two or more line sensors. A shading correction coefficient Snm (n is a line sensor number, m is a pixel number, both are positive integers) is obtained by dividing the full range of the A / D conversion output by the exposure time for obtaining the white balance. .

According to the seventh aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading apparatus according to the third aspect. A storage medium storing a control procedure of the image reading apparatus according to claim 8 is a storage medium storing a control procedure of the image reading apparatus according to claim 7, wherein the control procedure is performed for each pixel of two or more line sensors. A shading correction coefficient Snm (n is a line sensor number, m is a pixel number, both are positive integers) is obtained by dividing by a maximum value in all lines, and the shading correction coefficient is calculated for each color. .

According to the eighth aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading apparatus according to the fourth aspect.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the accompanying drawings will be described below.

FIG. 1 is a diagram showing an example of an image reading apparatus to which the present invention is applied. FIG. 1 shows a film scanner as an example of the image reading apparatus. The embodiment shown in FIG. 1 corresponds to all the claims described in the claims. The film scanner shown in FIG. 1 includes a light source unit 1 (LED light source), a film original (negative or positive (reversal) film) 2 illuminated by the light source unit 1, and a sub-scanning stage 3 on which the film original 2 is mounted. A projection lens 4 for forming an image of the film original 2 illuminated by the light source unit 1, and a monochrome 3-line CCD line provided on the same chip for converting the image formed by the projection lens 4 into an analog image signal A sensor 5, a preamplifier 6 for amplifying the analog image signal, an A / D converter 7 for converting an analog image signal output from the preamplifier 6 into a digital image signal,
An ASIC (shape-specific I / O) for performing shading correction or the like on the digital image signal output from the A / D converter 7
C) 8, an output line memory 9 for temporarily storing a digital image signal output from the ASIC 8, an SCSI interface 10 for outputting a digital image signal read from the output line memory 9 to a host computer (not shown), A shading memory 11 storing the above-mentioned shading correction coefficient, a motor driver 12 and a stepping motor M for moving the sub-scanning stage 3 by a predetermined distance, and a lighting time of the light source unit 1. A lighting time setting timer 13 for exposure adjustment, a driver 14 for outputting the lighting time set by the lighting time setting timer 13 for exposure adjustment to the light source unit 1, and an overall operation of the film scanner shown in FIG. CPU 15 and CPU 15
That stores a control program for operating the
M16 and RAM 17 for temporarily storing various operation data
It is composed of

In the above configuration, the correspondence with the claims is as follows. The illumination unit described in claim 1 corresponds to the light source unit 1. Similarly, the driving means
The motor driver 12, the stepping motor M, etc. correspond. Similarly, a monochrome three-line CCD line sensor 5 corresponds to the imaging means. Similarly, the image data maximum value detecting means corresponds to a program stored in the CPU 15 and the ROM 16 and the like.

Next, the operation of the film scanner shown in FIG. 1 will be briefly described. As described above, the film original 2 is illuminated by the light source unit 1 and is imaged on the monochrome three-line CCD line sensor 5. In order to enable reading of a color image, the light source unit 1 sequentially emits three colors of illumination light, R color, G color, and B color having different peak wavelengths. Thus, the light source unit 1 enables the color separation of the film original 2.

The monochrome 3-line CCD line sensor 5 reads a plurality of square pixels. Black and white 3 line CC
The D line sensor 5 determines the size of one side of the square pixel as P
Then, the configuration is such that the line interval of the three lines is 8P. That is, the three-line CCD line sensor 5 executes line reading at intervals of eight lines instead of reading adjacent lines.

Next, a monochrome 3-line CCD line sensor 5
The two-dimensional image can be read by moving the sub-scanning stage 3 by, for example, one line in a direction perpendicular to the direction of the one-dimensional image formed on the main scanning direction (main scanning direction). This is hereinafter referred to as small step movement.

