JPS61219258A - Image reader - Google Patents

Abstract

PURPOSE:To obtain an image of an excellent quality without distorting the image in a boundary section of respective reading scanning section by overlap ping the respective image information by the respective scanning and reading. CONSTITUTION:A preceding image information read by a first reading operation is stored in a line buffer through a gate 31 and a next stage image information is stored in a line buffer through a gate 33. The image information in a hatched overlapping portion of the line buffer 35 is supplied to a factor circuit 39, and other image information is supplied directly to an output line buffer 45 without through the factor circuit 39. The image information in the overlapping section of a line buffer 37 is also supplied to a factor circuit 41. Other image informa tion is directly supplied to the output line buffer 45. The respective factor circuits 39, 41 multiply the image informations of the overlapping sections sup plied from the line buffers 35, 37 respectively by predetermined factors K39, K41 to apply a weight, add by an adder 43 to make an average and synthesize, thereby an unnaturalness in a boundary between the respective image informations is removed.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention is directed to, for example, a facsimile machine, which irradiates light onto a particularly color original to be transmitted, receives reflected light or transmitted light from the original, and obtains image information of the original. The present invention relates to an image reading device.

[Technical Background and Problems of the Invention] In general, facsimile machines and the like use a solid-state sensor array consisting of a COD sensor or the like having a wide reading width that can read multiple lines at the same time to read an image of a document to be sent. After scanning the document electronically or mechanically with this sensor array in the first direction, that is, the main scanning direction, and reading image information corresponding to the reading width of the sensor array in one reading operation in the main scanning direction, The scanning operation is repeated by moving the document a predetermined distance in the sub-scanning direction perpendicular to the main-scanning direction, that is, by a pitch corresponding to the reading width of the sensor array, and then performing the next scanning operation in the main-scanning direction. ing.

In addition, in order to read the image of the document in the main scanning direction with the sensor array, light is irradiated to the image reading position of the document, and
A method using a reduction optical system that uses a lens to reduce the entire width of the image in the main scanning direction and focus it on the sensor array, in order to have the sensor array receive the reflected light from the original image. An erect, 1x, close-contact type that supplies image information to the sensor array through a rod lens array that is disposed across the entire width in the main scanning direction, with one end facing the image reading position and the other end facing the sensor array. There is a serial reading method in which image information is sequentially scanned and read in the main scanning direction while moving the sensor array in the main scanning direction.

The method using a reduction optical system and the erect equal-magnification close contact type scan electronically in the main scanning direction, but the method using a reduction optical system requires a larger structure because the optical path length to the lens becomes longer. The erect, same-magnification close-contact type method requires the use of multiple CCD sensors corresponding to the width in the main scanning direction, which has drawbacks such as high cost, whereas the serial reading method is mechanically The scanning method performs scanning in the main scanning direction, and has the advantage of being compact and economical.

Therefore, when configuring a color facsimile machine, it is recommended to adopt a serial reading method in which the sensor array is moved in the main scanning direction and the image information of the document is sequentially scanned in series in the main scanning direction to make it more economical and compact. This is preferable in this respect.

However, this serial reading method reads images while continuously and sequentially scanning the document, and therefore has the drawback that reading scanning takes time and the operation is slow.

In addition, when scanning and reading a document in the main scanning direction, an image of an area corresponding to the reading width of the sensor array is read in one scanning scan, and the image of the sensor array is read in the same manner in the next scanning scan in the main scanning direction. For each reading scan, an image of an area corresponding to the reading width of the sensor array is read. In this way, the image information having the area width read sequentially is sequentially arranged in the sub-scanning direction and reproduced to form the original image on the document, but as described above, the image information has a predetermined reading width. In a sensor array, there are differences in the characteristics of each sensor at both ends in the reading width direction, differences in illuminance at both ends,
Due to differences in mechanical accuracy, such as differences in the distance from each sensor at both ends to the document, and differences in shading correction, the image reading information read by each sensor at both ends of the sensor array may differ from the image readout information obtained by reading the same image. The problem is that they are also different. Therefore, if the read image information is simply lined up sequentially in the sub-scanning direction and reproduced, image discontinuity will occur at the boundaries of each image, that is, at the boundaries of each main scan. This naturally results in image distortion. In particular, in the case of a color image, the distortion appears not only in the shading of the image but also in the hue, making the distortion even more noticeable.

