JPH04367163A - Manual multilevel picture input device - Google Patents

Abstract

PURPOSE:To provide an accurate document reading data correction function realizing high reproducibility of original data in the manual multilevel picture input device. CONSTITUTION:On a reading guide 4 sending an image sensor manually, a standard density display part 5 having a plurarity of density bands changing each optical density in the main scanning direction is provided along the sub scanning direction. At the time of reading the document, the document reading data is corrected based on the difference between the density of the read standard density display part 5 and the standard density of a original blank part. Moreover, a standard density display part 30 may be provided at right angles to the standard density display part 5.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a manual multivalued image input device, and in particular, it corrects errors in image data due to unevenness in a light source or imaging system, as well as variations in photoelectric conversion characteristics between bits of an image sensor. The present invention relates to a manual multivalued image input device for inputting images.

0002

2. Description of the Related Art Main scanning is performed by receiving reflected and scattered light from the surface of a document with a one-dimensional image sensor (hereinafter simply referred to as an image sensor). Image input devices that perform sub-scanning by moving in a direction are widely used. Such image input devices include a shading correction device that corrects errors in document read data due to unevenness in the light source and imaging system, and variations in photoelectric conversion characteristics between bits of the image sensor.

In this shading correction, one density display plate is read prior to reading the original, and the original read data is corrected based on the read data and the difference in standard density of the density display plate that is known in advance. I was doing it.

By the way, some image input devices have a platen for placing an original, and others do not have a platen but have a handy scanner with a built-in image sensor placed directly on the original and manually move it. There is also a manual image input device that performs sub-scanning.

[0005] In an image input device having a platen on which a document can be placed, the density display plate is pasted or printed on the platen.

On the other hand, manual image input devices without a platen have the advantage that image information can be easily input regardless of the shape of the medium on which the image information is written or the position on the medium. Due to the structure, it is difficult to secure a place to provide the concentration display plate. Therefore, when reading a document using a manual image input device, the density of the margin area of the document is regarded as the standard density, and shading correction is performed based on the density of that area, or shading is corrected based on the fixed standard value set at the manufacturing stage. I was making corrections.

[0007]

[Problems to be Solved by the Invention] The above-mentioned prior art has the following problems. When obtaining binary data of a document using a manual image input device, there were no practical problems with the above shading correction method.

However, in recent years, there has been a demand for a multi-value image input device that can input multi-value data such as 64 gradations or 256 gradations and faithfully reproduce half-tone images. . In response to these demands, it has been difficult to accurately correct the halftone (gray) portions using the conventional method of correcting the document scan data using only the margins of the document, that is, the white information, as the standard density. . Furthermore, there is a problem in that correction using fixed standard values at the manufacturing stage cannot cope with changes in the optical system over time.

[0009] The purpose of the present invention is to solve the above problems,
It is an object of the present invention to provide a manual multi-value image input device having an accurate original read data correction function so as to obtain high reproducibility of the original even when inputting a multi-value image.

Another object of the present invention is to provide a manual multivalued image input device that is capable of highly accurate correction of read data of a document using a standard density plate extending in the sub-scanning direction.

[0011]

[Means for Solving the Problems] In order to achieve the above object, the invention of claim 1 provides a method for manually feeding an image sensor in the sub-scanning direction on a reading guide for each optical density in the main scanning direction. A standard density display section having a plurality of density bands with varying density is provided along the sub-scanning direction of the image sensor, and based on the density of the standard density display section read at the same time as the document is read and the difference between each standard density. , is characterized in that the document reading data is configured to be corrected.

[0012] The invention according to claim 2 provides that on the reading guide,
Further, a standard density display section having a plurality of density bands whose optical densities are varied in the sub-scanning direction is provided along the main scanning direction, and the document is corrected using the standard density display section in the main scanning direction. The present invention is characterized in that the read data is further subjected to the correction described in claim 1.

The invention of claim 4 is such that the invention of claim 1 or 2 is carried out for each of the three primary colors, and original reading data read in the three primary colors is corrected using a correction formula created for each color. It is distinctive in that it did so.

