JPH06189149A - Image input device - Google Patents

Abstract

PURPOSE:To provide an output enabling high-fidelity color reproduction even in the case of fine lines extended in a main scanning direction and overlapped only to the first line or second line of a photoelectric converting element group. CONSTITUTION:Since a photoelectric converting element provided with a filter for transmitting light in any color excepting for the first color containing most luminance information among three primary colors is existent in either of the first and second lines of a photoelectric converting element group 22 corresponding to the picture element of a read object for each color but is not existent in the other line, the average value of outputs from the photoelectric converting element is provided concerning the color existent in the correspondent lines of mutually adjacent two photoelectric converting element groups 21 and 23. The average value of this average value and the output of the photoelectric converting element concerning this color existent in only either of the first and second lines of the photoelectric converting group 22 is defined as the output of the photoelectric converting element provided with a filter for transmitting the light in the second or third color of the photoelectric converting element 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device, and more particularly to an image input device capable of reading color originals.

[0002]

2. Description of the Related Art For reproduction of colors in a color facsimile or a color copying machine, for example, an additive color mixture in which two or three colors of three primary colors, red, blue and green, are superposed on the basis of black (see FIG. 8). Was taken. The color C reproduced by this additive color mixture is represented by the following equation, where R is red, B is blue, and G is green. C = R (r) + B (b) + G (g) (1)

Here, (r), (b) and (g) are values determined by the intensity of each color, that is, the brightness. For example, when (r) = 1, (b) = 1, (g) = 1 in the equation (1), the color C is white, (r) = 0, (b) = 0, (g) = 0.
, The color C is black. Therefore, from the equation (1), for example, in order to faithfully reproduce the color of the original, the color strengths corresponding to the three primary colors obtained from the unit pixels of the original when read by the image sensor, (r), ( b) and (g) must be accurate. 9 and 10 are views showing a conventional image sensor, respectively. First, the conventional first image sensor shown in FIG. 9 will be described. This image sensor is a photoelectric conversion element group 51 to 5Z (Z> 1) corresponding to pixels to be read, for example, pixels of a color document.
Are arranged in the main scanning direction.

The width of the photoelectric conversion element group 51 is divided into three equal parts in the sub-scanning direction, and the photoelectric conversion element 51 provided with a green filter when viewed in the main scanning direction, for example, corresponding to each width.
a, a photoelectric conversion element 51b having a red filter, and a photoelectric conversion element 51c having a blue filter are arranged.

In this image sensor, for example, 1 m
When 16 photoelectric conversion element groups are arrayed per m, the width of the photoelectric conversion element groups in the main scanning direction becomes 1/16 mm or less. Therefore, the width of each color filter in the main scanning direction becomes 1/48 mm or less, and therefore, in order to manufacture such an image sensor, a highly accurate technique must be required. From the above, the conventional second image sensor as shown in FIG. 10 was considered.

Similar to the image sensor shown in FIG. 9, this image sensor has a structure in which photoelectric conversion element groups 61 to 6Z (Z> 1) corresponding to pixels to be read are arranged in the main scanning direction. .

The photoelectric conversion element groups 61 to 6Z are
It is composed of four photoelectric conversion elements arranged in the second row and the second column with the main scanning direction as the row direction and the sub-scanning direction as the column direction. For example, the photoelectric conversion element group 61 is arranged in the first row. The two photoelectric conversion elements 61a and 61b are each provided with a green filter that transmits green light containing the most luminance information, and the photoelectric conversion elements 61c and 61d arranged in the second row.
Each has a red filter and a blue filter.

In this image sensor, the light receiving area of the photoelectric conversion element, which is provided with a green filter that transmits green light containing the most luminance information, occupies more than half of the light receiving area of the photoelectric conversion element group. It is like this. This is because by receiving a larger amount of green light including a lot of altitude information from the unit pixel, it is attempted to obtain an output value that increases the resolution of the reproduced image.

[0009]

However, such a second conventional image sensor is pulled in the main scanning direction in which the width in the sub-scanning direction is narrower than the width of the photoelectric conversion element on an original having a white background, for example. When the black line is read by the photoelectric conversion elements 61a and 16b provided with the green filter, the reproduced green color is not white, black, or gray but magenta. To explain this using the equation (1), first, the outputs of the photoelectric conversion elements 61a and 61b in the first row are (g) = 0 because the black component of the line does not include the green component. is there. The outputs of the photoelectric conversion elements 61c and 61d on the second row are (r) = 1 and (b) = 1 because the background white of the document has red and blue components. Therefore, when color reproduction is performed from these, C = R + B, resulting in magenta that occupies the sum of red and blue due to the relationship of the three primary colors in the additive color mixture shown in FIG.