[Objective of the Invention] The present invention has been made in view of the above, and its object is to reproduce a high-quality image without distorting the image at the boundary between each reading scan caused by reading and scanning an image of a document. An object of the present invention is to provide an image reading device that generates image information to be obtained.

[Summary of the Invention 1 To achieve the above object, at least one image reading means scans the original in a first direction while irradiating the original with light to receive reflected light or transmitted light from the original; In a device that reads image information of a document by moving and scanning it relative to the document in a second direction perpendicular to the first direction each time scanning in the first direction is completed, the present invention provides an overlap control means for controlling the movement of the image reading area in each scan so that a part of the image reading area overlaps with the reading; and an overlap control means for controlling the movement of the image in each scan so as to overlap a part of the image reading area; The gist of the present invention is to have a composite image forming means for forming composite image information of the parts.

[Effects of the Invention] According to the present invention, the image information from each scan is read in an overlapping manner, and the composite image information of the overlap area is formed based on both image information of the overlap area. A high-quality image can be obtained without image distortion at the boundary. Further, by arranging a plurality of image reading means at predetermined intervals in the first scanning direction, the reading operation can be made faster.

[Embodiments of the invention] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a perspective view of a color facsimile apparatus to which an image reading apparatus according to a first embodiment of the present invention is applied. In the figure, both sides of the main body 1 extend upward to form left and right side walls 1a and 1b, and a fluorescent lamp 3 is disposed between the upper ends of the side walls 1a and 1b with both ends supported. . Below this fluorescent lamp 3, a pair of guide rails 5.5' are similarly supported parallel to the fluorescent lamp 3 at a predetermined distance between the side walls 1a and Ib. 5′
A carriage 7 for storing a rod array lens, a CCD sensor, etc. therein and for reading image information is disposed in the middle. The carriage 7 also has guide rails 5.
A belt 9 extending parallel to 5' is fixed with screws or the like, and is hung over a pair of left and right platens 11a and 11b disposed near the side walls 1a and 1b. The center of the left platen 11a is connected to the drive shaft of a motor 13, and when the motor 13 rotates, the platen 11a rotates and the belt 9 moves, thereby moving the carriage 7 along the guide rail 5.5. The side wall portions 1a and 1b are moved and scanned in the main scanning direction along '. An original 1 to be transmitted is located between the side wall portions 1a and ib of the main body 1 below the carriage 7.
15 is arranged opposite to the lower surface of the carriage 7.

The end of the document 15 is rotatably disposed between the side walls 1a and Ib of the main body 1, and a pair of document feed rollers 17 and 17' are rotatably driven by a motor (not shown).
When the rollers 17, 17' rotate, the original 15 is held between the O-rollers 17, 17' and moves in the sub-scanning direction perpendicular to the main scanning direction, that is, in the rear part of the main body 1 in the figure. It is designed to be sent in the direction of Further, directly below the fluorescent lamp 3, a side wall portion 1a is provided in parallel with the fluorescent lamp 3.
A rectangular flat light guide member 27 made of a transparent material is provided extending between and supported between Ib.

One end surface in the longitudinal direction of the flat light guide member 27 faces the fluorescent lamp 3 in close proximity, and the opposite end faces the carriage 7 and the document 1.
It is arranged to be located between 5 and 5. As a result, the light from the fluorescent lamp 3 enters the light guide member 27 from one end facing the fluorescent lamp 3, and illuminates the image reading position of the document 15 below the carriage 7 from the other end via the light guide member 27. It has become.

As shown in the exploded perspective view of FIG. 2, the carriage 7 includes a rod array lens 23, which is disposed with one end close to and facing the document 15, and has a reading width Wr of an array structure long in the sub-scanning direction, and this rod. It is arranged in close proximity to the other end of the array lens 23, and has a reading width Wr of an array structure consisting of a plurality of sensors arranged long in series in the sub-scanning direction like the rod array lens 23, and is an O-rad array. It consists of a COD sensor array 21 that reads image information from a document 15 through a lens 23, a connector 19 connected to this COD sensor array 21, and a carriage case 25 that stores each of these parts. The image information of the document 15 read by the COD sensor array 21 is supplied from the connector 19 to a control section to be described later. COD sensor array 21 and rod array lens 2
3 has a long reading width Wr in the sub-scanning direction as shown in the figure, so when the belt 9 moves to read the image of the document 15 in the main-scanning direction as described above, the reading width Wr is long in the main-scanning direction. An image in an area corresponding to the reading width Wr can be read in the same manner with the same operation.

