JP2000253242A - Picture reading system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a specified picture inhibitory in duplication at the point of reading the picture and to inhibit the fetching of picture data into a personal computer and the like, for example. SOLUTION: This picture reading system has a resolution conversion means 38 converting picture data which is read by a color image sensor 20 into prescribed resolution and a feature value extraction part 37 segmenting picture data whose resolution is converted into a block unit and extracting the local feature value of a picture for respective blocks that are segmented. The extracted feature value is transferred to the controller of a host computer 2 with picture data which is read and it is decided whether or not the specified picture is contained in the read picture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading system for reading an original and an image reading system including a control device for controlling the image reading device such as a host computer.

[0002]

2. Description of the Related Art In recent years, with the remarkable improvement in the performance of color scanners and color printers as input / output devices of color copiers and personal computers, it has become possible to easily obtain high-precision color reproductions. I have.

In particular, since a color copying machine is the simplest means for obtaining a color copy, an image recognition device for recognizing a specific image and prohibiting or restricting copying has been mounted.

[0004]

However, an effective method has not yet been established for a color scanner or a color printer alone, though there is a possibility of being abused.

[0005] Furthermore, recently, with the rapid spread of the Internet, the opportunity to come into contact with various images at the individual level has been increasing. By performing image processing such as gradation correction, color correction, and edge correction, higher quality printing is possible.

[0006] If an image whose duplication is originally prohibited on the network is made public, a crime such as taking in the image, performing various image processing with a computer, and outputting the image with a color printer may be caused. It could be.

That is, it is necessary to detect a specific image whose duplication is prohibited from the image to be handled, to prohibit reading of the specific image if the image is a specific image, and to prevent generation of a counterfeit. Further, from the viewpoint of preventing a crime caused by so-called mind, it is necessary to detect a specific image at the time of reading and prohibit the image from being taken into, for example, a personal computer.

The present invention has been made in view of the above problems, and has as its object to provide an image reading system capable of preventing reading of a specific image.

[0009]

According to the present invention, there is provided an image reading system comprising: an image reading device for reading an original and outputting image data; and a control device for controlling the image reading device to obtain image data. Wherein the image reading device outputs at least one of the read image data and the local feature amount of the image in accordance with an instruction from the control device. By performing a local feature extraction process that requires high speed on the image reading device side, the load on a control device such as a host computer can be reduced, and a specific image can be determined at high speed.

An image reading system according to the present invention comprises:
An image reading system that reads an original and outputs image data, and an image reading system that includes a control device that controls the image reading device and obtains image data, wherein the control device controls the image reading device to obtain an image data. A local feature value is obtained, and it is determined based on the local feature value whether a specific image exists in the obtained image data. This makes it possible for a control device such as a host computer to determine the presence or absence of a specific image.

In the image reading system according to the present invention, the image reading device performs the transfer of the image data and the transfer of the local feature value by the time the transfer of all the image data is completed in accordance with an instruction of the control device. Repeat alternately. This allows the image reading device to output local features using a small amount of memory resources,
On the control device side such as the host computer, the local feature amount can be divided and received, so that the determination time as to whether or not the specific image exists in the obtained image data can be substantially shortened. .

An image reading system according to the present invention comprises:
A pre-scan mode for roughly reading a document at a predetermined resolution, a reading area for an image obtained in the pre-scan mode, and a main scan mode for reading by specifying a reading resolution; It is determined whether or not the specified image is included in the received image data.
Thus, the specific image can be determined before the main scan for reading the image data with high resolution.

An image reading system according to the present invention comprises:
If it is determined that the specific image is included in the image data obtained in the prescan mode, reading in the main scan mode is prohibited. Thereby, reading of the image data of the specific image can be prohibited.

An image reading system according to the present invention comprises:
If it is determined that the specific data is included in the image data obtained in the pre-scan mode, reading the image at a higher resolution than in the pre-scan mode in the main scan mode is prohibited. As a result, image reading at a resolution sufficient for image formation can be prohibited.

An image reading system according to the present invention comprises:
If it is determined that the specific image is included in the image data obtained in the prescan mode, reading the image in a predetermined resolution range in the main scan mode is prohibited. As a result, it is possible to prohibit only reading in a resolution range in which a specific image can be sufficiently reproduced when printed.

An image reading system according to the present invention comprises:
If it is determined that the specific image is included in the image data obtained in the pre-scan mode, reading the color image in the main scan mode is prohibited. Thereby, reading of a color specific image represented by a bill or the like can be prohibited.

An image reading system according to the present invention comprises:
When it is determined that the specific image is included in the image data obtained in the pre-scan mode, predetermined image processing is performed on the image data read in the main scan mode. As a result, it is possible to clearly recognize that the print is a forgery even when printed.

An image reading system according to the present invention comprises:
A pre-scan mode for coarsely reading a document at a predetermined resolution, a read area for an image obtained in the pre-scan mode, and a main scan mode for reading by specifying a read resolution; It is determined whether or not the specified image is included in the received image data. Thus, it is possible to prevent a malicious act of reading a non-specific image in the pre-scan and reading a specific image in the main scan.

An image reading system according to the present invention comprises:
When it is determined that the specific image is included in the image data obtained in the main scan mode, predetermined image processing is performed on the read image data. As a result, it is possible to clearly recognize that the print is a forgery even when printed.

An image reading system according to the present invention comprises:
The prescan mode is omitted, a copy scan mode for reading a predetermined area at a predetermined resolution is provided, and it is determined whether or not a specific image is included in the image data obtained in the copy scan mode. This makes it difficult to copy a specific image in a system having a copy function of directly printing image data read using the image reading system.

An image reading system according to the present invention comprises:
When it is determined that the specific image is included in the image data obtained in the copy scan mode, predetermined image processing is performed on the read image data. This makes it possible to recognize that the copy is a counterfeit.

An image reading system according to the present invention comprises:
Image scaling processing is performed as the predetermined image processing. Thus, even if a non-specific image is erroneously determined to be a specific image, actual harm to the user can be minimized.

An image reading system according to the present invention comprises:
As the predetermined image processing, level conversion or requantization is performed on the value of each pixel. Since these processes are simple, the process when it is determined that the image is the specific image can be performed at high speed.

An image reading system according to the present invention comprises:
A predetermined pattern signal is superimposed on the image read as the predetermined image processing. As a result, even when the read image data is distributed using a network or the like, it is possible to specify the image reading apparatus that has performed the reading.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image reading system according to a first aspect of the present invention comprises an image reading device for reading a document and outputting image data, and a control device for controlling the image reading device to obtain image data. In the image reading system, the image reading device outputs at least one of read image data and a local feature amount of the image according to an instruction of the control device. By performing a local feature extraction process that requires high speed on the image reading device side, the load on a control device such as a host computer can be reduced, and a specific image can be determined at high speed.

An image reading system according to a second aspect of the present invention is an image reading system comprising an image reading device for reading a document and outputting image data, and a control device for controlling the image reading device to obtain image data. The control device controls the image reading device to obtain a local feature amount of the image, and determines whether a specific image exists in the obtained image data based on the local feature amount. I do. This makes it possible for a control device such as a host computer to determine the presence or absence of a specific image.

[0027] In the image reading system according to the third aspect of the present invention, the image reading device performs the transfer of the image data and the local transfer by the time the transfer of all the image data is completed in accordance with an instruction from the control device. The transfer of the feature amount is alternately repeated. As a result, the image reading device can output the local feature amount using a small amount of memory resources, and the control device such as a host computer can perform the output of the local feature amount.
Since the local feature amount can be divided and received, it is possible to substantially shorten the determination time for determining whether or not the specific image exists in the obtained image data.

According to a fourth aspect of the present invention, there is provided an image reading system, wherein a prescan mode for roughly reading a document at a predetermined resolution, a reading area and a reading resolution for an image obtained in the prescan mode are designated. And a main scan mode for reading the image data, and determining whether or not the specific image is included in the image data obtained in the prescan mode. Thus, the specific image can be determined before the main scan for reading the image data with high resolution.

The image reading system according to a fifth aspect of the present invention prohibits reading in the main scan mode when it is determined that a specific image is included in the image data obtained in the prescan mode. Thereby, reading of the image data of the specific image can be prohibited.

The image reading system according to claim 6 of the present invention, when it is determined that a specific image is included in the image data obtained in the pre-scan mode, in the main scan mode, Prohibit reading images at high resolution. As a result, image reading at a resolution sufficient for image formation can be prohibited.

In the image reading system according to the present invention, when it is determined that a specific image is included in the image data obtained in the prescan mode, a predetermined resolution is set in the main scan mode. Prohibit reading images in the range. As a result, it is possible to prohibit only reading in a resolution range in which a specific image can be sufficiently reproduced when printed.

In the image reading system according to the present invention, when it is determined that a specific image is included in the image data obtained in the pre-scan mode, a color image is read in the main scan mode. Ban. Thereby, reading of a color specific image represented by a bill or the like can be prohibited.

In the image reading system according to the ninth aspect of the present invention, when it is determined that a specific image is included in the image data obtained in the prescan mode, the image reading system reads the image data read in the main scan mode. Then, predetermined image processing is performed. As a result, it is possible to clearly recognize that the print is a forgery even when printed.

An image reading system according to a tenth aspect of the present invention specifies a prescan mode in which an original is roughly read at a predetermined resolution, a read area and a read resolution for an image obtained in the prescan mode. And a main scan mode in which the specific image is included in the image data obtained in the main scan mode. Thus, it is possible to prevent a malicious act of reading a non-specific image in the pre-scan and reading a specific image in the main scan.

In the image reading system according to the present invention, when it is determined that a specific image is included in the image data obtained in the main scan mode, a predetermined image is read from the read image data. Perform processing. As a result, it is possible to clearly recognize that the print is a forgery even when printed.

According to a twelfth aspect of the present invention, in the image reading system, the prescan mode is omitted, and a copy scan mode for reading a predetermined area at a predetermined resolution is provided. It is determined whether or not a specific image is included in the image data. This makes it difficult to copy a specific image in a system having a copy function of directly printing image data read using the image reading system.

In the image reading system according to the present invention, when it is determined that a specific image is included in the image data obtained in the copy scan mode, a predetermined image is read from the read image data. Perform processing. This makes it possible to recognize that the copy is a counterfeit.

An image reading system according to a twelfth aspect of the present invention performs image scaling processing as the predetermined image processing. Thus, even if a non-specific image is erroneously determined to be a specific image, actual harm to the user can be minimized.