When this black line is read by the photoelectric conversion element 61c provided with the red filter and the photoelectric conversion element 61d provided with the blue filter of the image sensor described above, the reproduced green color is white, black, or gray. But it turns green.

To explain this from the equation (1), first, the outputs of the photoelectric conversion elements 61a and 61b in the first row include the green component in the white background of the document, so that (g).
= 1. In addition, the photoelectric conversion elements 61c, 61 in the second row
The output of each d is (r) = 1 and (b) = 1 because the black of the line does not include both red and blue components.
Therefore, when color reproduction is performed from these, C = G and green is obtained.

Although the photoelectric conversion element group 61 has been described above, the reading of the unit pixel of each of the other photoelectric conversion element groups is similarly performed by the two photoelectric conversion elements in the first row to form a black line. When read, an output that gives a magenta color by color reproduction is obtained, and when a black line is read by the two photoelectric conversion elements in the second row, an output that gives a green color by color reproduction is obtained. Therefore, when a thin line having a width less than half of the width of the image sensor in the sub-scanning direction and extending in the main scanning direction is read only by the column of the photoelectric conversion element of the first row or the second row of the image sensor, There has been a problem that an accurate output cannot be obtained in color reproduction.

The number of thin lines extending in the main scanning direction on the document to be read is larger than that extending in the sub-scanning direction.
An image sensor that faithfully reads such an original is desired.

Therefore, in the image input device of the present invention, one photoelectric conversion element group in which four photoelectric conversion elements are arranged in two rows and two columns is made to correspond to the pixel of the object to be read, and the photoelectric conversion elements are mainly arranged. In the image sensor provided in the image input device having a plurality of arrays in the scanning direction, the thin line extending in the main scanning direction may be applied to only the first or second row of the photoelectric conversion element group. An image input device capable of obtaining an output capable of faithful color reproduction is provided.

[0015]

According to the present invention, one photoelectric conversion element group formed by arranging four photoelectric conversion elements in two rows and two columns is made to correspond to a pixel to be read, and the photoelectric conversion element group is formed. In an image input device including an image sensor having a plurality of arrays arranged in the main scanning direction, two photoelectric conversion elements in a diagonal direction out of the four photoelectric conversion elements forming each photoelectric conversion element group are provided. Of the four photoelectric conversion elements that constitute the photoelectric conversion element group, the first color filter that transmits the light of the first color that contains the most luminance information among the three primary colors Each of the two photoelectric conversion elements in 3 is provided with second and third color filters that transmit light of the second or third color of the three primary colors except the first color.
The arrangement of the second color filter and the third color filter is the second color for each photoelectric conversion element group in the main scanning direction with respect to the photoelectric conversion elements in the same row of the adjacent photoelectric conversion element groups. The filter and the third color filter are arranged to appear alternately. Further, an average value calculating means for performing the following processing on the output of each photoelectric conversion element is provided.

That is, the average value of the output values of the photoelectric conversion elements having the first color filters in the first row and the output values of the photoelectric conversion elements having the first color filter in the second row of the arbitrary pixel. And an output value of a photoelectric conversion element having second and third color filters of an arbitrary pixel, and second and third colors of pixels adjacent to the arbitrary pixel. A second average value calculating means for calculating an average value of the output values of the photoelectric conversion element having the filter for each color is provided.

[0017]

According to the image input device configured as described above, even if the read object exists only in the first row or the second row of the photoelectric conversion element group, there are few errors and it can be output. That is, first, the photoelectric conversion elements including the first color filter that transmits the light of the first color that contains the most luminance information among the three primary colors are present in both the first row and the second row. Therefore, for the colors existing in both of them, the average value of these two photoelectric conversion elements is simply taken as the output value for the light of that color corresponding to the pixel to be read.

On the other hand, the photoelectric conversion element provided with a filter that transmits the other colors of the three primary colors, that is, the light of the second or third color, corresponds to the pixel to be read in each color. It exists only in one of the first row and the second row of the photoelectric conversion element group, and does not exist in the other row.