[0014]

[Operation] According to the invention of claim 1 configured as described above, the original reading data is corrected each time the original is read one raster in the sub-scanning direction, so that the reading line is adjusted in the sub-scanning direction. CC may occur due to changes in the light intensity of the lamp illuminating the document surface, deflection of the document, or changes in the moving speed of the manual multi-level image input device in the sub-scanning direction.
Even if the sensitivity of the image sensor changes per raster or per bit due to changes in the light accumulation time of D, etc.
Stable and reproducible data can be read across the entire manuscript.

Further, according to the second aspect of the invention, it is possible to detect the reading error of the image sensor for each standard density of the standard density display section, which is known in advance, before reading the original, and based on this detection result, the reading error of the image sensor can be detected. Read data can be corrected. Since the reading error can be detected each time an image is input, it can be corrected in response to changes in the optical system over time. In addition to this, the correction described in claim 1 can be performed, and more stable and reproducible data can be read over the entire document.

According to the fourth aspect of the invention, it is possible to obtain well-corrected color document reading data.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 2(a) is a plan view of a manual multivalued image input device showing an embodiment of the present invention.

In the figure, the handy scanner 1 includes a lamp for illuminating the surface of a document 29, a reading element (image sensor) that receives reflected light from the lamp, and an amount of movement of the handy scanner 1 in the sub-scanning direction. It has a built-in encoder (none of which is shown) for detecting. The output signals of the reading element, encoder, etc. are
It is connected to a control device 3 via a cable 2.

The reading guide 4 is attached to the handy scanner 1.
A vertical member 4a extends in the sub-scanning direction, and a horizontal member 4b perpendicular to the vertical member 4a extends in the main scanning direction, that is, the direction in which the reading elements are arranged. The overall shape is L-shaped.

A density display plate 5 is attached to the vertical member 4a of the reading guide 4 and extends in the longitudinal direction (sub-scanning direction). In this example, the fracture position X-
As shown in the cross-sectional view at X, the concentration display plate 5 is attached to the stepped surface of the bottom part of the vertical member 4a.
It may be formed integrally with the vertical member 4a.

As shown in an enlarged view in FIG. 2(c), the density display plate 5 has density bands each having a width of several mm (for example, 2 mm width) having nine standard densities from black to white. 51 to 59 are printed. These nine concentration bands are just an example, and the present invention is not limited thereto.

FIG. 3 is a block diagram showing the configuration of a control device according to an embodiment of the present invention.

As shown in the figure, this control device is controlled by a microcomputer (CPU) 6.
A program for operating U6 is stored in ROM7. The control device includes a data input circuit 8, a position detection circuit 9,
It includes a lamp control circuit 10, an image data output circuit 11, and a RAM 12 for data storage.

Image data read by the image sensor 13 is taken into the control device from the data input circuit 8, and is stored in the RAM.
12 is stored. The position detection circuit 9 is for detecting the position of the handy scanner 1 based on the amount of movement when the handy scanner 1 is reciprocated in the sub-scanning direction.
Scheduled processing is performed based on signals supplied from an encoder 14 built into the handy scanner 1. A lamp control circuit 10 controls lighting of a lamp (for example, an LED lamp) 15 that illuminates the original.

Furthermore, the image data output circuit 11 performs control to output the multivalued image data processed by the control section to the outside.

Next, the image input operation of this embodiment will be explained. The image input operation includes an operation of reading the density of the density display plate 5 and an operation of reading the original density.

First, an outline of the image input operation will be explained. As shown in FIG. 2(a), the reading guide 4 is placed on top of the document in preparation for the reading operation, and then two sides of the handy scanner 1 are attached to the vertical member 4a and the horizontal member 4b of the reading guide 4. The reading start position, that is, the home position of the handy scanner 1 is determined by bringing the scanner into contact with each of the scanners.

Next, one line of data consisting of the density display plate 5 and original density is read from the image scanner,
The document density read data is corrected based on the density read data of the density display plate 5. Correction of original density reading data is processed in real time for each reading line.