The image reading system according to a thirteenth aspect of the present invention performs level conversion or requantization on the value of each pixel as the predetermined image processing. Since these processes are simple, the process when it is determined that the image is the specific image can be performed at high speed.

In the image reading system according to the present invention, a predetermined pattern signal is superimposed on the image read as the predetermined image processing. As a result, even when the read image data is distributed using a network or the like, it is possible to specify the image reading apparatus that has performed the reading.

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

(Overview of Image Reading System)
FIG. 1 is a diagram showing an entire image reading system to which the present invention is applied.

In FIG. 1, reference numeral 1 denotes an image reading device which reads a document and outputs digital color image data and local feature amounts of an image (the local feature amounts will be described later in detail). 2 is a host computer, 3 is, for example, a bidirectional parallel interface or SCSI (Small)
Computer System Interface
e) The image reading device 1 is connected to the host computer 2 by a cable 3. The host computer 2 outputs a plurality of types of commands to the image reading device 1 via the interface cable 3 to obtain image data and local feature amounts of the image. Reference numeral 4 denotes a network connected to the host computer 2. The host computer 2 can transfer image data to another computer (not shown) or an image forming apparatus (not shown) via the network 4.

(Regarding the Structure and Operation of the Image Reading Apparatus) FIG. 2 is a diagram showing the structure of the image reading apparatus 1 in the above image reading system.

In FIG. 2, reference numeral 6 denotes an original glass on which an original to be read is placed. Reference numeral 7 denotes a carriage for scanning and reading a document. The carriage 7 is a shaft not shown,
It is supported by a support member such as a rail, and the movement direction is regulated in one direction. Reference numeral 8 denotes a drive source for driving the carriage, which employs a stepping motor. Reference numeral 9 denotes a driving pulley, and 10 denotes a timing belt. The power generated by the driving source 8 is transmitted to the driving pulley 9 by the timing belt 10. Reference numeral 11 denotes a belt, and 12 denotes a driven pulley. The belt 11 is stretched between the driving pulley 9 and the driven pulley 12, and moves the carriage 7 in the direction d1 and the reverse direction as the driving pulley 9 rotates. An original 13 is placed on the original glass 6, and the original 13 is a carriage 7.
Is read line by line. Reference numeral 14 denotes a document cover, which is supported by a support unit 15 so as to be openable and closable. Reference numeral 16 denotes a reference acquisition position, on which a white reference plate is attached on the original glass. po1 is the home position of the carriage 7, and when the image reading apparatus is on standby, the carriage 7 is always located at the home position po1.

FIG. 3 is a diagram showing the internal structure of the carriage 7 of the image reading apparatus 1.

In FIG. 3, reference numeral 17 denotes a lamp for irradiating the original, 18 denotes an aperture for substantially specifying the image reading position, 19-1 and 19-2 denote reflection mirrors for reflecting light reflected from the original, and 20 denotes optical information. Is an image sensor that converts an image into an electric signal, and 21 is an imaging lens that forms an image on the image sensor 20. The image sensor 20 is fixed inside the carriage 7 and reflects the optical information reflected from the original 13 and reduced and imaged by the reflection mirrors 19-1 and 19-2 and the imaging lens 21 into a pair with the original surface. Read in one relationship.

The operation of the image reading apparatus configured as described above will be described below with reference to FIGS.

When the power of the apparatus is turned on, the carriage 7
Returns to the home position po1 regardless of the initial position. Thereafter, the aperture 18 is moved to the reference acquisition position 16 immediately below the reference plate, the lamp 17 is turned on, the reference plate is actually read, the amplification factor for the analog signal output from the image sensor 20 is determined, and the black and white level is determined. Correction (shading correction). Thereafter, it returns to the home position po1 again, and enters a standby state.

Next, an outline of the image reading operation of the image reading apparatus 1 will be described.

After the reading resolution and the reading range are set by the host computer 2 or the like shown in FIG. 1, when a reading instruction of the document is issued, the lamp 17 is turned on and the driving source 8 is rotated. , Timing belt 1
0, the driving force is transmitted to the carriage 7 via the driving pulley 9, the belt 11, and the driven pulley 12, and the carriage 7 is moved in the direction d1. This direction d1 is called a sub-scanning direction. Immediately before the carriage 7 reaches the head of the area corresponding to the reading range set by the host computer 3, the drive speed is changed from the host computer 3 to a speed corresponding to the reading resolution set in advance, and The reading of the placed document is started. Manuscript 13
Is illuminated by a lamp 17 through the original glass 6,
Light reflected from the original is reflected by reflection mirrors 19-1 and 19-2, and the image sensor 20
The image is reduced and imaged upward, and converted into an electric signal. When the reading operation for the specified reading range ends,
The carriage 7 is moved in the direction opposite to the direction d1 to return to the home position po1.

(Detailed Description of Optical System of Image Reading Apparatus) FIG. 4 is a perspective view showing details of the optical system of the image reading apparatus 1.

In FIG. 4, the reflection mirrors 19-1 and 19-2 are represented by lines for easy viewing. In FIG. 4, 22R is a line sensor array R for reading Red signals, 22G is a line sensor array G for reading Green signals, and 22B is a line sensor array B for reading Blue signals. A color filter corresponding to the color to be read is mounted on the surface of each line sensor array. As described above, in the first embodiment, an image is read using a so-called three-line color sensor. The direction of the line sensor array is referred to as a main scanning direction.

Reference numeral 23R denotes a reading line R indicating a position on the original glass 6 to be read by the line sensor array R.
22G is a reading line G indicating a position on the original glass 6 to be read by the line sensor array G,
Reference numeral 22B denotes a reading line B indicating a position on the document glass 6 read by the line sensor array B. Since the position of the line sensor array for reading each color is different in the three-line color sensor, one position (line) of the document
Cannot be read simultaneously. For this reason, as described later, means for delaying the obtained image data by a predetermined amount is required.

FIG. 5 is a block diagram showing the image data processing of the image reading apparatus 1.

In FIG. 5, reference numeral 20 denotes an image sensor, which is composed of a three-line sensor array as described above, and outputs analog image information in R, G, and B color line units. Reference numeral 24 denotes an amplifier and an A / D converter, which amplifies analog image information output from the image sensor 20 with a predetermined gain and converts an analog signal amplified by the A / D converter into a digital signal. 2
Reference numeral 5 denotes a shading correction unit that normalizes the input digital image signal with respect to a previously acquired dynamic range of black and white. Reference numeral 26 denotes a line correction unit which corrects the difference in the line sensor array position of each color described above, and makes the R, G, and B lines equivalent to reading the same original position (line). The operation of the line correction unit 26 will be described later in detail. A first resolution conversion unit 27 converts the resolution of the image data output from the line correction unit 26 based on the parameters specified by the host computer 2. First resolution converter 27
Will be described later in detail. Reference numeral 28 denotes a color processing unit which reduces the influence of unnecessary absorption bands on the spectral spectrum existing in the color filters on the line sensor array, thereby enabling vivid color reproduction. A buffer 29 temporarily stores the image data processed in the above process. This is a means for absorbing a difference in communication speed with the outside and outputting image data to an external device at a higher speed.
Reference numeral 30 denotes an interface unit. In the first embodiment, the image reading device 1 and the host computer 2 are SCSI
(Small Computer System In
The image reading apparatus 1 outputs image data and local feature amounts of an image to be described later to the host computer 2 via the interface unit 30, and also reads a reading range and a reading from the host computer 2. Read parameters such as resolution can be obtained.

Next, reference numeral 32 denotes a CPU for controlling an operation sequence and the like of the image reading apparatus 1. A motor control unit 33 outputs a drive signal (more precisely, an excitation signal for a stepping motor) to a motor 8 for moving the carriage 7 of the image reading apparatus. Reference numeral 34 denotes a line correction unit control signal. The CPU 32 controls the operation of the line correction unit 26 based on the line correction unit control signal 34. Reference numeral 35 denotes a first resolution conversion unit control signal.
2 controls the operation of the first resolution conversion unit 27 by the first resolution conversion unit control signal 35. 36 is a motor control unit control signal, and the CPU 32 is a motor control unit control signal 3
6, the rotation speed of the motor 8 is controlled via the motor control unit 33.

Reference numeral 37 denotes a feature amount extraction unit which divides the read image data into predetermined blocks and extracts a local feature amount for each block. Reference numeral 38 denotes a second resolution conversion unit which converts read image data into a fixed resolution, for example, 75 dpi (dot per inch) regardless of the reading resolution designated by the host computer 2. Reference numeral 39 denotes a feature value calculation unit that performs a predetermined calculation on the image data converted to a fixed resolution by the second resolution conversion unit, thereby calculating a local feature value of the image.
40 is a parameter setting signal. The parameter setting signal 40 connects between the feature amount extraction unit 37 and the CPU 32, and the CPU 32 sets parameters necessary for operation to the feature amount extraction unit 37. Configuration of feature amount extraction unit 37,
The operation and the operation will be described later in detail.

The local feature values of the image extracted by the feature value extraction unit 37 are sent to the interface unit 30,
The data is transferred to the host computer 2 via the CSI.

(Detailed Description of Line Correction Unit) Next, the optical system of the image reading apparatus will be described in more detail with reference to FIG.

FIG. 6 shows the carriage 7 of the image reading apparatus 1.
FIG. 5 is a schematic diagram when is viewed from the side. For simplicity, the lamp 17 and aperture 18 shown in FIG. 3 are omitted.

The line sensor array R (22R) arranged on the image sensor 20 reads the red image information.
It is. The line sensor array G (22G) is Gre
The image information of en is read, and the position of the read line on the original glass 6 is PG. The line sensor array B (22B) reads the image information of Blue,
The position of the reading line on the original glass 6 is PB.

Assuming now that the image is being read, the carriage 7 is moving in the sub-scanning direction (d1), and the position of PB is the reading line with respect to the document 13, and the position of the PG is next. The position is finally the reading line at the position of PR. In other words, the same position (line) on the document
, First, Blue image data is obtained, then Green, and finally, Red image data is obtained. First obtained Blue image data and next obtained Green
Of the image data for a predetermined number of lines,
When the image data of
And output the image data of Green, the R, G, and B line positions can be aligned and output.

Next, the structure of the image sensor 20 alone will be described. FIG. 7 is a view of the image sensor 20 viewed from the line sensor array side. The line sensor arrays of each color are arranged in a line in the main scanning direction, and L1 and L1 are arranged between the line sensor arrays of each color in the sub-scanning direction.
There is an interval of L2.

In FIG. 7, "□" indicates an individual pixel of the line sensor array.
□ ′ is the size of one pixel at 600 dpi of the image reading device.