The photoelectric conversion element provided with a filter that transmits the light of the second or third color in any of the two photoelectric conversion element groups adjacent to the focused photoelectric conversion element group is It exists only in one of the second row and the first row, which is different from the row in the photoelectric conversion element group of interest. Therefore, the output of the photoelectric conversion elements in the non-existing row in the focused photoelectric conversion element group is calculated as an average of the outputs of the photoelectric conversion elements for the color in the corresponding rows of the two adjacent photoelectric conversion element groups. Apply the value. Then, the average value of the average value and the output of the photoelectric conversion element for this color, which is present only on the first row or the second row of the focused photoelectric conversion element group, of the focused photoelectric conversion element, The output value of the photoelectric conversion element provided with a filter that transmits light of the other colors of the three primary colors, that is, the second or third color.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image input device according to the present invention.

The image sensor 11 is a color sensor provided in the image input device for reading characters and figures on a document. Here, the configuration of the image sensor 11 will be described with reference to FIG.

FIG. 2 is an array diagram of a photoelectric conversion element group provided with a color filter of an image sensor provided in the image input device according to the present invention. The photoelectric conversion element groups 21 to 2Z (Z> 1) corresponding to the unit pixel to be read are arranged in the main scanning direction. The photoelectric conversion element groups 21 to 2Z form a matrix of 2 rows and 2 columns, which is composed of photoelectric conversion elements provided with color filters and has rows in the main scanning direction and columns in the sub scanning direction.

The color filter includes a green filter as a color filter that transmits light of a color containing a lot of luminance information,
Other color filters include a red filter and a blue filter, which are arranged as shown below.

First, regarding the photoelectric conversion element group 21, for example, a green filter that transmits green light is arranged in the photoelectric conversion elements 21a and 21d in one of two diagonal directions. .

A blue filter is arranged on one of the two photoelectric conversion elements 21b in the other diagonal direction, and a red filter is arranged on the other photoelectric conversion element 21c. And other photoelectric conversion element groups 22 to 2
Similarly for Z (Z> 2), 2 rows 2
A green filter is arranged on one of the two photoelectric conversion elements located in one diagonal direction of the photoelectric conversion elements of the row, and a red filter is arranged on one of the two photoelectric conversion elements located in the other diagonal direction. , And a green filter on the other side. Further, the red filter and the blue filter are arranged so that the respective first and second rows appear alternately when viewed between the photoelectric conversion element groups.

That is, in the first row, the photoelectric conversion element 21b of the photoelectric conversion element group 21 is provided with a blue filter, so that the photoelectric conversion element 22a of the photoelectric conversion element group 22 adjacent thereto has a red filter. A filter is provided, and the photoelectric conversion element 23b of the photoelectric conversion element group 23 adjacent to the filter is further provided with a blue filter. Similarly, in the second row, since the photoelectric conversion element 21c of the photoelectric conversion element group 21 has a red filter, the photoelectric conversion element 22d of the photoelectric conversion element group 22 adjacent thereto has a green filter. , And the photoelectric conversion element 2 of the photoelectric conversion element group 23 adjacent to this
3c is equipped with a red filter.

When the image sensor 11 receives the timing pulse (a) shown in FIGS. 4 and 5, the photoelectric conversion elements 21a to 2Zb (Z> 1) and the photoelectric conversion elements 21c to 2Zd (Z> 1) are row by row. ), The two photoelectric conversion elements in the same column are simultaneously read and driven, and the image output read up to the photoelectric conversion element in the first row is read to the analog / digital conversion unit 12a and the photoelectric conversion element in the second row. The image output is simultaneously sent to the analog / digital conversion unit 12b for each column. Here, returning to the description of FIG.

Analog / digital converters 12a, 12
Reference numeral b is for converting the form of the image output sent from the image sensor 11 upon receiving the timing pulse (b) from an analog signal to a digital signal and sending it to the arithmetic processing unit 13. In particular, the analog / digital conversion unit 12a handles the image output of the photoelectric conversion element in the first row, and the analog / digital conversion unit 12b handles the image output of the photoelectric conversion element in the second row.

The arithmetic processing unit 13 calculates an appropriate image output value for each photoelectric conversion element corresponding to an arbitrary pixel from the read data when receiving the timing pulse.
Here, the configuration of the arithmetic processing unit 13 will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the arithmetic processing unit of the image input apparatus according to the present invention.