Next, the operation of the control device for image input will be explained in detail. FIG. 4 is a flowchart showing the image input operation.

In the figure, first, in step S1, the lamp 15 is turned on. When the light output of the lamp becomes stable, the process proceeds to step S2.

In step S2, the standard concentration plate section 5
Read one raster of data including. The read density data of the density display plate 5 and the document portion are stored in a predetermined storage area in the RAM 12 or in a line memory (not shown).

Next, the process proceeds to step S3, where a density data correction formula, which will be described later, is calculated. This correction formula is calculated by first detecting the maximum and minimum density values from the data read by the image sensor 13 on the document portion, and then selecting from the known density data on the density display plate 5 that is greater than or equal to the maximum value. The nearest density band and the density band that is less than or equal to the minimum value and closest to it are determined. Next, a predetermined number of intermediate density bands are determined by equally dividing the plurality of density bands sandwiched between these density bands. And image sensor 1
The difference between the output data for each of the density bands of No. 3 and the known density data of these density bands is detected, and a correction formula is calculated based on this.

In step S4, one line of the original is read, and this read data is corrected according to the correction formula. In step S5, the corrected data for one line is output to another device (not shown). In step S6,
Determine whether reading and correction of the original have been completed. If the determination in step S6 is negative, step S2
Then, the density of the next reading line is read, and the correction is made by repeating the above process.

[0034] In this way, the process continues until the determination in step S6 becomes affirmative, and correction of the image read data of the original is performed in real time in response to the reading operation.

Next, the process of step S3 will be explained in detail with reference to the flowchart of FIG.

After the process of step S2 in FIG.
When the raster original data is read, step S in FIG.
Proceeding to step 31, the maximum and minimum density values in the one raster document data are detected. Next, in step S32, from among the density bands 51 to 59 of the standard density plate 5, a density band A with a known density that is greater than or equal to the maximum value of the document data and closest to this is determined. Subsequently, in step S33, the density bands 51 to 5 of the standard density plate 5 are
9, a density band B with a known density that is less than or equal to the minimum value of the document data and closest to this is determined.

Next, the process proceeds to step S34, where an appropriate number of predetermined intermediate density bands are determined from the density bands A to B. Preferably, the density bands are determined to equally divide the density bands A to B.

For example, as shown in FIG. 6, the maximum and minimum values of the reading density of one raster of the original are "53", respectively.
”, “8”, the steps S32, S
At step 33, the densities "55" and "7" of the density band of the standard density plate 5 are respectively determined. Next, if it is determined in advance that two density bands are determined from the maximum and minimum densities "55" to "7", in step S34, the density bands of the standard density plate 5 are "39" and "7". 23'' is determined.

[0039] The process then proceeds to step S35, where a process of calculating the first correction formula is performed. That is, as shown in FIG. 7, the concentration band number 2 of the standard concentration plate 5
, 4, 6, and 8 are the values shown in column A, and their read densities are 8, 25, 38, and 53, respectively, as shown in column B. 8～
25 to known concentrations 7-23, concentrations 26-38 to known concentrations 24-39, and concentrations 39-53 to known concentrations 40-
A correction formula moving to step 55 is calculated.

This correction formula is as follows.

Correction formula for transferring density values 8 to 25 to known density values 7 to 23 Correction value = 7 + (23-7) x (input data - 8) ÷ (25-8)
...(1) Correction formula for transferring the density values 26 to 38 to the known density values 24 to 39 Correction value = 24 + (39 - 24) x (input data - 26) ÷ (38
-26)...(2) Correction formula for transferring the density values 39 to 53 to the known density values 40 to 55 Correction value = 40 + (55 - 40) x (input data - 39) ÷ (53
-39)...(3) Through the above processing, the maximum and minimum density values of the scanned data of the original are forcibly corrected to the white (density 63) and black (density 0) of the density display plate 5, respectively. Since the density can be corrected according to the maximum and minimum density values of the read data (in the above example, "55" and "7"), the read data can be corrected with high precision. Can be done.

Next, referring to the functional block diagram of FIG.
The operation of original data correction according to the present invention will be explained.