In a general image sensor, L1 and L2 are equal, and L1 and L2 each have a value that is an integral multiple of the read pixel size. For example, in the first embodiment,
L1 and L2 are equivalent to eight lines when converted to 600 dpi lines, that is, the line sensor array of each color is 600 dpi.
/ 8 = 75 dpi. As described above, the same position (line) cannot be read simultaneously with an image sensor having such a structure, and the line correction unit 26 corrects this as described above.

Next, the operation of the line correction section 26 will be described in detail with reference to FIG. FIG. 8 is a diagram showing the operation principle of the line correction unit 26. In FIG. 8, 50 is Green.
Is a memory area that stores the image data of Blue in line units, and 51 is a memory area that stores the image data of Blue in line units.

The image reading apparatus according to the first embodiment applies the Blue, Green
The data is read in the order of n and Red. Since the interval between each line sensor array is equivalent to 8 lines of 600 dpi,
When reading an image at 600 dpi, the image data of 8 lines is read for Green image data, and
The image data of 16 lines is stored for the image data of ue, and when the image data of Red is read, the image data of 8 lines before is read for the image data of Green, and the image data of 16 lines is stored for the image data of Blue.
If the image data before the line is output, it is the same as reading at the same position on the document.

In this way, the image is read once at 600 dpi in the sub-scanning direction, converted to a lower resolution after performing the above-described line correction, and if the resolution is lower than 600 dpi, the image can be read at all resolutions. Can be. However, in this case, there is a premise that an image is read once at 600 dpi, so that the reading speed cannot be increased. This problem can be dealt with by reading an image while moving the carriage in the sub-scanning direction at a high speed and changing the setting of the line correction unit 26.

FIG. 9 is a diagram showing the operation of the line correction unit when reading an image at a resolution of 300 dpi in the sub-scanning direction.

The moving speed of the carriage when reading an original at 600 dpi, that is, the moving speed in the sub-scanning direction d1 is V
Then, the moving speed of the carriage when reading the original at 300 dpi is set to 2V. That is, the moving speed of the carriage is set to be twice that at the time of reading at 600 dpi. The carriage moving speed Vx at an arbitrary reading resolution is, for example, a reference reading resolution of 600 dp.
Assuming that the carriage movement speed in reading i and 600 dpi is V, and the actual reading resolution is X [dpi], it can be expressed as (Equation 1).

[0072]

(Equation 1)

In the case where an image is read at 300 dpi, the moving speed of the carriage is twice that of 600 dpi, so that the moving distance per unit time is also twice. Since the distance between the line sensor arrays of each color does not always change, if the moving speed of the carriage is doubled, the moving distance when the image reading device reads one line of image data is also doubled. The number of lines of the image data to be stored may be ２. That is, as shown in FIG. 9, the interval between the line sensor arrays is equivalent to eight lines of 600 dpi, that is, 30 lines.
When reading an image at 300 dpi, four lines of image data are stored for Green image data, and eight lines of image data are stored for Blue image data. R
When the image data of ed is read, the image data of four lines before is read for Green image data,
As for the ue image data, if the image data of eight lines before is output, it is the same as reading at the same position on the document.

Table 1 shows a generalization of the above.

[0075]

[Table 1]

That is, in the first embodiment, as shown in (Table 1), the reading resolution is set to an integral multiple N based on 75 dpi. At this time, the number of delay lines of Green image data stored in the Green memory 50 is N,
The number of delay lines of Blue image data stored in the Blue memory 51 can be generalized to 2 × N. These settings are performed by the CPU 32 in FIG.
4 to the line correction unit 26. The carriage moving speed Vx at each resolution is given by (Equation 1). In FIG. 5, the motor control unit 3 is controlled by the motor control unit control signal 36 from the CPU 32.
3 is performed.

As described above, the difference in the reading position caused by the difference in the position of the line sensor array of the image sensor 20 is corrected.
Is in the same state as when the same line of the document is read.

(Detailed Description of Resolution Conversion Unit) As described above, the line correction unit 26 corrects the difference in the reading position of each color in the carriage movement direction, that is, the sub-scanning direction. At this time, the designation of the reading resolution is a discrete value, but the actual image reading device 1
Must accept the designation of the reading resolution in units of 1 dpi from the host computer 2 and correct the image data to the required resolution before outputting it. Line correction unit 2
The processing performed in step 6 is positioning in the sub-scanning direction.
No conversion is performed on the image data in the main scanning direction.

The first resolution converter 27 performs these processes. Hereinafter, the processing in the first resolution converter will be described in detail.

First, a description will be given with reference to FIG. For simplicity, it is assumed that the host computer 2 has designated the image reading device 1 to read at 200 dpi. 20
When reading at 0 dpi is designated, the CPU 32 sets the carriage moving speed for the reading resolution of 225 dpi for the motor control unit 33. According to (Table 1), this is 2.7 times the carriage moving speed V at 600 dpi. Next, the CPU 32 similarly sets the reading resolution of 225 dpi for the line correction unit 26. That is, the delay amount of the Green memory is set to 3 lines, and the delay amount of the Blue memory is set to 6 lines.
It is set for each line (see FIG. 8 or FIG. 9).

When an image is read with these settings,
The line correction unit 26 outputs 225d in the sub-scanning direction.
pi resolution image data is output.

Here, as an example, a case is described in which an image is read at a resolution of 225 dpi when a resolution of 200 dpi is specified. However, the specified value of the reading resolution for the image reading apparatus according to the first embodiment and the motor Table 2 shows the relationship between the settings for the control unit 33 and the line correction unit 26, that is, the actual reading resolution.

[0083]

[Table 2]

That is, when the resolution in the sub-scanning direction requested by the host computer 2 is 30 to 75 dpi,
At a reading speed of dpi (referring to Table 1, this speed is eight times the reading speed of 600 dpi), and when the resolution in the sub-scanning direction requested by the host computer 2 is 76 to 150 dpi, 150dp
The image is read at a reading speed of i.

FIG. 10 is a diagram showing a resolution conversion algorithm.

First, the resolution conversion algorithm in the main scanning direction will be described in detail with reference to FIG.

In FIG. 10, reference numeral 53 denotes one pixel of 600 dpi. However, for ease of explanation, the actual pixel size is ignored and the center position of one pixel of 600 dpi is shown. For each pixel of 600 dpi, P
600_0, P600_1, P600_2 ... P60
The numbers 0_6 ... are assigned, and these are codes indicating the positions of the pixels. Hereinafter, for convenience, the pixel values at these positions are represented as * P600_0, for example, the pixel value corresponding to the position of P600_0 (the concept of the pointer in the C language is loosely used).

First, image information of 600 dpi is converted to 200d.
The case of conversion to pi will be described. The position of the first pixel after conversion is always the first pixel of 600 dpi, that is, P600
It shall be aligned to the position of _0. Therefore, the first pixel position at 200 dpi is P200_0, which is the same as P600_0. Since the location is the same, the pixel value also adopts the same value as P600_0, that is, * P600_0.

The next pixel position is P200_1. To obtain this pixel value, the position of P200_1 is set to 600d.
Consider that the pixel position is represented by pi. Since (600/200) × 1 = 3 using a simple proportional expression, P20
0_1 = P600_3. Therefore, the pixel value at the position of P200_1 is * P200_1 = * P600_3.
Similarly, * P200_2 = * P600_6 can also be obtained.

Next, the image information of 600 dpi is converted to 300 dpi.
The case of conversion to i will be described. The position of the first pixel after conversion is always the first pixel of 600 dpi, that is, P600_
It shall be aligned to the position of 0. Since the head pixel position of 300 dpi is the same as P600_0, the pixel value is also P6
The same value as 00_0, that is, * P600_0 is adopted.

The next pixel position is P300_1. To obtain this pixel value, the position of P300_1 is set to 600d.
Consider that the pixel position is represented by pi. Since (600/300) × 1 = 2 using a simple proportional expression, P30
0_1 = P600_2. Therefore, the pixel value at the position of P300_1 is * P300_1 = * P600_2.
Similarly, * P300_2 = * P600_4, and further *
P300_3 = * P600_6 can be obtained.

Next, the image information of 600 dpi is converted to 400 dpi.
The case of conversion to i will be described. The position of the first pixel after conversion is always the first pixel of 600 dpi, that is, P600_
It shall be aligned to the position of 0. Since the head pixel position of 400 dpi is the same as P600_0, the pixel value is also P6
The same value as 00_0, that is, * P600_0 is adopted.

The next pixel position is P400_1. To obtain this pixel value, the position of P400_1 is set to 600d.
Consider that the pixel position is represented by pi. When calculated using a simple proportional expression, (600/400) × 1 = 1.5, which indicates that P400_1 exists between P600_1 and P600_2. Therefore, the pixel value of P400_1 is calculated as (Equation 2) using the position information of 1.5.

[0094]

(Equation 2)

In this method, the position where the pixel after the resolution conversion is located is determined with reference to the pixel position of 600 dpi, and a weighting operation is performed based on the distance from the adjacent pixel of 600 dpi to obtain the pixel value after the resolution conversion. It is nothing but being.

When the above concept is applied to P400_2, (600/400) × 2 = 3.
_2 exists at the position of P600_3. Therefore, * P400_2 = * P600_3.

Further, when the above concept is applied to P400_3, (600/400) × 3 = 4.5, and
It can be seen that P400_3 exists between P600_4 and P600_5. Therefore, the pixel value of P400_3 is calculated as (Equation 3) using the position information of 4.5.

[0098]

(Equation 3)

The pixel values of the subsequent pixels can be obtained in the same manner.

The resolution conversion to 500 dpi can be processed in exactly the same way.

As described above, the conversion from 600 dpi to another resolution has been described as the resolution conversion processing in the main scanning direction.
If the original resolution is higher than the converted resolution, the method is applicable in any case if the original resolution and the converted resolution are known.

For example, image data in the sub-scanning direction output at a resolution of 225 dpi by line correction can be converted to, for example, 200 dpi in the same manner. In the first embodiment, the above-described method is also used for resolution conversion in the sub-scanning direction.

(Outline of Feature Extraction Unit) Next, FIG.
The feature amount extraction unit 37 will be described in detail with reference to FIG.

FIG. 11 is a diagram showing in detail the structure of the feature amount extraction unit 37.