By the way, the arithmetic processing section 13 includes the flip-flops 311 to 316 and 321 to 326 and the average value circuits 33 to 3.
7, 43 to 47, each of which is driven by receiving the timing pulse (c) shown in FIGS. 4 and 5.

The flip-flop 312 is connected in series to the flip-flop 311 connected so as to receive the image output sent from the analog / digital converter 12a. A flip-flop 314 is connected in series to the flip-flop 313, a flip-flop 315 is connected to the flip-flop 314, and a flip-flop 316 is connected to the flip-flop 315 in series.

Further, the analog / digital converter 12b
The flip-flop 322 is connected in series to the flip-flop 321 connected so as to receive the image output sent from the flip-flop 322, the flip-flop 323 to the flip-flop 323, the flip-flop 324 to the flip-flop 324, and the flip-flop 324 to the flip-flop 323. A flip-flop 325 is connected in series to the flip-flop 324, and a flip-flop 326 is connected in series to the flip-flop 325.

These flip-flops send the held image output by receiving a timing pulse. Therefore, since each flip-flop is connected in series, each time the timing pulse (c) is received,
The data will be transferred to the adjacent flip-flop. Further, since the flip-flops 311 to 316 which handle the data of the first row and the flip-flops 321 to 326 which handle the data of the second row of the image sensor receive the timing pulse (c) at the same time, they are read by the image sensor. The obtained data of the photoelectric conversion elements in the same row are always located in the same row even in the two flip-flop rows, and the data are moving forward. Here, the image output to be processed is the flip-flop 31 surrounded by the broken line.
3, 314, 323, and 324.
The averaging circuits 33 to 37 and 43 to 47 are circuits that calculate the average value of data.

The averaging circuit 33 is a flip-flop 313.
And 324, and when the timing pulse (e) is received, the data held in these are averaged, and
The data is sent to the switch 24G via the G line.

The averaging circuit 34 includes a flip-flop 32.
2 and 326 and averages the data held in them upon receiving the timing pulse (d). The averaging circuit 35 averages the average value calculated here and the data of the flip-flop 314 by receiving the timing pulse (e), and sends this data to the switch 14G via the R line.

The averaging circuit 36 includes a flip-flop 311.
And 315 and receives the timing pulse (d) and averages the data held therein. Further, the averaging circuit 37 averages the average value calculated here and the data of the flip-flop 323 and receives the timing pulse (e), and sends this data to the switch 24B via the B line. .

The averaging circuit 43 is a flip-flop 314.
And 323 are connected to each other, and when the timing pulse (c) is received, the data held therein are averaged, and the switch 1
Send to 4G via G'line.

The averaging circuit 44 includes a flip-flop 31.
2 and 316 and averages the data held therein upon receiving the timing pulse (d). Further, when the timing pulse (e) is received, the averaging circuit 45 averages the average value calculated here and the data of the flip-flop 324, and this result is averaged through the R ′ line to the switch 14R. Send to.

The averaging circuit 46 includes a flip-flop 32.
1 and 325 connected to average the data held therein upon receiving the timing pulse (d). Further, when the timing pulse (d) is received, the averaging circuit 47 averages the average value calculated here and the data of the flip-flop 313, and sends this data to the switch 14B via the B ′ line.

The switch 14G connects the line G and the line G '
In addition, the switch 14B switches between the line B and the line B '.
R selects line R and line R ′ based on the timing pulse (f) and switches them. As a result, the data sent via each selected line is stored in the storage unit 1.
5 will be sent. The storage unit 15 includes the arithmetic processing unit 1.
The data processed in step 3 is stored for each line and color of the read document. Next, the operation of this image input device will be described. 4 and 5 are diagrams showing timing pulses input to each component of the image input apparatus of the present invention.

(A) is a timing pulse input to the image sensor 11, (b) is a timing pulse input to the analog / digital converters 12a and 12b,
(C) shows flip-flops 311 to 311 of the arithmetic processing unit 13.
Timing pulses input to 316, 321-326, (d) are timing pulses input to the averaging circuits 34, 36, 44, 46, and (e) is averaging circuits 33, 3
5, 37, 43, 45, 47 are timing pulses input, and (f) is a timing pulse input to the switchers 14G, 14B, 14R.

Each component of the image input device starts its operation at the rising portion of these timing pulses, operates at the high level portion, and stops its operation at the falling portion.