In the structure configured as described above, the carriage 7
is rotated by the motor 13 to rotate the platens 11a and 11b.
and the image 1 of 15 in the main scanning direction via the belt 9!
+ When moving and scanning in the main scanning direction to read information,
Light from the fluorescent lamp 3 is transmitted through the light guide member 27 and illuminates the image reading position of the document 15 facing below the carriage 7 . As a result, the reflected light of the image of the original 15 irradiated with light via the light guide member 27 is detected by the CG[) sensor array 21 via the rod 7 ray lens 23 of the carriage 7, and is equivalent to the reading width Wr. The image of the area is read at one time. When the carriage 7 finishes scanning from end to end in the main scanning direction due to the rotation of the motor 13, the carriage 7 is returned to its original position by the reverse rotation of the motor 13, and the document feeding roller 17.1
The original 115 is sent out a predetermined distance in the sub-scanning direction by the rotation operation 7'. When the feeding operation in the sub-scanning direction is completed, the reading operation of the carriage 7 in the main scanning direction by the motor 13 is started again, and the same operation is repeated thereafter. Image information read by the COD sensor array 21 in this repeated reading operation is supplied to a control section to be described later.

In this case, after one scan of an image in an area corresponding to the reading width Wr is read by the movement of the COD sensor array 21 of the carriage 7 in the main scanning direction, the document feeding rollers 17, 1
If the original IW 15 is sent out a predetermined distance in the sub-scanning direction by 7', it is possible to completely read all images without missing any reading if the original IW 15 is sent out a distance corresponding to the reading width Wr. The movement in the sub-scanning direction is controlled via rollers 17 and 17' so that the feed is sent a distance shorter than the distance corresponding to the width Wr, and as a result, as shown in FIG. The same image portion 29 is read in an overlapping manner during the reading operation and the next reading operation in the main scanning direction. That is, as shown in FIG. 3(a), the first reading operation is performed with the reading width Wr, and then the second reading operation is performed using the first reading width Wr as shown in FIG. 3(b). This is done so that the image portion 29 overlaps with the reading operation. By doing this, all the reading operations overlap, so by processing this overlap part 29 as described later and forming a composite image, image distortion that conventionally occurs at the boundary between each reading scanning operation can be eliminated. This is what we are trying to remove.

FIG. 4 shows an embodiment of an image synthesis processing circuit for forming a composite image of the overlap portion between each image scan. FIG. 5 is a diagram for explaining the effect.

In FIG. 4, the preceding image information read in the above-mentioned first reading operation is passed through a gate 31 to a lineback system formed of, for example, a flip-flop or a memory circuit.
Next stage image information stored in the line buffer 35 and read in the second reading operation is stored in a similar line buffer 37 via the gate 33. Each image information stored in the line buffer 35 and line buffer 37 is read @Wr by one operation of the carriage 7 in the main scanning direction.
The image information read by the CD sensor array 21 is stored in each line buffer 35, 37 in the reading width direction (ie, sub-scanning direction) of the sensor array 21. Therefore, the image information 835. which is output from each line buffer 35.37.
837 are output in parallel in the reading width direction. In each of the image information 835 and 837 shown in FIG. 5, the horizontal axis direction indicates the reading width direction, and the vertical axis direction indicates the level of the image information output from the line buffer 35.degree. 37. In the preceding image information 835 stored in the line buffer 35, as shown in the line buffer 35 in FIG. 4 and the image information S35 in FIG. In the next stage image information 837 stored in the line buffer 37, the line buffer 3 in FIG.
7 and the image information 837 in FIG.
It shows an image portion 29 that overlaps in the reading width direction due to the second reading operation.

In FIG. 4, the image information of the hatched overlap portion of the line buffer 35 is supplied to the first coefficient circuit 39, and the other image information is directly supplied to the output line buffer 45 without going through this coefficient circuit 39. There is. Further, the image information of the overlapping portion of the line buffer 37 indicated by diagonal lines is supplied to the second coefficient circuit 41, and the other image information is directly supplied to the output line buffer 45 without going through the coefficient circuit 41. The outputs of each coefficient circuit 39 and 41 are added by an adder 43 to an output line buffer 45.
is being supplied to. Each coefficient circuit 39.41
39. applies a predetermined coefficient to the image information of the overlapped portion supplied from the line buffers 35 and 37, respectively. to 4
Weighted by multiplying by 1, this coefficient is given 39. is multiplied by 41, weighted, and added in an adder 43, averaged, and synthesized to remove unnaturalness at the boundaries between each piece of image information.