In FIG. 11, reference numeral 38 denotes a second resolution converter, which converts input image data into a fixed resolution regardless of the reading resolution designated by the host computer 2. Reference numeral 54 denotes a memory, and the image data converted to a fixed resolution by the second resolution converter 38 is temporarily stored in the memory 54. 55 is a characteristic color counter,
For a plurality of predetermined feature colors, the number of pixels included in a predetermined range (= similar colors) is counted to generate feature vector data. Reference numeral 56 denotes a template selection unit which compares the feature vector data generated by the feature color counter 55 with a plurality of templates prepared in advance.
Select the template with the closest Euclidean distance.
Reference numeral 57 denotes a template storage memory in which a plurality of templates used for comparison with the feature vector in the template selection unit 56 are stored. The range counted as the characteristic color in the characteristic color counter 55 and the plurality of templates stored in the template storage memory 57 are C
Written by the PU 32 via the parameter setting signal 40. Further, the CPU 32 obtains template information from the host computer 2 via the interface unit 30. Reference numeral 58 denotes a buffer which stores the number of the template selected by the template selecting unit 57, and the Euclidean distance between the feature vector data and the template. These feature amounts stored in the buffer 58 are sent to the interface unit 30 and sent to the host computer 2 via SCSI.

Reference numeral 60 denotes a main / sub pixel counter which counts the number of input image data in the main scanning direction and the sub scanning direction, and outputs an interrupt signal 63 to the CPU 32 every time a predetermined count is reached. Further, the CPU 32 sets control parameters for the second resolution converter 38 via the parameter setting signal 40.

(Regarding the second resolution conversion means)
The resolution converter 38 will be described in detail with reference to FIGS.

The input to the second resolution converter 38 is performed from a stage preceding the first resolution converter 27. The reason will be described below. As described above, the image data output from the line correction unit 26 corrects the distance between the RGB lines in the sub-scanning direction due to the different positions of the line sensor arrays for each color. At this point, the resolution in the main scanning direction remains output from the image sensor, and no processing is performed. That is, in the configuration described above, the line correction unit 26 outputs image data having a resolution of 600 dpi in the main scanning direction.

As described above, at the time of output from the line correction section 26, the resolution in the main scanning direction is always 600 dp regardless of the reading resolution specified by the other device 31.
i, it is fixed at a certain resolution, for example, 75
Conversion to dpi can be performed by a single, parameter-invariant processing system. If the output of the first resolution conversion unit 27 is used to convert the data to a fixed resolution, for example, 75 dpi, image data of various resolutions must be handled, and the hardware becomes complicated.

In the sub-scanning direction, the line data output from the line correction section 26 is, as shown in Table 2, 75 dpi, 150 dpi, 225 dpi, 300 dpi.
dpi, 375 dpi, 450 dpi, 525 dpi,
600 dpi. Most importantly, they are all multiples of 75 dpi.
In order to convert these data into the above-mentioned predetermined resolution and 75 dpi, 1 / integer processing may be performed, which can be performed very easily.

The CPU 32 operates in the interface unit 30.
As described above, the image reading conditions transferred from the host computer 2 via the host computer 2 and the line correction unit 26, the first resolution conversion unit 27, and the motor control unit 33 of the image reading device are controlled based on the image reading conditions. But also C
The PU 32 specifies the processing in the sub-scanning direction to the second resolution conversion unit 38, and more specifically, specifies the thinning rate for all the lines. Of course, since the main scanning direction is constant regardless of the reading resolution, the pixel thinning rate in the line is fixed. (Table 3) shows the setting contents of the thinning rate for the second resolution converter 38.

[0112]

[Table 3]

As shown in Table 3, by setting the fixed pixel thinning rate to 2 in the main scanning direction, image data of 600 dpi is once converted to 300 dpi. By performing the thinning process in this manner, the amount of image data to be processed thereafter can be significantly reduced.

In the sub-scanning direction, the line thinning rate is changed according to the reading resolution. As a result, as shown in the column of “resolution after thinning rate” in Table 3, the resolution of main scanning × sub-scanning is 300 dpi × 75 dpi or 300 dpi × 1.
It is converted to 50 dpi.

Next, the image data obtained by the thinning processing is always averaged by 7 in both the main scanning and sub-scanning directions.
Conversion to a fixed resolution of 5 dpi. First, when the data is converted into 300 dpi in the main scanning direction and 75 dpi in the sub scanning direction by the thinning process, the value of 4 × 1 pixels is averaged using four pixels in the main scanning direction and one line of pixels in the sub scanning direction. I do. Further, 300 dpi in the main scanning direction is obtained by the thinning process.
X When converted to 150 dpi in the sub-scanning direction, the values of 4 × 2 pixels are averaged using four pixels in the main scanning direction and pixels for two lines in the sub-scanning direction.

Through the above processing, image data of a constant resolution of 75 dpi is obtained in both the main scanning and sub-scanning directions.

The resolution of 75 dpi is the optical resolution originally possessed by the image reading device, for example, the optical resolution of 600 dpi of the image reading device of the first embodiment.
The value is sufficiently smaller than i. By extracting the image feature using the image data converted to a resolution sufficiently smaller than the optical resolution of the apparatus, the feature is extracted based on the same reference regardless of the reading resolution designated by the host computer 2. can do. This means that when recognizing a specific image based on the aforementioned image feature amount,
Since the fixed resolution can be substantially eliminated, for example, after reading a specific image at a high resolution, a reduced-size copy-prohibited image is printed, or conversely, a specific image is read at a low resolution. Thereafter, a malicious act such as enlarging and printing a copy prohibited image can be prevented.

Although not directly described in the above description, it is possible to easily cope with a case where a resolution of 600 dpi or more is designated as the reading resolution by the host computer 2 by changing the setting of the second resolution conversion unit. Needless to say.

The fixed resolution used to extract the image feature is not limited to 75 dpi. For example, if the optical resolution of the image reading device is about 2400 dpi, there is no problem even if the processing is performed with 300 dpi as the fixed resolution for extracting the feature amount. Also, even if the optical resolution of the image reading device is about 600 dpi,
If the reading resolution range of the apparatus is set from 150 dpi, the resolution for extracting the feature amount is 150 dpi.
It may be i. Thus, the resolution for feature extraction is
Although it can be flexibly determined according to the reading resolution range of the image reading device, according to experiments performed by the present inventors, in the existing, particularly flat-bed type image reading device, the image feature amount is set to 300 dpi or less and 75 dpi or more. With a fixed resolution for extraction, a specific image can be finally recognized with high accuracy.

As described above, the first embodiment
In this example, the output of the line correction unit 26 is converted into a predetermined resolution by the thinning process and the averaging process. However, the averaging process is always performed on at least the image data in the main scanning direction. In the first embodiment, R obtained from the image reading device
An image feature amount for recognizing a specific image is obtained based on the GB image data. However, in an image reading apparatus, there are limitations on the position accuracy of an image sensor, the driving accuracy of a carriage, and the like. Information may not be correctly reflected. In the thinning process, an erroneous image density may be stochastically generated at an edge portion.
In the above, when converting to a fixed resolution, the averaging process is prioritized over the thinning process, and the averaging process is always performed at least in the main scanning direction. On the basis of this argument, when the actual reading resolution in the sub-scanning direction is 525 dpi in Table 2 or the like, the processing block size becomes large, but a method in which only the averaging processing is performed without performing the thinning processing can be considered. This is an effective means for reducing erroneous determination even when the reading position accuracy of the reading device is poor.

(Regarding Operation of Characteristic Color Extraction Unit) Next, the operation of the characteristic color extraction unit in the image reading system according to the present invention will be outlined first with reference to FIG.

The second resolution conversion unit 38 allows, for example,
The RGB image signal converted to a constant resolution of 5 dpi is
Once stored in the memory 54. The RGB image signals stored in the memory 54 are cut out in block units of a predetermined size and sent to the characteristic color counter 55 as RGB point sequential signals. The size of the above block is, for example, 50 ×
It is set to 50 pixels (2500 pixels).

The characteristic color counter 55 counts the number of pixels falling within a range of RGB values predetermined as characteristic colors with respect to the input RGB image signal. The count range is determined by the CPU 32 via the parameter setting signal 40 by the CPU 32 based on information previously obtained from the host computer 2 via the interface unit 30.
It is set to 5, but if it is assumed that the specific image to be recognized does not change, it may be fixedly stored in some storage means of the image reading apparatus.

In the first embodiment, three different colors included in a specific image are defined as characteristic colors, and the number of pixels determined to be characteristic colors is counted for each block. 1
When the characteristic color count of the block is completed, the result is transferred to the template selecting unit 56. The output from the characteristic color counter 55 is obtained by counting the number of a plurality of characteristic colors existing in a 50 × 50 pixel block. Since the number of characteristic colors is 3, this is 3
It can be considered that a dimensional feature vector is output. That is, the characteristic color counter 55 generates a characteristic vector.

The template selecting unit 56 stores the feature vector generated by the feature color counter 55 and a plurality of templates stored in the template storage memory 57 in advance.
The comparison is performed based on the dimensional Euclidean distance, the closest template is selected, and the template number and the three-dimensional Euclidean distance are stored in the buffer 58. The nearest neighbor template number and the three-dimensional Euclidean distance serve as indices indicating the similarity between the input image data and the specific image.

The total number of pixels processed by the characteristic color counter 55 is counted and managed by the main / sub-pixel counter 60. When the counted result of the number of pixels processed reaches a predetermined amount, the main / sub-pixel count is calculated. The pixel counter 60 generates an interrupt signal 63 to the CPU 32. In response to the interrupt signal 63, the CPU 32 controls the interface unit 30 so that the nearest template number stored in the buffer 58,
The dimensional Euclidean distance is output to the host computer 2. The details of communication with the host computer 2 will be described later.

(Characteristic Color Counter) Next, the characteristic color counter 55 will be described in more detail. FIG. 12 is a diagram showing the configuration of the characteristic color counter 55.

In FIG. 12, 70_C0, 70_C1,
70_C2 is a characteristic color detecting unit that detects each independent characteristic color. In the embodiment, since three characteristic colors are detected, three color detection units are provided. Since there is no difference in configuration between the characteristic color detectors except that they detect different colors, only one color is shown in detail.

A comparator 71 compares the input RGB image data with a predetermined value and detects whether or not the image data falls within a predetermined range. An AND gate 72 performs an AND process on the output of the comparator 71 and outputs the result. A counter 73 counts the number of times the output of the AND gate becomes 1. A count buffer 74 accumulates the count result of the counter 73.