At first, the timing pulses shown in FIG. 4 are input respectively. First, the timing pulse (a)
Is started, the reading operation of the image sensor 11 is performed by the photoelectric conversion element 21 in the first row, first column and the second row, first column.
An image output in the form of an analog signal is read from the corresponding pixel on the original by a and 21c. Then, when the timing pulse (b) rises, the analog / digital converters 12a and 12b convert the image outputs read by the image sensor 11 from analog signals to digital signals.

Furthermore, when the timing pulse (c) rises, the flip-flops 311 to 3 of the arithmetic processing unit 13
Of the 16 and the flip-flops 321 to 326, the flip-flop 311 and the flip-flop 321 hold image outputs in the form of digital signals from the analog-digital conversion unit 12a and the analog-digital conversion unit 12b, respectively.

After that, the falling timing pulse (a)
When the image sensor 11 rises again, the image sensor 11 next detects the photoelectric conversion elements 21b and 21d in the first row, second column and the second row, second column.
The image output is read from the corresponding pixel on the document.

When the timing pulse (b) rises, the analog / digital converters 12a and 12b convert the read image output into a digital signal form. Further, when the timing pulse (c) rises, the flip-flop 311 of the arithmetic processing unit 13 flips the held image output read by the photoelectric conversion element 21a in the first row, first column, which has been held. The image output read by the photoelectric conversion element 21b in the first row and second column of the analog / digital conversion unit 12a is held while being sent to the digital camera 312.

The flip-flop 321 holds the image output read by the photoelectric conversion element 21c in the second row and the first column, which is held in the flip-flop 321, and sends the image output to the flip-flop 322 and the second output of the analog-digital converter 12b. The image output read by the photoelectric conversion element 21d in the second row is held.

Thus, the timing pulse (a),
The image sensor 11 and the analog / digital converters 12a and 12 are caused by the rising and falling of (b) and (c).
b, and the flip-flops 311 to 316 of the arithmetic circuit 13
And 321 to 326, a series of operations is repeated.

Then, the photoelectric conversion element 21a in the first row and first column
The image output read by the flip-flop 316
And when the image output read by the photoelectric conversion element 21c in the second row and the first column advances to the flip-flop 326, the timing pulses (d), (e), and (f) are as shown in FIG. change. The state of the arithmetic processing unit 13 in this case is shown as a first pattern in FIG.
The calculation processing operation of No. 3 will be described. Here, in FIG. R. B is attached. G. R. B
And a flip-flop that holds an output of image information read by a photoelectric conversion element having a green filter, a photoelectric conversion element having a red filter, and a photoelectric conversion element having a blue filter, respectively. .

For example, the flip-flop 316 holds the image output read by the photoelectric conversion element 21a having a green filter, and the flip-flop 326 holds the image output read by the photoelectric conversion element 21c having a red filter. Holds the image output. The flip-flop 315 holds the image output read by the photoelectric conversion element 21b having a blue filter.
Holds the image output read by the photoelectric conversion element 21d having a green filter. Below, the flip-flops 314 to 311 are provided with the photoelectric conversion elements 22a and 22a, respectively.
b, 23a, and 23b hold the read image output, and flip-flops 324 to 321 respectively,
The image output read by the photoelectric conversion elements 22c, 22d, 23c, and 23d is held. At this time, the switching device 14
The G, 14B, and 14R are connected to send the data of the G line, the B line, and the R line to the storage unit 15, respectively. Therefore, the timing pulse (d) is averaged by the averaging circuits 34, 36,
44 and 46, and the timing pulse (e) is input to the averaging circuits 33, 35, 37, 43, 45 and 47, but the switchers 14G, 14B and 14R are G line and B, respectively.
The signal sent via the line and the R line is stored in the storage unit 1.
Flip-flop 3 because it is connected to send to 5
Attention is paid to 3, 34, 35, 36 and 37.

The image output read by the photoelectric conversion element 21a in the first row and the first column is transferred to the flip-flop 316, and the image output read by the photoelectric conversion element 21c in the second row and the first column is transferred to the flip-flop 326. When the averaging circuit 34 receives this timing pulse after the advanced time t1, the image output of the photoelectric conversion element 21c held in the flip-flop 326 and the image output of the photoelectric conversion element 23c held in the flip-flop 322 are received. And calculate the average. When the averaging circuit 36 receives this timing pulse, the averaging circuit 36 holds the photoelectric conversion element 21 held in the flip-flop 315.
The average of the image output of b and the image output of the photoelectric conversion element 23b held in the flip-flop 311 is calculated.