20 is the handy scanner 1 (FIG. 2(a)
This is a line memory that stores one raster of data including a standard density plate portion read by an image sensor (see ). As shown in the figure, this line memory 20 stores data 20a for one raster of the original portion and read data 20b of the standard density plate 5.

Reference numeral 21 denotes a maximum and minimum value detecting section for detecting the maximum and minimum values of the density when the data 20a of the document portion is stored in the line memory 20. A memory 22 stores known concentration data for each concentration band of the standard concentration plate 5.

23 determines a density band to be used for correction processing from the maximum and minimum density values of the data 20a of the original portion detected by the maximum and minimum value detection section 21 and the known density data 22. , and then a correction processing control section that supplies data corresponding to the density band to a comparator and a correction formula, which will be described later. The correction processing control unit 23 mainly performs steps S32 to S in FIG.
35 processes are performed.

Comparators 24a to 24c determine the density range to which each bit of the read data of the original portion read from the line memory 20 belongs. Comparators 24a-24
The reference value of c is set by the correction processing control section 23.

25a to 25c are the comparators 24a to 24
The correction equation is enabled by the output of c. For example, 25a is the correction formula (1), 25b is the correction formula (2), and 25c is the correction formula (3). Preferably, the format of the correction equation is stored in the correction equations 25a to 25c, and variables that change for each raster in the correction equation are set for each raster by the correction processing control section 23.

Reference numeral 26 denotes a line memory that stores the correction data of the document portion corrected by one of the correction formulas 25a to 25c and outputs it to another device (not shown).

The read data 20a of the original portion stored in the line memory 20 is sent bit by bit to the comparators 24a to 2.
Sent to 4c. When the input data of the comparator 24a is 8≦input data≦25, the comparator 24b detects that the input data is 2.
When 5<input data≦38, the comparator 24c outputs, for example, a high level signal when the input data is 38<input data≦53. The correction formulas 25a to 25c are enabled when they receive high level signals from the comparators 24a to 24c, and correct the density of 1 bit of the input read data 20a of the document portion. The corrected data is sent to the line memory 26 and temporarily stored.

As described above, when the correction processing for one raster of the document portion including the standard density plate 5 is completed, the data of the next one raster, which has been moved by a predetermined width in the sub-scanning direction, is transferred from the image sensor to the line memory 20. and the same correction process as above is executed.

As described above, according to this embodiment, the correction process is performed each time one line of original data is read while moving the manual multivalued image input device in the sub-scanning direction. During this time, the amount of light from the lamp that illuminates the document surface may change, the document may sag, or the light accumulation time of the CCD may change due to changes in the moving speed of the manual multilevel image input device in the sub-scanning direction. Even if the sensitivity of the image sensor changes every raster or every bit, stable and reproducible data can be read over the entire document.

Further, the maximum and minimum values of the density of the read data of the original are respectively determined from the white (density 6) of the density display plate 5.
3) Since the density is corrected according to the maximum and minimum density values of the read data without forcibly correcting it to black (density 0), the read data can be corrected with high precision. It can be carried out.

Next, a second embodiment of the present invention will be described. In this embodiment, as shown in FIG.
In addition to the first density display plate 5 of the first embodiment, a second density display plate 30 extending in the longitudinal direction (main scanning direction) of the horizontal member 4b is provided. The feature is that it also performs density correction based on .

The second concentration display plate 30 is shown in FIG.
(b) and (a) As shown in the enlarged circle in the figure, each has a standard density of 5 levels from black to white.
Density bands 31 to 35 of m width (for example, 2 mm width) are printed. These five concentration bands are just an example, and the present invention is not limited thereto.

Next, the image input operation using the reading guide 4 configured as described above will be explained with reference to the flowchart shown in FIG. In the figure, first, step S11
The lamp 15 is turned on. When the light amount of the lamp 15 becomes stable, the process proceeds to step S12, and it is determined based on the output signal of the encoder 14 whether the image sensor is positioned above the expected density band of the second density display plate 30.