For this reason, the first coefficient circuit 39 has a coefficient of 39 as shown in FIG. has value. Further, the second coefficient circuit 41 has a coefficient 41 as shown in FIG. 5, and this coefficient 41 is opposite to the coefficient 41 in that the value of the left side portion in the figure is smaller in the reading width direction. It has a gradually sloping value. Therefore, the image information of each overlap portion from the line buffer 35.37 processed by each coefficient circuit 39.41 is 39.
．． 41. Image information 839.841 from each coefficient circuit 39.41 subjected to coefficient processing in this way
is added in the adder 43, the image information 845 in FIG.
The images are combined as shown in , and the boundaries between each piece of image information are unnatural and unnoticeable. The image information thus synthesized is supplied from the adder 43 to the output line buffer 45 and inserted between the non-overlapping portions of the image information directly supplied from the line buffers 35 and 37.

FIG. 6 is a block diagram showing another embodiment of the image synthesis processing circuit. In FIG. 4, a coefficient circuit and an adder are used to perform weighting and averaging processing to synthesize the images of the overlapped portion, whereas in FIG. 6, a data selector 47 and a line counter 49
Line buffer 35 in the overlap part using
Advance image information and line buffer from? A composite image is formed by performing image processing such that the next-stage image information from 37 is interwoven alternately with a relatively narrow width.

That is, as shown in FIG. 7(a), for the overlap part 29 between the preceding image information read in the first reading operation and the next stage image information read in the second reading operation, As shown in (b), this overlapping portion is divided into a plurality of narrow width areas in the reading width direction (that is, the sub-scanning direction), and the line counter 49 controls the data selector 47, and the line buffer 35 is used for each area. By alternately extracting the preceding image information from the line buffer 37 and the next image information from the line buffer 37 and supplying them to the output line buffer 45, the preceding image and the next image are alternately intertwined with each other in a narrow width in the overlapped area. It forms a composite image of the parts.

By compositing both images in such a narrow width that they are intertwined with each other alternately, the image of this composite part becomes unnatural and unnoticeable.
Tree/If you intertwine both images alternately with a width narrower than 1m,
This is an application of the property that images appear to be averaged due to human visual characteristics.

FIG. 8 shows still another embodiment of the invention.

In the figure, a lens 53, c
A first reading section 59 consisting of a cotter array 55, an illumination light source 57, a lens 61, and a CCD11? A first reading section 67 consisting of a sensor array 63 and an illumination light source 65 is provided, and by moving the carriage 51 in the main scanning direction along a guide rail 69,
As shown in the figure, the moving distance in the main scanning direction is halved, thereby speeding up the reading process in the main scanning direction.

Further, white reference plates 71 and 73 made of white ceramic for shading correction are arranged on both sides of the original M15 in the main scanning direction, and when the carriage 51 moves to the left end in the figure, the first reading section 59 is moved to the left side. The white reference plate 71 is read, and when the white reference plate 71 is moved to the right, the second reading unit 67 reads the right white reference plate 73, thereby making it possible to correct the read image information due to fluctuations in light from each illumination light source. .

With this configuration, the movement in the main scanning direction is only half, so the speed is increased, and the illumination light source scans the original 15 from an oblique direction laterally with respect to the image reading lens and the CCOt sensor array. Because it is illuminated, when there is only one reading section, the device becomes thicker by the amount of lateral protrusion of the light source when the carriage moves in the main scanning direction.
However, by providing two reading sections in this manner, the size is reduced accordingly.

Although this embodiment describes the case where two reading sections are provided, the invention is not limited to this, and speeding up can be achieved by providing a plurality of reading sections.

This example also uses a color facsimile machine that adopts the serial reading method, but as a CCD sensor array, RGB three-color filters are attached to each dot, and each of the three RGB dots forms one pixel. Constituent CCD
This is a linear array, but is not limited to this.

FIG. 10 shows another embodiment. This embodiment has two image reading units 5 in the main scanning direction as shown in FIG.
9.67, the image reading sections 59.67 are arranged so as to overlap in the main scanning direction as shown in FIG. As shown in the figure, by performing image synthesis processing by weighting and averaging, it is possible to prevent the unnaturalness of the boundary from becoming noticeable due to differences in the characteristics of the two left and right image a reading sections.

That is, the image information read by the left image reading section 59 is stored in the line buffer 79 via the gate 75,
Further, the image information read by the right image reading section 67 is stored in the line buffer 81 via the gate 77. Image information 879. stored in each line buffer 79.81.
Reference numeral 881 indicates image information read in such a manner that the shaded portions overlap as shown in FIG.