After that, the timing pulse (e) is input to the averaging circuits 33, 35 and 37. Then, the averaging circuit 33 causes the image output of the photoelectric conversion element 22b held by the flip-flop 313, the image output of the photoelectric conversion element 22b held by the flip-flop 324, and the photoelectric conversion element 22c held by the flip-flop 324. Calculate the average with the image output of. The average value calculated here is hereinafter referred to as an output value A.

The averaging circuit 35 is a flip-flop 314.
Then, the average of the image output of the photoelectric conversion element 22a held in and the average value calculated by the averaging circuit 34 is calculated. The average value calculated here is hereinafter referred to as an output value B. The averaging circuit 37 calculates the average of the image output of the photoelectric conversion element 22d held in the flip-flop 323 and the average value calculated by the averaging circuit 36. The average value calculated here is hereinafter referred to as an output value C. Calculated output value A. B. C is the storage unit 15 via the switches 14G, 14B, 14R, respectively.
Remembered in.

In the calculation of the image output in the calculation processing section as described above, in the photoelectric conversion element group 22 corresponding to the pixel to be read here, first, the photoelectric conversion elements 22b and 22c each having a green filter are respectively processed. Exists in both the first row and the second row, so these two photoelectric conversion elements 22b, 22
The average value of the outputs of c is set as the output value for the light of that color.

On the other hand, the photoelectric conversion element 22a provided with the red filter exists only in the first row of the photoelectric conversion element group 22 and does not exist in the second row. Further, the photoelectric conversion elements 21 and 23 adjacent to the photoelectric conversion element group 22 are present in the second row.

From this, the output of this photoelectric conversion element in the second row of the photoelectric conversion element group 22 is set to the adjacent photoelectric conversion element group 2
The average value of the outputs of the photoelectric conversion elements 21c and 23c in the second row of 1 and 23 is used. The average of this average value and the photoelectric conversion element 22a in the first row of the photoelectric conversion element group 22 is used as the output of the photoelectric conversion element of the photoelectric conversion element group 22 provided with the red filter.

Similarly, the photoelectric conversion element 22d provided with the blue filter exists only in the second row of the photoelectric conversion element 22,
It doesn't exist in the first line. Further, the photoelectric conversion elements 21 and 23 adjacent to the photoelectric conversion element group 22 are present in the first row.

From this fact, the output of this photoelectric conversion element in the first row of the photoelectric conversion element 22 is adjacent to the photoelectric conversion element group 21,
The average value of the outputs of the photoelectric conversion elements 21b and 23b in the first row of 23 is used. Then, the average of this average value and the photoelectric conversion element 22d in the second row of the photoelectric conversion element group 22 is used as the output of the photoelectric conversion element of the photoelectric conversion element group 22 provided with the blue filter.

Therefore, the photoelectric conversion elements provided with filters of green, red, and blue colors are present in the first and second rows of the photoelectric conversion element group corresponding to the pixel to be read, or in the first row.
If it does not exist in either the first row or the second row, it is corrected by the neighboring photoelectric conversion element groups. For this reason, even if the thin line extending in the main scanning direction extends only to the first row or the second row of the photoelectric conversion element group, an output capable of faithful color reproduction can be obtained.

At t2 in FIG. 5, the switching devices 14G, 1
By inputting the timing pulse (f) to 4B and 14R, the switchers 14G, 14B and 14R send the signals sent from the G'line, B'line and R'line to the storage section 16, respectively. It is switched.

In the case of this second pattern, as shown in FIG. 7, for example, the flip-flop 316 holds the image information read by the photoelectric conversion element 22a provided with a red filter, and the flip-flop 326 is held. Holds the image information read by the photoelectric conversion element 22c having a green filter.

The flip-flop 315 holds the image information read by the photoelectric conversion element 22b having a green filter, and the flip-flop 325 holds the image information read by the photoelectric conversion element 22d having a blue filter. Image information is stored.

Below, the flip-flops 314 to 311
To photoelectric conversion elements 23a, 23b, 24a, 24, respectively.
b holds the read image information, and the flip-flops 324 to 321 respectively store the photoelectric conversion element 23.
The image information read in c, 23d, 24c, and 24d is held.