The characteristic color counter 55 having the above configuration will be described in detail below. The characteristic color counter 55 is a part that detects three specific colors included in the specific image and detects the respective numbers. Here, for the sake of simplicity, the characteristic color counter 55 of the characteristic color detection unit 70_C0 The operation will be described in detail. First, the input RGB signals are compared with the designated color signal by the comparator 71. The designated color signal is set in the register group of the comparator 71 by the CPU 32 via the parameter setting signal 40, and more specifically indicates the count range of the characteristic color. The designated color signal designates a color included in the specific image, is obtained in advance by performing statistical processing on the color included in the target specific image, and is generally used for the background color or pattern of the specific image. A color distributed in a range, a vermilion of an imprint, or the like is used. In addition, when specifying a color, the upper and lower limits of RGB are set, for example, as r_ref1 (lower limit for the R signal) and r_ref2 (upper limit for the R signal) in order to give the specified color a width. , Pixels in these ranges are treated as specific color pixels. The output of the comparator 71 is collected by an AND gate 72. When the input image signal is within the range of the characteristic color, all outputs from the comparator become 1 and the AND gate 7
The output of 2 becomes 1. The number of the specific color pixels detected in this way is counted by the counter 73.

The counting is performed on a block basis. Here, the block is a block in which the read image is divided into a plurality of pixels in the main scanning direction and the sub-scanning direction. In this case, 50 pixels are used as a unit for the fixed resolution pixels converted by the second resolution conversion unit 38. A rectangle of 50 × 50 pixels is defined as one block. Therefore, the counter 7
Reference numeral 3 indicates that the count result is stored in the count buffer 74 for each input of 50 pixels and reset. Count buffer 74
Exist in the number of blocks in the main scanning direction, and one block of data is recorded in the sub-scanning direction. At the time of recording from the counter 73 to the count buffer 74, the addition result to the data already written in the count buffer 74 is always written, that is, by performing the read-modify-write operation, the characteristic color of one block in the sub-scanning direction is obtained. The number of pixels is accumulated. When the data input for one block is completed in the sub-scanning direction, the contents of the count buffer 74, that is, the result of counting the characteristic colors obtained for each block are passed to the template selection unit 56 and reset to zero.

The above operation is also performed in parallel by the characteristic color detecting sections 70_C1 and 70_C2. Three characteristic colors are counted for a predetermined designated color signal, and the count result is 3 It is passed to the template selection unit 56 as a dimension vector, that is, a feature vector.

FIG. 13 is a diagram showing the data structure of the feature vector passed to the template selecting section 56. In the figure, a thick solid line indicates the break of each block, and C0 (n),
C1 (n) and C2 (n) indicate the result of the characteristic color pixel count counted in the n-th block, respectively, and indicate that one block characteristic data is composed of three specific color pixel numbers. I have.

(Regarding Template Selection Unit) Next, the template selection unit 56 will be described in detail.

FIG. 14 is a flowchart showing the operation of the template selection unit. In the following description, FIG. 11 and FIG.
Use 4 together.

When a feature vector composed of count values of three feature colors is passed from the feature color counter 55 to the template selection unit 56 for each block, the feature vector and the template are compared. First, a feature vector for each block is obtained (step 1). The acquired data is Cn = (C0
(N), C1 (n), C2 (n)) (where n is the block number). It is determined whether or not the magnitude | Cn | of Cn is equal to or greater than a predetermined value (step 2). If the number is equal to or more than a certain value, a template closest to Cn is searched from the templates stored in the template storage memory 57. The templates in the template storage memory 57 are Tm = (TC0 (m), TC1 (m), TC2
(M)) (where m is the reference data number m = 1 to M), and the distance Dnm = | Cn−Tm |
The Dnm at which (the Euclidean distance of the three-dimensional vector) becomes minimum is detected, and the template number m and the distance data Dmin are stored in the buffer 58 (step 3).
If | Cn | does not exceed a certain value in step 2, the template search in step 3 is not performed, and a template number (eg, M + 1) for which no template is defined and a value Dmax equal to or greater than the maximum value that Dnm can take are used. The data is stored in the buffer 58 (step 4). The distance data thus stored in the buffer 58 and the template number m are local feature amounts of the image.

Here, the template stored in the template storage memory 57 will be described in detail.

The template storage memory 57 is composed of a RAM, and a plurality of templates stored in the template storage memory 57 are written by the CPU 32 via the parameter setting signal 40. CPU 32
Has acquired the template information from the host computer 2 via the interface unit 30. The template is obtained in advance from the specific image to be processed, and these are stored in the host computer 2.

Next, a method for creating a template will be described. FIG. 15 is a diagram illustrating a relationship between a template and a specific image. As shown in FIG. 15, the template is based on the case where the target specific image is placed in the horizontal position as a reference (a),
When the target specific image is rotated from the horizontal position by a small angle unit (b) and (c), and when the positional relationship between the block and the specific image is shifted in horizontal and vertical directions by several pixels (d) For each block in (), the number of pixels corresponding to each characteristic color is obtained as a template. However,
Since the number of templates obtained as described above is enormous, a representative one is extracted using a clustering method such as vector quantization.

(Regarding Transfer of Feature Amount) As described above, the local feature amount for an image divided into blocks, that is, the template number, the feature vector, and the inter-template distance are temporarily stored in the buffer 58 shown in FIG. Is stored in When storage in the buffer 58 is completed for a predetermined number of blocks, the main / sub-pixel counter generates an interrupt signal 63 to notify the CPU 32 that significant data is stored in the buffer 58.

Next, the process of outputting these characteristic amounts stored in the buffer 58 to the host computer 2 will be described.
This will be described with reference to FIGS.

FIG. 16 shows the host computer 2 and the image reading device 1 (more precisely, the interface unit 3).
FIG. 4 is a diagram showing the procedure for commands exchanged between the data and the data to be transferred. A solid arrow in the drawing indicates that a command has occurred in that direction, and a broken arrow indicates that data is sent in that direction.

In the following description, the SCSI will be described as an example for the sake of simplicity. Of course, the same procedure is adopted for other interfaces if the host computer and the image reading apparatus can communicate bidirectionally. be able to.

When reading image data, first, the host computer 2 sends a TES to the image reading device 1.
Issue a T UNIT READY command. Upon receiving this command, the image reading device 1 returns the status of the image reading device, such as BUSY or READY, to the host computer 2 (Step 100). The host computer 2 executes TE until the returned state becomes READY.
Issue a ST UNIT READY command periodically.

When the image reading device 1 returns READY in response to the TEST UNIT READY command, the host computer 2 determines that the image reading device 1 is in a readable state, and issues a MODE SELECT command. With this command, the host computer 2
Passes control parameters to the image reading device 1.
The control parameters include a parameter for selecting data output from the image reading device in a scanning operation to be performed. That is, the user selects whether to read the document and output the image data, read the document and output the local feature amount, or output both (step 101).

Next, the host computer 2 issues a SET WINDOW command to the image reading device 1. Following this command, the host computer 2 passes the image reading conditions to the image reading device 1. The image reading conditions include information such as an image reading start position, a reading range (image size), and an image reading resolution (step 102). On the image reading device side, the setting of the second resolution converter 38 (see FIG. 11) is performed based on the resolution information passed by this command.

If it is specified in step 101 that at least the local feature value of the image is to be output, the host computer 2 issues a SEND command to the image reading device 1, and subsequently, the host computer 2 issues the SEND command described above. The template is transferred (step 103).

Next, the host computer 2 issues a SCAN command to the image reading device 1. Thereby, the image reading apparatus 1 starts the rotation of the driving source (the driving source 8 in FIG. 2) and prepares for image reading (step 104).

Next, the host computer 2 issues a GET PIXELNUMBER command to the image reading device 1. Upon receiving this command, the image reading device 1 calculates the actual number of pixels per line, the amount of data, and the like from the image size and the reading resolution received in step 102, and returns the result to the host computer 2 (step 105). ). In this way, SET WIND
The reading device returns the actual setting value for the reading condition specified by the OW command, so that, for example, when the specified value of the reading range requested by the host computer is higher than the accuracy handled by the image reading device, (The host computer follows the value returned from the image reading device).

Next, the host computer 2 sends a GET DATABUFFER STA to the image reading device 1.
Issues a TUS command. Upon receiving this command, the image reading device 1 returns the amount of image data and the amount of feature not yet transferred to the host computer 2 (step 106).

Next, when the host computer 2 has instructed the image reading apparatus 1 to output at least image data in step 101, the host computer 2 sets READ (1)
A command is issued, and a predetermined amount of image data is received from the image reading device 1 (step 107).

Next, if the host computer 2 has instructed the image reading device 1 to output at least the local feature value of the image in step 101, the REA
A D (2) command is issued, and a local feature amount of a predetermined amount of the image is received from the image reading device 1 (step 10).
8).

The processing from step 106 to step 108 is repeated until it is determined in step 106 that there is no remaining data to be transferred.

As described above, in the first embodiment, when the host computer 2 acquires both the image data and the local feature of the image, the host computer 2 obtains both the image data and the local feature of the image. The acquisition is repeated alternately. For example LE
Considering a TTER size document, the local feature amount of the image is about 600 bytes, and if this is to be transferred collectively, it must be stored in the buffer 58 until the image reading is completed. Must be expanded to the maximum document size. However, by alternately outputting the image data and the local feature amount of the image, the buffer 58 on the image reading device side needs only about 40 bytes. This is a capacity that can be called a register rather than a memory, and hardware can be easily realized. Further, by alternately acquiring the image data and the local feature amount of the image, the host computer 2 can sequentially process the acquired local feature amount of the image. There is also an effect that the time required for determining an image can be substantially reduced.

According to the procedure described above, the image data and the local feature amount of the image are transferred from the image reading device 1 to the host computer 2.

(Recognition of Specific Image by Host Computer) FIG. 17 is a diagram showing the overall configuration of the host computer 2.

In FIG. 17, reference numeral 80 denotes an interface for outputting a command to the image reading device 1 or
It receives image data and local feature amounts of images. The interface 80 includes a serial interface for receiving information from a keyboard and a mouse, but these are omitted. Reference numeral 81 denotes a working memory, which is constituted by a RAM. Reference numeral 82 denotes a data bus, and all communications between modules in the host computer 2 are performed via this bus. Reference numeral 83 denotes a storage such as a hard disk device, which stores an application program for processing input data. The image data read by the image reading device 1 is temporarily stored in the work memory 81 and then stored in the storage 83 based on a user's instruction.
Can also be stored. A video memory 84 stores display data. A display device 85 such as a CRT displays data stored in the video memory 84. A CPU 86 controls the overall operation of the host computer 2 and executes a program stored in the work memory 81 to process input data. 8
Reference numeral 7 denotes a ROM which stores a program which is started first when the power of the host computer 2 is turned on.