Here, as described above, the three-line CCD
The line sensor 5 reads an image at intervals of eight lines instead of reading an adjacent line. Therefore, if the small-step movement is performed at one-line intervals, the line that has already been read is reached in the eighth small-step movement. Thus, the eighth small-step movement is not performed, but a large-step movement is performed to move 24 (8 lines × 3) lines at a time.

After the large step movement, the small step movement is repeated again. By repeating the small-step movement and the large-step movement in this manner, it is possible to obtain R, G, and B analog image signals for the entire screen. Specifically, at the time of image reading, the illumination light of three colors (R, G, B) is sequentially blinked, and the sub-scan of the small step movement and the large step movement are repeated.
An analog image signal of each line of R, G, and B colors is obtained.

The quantization of the read analog image signal is as follows.
This is performed by the A / D converter 7. The digital image signal output from the A / D converter 7 is sequentially converted into an ASI signal for each line.
The data is transferred to C8, and shading correction is performed for each pixel. Here, the shading correction coefficient is
It is calculated from the transmitted light of a transparent portion where the film original 2 does not exist on the sub-scanning stage 3, and is written in the shading memory 11 directly connected to the ASIC 8. When a three-line CCD line sensor is used, it is necessary to perform shading correction for all pixels for three lines. Otherwise, the relationship between the input light amount and the level of the image data becomes non-linear due to the level fluctuation for each line, or the quality of the read image deteriorates due to blooming. Note that, in FIG. 1, a line indicated by a thick line indicates a bus. The line connecting the CPU 15 and the motor driver 1 may be a normal line or a bus.

FIGS. 2 and 3 are explanatory diagrams showing an example of the image reading operation of the film scanner shown in FIG. In FIG. 2, the film original 2 is divided into a first area and an n-th area by a large step pitch as shown in FIG. 2A, and a small step is performed in each area as shown in FIGS. Small steps 1 to 7 are divided according to the pitch.

In the film original 2, L111 to L1
The meaning of 73 and the like is as follows. For example, in L173, the first “1” means the first area (large step). In L173, "7" at the center means a small step. The last "3" in L173 means the third line sensor (sensor number) of the three-line CCD line sensor.

The film scanner shown in FIG.
As shown in (b), in small step 1, L111
~ L113 is read. Next, as shown in FIG. 2C, the film scanner performs L12
Read 1 to L123. Thereafter, similarly, reading is performed in small step units, and in small step 7, FIG.
As shown in (e), L171 to L173 are read.

In the small steps 1 to 7 described above, the first
All the images in the area have been read. next,
As shown in FIG. 2F, the film scanner shown in FIG. 1 performs a large step movement (8 × 3 = 24 small step movements) to read the second area. in this way,
The film scanner shown in FIG. 1 captures the entire image by repeating large-step movement and small-step movement.

FIG. 3 is an explanatory view showing another example of the image reading operation of the film scanner shown in FIG. In FIG. 3, only the large step movement is performed, and in the i-th area (i = 1
In (n) to (n), the small step movement as shown in FIGS. 2 (b), (c) and (d) is not performed. In the case of reading a thumbnail, the reading method shown in FIG. 3 is useful.

FIGS. 4 to 10 are flowcharts showing the operation of the film scanner shown in FIG. 1 including the operation with the host computer. These flowcharts describe steps until the color image is actually captured by the host computer. As shown in FIG. 4, in step S1, the CPU of the host computer transmits a shading data measurement command to the film scanner (see A in FIG. 4).

As shown in FIG. 5, the film scanner C
The PU 15 finishes the initialization of the scanner main body in step S20, and stands by in this state. The initialization is executed by turning on the power of the film scanner or the like. Upon receiving the shading data measurement command (see A), the CPU 15 proceeds to step S21 and determines that a command has been received from the host computer.