If the determination in step S12 is affirmative, the process proceeds to step S13, where the density of one line of the scheduled density band is read, and the read density data of the second density display plate 30 is stored in a predetermined memory in the RAM 12. Store in area.

In step S14, it is determined whether all the densities on the second concentration display plate 30 have been read. This determination may be made, for example, based on the number of times the data has been stored in the storage area, or may be made based on the amount of movement of the handy scanner 1 from the home position.

If the determination in step S14 is negative, the process returns to step S12, and it is determined whether the image sensor is positioned above the next density band. If the determination in step S4 is affirmative, the process proceeds to step S15, where a concentration data correction formula, which will be described later, is calculated. This correction formula is calculated based on the output data of the image sensor 13 and the second density display plate 3.
0 and the known density data of each of the density bands 31 to 35 is detected and calculated based on this.

In step S16, one raster of original data including the density bands 51 to 59 of the first density display plate 5 is read. Further, in step S17, density correction in the main scanning direction is performed on one raster worth of data including the density bands 51 to 59.

For example, as shown in FIG. 10, the known density levels of the density bands 31 to 35 of the second density display plate 30 are the values shown in column A, and the actual reading level is Assuming the values shown in column B, Figure 7
A correction formula is created in the same manner as explained in .

The results of the correction formula are shown below.

Correction formula for shifting the value of range a to range a1. Correction value = 0 + (15-0) x {input data - (-1)} ÷ {15
-(-1)}...(4) Correction formula for shifting the value of range b to range b1. Correction value = 16 + (31-16) x (input data - 16) ÷ (30
-16)...(5) Correction formula for shifting the value of range c to range c1. Correction value = 32 + (47-32) x (input data - 32) ÷ (46
-32)...(6) The correction formula for shifting the value of range d to range d1 is shown in equation (4).

Correction value=48+(63-48)×(input data-47)÷(63
-47)...(7) For example, if the input data, that is, the image reading data is "12
”, this value corresponds to the range “-3” to “16”, that is, range a, so use equation (4) to find the correction value. Also, if the input data is “54”, it is “47”. ~“6
Since this corresponds to the range 1'', that is, the range d, the correction value is found using equation (7).

As described above, when the correction of data for one raster including each density band of the first density display plate 5 is completed using the first correction formula, step S1
Proceed to step 8. The corrections in steps S18 and S19 are the same as the processes in steps S3 and S4 in FIG. Therefore, detailed explanation will be omitted.

As described above, when the correction processing of one raster's worth of original data in the main and sub-scanning directions is completed, the process advances to step S20, and the corrected data is output to another device.

In step S21, it is determined whether or not all the data for one page of the original has been read by the image sensor of the manual multivalued image input device.If negative, the process returns to step S16 and sub-scanning is performed. The next one moved slightly in the direction
Raster data is read. Thereafter, the same processing as described above is executed.

[0067] If the determination in step S21 is affirmative, the series of processes described above ends.

As described above, according to this embodiment, each time one line of original data is read by moving in the sub-scanning direction, the main,
Since corrections are made based on the auxiliary density display plates 30 and 5, density corrections based on changes over time in the sensitivities of the lamps, optical systems, and image sensors can be performed first by corrections in the main scanning direction. In addition, due to correction in the sub-scanning direction, while the reading line is moved in the sub-scanning direction, the light intensity of the lamp that illuminates the document surface may change, the document may be deflected, or the sub-scanning of a manual multi-level image input device may change. Even if the sensitivity of the image sensor changes on a raster-by-raster or bit-by-bit basis due to a change in the light accumulation time of the CCD due to a change in the moving speed in the direction, the density can be corrected. Therefore, according to the manual multivalued image input device of this embodiment, stable and reproducible data can be read over the entire document.

Next, a third embodiment of the present invention will be described. In this embodiment, the reading density of original data is corrected using a color manual multi-value image input device in the same way as in the first and second embodiments. The reading guide 4 shown in FIG. 2 or 8 is used as a reading guide for correcting the reading density.

FIG. 11 is a flowchart of the process of correcting the density of original data read by the color image sensor using the first and second density display plates 30 and 5 using the one shown in FIG. 8 as a reading guide. show.