The timing pulse (d) is averaged by the averaging circuit 3
4, 36, 44, 46 are input to the switch 14G,
From the state of 14B and 14R, the averaging circuits 44 and 4 are used here.
Only the timing pulse input to 6 will be noted. When receiving the timing pulse, the averaging circuit 44 calculates the average of the image output of the photoelectric conversion element 22a held in the flip-flop 316 and the image output of the photoelectric conversion element 24a held in the flip-flop 312. Further, when the averaging circuit 46 receives this timing pulse, the image output of the photoelectric conversion element 22d held in the flip-flop 325,
Photoelectric conversion element 24 held in flip-flop 321
The average with the image output of d is calculated.

Thereafter, the timing pulse (e) is input to the averaging circuits 43, 45 and 47. Then, the averaging circuit 43 calculates the average of the image output of the photoelectric conversion element 23d held in the flip-flop 323 and the image output of the photoelectric conversion element 23a held in the flip-flop 314. The averaging circuit 45 calculates the average of the image output of the photoelectric conversion element 23c held in the flip-flop 324 and the average value calculated by the averaging circuit 44. Averaging circuit 47
Is the photoelectric conversion element 2 held in the flip-flop 313
The average of the image output of 3d and the average value calculated by the averaging circuit 46 is calculated.

The calculated image outputs are output to the switch 1 respectively.
It is stored in the storage unit 15 via 4G, 14B, and 14R. In this way, the same effect as in the case of the first pattern in the arithmetic processing section can be obtained.

[0067]

As described above, in the image input device of the present invention, four photoelectric conversion elements are arranged in two rows and two columns.
The photoelectric conversion element group of is made to correspond to the pixel of the reading object,
For the image sensor provided in the image input device in which a plurality of photoelectric conversion elements are arranged in the main scanning direction, the first row or the second row of the photoelectric conversion element group among the thin lines extending in the main scanning direction.
Even if only the line is applied, an output that enables faithful color reproduction can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image input device according to the present invention.

FIG. 2 is a diagram showing an array of photoelectric conversion element groups provided with color filters in an image sensor provided in the image input apparatus according to the present invention.

FIG. 3 is a block diagram showing a configuration of an arithmetic processing unit of the image input apparatus according to the present invention.

FIG. 4 is a diagram showing a timing chart under the first condition.

FIG. 5 is a diagram showing a timing chart under a second condition.

FIG. 6 is a diagram showing a first pattern of the arithmetic processing unit.

FIG. 7 is a diagram showing a second pattern of the arithmetic processing unit.

FIG. 8 is a diagram illustrating additive color mixing and subtractive color mixing.

FIG. 9 is an array diagram of photoelectric conversion elements provided with respective color filters as viewed from the light receiving surface of the conventional first image sensor.

FIG. 10 is an array diagram of photoelectric conversion elements provided with respective color filters as viewed from the light receiving surface of the conventional second image sensor.

[Explanation of symbols]

 11 image sensor 12a analog / digital conversion unit 12b analog / digital conversion unit 13 arithmetic processing unit 14G switching unit 14B switching unit 14R switching unit 15 storage unit

Claims (1)

[Claims] 1. A photoelectric conversion element group formed by arranging four photoelectric conversion elements in two rows and two columns is made to correspond to a pixel of an object to be read, and a plurality of the photoelectric conversion element groups are arranged in the main scanning direction. In an image input device equipped with an image sensor, among the four photoelectric conversion elements forming each photoelectric conversion element group, among the three primary colors provided corresponding to the two photoelectric conversion elements in a diagonal direction First, which contains the most brightness information
A first color filter for transmitting light of the color, and corresponding to two diagonal photoelectric conversion elements of the four photoelectric conversion elements constituting the photoelectric conversion element group. Seeing the photoelectric conversion elements in the same row of the adjacent photoelectric conversion element groups, the first color among the three primary colors arranged so as to appear alternately for each photoelectric conversion element group in the main scanning direction. An output value of the photoelectric conversion element having second and third color filters for transmitting light of a second or third color to be excluded, and the first filter of the first row obtained from an arbitrary pixel; A first average value calculating means for calculating an average value with an output value having the first color filter in the second row; and the photoelectric conversion element having the second and third color filters of the arbitrary pixel. Output value of the pixel and the pixel of the pixel adjacent to the arbitrary pixel And the third image input apparatus characterized by the average value of the average of the output value of the photoelectric conversion element and a second average value calculating means for calculating for each color with a color filter.