In step S22, the CPU 15 of the film scanner determines that the command is a shading data measurement command, and determines in step S40 shown in FIG.
Proceed to. In step S40 shown in FIG. 6, the CPU 15 of the film scanner moves the sub-scanning stage 3 to the white balance point. Here, the white balance point is a transparent portion (shading correction window) where there is no film original 2, and the three-line CCD line sensor 5 includes the light source unit 1, the projection lens 4 and the three-line CC
An analog image signal determined by the total spectral sensitivity of the D line sensor 5 is output. Note that, as is well known, there is one using reflected light from a reference white plate as a white balance point.

The movement of the sub-scanning stage 3 to the white balance point is performed by the CPU 15 by the motor driver 12.
And the stepping motor M is driven. In step S41, the CPU 15
Is the exposure adjustment lighting time setting timer 13 shown in FIG.
Initial light emission times Trs, Tgs, R, G, and B, respectively.
Tbs is set, and the light source unit 1
To send to. Here, the initial light emission time Trs, Tg
s and Tbs are such that the monochrome three-line CCD line sensor 5 does not saturate (for example, about 0.7 times the saturated light emission amount).
Of light emission.

In step S42, the CPU 15
The R-LED of the light source unit 1 is set to the initial light emission time Trs
Only emit light. In step S43, the CPU 15
Reads analog image data from the three-line CCD line sensor 5 shown in FIG. 1 (pixel unit), converts the analog image data into digital image data (pixel unit) in the AD converter 7, and then outputs the three-line CCD red data Ls1r, Ls2r, L
Output as s3r.

FIG. 11 shows the three-line CCD red data L
It is a figure showing an example of s1r, Ls2r, and Ls3r. In this example, the number of pixels in one line is 5000 pixels, and the full range of the AD converter 7 is 4095 (12 bits). In this case, each pixel data is not saturated. In step S44 of FIG. 6, the CPU 15 stores all the three-line CCD red data Ls1r, Ls2r, Ls3r read in step S43 in the RAM 17. The RAM 17 stores image data of all pixels read by the monochrome three-line CCD line sensor 5.

In step S45, the CPU 15
Ls1r, Ls2r, Ls stored in the RAM 17
From 3r, a maximum value Rmax is obtained for each pixel. In the example shown in FIG. 11, the maximum value Rmax exists in the CCD 3. Here, steps S44 and S45 are as follows.
This corresponds to an image data maximum value detecting means described in claim 1.

In step S46, the CPU 15
The light emission time Tr of the R-LED of the light source unit 1 is obtained based on the following equation. Tr = Trs × 4095 / Rmax This light emission time gives an exposure amount at which the maximum image data output is in the full range of the AD converter 7. In the above equation, “4095” means the full range (12 bits) of the AD converter 7. Step S46
Corresponds to the third aspect of the present invention.

In step S47, the CPU 15
The R-LED of the light source unit 1 emits light for the initial light emission time Tr. In step S48, the CPU 15
Reads out each analog pixel data from the three-line CCD line sensor 5 shown in FIG. 1, converts it into digital pixel data in the AD converter 7, and outputs it as three-line CCD red data Ls1r, Ls2r, Ls3r.

FIG. 12 shows the three-line CCD red data L
FIG. 4 is a diagram illustrating an example of s1r, Ls2r, and Ls3r, and illustrates white balance. As is clear from FIG. 12, the maximum value of the pixel data (see CCD 3) is “4095” which is the full range of the AD converter 7. In step S49, the CPU 15 determines in step S48
All three-line CCD red data Ls read in
1r, Ls2r, and Ls3r are stored in the RAM 17. R
The AM 17 stores image data of all pixels read by the monochrome three-line CCD line sensor. Steps S40 to S49 correspond to the second aspect of the present invention.

In step S50, the CPU 15
3-line CCD red data Ls1 stored in RAM 17
r, Ls2r, and Ls3r are read out, and A
The full-range “4095” of the D converter 7 is divided by the pixel data to obtain a shading correction coefficient S for each pixel.
Find DRnm.