[0071] In step S41, first, the lamp is turned on,
When the amount of light becomes stable, the process advances to step S42. In step S42, it is determined whether the image sensors for three colors, R, G, and B, are positioned on the planned density band of the second density display plate 30. When it is determined that the image is located on the planned density band, the process advances to step S43, and the density of one line of the density band is read for each color of R, G, and B. Then, the process advances to step S44, where it is determined whether all density bands 55 to 51 have been read. If this determination is negative, the process returns to step S42, and the next density band is read by the R, G, and B color image sensors.

In the above manner, all density bands 31 to 3
5 is read, the process advances to step S45, and R, G,
A first correction formula is created for each B color. This correction formula is created in the same manner as described in the second embodiment.

Next, the process advances to step S46, and one raster of data including each of the density bands 51 to 59 of the first density display plate 5 is read for each color of R, G, and B. The read data is temporarily stored in line memories for each color of R, G, and B.

In step S47, density correction is performed on the data stored in the line memory using the first correction formula. In step S48, density bands 31 to 31
A second correction formula for each color of R, G, and B is created from the 35 known density levels and the reading level corrected in step S47. An example of how to create this correction formula is shown in Figure 12.
will be explained in detail later.

In step S49, density correction is performed bit by bit using the second correction formula on one raster worth of original data to which the first correction has been applied. When the correction of one raster's worth of original data is completed in this way, the process advances to step S50, and the corrected data of each color of R, G, and B is output to another device.

In step S51, it is determined whether all the data for one page of the original has been read. If this determination is negative, the process returns to step S46 and the document is moved a little in the sub-scanning direction. The read raster is scanned. Then, the same process as above is repeated.

[0077] As a result of repeating the above processing, if the judgment in step S51 becomes affirmative, the series of processing described above ends.

Next, a specific example of step S48 is as follows.
This will be explained with reference to FIG. In step S47 of FIG. 11, when the data for one raster of each color of R, G, and B is corrected in the main scanning direction, step S47 of FIG.
Proceeding to step 481, the maximum value and minimum value of each color are detected from one raster document data of each color of R, G, and B.

Next, the process advances to step S482, and the known density bands that are equal to or greater than the maximum value of the document data and are closest to it are selected from the first standard density plate 5 such as R, G,
It is determined for each color of B. Subsequently, the process proceeds to step S483, where density bands of known densities that are less than and closest to the minimum value of the document data are determined for each color of R, G, and B from the first standard density plate 5. .

Next, the process advances to step S484, and from among the maximum and minimum density bands determined in steps S482 and S483, a predetermined appropriate number of intermediate density bands are selected for each color of R, G, and B. It is determined. Then, the process proceeds to step S485, where R, G
, B, a second correction formula is calculated for each. The method of calculating this second correction formula is the same as that described in the first embodiment.

As is clear from the above description, according to this embodiment, density correction due to changes over time in the sensitivity of the lamp, optical system, and image sensor, deflection of the original due to scanning the original, It is possible to read high-quality, reproducible color original data that has been subjected to density correction for changes in the light accumulation time of the CCD due to changes in the moving speed in the sub-scanning direction of the manual multi-level image input device. .

[0082]

As is clear from the above description, the invention according to claim 1 uses a density display plate extending in the sub-scanning direction to correct the density of each bit every time one raster of original data is read. Therefore, the deflection of the original due to scanning the original by moving the manual multi-value image input device in the sub-scanning direction, and the change in light accumulation time of the CCD due to changes in the moving speed of the manual multi-value image input device It is also possible to correct density unevenness in read data due to changes, etc., and it is possible to read original data with high quality and reproducibility.

According to the invention of claim 2, in addition to the correction of claim 1, it is possible to correct errors in image data due to irregularities in the light source and imaging system, as well as variations in photoelectric conversion characteristics between bits of the image sensor. . Therefore, errors in image data caused by changes in the device over time can be easily corrected, and original data with better quality and reproducibility can be read.