Hereinafter, the process of recognizing a specific image by the host computer 2 will be described with reference to FIG. 17, FIG. 18, FIG.
This will be described with reference to FIGS. 21, 22 and 23.

In the following description, it is assumed that, for simplicity, the host computer 2 has acquired all the local features of the image. Of course, this process can be interrupted on the way and restarted when the local feature of the next image is obtained.

The above-mentioned local feature value of the image is passed from the image reading device 1 to the interface 80 of the host computer 2 and stored in the working memory 81.

FIG. 18 is a diagram showing a data structure in the working memory 81. In the figure, TN (n) is a template number closest to the feature vector obtained for each block. D (n) is the distance Dmin or Dmax between the feature vector and the template closest to the feature vector, obtained for each block.
FIG. 19 shows images of TN (n) and D (n) given to each block of an actual specific image.

FIG. 19A shows an image including a specific image, and FIG. 19B shows the value of TN (n) for each block. Here, the template number is 254 at maximum, and is defined as a template. The number which is not given is 254
+ 1 = 255. (C) shows D for each block.
The value of (n) is shown in FIG.
The value indicates max or a value close to max, and means that the image is not completely similar in color to the specific image. Also, 02 in the figure is Dmin, which means that the value of the distance between the feature vector and the template is 0 or a value close thereto, that is, an image whose color is very similar to the specific image. Also, the 01 part in the figure indicates an intermediate value, that is, an ambiguous image.

The host computer 2 determines the presence or absence of a specific image based on the distribution state of TN (n) and D (n) developed on the working memory 81 and a frame mask described later.

First, a description will be given of a frame determination process performed using D (n). In the frame determination process, a group of a plurality of adjacent blocks is regarded as one frame, and the frame is processed while shifting its center position from the upper left of the input image horizontally and vertically in units of one block.

Next, a frame mask will be described with reference to FIG. FIG. 20 is a diagram showing the structure of the frame mask. The frame mask is used to mask blocks constituting a frame, and a plurality of masks having different mask angles are prepared as shown in FIG. In FIG. 20, a hatched square indicates a mask block, and a white square indicates a non-mask block.
It is stored in the storage 83 of the host computer 2 as a part of the program.

FIG. 21 is a flowchart showing the processing contents for one frame in the frame processing.

First, the distance D (n) between the feature vector and the selected template is set for the block at the center of the frame.
Is read and compared with the threshold value Th1, and if it is larger than the threshold value Th1 (the distance is far), it is determined that there is no specific image for this frame, and the process moves to the next frame. If it is equal to or smaller than the threshold Th1 (the distance is short), one of the frame masks is obtained (step 201, step 20).
2).

The acquired frame masks are sequentially checked for each block, and the following processing is skipped for the mask blocks, and the corresponding block D (n) is acquired from the work RAM 64 for the non-mask blocks. (Steps 203 and 204).

The obtained D (n) is successively added to Dsum (step 205), and a counter value Bnum for counting the number of processed blocks is incremented (step 206). The processing from step 203 to step 206 is performed until the blocks constituting the frame are completed (step 207). From the block number counter value Bnum and the sum of the distances Dsum, the average distance Dme
An is determined (step 208), and this is compared with a threshold Th2. If Dmean ≦ Th2, it is determined that there is a high possibility that the specific image is included in the image (step 20).
9). If Dmean> Th2, it is determined that there is no specific image, and the frame mask is changed and step 20 is performed.
Steps 2 to 209 are repeated (step 210).

When it is determined that there is a high possibility that the specific image is included in the image being processed in the above-described frame determination processing, a final determination is made. FIG. 2 shows the final determination process thereafter.
2 and FIG.

FIG. 22 is a diagram showing rotation angle correction in the final determination. In the final judgment, a template number in which a template number closest to the feature vector of each image block is described is described.
N (n) is used. However, the image cut out by the frame determination processing may include a specific image that is not in the normal arrangement.

Step 20 of the frame determination process described above
In step 9, the angle at which the specific image is arranged can be estimated at the frame determination stage depending on the type of the frame mask used when it is determined that the specific image is likely to be included in the image. T based on this information
N (n) itself is relocated to the normal position. FIG. 22 shows the situation, in which (a) shows the state before rotation correction,
(B) shows the situation after rotation correction. In each figure,
The positions of ○, □ and △ correspond.

Next, the final judgment processing will be described with reference to FIG. FIG. 23 is a diagram illustrating the relationship between the frame, the block, and the recognition processing in the final determination, and it is assumed that the rotation correction described above has been performed. The symbols, □, and Δ in the figure correspond to those in FIG. In FIG. 22B, the block after the normal arrangement is partly in a stepped shape. However, in the final determination, as shown in FIG. 23, the processing is performed assuming that the specific image is the normal arrangement.

In FIG. 23, reference numeral 75 denotes a set of blocks in which TN (n) has a value other than 255 (= template not defined) for a frame determined to have a high possibility that a specific image is present in the frame determination. is there. Reference numeral 76 denotes a block included in the block set, and a template is described as a histogram for each block for ease of explanation. Reference numeral 77 denotes a final determination unit, which is configured by a neural network. Reference numeral 78 denotes an input layer of the neural network, 79 denotes an intermediate layer of the neural network, and 80 denotes an output layer of the neural network. Reference numeral 81 denotes a comparing unit that compares two outputs output from the output layer 80 and selects a larger one.

Now, the blocks converted to the normal arrangement position by the rotation correction have template numbers TN respectively.
(N). Since the template number is actually the feature vector itself included in the specific image, these can be represented by a histogram as shown in a block 76 in FIG. The frequency of this histogram is input to the input layer 78 of the final determination unit 77. The input layer 78 has three nodes for one input unit to correspond to the three-dimensional information of the histogram, and the frequency of the histogram is input to each node. The frequency is input to the nodes corresponding to all the blocks. In the neural network, the operation is performed in the intermediate layer 79 by the weighting operation previously learned, and the output layer 80
Then, the degree of the specific image and the degree of the non-specific image are output. Finally, the comparing means 81 selects and outputs the one having a higher degree of output. Therefore, the comparison means 8
The output of 1 is a binary output indicating whether or not the input image is a specific image.

By the above operation, the specific image can be detected.

(Regarding Image Reading Procedure by Image Reading System in First Embodiment) The image reading procedure of the image reading system described above will now be described in detail.

First, the outline will be described with reference to FIG. The following procedures are all executed by the CPU 86 by activating a predetermined program stored in the storage 83.

In general, when reading an image by controlling the image reading apparatus 1, the whole document is roughly scanned in a pre-scan mode (hereinafter referred to as a preview).
The image data obtained in the preview is temporarily stored in the working memory 81 from the interface 80 via the data bus 82, and then transferred to the video memory 84, where the display device 85
Will be displayed. Based on the displayed screen, a trimming range is designated using a pointing device such as a mouse (not shown), and a reading resolution and other reading conditions are further designated using a keyboard or the like. (Referred to as scanning) to control the image reading apparatus 1 to obtain image data. The image data obtained by the main scan is transferred from the interface 80 to the work memory 81 via the data bus 82, and then predetermined image processing is performed on the work memory 81 to obtain final image data. This image data is also transferred to the video memory 84 and displayed on the display device 85. The image data thus obtained can be stored and stored in the storage 83, or can be transferred to another device via the interface 80.

The procedure for reading an image in the image reading system will be described below in detail with reference to FIGS. 5, 16, 17 and 24.

FIG. 24 is a flowchart showing an image reading procedure according to the first embodiment.

First, the entire document is previewed at a coarse resolution (step 301). The preview resolution in the first embodiment is set to 30 dpi. The host computer 2 receives the MODE SEL via the interface 80.
The ECT command and the SETWINDOW command are output, the full-size area is read at 30 dpi, and the image reading apparatus 1 is controlled to output both the image data and the local feature amount of the image (see FIG. 16 for the SCSI command). Upon receiving these commands, the image reading apparatus 1 reads the original at a resolution of 75 dpi (Table 2), and the actual reading resolution of 30 to 75 dpi is 7
5 dpi), is converted to 30 dpi by the already described first resolution conversion unit 27 (see FIG. 5) and output to the host computer 2, and the feature amount extraction means 37 (also described above) (See FIG. 5), the local feature amount of the image is extracted and output to the host computer 2.

Next, the host computer 2 displays the received image data (step 302), and includes the specific image in the image in accordance with the procedure already described in detail, based on the local features of the image sequentially input. It is detected whether or not it is performed (step 303).

If it is determined that a specific image is included in the preview image, a predetermined message indicating that the specific image has been detected is displayed on the display device 85 of FIG. finish.

On the other hand, when it is determined that the specific image is not included in the preview image, a rectangular trimming range is indicated by a pointing device (not shown) with respect to the displayed preview image, so that the reading area to be main-scanned is displayed. Is specified (step 305), and the reading resolution is specified using a keyboard (not shown) (may be selected from a pull-down menu using a mouse) (step 306). Further, another reading mode is designated as necessary (step 307). The designation in step 307 includes, for example, color / monochrome designation for designating whether an image is read in color or monochrome, bit precision designation for designating how many bits per pixel are to be read, setting of a tone curve, brightness and the like. Setting the contrast,
Specify negative / positive to specify whether to perform negative reading or positive reading, specify magnification when transferring the read image data directly to a printer to operate like a copier, remove moiré, and emphasize edges This includes specifying the type of filter to perform.

Some of the image reading conditions set in steps 305, 306, and 307 are
It is transferred from the host computer 2 to the image reading device 1 via the interface 80 as a DE SELECT command or a SET WINDOW command. In the main scan, a command is output so as to output only the image data without outputting the local feature amount of the image.

The image reading device 1 executes the main scan according to the designated image reading conditions (step 30).
8) Output image data. In the host computer 2, the transferred image data is processed in step 307.
In accordance with the reading mode designated by (1), image processing such as level conversion of an image according to a tone curve and adjustment of brightness and contrast are performed (step 309). The image data output from the image reading device 1 in this manner is
Some are processed on the image reading device side, and others are processed on the host computer side.

Generally, processing requiring high speed (for example, a filter that requires multiplication) is a simple processing (for example, tone curve) that can be performed by accessing the lookup table on the image reading device side where the merit of hardware can be utilized. In many cases, image processing such as level conversion based on image processing is performed on the host computer side, but ultimately each image processing is performed on the image reading apparatus side and the host computer in accordance with the performance required for the image reading apparatus and the cost required. Decide which side to do.

In the first embodiment, among the reading mode designations performed in step 307, processing based on color / monochrome designation, bit precision designation, and filter processing are performed by the image reading device side, and tone curve setting,
Processing based on brightness, contrast setting, negative / positive designation, and magnification designation is performed on the host computer side.