FIG. 13 is a diagram showing an example of a shading correction coefficient obtained for each CCD in a pixel unit by the above method. As shown in FIG. 12, the shading correction coefficient of the pixel having the maximum value in FIG.
It has become. This means that the pixel need not be corrected. FIG. 14 shows a waveform shaped using the shading correction coefficient shown in FIG. 13, and the output waveform becomes flat.

Steps S51 to S59 shown in FIG.
-To determine the light emission time Tg of the LED (step S52) and the shading correction coefficient SDGnm (step S53) relating to the green data.
Since it is the same as the processing for red data shown in S50,
The description is omitted. Step S60 shown in FIG.
Steps S68 to S68 are for obtaining the emission time Tb (step S58) and the shading correction coefficient SDBnm (step S59) for the blue data in the B-LED, and are the same as the processing for the red data shown in steps S42 to S50. Description is omitted.

In step S69 of FIG.
5 stores the shading correction coefficient for each color and each pixel from the shading memory 11 to the ASIC 8. In step S70, the CPU 15 sends a shading correction coefficient SD (SDRn) to the host computer.
m, SDGnm, SDBnm) is transmitted (see FIG. 8B). Then, the shading correction coefficient determination processing ends.

The steps S40 to S70 correspond to the invention described in claim 4. As shown in FIG. 4, the CPU of the host computer receives a shading correction coefficient SD determination end signal from the film scanner (see B in FIG. 4). In step S2 of FIG. 4, the host computer determines whether or not preparation for shading correction has been completed. In this case, since the shading correction coefficient SD determination end signal has been received, the process proceeds to step S3.

In step S3, the CPU of the host computer waits for the operator to input a scan start instruction. When the operator inputs a scan start instruction, the process proceeds to step S4, where a scan start command is transmitted to the film scanner (see C in FIG. 4). In FIG. 5, the CPU 15 of the film scanner receives a scan start command (see C), proceeds to step S21, and determines that a command has been received from the host computer.

In step S22 of FIG. 5, the CPU 15 of the film scanner determines that the command is a scan start command, and proceeds to the scan processing shown in FIG.
After outputting the scan start command in step S4 shown in FIG. 4, the host computer starts the scanning process in step S5. In step S6,
The host computer sends the input resolution to the film scanner. In this case, a full resolution (a resolution in which the film original 2 corresponds to the number of CCD pixels) is transmitted as the scan resolution (see D in FIG. 4).

On the other hand, the CPU 15 of the film scanner
As shown in the flowchart of FIG. 9, after initialization in step S71, in step S72, reception of an input resolution transmitted from the host computer is waited (see D in FIG. 9). When the input resolution (see D in FIG. 9) is received from the host computer, the process proceeds from step S72 to step S73.

In step S73, the CPU 15
Set the resolution. Specifically, a small step pitch of the stepping motor M and a main scanning complement pitch are set. Further, a count upper limit value I of the small step pitch counter is set. In this case, since the three-line CCD line sensor 5 executes line reading at intervals of eight lines, "7" is set as the count upper limit value I.

Next, at step S74, the CPU 1
Reference numeral 5 gives an instruction to the motor driver 12 to operate the motor M to move the sub-scanning stage 3 to the initial position (reading start position) in the sub-scanning direction. In step S75, the count value I of the small step pitch counter indicating the small step pitch is set to 1 (initial value).

In parallel with the above operation, the host computer, as shown in step S7 of FIG.
The count value h of the area counter for counting the numbers of the plurality of areas provided above is set to 1 (initial value). continue,
As shown in step S8 of FIG. 4, the CPU of the host computer sets the count value I of the small step pitch counter indicating the small step number in the area to 1 (initial value). Thus, the CPU of the host computer corresponds to the small step 1 in the first area.

The CPU 15 of the film scanner
In step S76 of FIG. 9, step S76 shown in FIG.
The light emission time Tr of the R-LED obtained in 46 is set in the light emission time setting timer 13 shown in FIG. Subsequently, in step S77, the CPU 15 causes the light source unit 1 to pulse-light the R-LED for the set time.