Furthermore, according to the fourth aspect of the invention, color original data with good quality and reproducibility can be read.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing the configuration of a first embodiment of the present invention.

FIG. 2 is a plan view of a manual multivalued image input device.

FIG. 3 is a block diagram showing the hardware configuration of a manual multivalued image input device.

FIG. 4 is a flowchart of a correction operation in the first embodiment.

5 is a flowchart showing details of step S3 in FIG. 4. FIG.

FIG. 6 is an explanatory diagram of the operation of FIG. 5.

FIG. 7 is an explanatory diagram of the operation of creating a correction formula.

FIG. 8 is a plan view of a reading guide used in the second embodiment.

FIG. 9 is a flowchart of a correction operation in a second embodiment.

FIG. 10 is an explanatory diagram of the operation of creating a correction formula.

FIG. 11 is a flowchart of a correction operation in the third embodiment.

12 is a flowchart showing details of step S48 in FIG. 11. FIG.

[Explanation of symbols]

4... Reading guide, 5... First concentration display plate, 30...
First concentration display plate, 20, 26...line memory,
21... Maximum and minimum value detection section, 23... Correction processing control section, 2
4a to 24c...Comparators, 25a to 25c...Correction formulas.

Claims (4)

[Claims] 1. A handy scanner having a one-dimensional image sensor that receives reflected and scattered light from a document is configured to perform sub-scanning by manually feeding it in a direction perpendicular to the main-scanning direction of the one-dimensional image sensor. In the manual multivalued image input device, the one-dimensional image sensor is provided along the sub-scanning direction of the one-dimensional image sensor on the reading guide for smoothly manual feeding of the handy scanner, and each optical density is changed in the main-scanning direction. a standard density display means having a plurality of density bands, and a read density of the plurality of density bands in one raster of original density data including the plurality of density bands of the standard density display means read by the one-dimensional image sensor; and a means for detecting a difference in known density for each density, a correction formula calculation means for calculating a correction formula for correcting the original density data based on the difference, and correcting the original density data using the correction formula. What is claimed is: 1. A manual multivalued image input device, characterized in that it is equipped with a processing means for processing the image. 2. A handy scanner having a one-dimensional image sensor that receives reflected and scattered light from a document is manually fed in a direction perpendicular to the main scanning direction of the one-dimensional image sensor to perform sub-scanning. In the manual multivalued image input device, the one-dimensional image sensor is provided along the main scanning direction of the one-dimensional image sensor on the reading guide for smoothly manual feeding of the handy scanner, and the optical density of each is varied in the sub-scanning direction. a first standard density display means having a plurality of density bands arranged along the sub-scanning direction;
a second standard density display means having a plurality of density bands whose respective optical densities are varied in the main scanning direction; and a storage means for storing the density of the first standard density display means read prior to reading the document. and detecting the difference between the read density of the first standard density display means and the known density for each density, and calculating a first correction formula for correcting the read document density data based on the difference. 1 correction formula calculating means and the document density data including a plurality of density bands of the second standard density display means read after reading the density of the first standard density display means, using the first correction formula. and a second correction that calculates a second correction formula calculated for each density based on the difference between the density of the density band of the second standard density display means after correction and the known density. an expression calculation means, and the second
1. A manual multi-valued image input device comprising processing means for correcting the corrected document density data using the correction formula. 3. The correction formula calculation means according to claim 1 or the second correction formula calculation means according to claim 2 calculates the maximum density of the document read data from the known densities of the plurality of density bands of the standard density display means. Select the concentration that is greater than and closest to the value, the concentration that is less than and closest to the minimum value, and the intermediate concentration between these concentrations, and based on the difference between these concentrations and their corresponding read densities, A manual multivalued image input device, characterized in that it calculates a correction formula. 4. The manual multivalued image input device according to claim 1, wherein a color one-dimensional image sensor is used, and each density band of the standard density display means read by the color one-dimensional image sensor is 1. A manual multi-valued image input device, characterized in that a correction formula is calculated for each of the three primary colors based on the density difference between the two, and read original density data is corrected using the correction formula.