The image data on which the image processing has been completed is displayed on the image display device 85 (step 310), and a series of processing ends.

According to the image reading procedure described above, it is determined whether or not a specific image is included in the document at the time of the preview, and if the specific image is included in the preview image, the actual scan itself is prohibited. Therefore, it becomes difficult to read the specific image in the main scan. This can prevent counterfeiting.

From the viewpoint of a program operating on the host computer 2, the image data that can be stored in the storage 83 or transferred via the interface 80 is limited to the actual scanned image, and the preview image is further By making it inaccessible from other applications, it becomes practically difficult to capture the specific image into the host computer 2.

Embodiment 2 Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings.

The second embodiment differs from the first embodiment only in the image reading procedure of the image reading system. The configuration of the image reading system, the configuration of the image reading device, the hardware of the image reading device, and the localization of the image are different. The process of extracting the characteristic feature, the process of recognizing the specific image in the host computer, and the like are common, and thus the description is omitted.

Embodiment 2 (Regarding Image Reading Procedure by Image Reading System in Embodiment 2) Embodiment 2
Will be described in detail.

First, the outline will be described with reference to FIG. The following procedures are all executed by the CPU 86 by activating a predetermined program stored in the storage 83.

In general, when reading an image by controlling the image reading apparatus 1, the whole document is roughly scanned in a pre-scan mode (hereinafter referred to as a preview), and
The image data obtained in the preview is temporarily stored in the working memory 81 from the interface 80 via the data bus 82, and then transferred to the video memory 84, where the display device 85
Will be displayed. Based on the displayed screen, a trimming range is designated using a pointing device such as a mouse (not shown), and a reading resolution and other reading conditions are further designated using a keyboard or the like. (Referred to as scanning) to control the image reading apparatus 1 to obtain image data. The image data obtained by the main scan is transferred from the interface 80 to the work memory 81 via the data bus 82, and then predetermined image processing is performed on the work memory 81 to obtain final image data. This image data is also transferred to the video memory 84 and displayed on the display device 85. The image data thus obtained can be stored and stored in the storage 83, or can be transferred to another device via the interface 80.

The image reading procedure in the image reading system will be described below in detail with reference to FIGS. 5, 16, 17 and 25.

FIG. 25 is a flowchart showing an image reading procedure according to the second embodiment.

First, the whole document is previewed at a coarse resolution (step 401). The preview resolution in the second embodiment is set to 30 dpi. The host computer 2 receives the MODE SEL via the interface 80.
The ECT command and the SETWINDOW command are output, the full-size area is read at 30 dpi, and the image reading apparatus 1 is controlled to output both the image data and the local feature amount of the image (see FIG. 16 for the SCSI command). Upon receiving these commands, the image reading apparatus 1 reads the original at a resolution of 75 dpi (Table 2), and the actual reading resolution of 30 to 75 dpi is 7
5 dpi), is converted to 30 dpi by the already described first resolution conversion unit 27 (see FIG. 5) and output to the host computer 2, and the feature amount extraction means 37 (also described above) (See FIG. 5), the local feature amount of the image is extracted and output to the host computer 2.

Next, the host computer 2 displays the received image data (step 402), and includes the specific image in the image according to the procedure already described in detail, based on the local feature amount of the image sequentially input. Detect whether or not it is This detection is processed in parallel with the display process.

Next, a reading area to be fully scanned is designated for the preview image displayed by indicating a rectangular trimming range with a pointing device (not shown) (step 403), and a keyboard (not shown) is used by using a keyboard (not shown). Specify the reading resolution (may be selected from the pull-down menu using) (step 40)
4). Further, another reading mode is designated as necessary (step 405). The designation in step 405 includes, for example, color / monochrome designation for designating whether to read an image in color or monochrome, bit precision designation for designating how many bits per pixel read accuracy, setting of a tone curve, brightness and the like. Setting the contrast,
Specify negative / positive to specify whether to perform negative reading or positive reading, specify magnification when transferring the read image data directly to a printer to operate like a copier, remove moiré, and emphasize edges This includes specifying the type of filter to perform.

If it is determined that the specific image is included in the preview image (step 406), step 4
It is checked whether or not the reading resolution specified in 04 satisfies the scan prohibition condition (step 407). In the second embodiment, the scan prohibition condition specifies the resolution in the prescan, that is, a resolution higher than 30 dpi. However, in general, in order to forge a copy-prohibited document, the details of the document can be reproduced. Since it is necessary to read a document at a resolution, a specific resolution range can be set as a scan prohibition condition. For example, 150dp
Reading at a resolution of i or higher can be prohibited.

Now, it is determined that the image data previewed in step 406 contains a specific image, and step 4
If the reading resolution specified in 07 satisfies the above-described scanning prohibition condition, the process returns to step 404. Here, it is also possible to perform a display that warns the user to set a reading resolution that does not satisfy the prohibition condition.

On the other hand, if it is determined in step 406 that the specified image is not included in the previewed image data, or if it is determined in step 407 that the specified reading resolution does not satisfy the scan prohibition condition, step 4 is executed.
03, a part of the image reading conditions set in steps 404 and 405 are transferred from the host computer 2 to the image reading apparatus 1 via the interface 80 as a MODE SELECT command or a SET WINDOW command. In the main scan, a command is output so as to output only the image data without outputting the local feature amount of the image.

The image reading device 1 executes a main scan according to the designated image reading conditions (step 40).
8) Output image data. In the host computer 2, step 405 is performed on the transferred image data.
According to the reading mode designated by (1), image processing such as level conversion of an image according to a tone curve and adjustment of brightness and contrast is performed (step 409). The image data output from the image reading device 1 in this manner is
Some are processed on the image reading device side, and others are processed on the host computer side.

Generally, processing requiring high speed (eg, a filter requiring multiplication) is a simple processing (for example, tone curve) that can be performed by accessing the look-up table on the image reading device side where the merit of hardware can be utilized. In many cases, image processing such as level conversion based on image processing is performed on the host computer side, but ultimately each image processing is performed on the image reading apparatus side and the host computer in accordance with the performance required for the image reading apparatus and the cost required. Decide which side to do.

In the second embodiment, among the reading mode designations performed in step 405, the process based on the color / monochrome designation, the bit precision designation, and the filtering process are performed on the image reading device side, and the tone curve setting,
Processing based on brightness, contrast setting, negative / positive designation, and magnification designation is performed on the host computer side.

[0209] The image data on which the image processing has been completed is displayed on the image display device 85 (step 410), and a series of processing ends.

According to the image reading procedure described above, it is determined whether or not a specific image is included in the document at the time of the preview, and if the specific image is included in the preview image, the reading resolution in the main scan is determined. , It becomes difficult to read a specific image having accuracy that can withstand forgery in the main scan. This can prevent counterfeiting.

From the viewpoint of a program operating on the host computer 2, image data that can be stored in the storage 83 or transferred via the interface 80 is limited to a fully scanned image, and a preview image is By making it inaccessible from other applications, it becomes practically difficult to import specific image data with high resolution, that is, usable for forgery, into the host computer 2.

(Embodiment 3) Hereinafter, Embodiment 3 of the present invention will be described with reference to the drawings.

The third embodiment differs from the first embodiment only in the image reading procedure by the image reading system. The configuration of the image reading system, the configuration of the image reading device, the hardware of the image reading device, and the localization of the image are different. The process of extracting the characteristic feature, the process of recognizing the specific image in the host computer, and the like are common, and thus the description is omitted.

(Regarding Image Reading Procedure by Image Reading System in Third Embodiment) Third Embodiment
Will be described in detail.

First, the outline will be described with reference to FIG. The following procedures are all executed by the CPU 86 by activating a predetermined program stored in the storage 83.

Generally, when reading an image by controlling the image reading apparatus 1, the whole document is roughly scanned in a pre-scan mode (hereinafter, referred to as a preview).
The image data obtained in the preview is temporarily stored in the working memory 81 from the interface 80 via the data bus 82, and then transferred to the video memory 84, where the display device 85
Will be displayed. Based on the displayed screen, a trimming range is designated using a pointing device such as a mouse (not shown), and a reading resolution and other reading conditions are further designated using a keyboard or the like. (Referred to as scanning) to control the image reading apparatus 1 to obtain image data. The image data obtained by the main scan is transferred from the interface 80 to the work memory 81 via the data bus 82, and then predetermined image processing is performed on the work memory 81 to obtain final image data. This image data is also transferred to the video memory 84 and displayed on the display device 85. The image data thus obtained can be stored and stored in the storage 83, or can be transferred to another device via the interface 80.

Hereinafter, the image reading procedure in the image reading system will be described in detail with reference to FIGS. 5, 16, 17 and 26.

FIG. 26 is a flowchart showing an image reading procedure according to the third embodiment.

First, the entire document is previewed at a coarse resolution (step 501). The preview resolution in the third embodiment is set to 30 dpi. The host computer 2 receives the MODE SEL via the interface 80.
The ECT command and the SETWINDOW command are output, the full-size area is read at 30 dpi, and the image reading apparatus 1 is controlled to output both the image data and the local feature amount of the image (see FIG. 16 for the SCSI command). Upon receiving these commands, the image reading apparatus 1 reads the original at a resolution of 75 dpi (Table 2), and the actual reading resolution of 30 to 75 dpi is 7
5 dpi), is converted to 30 dpi by the already described first resolution conversion unit 27 (see FIG. 5) and output to the host computer 2, and the feature amount extraction means 37 (also described above) (See FIG. 5), the local feature amount of the image is extracted and output to the host computer 2.

Next, the host computer 2 displays the received image data (step 502) and, based on the local feature values of the sequentially input images, includes the specific image in the images according to the procedure already described in detail. Detect whether or not it is This detection is processed in parallel with the display process.

Next, for the preview image displayed, the reading area to be fully scanned is designated by indicating a rectangular trimming range with a pointing device (not shown) (step 503), and a keyboard (not shown) Specify the reading resolution (may be selected from the pull-down menu using) (step 50).
4). Further, another reading mode is designated as necessary (step 505). The designation in step 505 includes, for example, color / monochrome designation for specifying whether an image is read in color or monochrome, bit precision designation for specifying how many bits per pixel are to be read, tone curve setting, brightness, Setting the contrast,
Specify negative / positive to specify whether to perform negative reading or positive reading, specify magnification when transferring the read image data directly to a printer to operate like a copier, remove moiré, and emphasize edges This includes specifying the type of filter to perform.