In step S78, the CPU 15
A read instruction is output to the three-line CCD line sensor 5. Accordingly, the three-line CCD line sensor 5 outputs the three red line data (LhI1r, LhI2r,
LhI3r) is output to the host computer via the A / D converter 7, the ASIC 8, the output line memory 9, and the SCSI interface 10 (see steps S79 and E). Here, the h is the area number of the large step movement (h-th area), I is the small step number, and 1r is the first C
Red data of the CD line sensor, 2r means red data of the second CCD line sensor, and 3r means red data of the third CCD line sensor. Specifically, in step S79, the three red line data (L111r, L112
r, L113r) is transmitted to the host computer.

As shown in FIG. 4, the CPU of the host computer receives red three-line data (LhI1r, LhI2r, LhI3r) from the film scanner (see E in FIG. 4). Steps S80 to S83 shown in FIG.
, The green three-line data (LhI1g, LhI
2g, LhI3g) is output to the host computer via the A / D converter 7, the ASIC 8, the output line memory 9, and the SCSI interface 10 (see F). The operation is the same as that in steps S76 to S79 for red, and a description thereof will be omitted.

Similarly, steps S84 to S8 shown in FIG.
7, the blue three-line data (LhI1b, Lh
I2b, LhI3b) are converted to an A / D converter 7, an ASIC 8,
Output line memory 9, SCSI interface 10
(See G). The operation is the same as that in steps S76 to S79 for red, and a description thereof will be omitted.

As shown in FIG. 4, in step S10, the host computer sets the green three-line data (L
hI1g, LhI2g, LhI3g) (see F). Similarly, in the host computer shown in FIG. 4, in step S11, the blue three-line data (LhI1
b, LhI2b, LhI3b) (see G).
In step S88 shown in FIG.
The sub-scanning stage 3 is moved in small steps by one line in the sub-scanning direction.

Next, in step S89, the CPU 1
5 updates the count value I of the small step pitch counter by +1. Thereby, next, the small step 2 of the first area is scanned.

In step S90, the CPU 15
It is determined whether all the small steps (seven steps) in the area have been scanned. If it is determined that scanning has not been performed, the process returns to step S76, and step S76
To S89 are repeated. In step S90,
If it is determined that all have been scanned, step S
The process proceeds to 91, where the sub-scanning stage 3 is moved by a large step for 24 lines, and then proceeds to step S92.

In step S12 shown in FIG. 4, the CPU of the host computer updates the count value I of the small step pitch counter by +1. by this,
The CPU of the host computer corresponds to the scanning of the small step 2 of the first area. In step S13, the first
It is determined whether all the small steps (seven steps) of the area have been scanned. If it is determined that the scanning of the small step is not completed, the process returns to step S9,
Steps S9 to S13 are repeated.

By repeating the processing of steps S9 to S13, the R, G, and
The three line data of the B color is received (see E, F, and G), and all of the small steps can be scanned. If it is determined in step S13 that the scanning of all the small steps has been completed, the process proceeds to step S14.

In step S14, the CPU of the host computer combines the line data in the area where all the small-step scans have been completed. The synthesis of the line data may be performed not by the host computer but by the ASIC 8 of the film scanner shown in FIG. 1 and transmitted to the host computer. Step S1
In 5, the CPU of the host computer updates the count value h of the area counter by +1.

In step S16, it is determined whether or not the count value h of the area counter has reached a specified value. If it is determined that the time has not reached, the process proceeds to step S17, and the CPU of the host computer issues a scan continuation command to the film scanner (see H in FIGS. 4 and 9). If it is determined in step S16 that the count value h of the area counter has reached the specified value, the flow advances to step S18 to issue a scan end command (see J in FIGS. 4 and 9). Here, the width W of each area obtained by dividing the film manuscript 2 into a plurality is represented by pixel size ×
It becomes line interval × 3 (sub scanning direction). Therefore, the document image is divided into document size × magnification of projection lens 4 / W (= area count upper limit value). The host computer transmits a scan end command after waiting for the count value h of the area counter to reach the upper limit value.