Note that in FIG. 12, the horizontal axis direction of the graph showing each information is the main scanning direction. The image information 879 and 881 of the overlapped portion are respectively sent to the coefficient circuit 39 in FIG.
A coefficient circuit similar to 41 is supplied to a first and second coefficient circuit 83°85 with 83°K85;
3.85 with a coefficient of 83. is weighted by multiplying by 85, added as weighted image information 883.885 in an adder 87, and supplied to an output line buffer 89 as composite image information S89. In the composite image formed in this way, the boundary between the left and right images is unnatural and unnoticeable.

FIGS. 13 and 14 show still another embodiment. In contrast to the embodiments shown in FIGS. 10 to 12, which performed weighted averaging and synthesis processing using coefficient circuits and adders, this embodiment uses a data selector 91 and a line counter 93 to eliminate overlapping portions. A composite image is formed by interweaving both image information alternately, and corresponds to the embodiment shown in FIG.

That is, as shown in FIG. 14(a), for the overlapped portion of the left image information read by the left image reading unit and the right image information read by the right image reading unit, the overlapped portion shown in FIG. 14(b) is As shown, this overlapping portion is divided into a plurality of narrow width areas in the sub-scanning direction, and the line counter 93 controls the data selector 91, and the left side image information from the line buffer 79 and the left side image information from the line buffer 81 are sent to each area. By alternately extracting the right side image information and supplying it to the output line buffer 789, the left side image and the right side image are alternately intertwined in a narrow width like the teeth of a comb in the overlapping area to create a composite image of the overlapping area. It is what forms the. By compositing the images in such a way that they are intertwined alternately, the image of this composite part becomes less unnatural and less noticeable, but this is an application of the same property as in the case of Figure 6. It is.

Note that in each of the above embodiments, the position of the boundary between each image is constant, but it does not need to be constant, and may be changed appropriately using, for example, random numbers.
The border becomes even less noticeable.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a color facsimile machine to which an image reading device according to an embodiment of the present invention is applied, and FIG.
3 is an explanatory diagram showing the operation of the device shown in FIG. 1, FIG. 4 is a block diagram of the image synthesis processing circuit that is the main part of the device shown in FIG. 5 is an explanatory diagram showing the action of FIG. 4, FIG. 6 is a block diagram of an image synthesis processing circuit according to another embodiment of the present invention, FIG. 7 is an explanatory diagram showing the action of FIG. 6, and FIG. 9 is an explanatory diagram for explaining the operation of FIG. 8, FIG. 10 is a block diagram of an image synthesis processing circuit according to another embodiment of the invention, and FIG. 11 is a block diagram of another embodiment of the invention. and FIG. 12 are explanatory diagrams showing the action of FIG. 10, FIG. 13 is a block diagram of an image synthesis processing circuit according to yet another embodiment of the present invention, and FIG. 14 is an explanatory diagram showing the action of FIG. 13. It is. 3... Fluorescent light 7.51... Carriage 1
5... Original 21... CCD sensor array 23... Rod array lens 35.37.75.77... Line buffer 39.4
1.83.85...Coefficient circuit 43.87...Adder 47.91...Data selector 49.93...Line counter 59.67...Image reading section Figure 3, Figures 6-7 Figure 11 Figure 13 Figure 12

Claims (3)

[Claims] (1) At least one image reading means scans the document in a first direction while irradiating the document with light, and receives reflected light or transmitted light from the document, and each time scanning in the first direction is completed. In a device that reads image information of a document by moving and scanning it relative to the document in a second direction perpendicular to a first direction, the movement of the image reading means is controlled by changing the image reading area in each scan. An overlap control means for controlling the reading so that a part thereof overlaps, and a combination for forming composite image information of the overlap part based on both image information of the overlap part of each image information read in an overlap manner. An image reading device comprising an image forming means. (2) The composite image forming means is characterized in that it has a weighting means that weights each piece of image information in the overlapped portion by multiplying it by a predetermined coefficient, and an addition means that adds the weighted image information. An image reading device according to claim 1. (3) The composite image forming means includes a division control means that divides the overlapped portion into a plurality of narrow width regions, and a division control means that alternately transmits both image information of the overlapped portion to the plurality of narrow regions divided by the division control means. 2. The image reading device according to claim 1, further comprising an arrangement means for arranging the images.