Next, in step S19, the CPU of the host computer displays the scanned image on the monitor of the host computer, and ends the processing. The scan continuation command or the scan end command is received in step S92 of the film scanner as shown in FIG. 9 (see H and J). When a command is received from the host computer in step S92, the process proceeds to step S93.

In step S93, the CPU 15
It is determined whether the received command is a scan end command (J) indicating the end of the scan or a scan continuation command (H). If the command is a scan end command, the process proceeds to step S94, and the sub-scanning stage 3 is moved to the initial position. If the command is a scan continuation command, the process returns to step S75, and the processes in steps S75 to S92 are repeated.

In the above description, it has been described that full image input for reading all the adjacent lines is performed by the small step movement in the first area to the n-th area shown in FIG. However, the present invention is not limited to this. For example, reading may be performed every two lines.
As shown in FIG. 3, one line may be read at least every time a large step movement is performed.

In the image reading apparatus shown in FIG.
Although the number of D line sensors has been described as three, the present invention is not limited to this, and it is sufficient to have two or more CCD line sensors. In the image reading apparatus shown in FIG. 1, the CCD line sensor has been described as a monochrome CCD line sensor, but the present invention can be applied to an apparatus having two or more color CCD line sensors.

Further, in the image reading apparatus shown in FIG. 1, seven small steps are set in each of the first area to the n-th area of the large step, but the present invention is not limited to this. The number of small steps within may be arbitrary.
In the above-described embodiment, the control program of the CPU 15 is stored in the ROM 16 of the image reading apparatus. However, the present invention is not limited to this. Alternatively, a recording medium such as a hard disk or a hard disk may be used.

In this case, a recording medium such as a hard disk of the host computer stores a control program for executing the flowcharts shown in FIGS. Then, the CPU of the host computer reads the program from a recording medium such as a hard disk and stores the program in a memory of the host computer. This allows the CPU of the host computer to execute the control program. The control program stored in a recording medium such as a hard disk is stored in a storage medium such as a CD-ROM so that the control program can be set up in a host computer in advance. This corresponds to the invention described in claims 5 to 8.

The control program of the CPU 15 can be downloaded from a terminal such as a personal computer (personal computer) as driver software or firmware by accessing a homepage via the Internet. For example, while accessing the website from a personal computer, click (select) a film scanner, one of the image reading devices, from the product display on the screen, and then click the driver software or firmware that matches the OS environment of the personal computer. This is an embodiment in which downloading is performed by (selection).

Next, a connection form between a terminal such as a personal computer and the Internet will be described using a general dial-up connection as an example. That is, a terminal such as a personal computer is connected to a telephone line via a modem or a terminal adapter, and the telephone line is connected to a modem or a terminal adapter of an Internet connection service company provider. The provider's modem or terminal adapter is connected to a server that is the provider's computer. The server is connected to the Internet for 24 hours via a router for setting a relay route. From a terminal such as a personal computer, make a call when necessary, and connect to the Internet (homepage) via the server of the provider. Note that the Internet connection is not limited to dial-up connection, and there is also a connection that always connects to a provider using a dedicated line.

Further, a CPU of a host computer may be used instead of the CPU 15 of the image reading device. Also,
Instead of the RAM 17 of the image reading device, a memory and a hard disk of a host computer may be used. Also,
In the above-described embodiment, the interface with the host computer is the SCSI interface 10, but another interface (IEEE 1394, US
B, parallel, etc.).

In the above embodiment, the light source unit 1 shown in FIG. 1 has been described as irradiating three colors of illumination light, R, G, and B colors having different peak wavelengths sequentially. However, the present invention is not limited to this, and can be applied to, for example, monochromatic light. As an image reading apparatus using monochromatic light, there is a flat head scanner for reading an original (reflective original) which does not mainly transmit light. As a device that uses two colors of illumination light, for example, there is a device that corrects a defect in a black and white image with infrared light (IR).

In the above embodiment, the image reading apparatus using a plurality of monochrome CCD line sensors is
The case where a plurality of monochrome CCD line sensors are provided in parallel in the sub-scanning direction has been described as an example. However, the present invention is not limited to this, and includes an image reading apparatus in which a plurality of CCD line sensors are provided in a line in the main scanning direction. When a single CCD line sensor has a large number of pixels and sequentially outputs pixel outputs from the shift register in the same form, it takes a long time.
The present invention can also be applied to an image reading apparatus having a configuration in which the shift register unit of the CD line sensor is divided into a plurality of areas, and the divided shift registers output the data.

[0077]

According to the first aspect of the present invention, a plurality of C
In an image reading apparatus using a CD line sensor, a plurality of analog image data output from two or more line sensors are converted into digital image data by one scan in a main scanning direction, and the plurality of converted digital image data are converted. From the maximum value. Therefore, it is useful for obtaining an accurate shading correction coefficient in the image reading device.

According to the second aspect of the present invention, a plurality of CCs
In an image reading apparatus using a D line sensor, in one scan in the main scanning direction, all image data (for all pixels) output from a plurality of CCD line sensors are considered, and a white value is set based on a maximum value. The balance can be determined for each color. Therefore, it is useful for obtaining an accurate shading correction coefficient in the image reading device.

According to the third aspect of the present invention, a plurality of CCs
In an image reading apparatus using a D-line sensor, in one scan in the main scanning direction, exposure for obtaining an optimal white balance in consideration of all image data (for all pixels) output from a plurality of CCD line sensors. Time can be determined. Therefore, it is useful for obtaining an accurate shading correction coefficient in the image reading device.

According to the fourth aspect of the present invention, a plurality of CCs
In an image reading apparatus using a D-line sensor, the shading correction coefficient Snm of each pixel can be accurately obtained for each color, and a high-quality image can be obtained.
According to the fifth aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading apparatus according to the first aspect.

According to the sixth aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading apparatus according to the second aspect. According to the seventh aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading device according to the third aspect. According to the eighth aspect of the present invention, it is possible to provide a storage medium for storing a control procedure for the image reading apparatus according to the fourth aspect.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example (film scanner) of an image reading apparatus to which the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of an image reading operation of the film scanner shown in FIG.

FIG. 3 is an explanatory diagram showing an example of an image reading operation of the film scanner shown in FIG.

FIG. 4 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 5 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 6 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 7 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 8 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 9 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 10 is a flowchart showing an operation of the film scanner shown in FIG. 1 including an operation with a host computer.

FIG. 11 is a diagram showing an example of three-line CCD red data.

FIG. 12 is a diagram illustrating an example of white balance of 3-line CCD red data.

FIG. 13 is a diagram illustrating an example of a shading correction coefficient obtained in pixel units for each three-line CCD red data.

14 is a diagram showing an example of waveform shaping using the shading correction coefficient shown in FIG.

[Explanation of symbols]

Reference Signs List 1 light source unit 2 film original (negative, positive (reversal) film) 3 sub-scanning stage 4 projection lens 5 3 line CCD line sensor 6 preamplifier 7 A / D converter 8 ASIC (IC for specific application) 9 output line memory 10 SCSI interface 11 Shading memory 12 Motor driver 13 Lighting time setting timer for exposure adjustment 14 Driver 15 CPU 16 ROM 17 RAM M Stepping motor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/60 H04N 1/40 D 1/401 101A 1/48 1/46 A F term (Reference) 5B047 AA05 AB04 CB04 DA04 DB01 5C062 AA06 AB17 AC27 AC58 5C072 AA01 BA08 BA19 DA12 EA05 FA07 FB12 UA02 UA06 VA03 5C077 LL04 LL19 MM03 MM22 MP08 PP06 PP32 PP37 PP43 PQ12 RR01 SS01 SS03 TT09 5C033 HA13 MA13 MA03 HA03 MA13 HA03

Claims (8)

[Claims] An illumination device for illuminating a document, a sub-scanning stage for mounting the document and moving in a sub-scanning direction, and two or more line sensors for receiving light from the document by a plurality of pixels are on the same chip. A plurality of analog image data in the main scanning direction indicating the received light intensity of each of the plurality of pixels, which is configured to be provided on the top or configured to output the same line sensor with a plurality of taps, is output for each line sensor. An imaging unit that drives the sub-scanning stage in the sub-scanning direction; and A / A that converts two or more lines of analog image data sequentially output from two or more line sensors provided in the imaging unit.
An image data maximum value detecting means for obtaining digital image data by D-conversion and obtaining a maximum value of digital line image data in all the series. 2. The image reading device according to claim 1, wherein the illumination unit sequentially emits one or more colors at each preset initial exposure time, and the imaging unit is provided on the sub-scanning stage. Receiving the reflected light of the reference white plate or the light passing through the transparent window,
Outputting image data indicating the received light intensity of each of the pixels of the two or more line sensors, and wherein the image data maximum value searching means obtains a white balance based on the maximum value of each color of the digital image data. An image reading apparatus characterized by the above-mentioned. 3. The image reading device according to claim 2, wherein the white balance detecting means divides a full range of the A / D conversion output by a maximum value of the digital image data, and divides a value obtained by the division into the initial value. An image reading apparatus, wherein an exposure time for obtaining white balance is determined by multiplying the exposure time. 4. The image reading apparatus according to claim 3, wherein the shading correction coefficient Snm (n is a line sensor number, m is a pixel number, and both are positive integers) of each pixel of two or more line sensors is A / A. An image reading apparatus, wherein each of the D-converted image data is obtained by dividing the image data by a maximum value in all lines, and the shading correction coefficient is calculated for each color. 5. An illuminating means for illuminating a document, a sub-scanning stage for mounting the document and moving in a sub-scanning direction, and two or more line sensors for receiving light from the document by a plurality of pixels on the same chip And a plurality of analog image data in the main scanning direction indicating the received light intensity of each of the plurality of pixels is output for each of the line sensors. An imaging unit that drives the sub-scanning stage in the sub-scanning direction; and A / A that converts two or more lines of analog image data sequentially output from two or more line sensors provided in the imaging unit.
A digital image data obtained by D-conversion, and an image data maximum value detecting means for obtaining a maximum value of digital line image data in the entire series. The illumination means sequentially emits one or more colors at each preset initial exposure time, and the imaging means receives reflected light of a reference white plate provided on the sub-scanning stage or light transmitted through a transparent window. , 2
Outputting image data indicating the light receiving intensity of each of the pixels of the one or more line sensors, and wherein the image data maximum value searching means obtains a white balance based on the maximum value of each color of the digital pixel data. A storage medium for storing a control procedure of a characteristic image reading apparatus. 6. The storage medium for storing a control procedure of the image reading apparatus according to claim 5, wherein the control procedure is such that the white balance detection means sets a full range of the A / D conversion output to a maximum value of the digital image data. A storage medium for storing a control procedure of the image reading apparatus, wherein the initial exposure time is multiplied by a value obtained by the division to determine an exposure time for obtaining white balance. 7. A storage medium for storing a control procedure of the image reading apparatus according to claim 6, wherein the control procedure comprises: a shading correction coefficient Snm (n is a line sensor number, m is a line sensor number) of each pixel of two or more line sensors. A pixel number (both positive integers) obtained by dividing the full range of the A / D conversion output by the exposure time for obtaining the white balance. 8. A storage medium for storing a control procedure of the image reading apparatus according to claim 7, wherein the control procedure includes a shading correction coefficient Snm (n is a line sensor number, m is a pixel number) of each pixel of two or more line sensors. A storage medium for storing a control procedure of the image reading apparatus, wherein a pixel number (both a positive integer) is obtained by dividing the maximum value of all lines by a maximum value, and the shading correction coefficient is calculated for each color.