If it is determined that the specific image is included in the preview image (step 506), step 5
Regardless of the result of the color / monochrome designation performed in step 05, the reading mode is forcibly reset to monochrome reading (step 506). On the other hand, when the specific image is not included in the preview image, step 506 is skipped, and steps 503, 504, and 50 are performed.
A part of the image reading conditions set in
As a SELECT command or a SET WINDOW command, the interface 80
Is transferred to the image reading apparatus 1 via the. In the main scan, a command is output so as to output only the image data without outputting the local feature amount of the image.

The image reading device 1 executes the main scan according to the designated image reading conditions (step 50).
8) Output image data.

The host computer 2 performs image processing such as level conversion of an image according to a tone curve and adjustment of brightness and contrast, for example, according to the reading mode specified in step 505 on the transferred image data ( Step 509). As described above, part of the image data output from the image reading device 1 is processed by the image reading device, and the other is processed by the host computer. In the third embodiment, when a specific image is detected, only a monochrome image can be read. In that case, the processing in step 509 is limited to only monochrome processing.

In general, processing requiring high speed (eg, a filter requiring multiplication) is a simple processing (for example, tone processing) that can be performed by accessing a look-up table on the image reading apparatus side where the advantages of hardware can be utilized. In many cases, the level conversion of an image based on a curve is performed on the host computer side, but ultimately each image processing is performed by the image reading apparatus side and the host in accordance with the performance required for the image reading apparatus and the cost required. Decide which to use on the computer side.

In the third embodiment, among the reading mode designations performed in step 505, processing based on color / monochrome designation, bit precision designation, and filter processing are performed on the image reading device side, and tone curve setting,
Processing based on brightness, contrast setting, negative / positive designation, and magnification designation is performed on the host computer side.

The image data on which the image processing has been completed is displayed on the image display device 85 (step 510), and a series of processing ends.

According to the image reading procedure described above, it is determined whether or not a specific image is included in a document at the time of a preview. If the specific image is included in the preview image, a monochrome image , And it becomes substantially difficult to read a specific image. This can prevent counterfeiting.

From the viewpoint of a program operating on the host computer 2, the image data that can be stored in the storage 83 or transferred via the interface 80 is limited to the actual scanned image, and the preview image is By making it inaccessible from other applications, it becomes practically difficult to import the specific image data into the host computer 2 as color data.

Embodiment 4 Hereinafter, Embodiment 4 of the present invention will be described with reference to the drawings.

The fourth embodiment is different from the first embodiment only in the image reading procedure by the image reading system and the processing of the main scan image data in the host computer 2 except for the configuration of the image reading system and the configuration of the image reading apparatus. Since the hardware of the image reading device, the process of extracting the local feature of the image, the process of recognizing the specific image in the host computer, and the like are common, the description is omitted.

Embodiment 4 (Regarding Image Reading Procedure by Image Reading System in Embodiment 4) Embodiment 4
Will be described in detail.

First, the outline will be described with reference to FIG. The following procedures are all executed by the CPU 86 by activating a predetermined program stored in the storage 83.

In general, when reading an image by controlling the image reading device 1, the whole document is roughly scanned in a pre-scan mode (hereinafter referred to as a preview), and
The image data obtained in the preview is temporarily stored in the working memory 81 from the interface 80 via the data bus 82, and then transferred to the video memory 84, where the display device 85
Will be displayed. Based on the displayed screen, a trimming range is designated using a pointing device such as a mouse (not shown), and a reading resolution and other reading conditions are further designated using a keyboard or the like. (Referred to as scanning) to control the image reading apparatus 1 to obtain image data. The image data obtained by the main scan is transferred from the interface 80 to the work memory 81 via the data bus 82, and then predetermined image processing is performed on the work memory 81 to obtain final image data. This image data is also transferred to the video memory 84 and displayed on the display device 85. The image data thus obtained can be stored and stored in the storage 83, or can be transferred to another device via the interface 80.

Hereinafter, the image reading procedure in the image reading system will be described in detail with reference to FIGS. 5, 16, 17 and 27.

FIG. 27 is a flowchart showing an image reading procedure according to the fourth embodiment.

First, the entire document is previewed at a coarse resolution (step 601). The preview resolution in the fourth embodiment is set to 30 dpi. The host computer 2 receives the MODE SEL via the interface 80.
The ECT command and the SETWINDOW command are output, the full-size area is read at 30 dpi, and the image reading apparatus 1 is controlled to output both the image data and the local feature amount of the image (see FIG. 16 for the SCSI command). Upon receiving these commands, the image reading apparatus 1 reads the original at a resolution of 75 dpi (Table 2), and the actual reading resolution of 30 to 75 dpi is 7
5 dpi), is converted to 30 dpi by the already described first resolution conversion unit 27 (see FIG. 5) and output to the host computer 2, and the feature amount extraction means 37 (also described above) (See FIG. 5), the local feature amount of the image is extracted and output to the host computer 2.

Next, the host computer 2 displays the received image data (step 602), and includes the specific image in the image according to the procedure already described in detail, based on the local feature amount of the image sequentially input. Detect whether or not it is This detection is processed in parallel with the display process.

The reading area to be fully scanned is designated for the preview image displayed next by indicating a rectangular trimming range with a pointing device (not shown) (step 603), and a mouse (mouse) not shown is used. Is used to specify the reading resolution (may be selected from the pull-down menu) (step 60).
4). Further, another reading mode is designated as necessary (step 605). The designation in step 605 includes, for example, color / monochrome designation for designating whether an image is read in color or monochrome, bit precision designation for designating how many bits per pixel read accuracy, tone curve setting, brightness and brightness. Setting the contrast,
Specify negative / positive to specify whether to perform negative reading or positive reading, specify magnification when transferring the read image data directly to a printer to operate like a copier, remove moiré, and emphasize edges This includes specifying the type of filter to perform.

Next, part of the image reading conditions set in steps 603, 604, and 605 are as follows:
MODE SELECT command or SET WINDO
As a W command, the host computer 2 sends a SCSI
Is transferred to the image reading apparatus 1 via the. In the main scan, a command is output so as to output only the image data without outputting the local feature amount of the image.

The image reading apparatus 1 executes a main scan according to the designated image reading conditions (step 60).
6) Output image data. When receiving the image data, the host computer 2 stores the image data in the working memory 81.

If it is determined that a specific image is included in the preview image (step 607), predetermined specific forgery prevention image processing is performed (step 60).
8) On the other hand, if the specific image is not included in the preview image, the image processing designated in step 605 is executed (step 609). When the specific image is not included in the preview image, the host computer 2 converts the transferred image data according to the reading mode specified in step 605, for example, level conversion of the image according to a tone curve, brightness, and the like. And image processing such as contrast adjustment.

The image data on which the image processing has been completed is displayed on the image display device 85 (step 610), and a series of processing ends.

Next, the image processing for preventing forgery performed in step 608 will be described in detail.

FIG. 28 is a diagram showing the contents of the first image processing for preventing forgery.

FIG. 28A shows the contents of level conversion of an image for preventing forgery. In general, a specific image for which copying is generally prohibited is often occupied by a high-brightness area, such as a watermark in a banknote. By converting a high-brightness portion to a low-brightness portion in such an image, for example, the watermark portion can be made to have a very yellowish color. Naturally, when such an image is printed, it can be seen at a glance that the image is a counterfeit. In the fourth embodiment, forgery prevention image processing is performed using a luminance system. When image data is printed, the density of the low-density portion is increased with respect to the density-converted image data. The same effect can be obtained by the processing.

Further, as shown in FIG. 28 (b), when the conversion table of FIG. 28 (a) is stepped, a higher forgery prevention effect can be obtained. Recently, photo retouching software has been readily available, and it has become possible to perform an inverse conversion of an image once subjected to level conversion, although an error occurs. However, when the conversion is performed in a step-like manner as in (b), the lower bits of the data are truncated (that is, the information amount is lost due to the requantization), so that it is difficult to perform normal inverse conversion.

According to the above-described image reading procedure, it is determined whether or not a specific image is included in the original at the time of the preview. If the specific image is included in the preview image, it is obtained in the main scan. Level conversion processing is performed on the resulting image. This makes it difficult to obtain a normal image even if the obtained image data is printed, thereby preventing forgery.

FIG. 29 is a diagram showing the contents of the second image processing for preventing forgery.

FIG. 29 is a diagram showing a forgery prevention pattern used for forgery prevention image processing. 29, reference numeral 90 denotes a cell obtained by dividing an image into a predetermined number of pixels, and reference numeral 91 denotes a pixel arranged in each cell.

In the fourth embodiment, each cell 90 composed of 4 × 4 pixels is defined, and the pixel 91 in this cell is converted to yellow irrespective of the original pixel value (in terms of brightness system). , R, G, and B signals are set to a minimum value of 0,
Is the maximum value FF. Hereinafter referred to as a yellow pattern). By arranging the cells in which the color of one pixel has been converted in a predetermined cycle in this manner, it is possible to embed a pattern that is difficult to identify visually with an image. In the yellow pattern, a company name or a serial number can be embedded by changing the cell arrangement.

When an image in which such a yellow pattern is embedded is printed, the device that has read the image from the pattern arrangement state can be tracked.

Further, a pattern (hereinafter referred to as an LSB pattern) for setting the LSB of the image data to 0 and embedding the LSB of the image data to 1 for the other pixels is embedded in the pixel 91 of FIG. You can also. This pattern cannot be detected visually, and it is difficult to detect the pattern from a printout image. However, since the LSB pattern can be detected as long as the specific image exists as digital data, it is possible to specify a path when the data of the specific image flows out from the host computer via the Internet or the like. Of course, it is not a simple thing like the LSB pattern, and it is also possible to embed an encrypted code.

By embedding such a specific pattern in the original image, it is possible to indirectly suppress counterfeiting.

(Embodiment 5) Hereinafter, Embodiment 5 of the present invention will be described with reference to the drawings.

In contrast to the first embodiment, the fifth embodiment differs from the first embodiment only in the image reading procedure of the image reading system. The configuration of the image reading system, the configuration of the image reading apparatus, the hardware of the image reading apparatus, and the localization of images Since the process of extracting the feature amount and the process of recognizing the specific image in the host computer are common, the description is omitted.

(Regarding Procedure for Reading Image by Image Reading System in Fifth Embodiment) Fifth Embodiment
Will be described in detail.

First, the outline will be described with reference to FIG. The following procedures are all executed by the CPU 86 by activating a predetermined program stored in the storage 83.

Generally, when reading an image by controlling the image reading apparatus 1, the whole document is roughly scanned in a pre-scan mode (hereinafter, referred to as a preview).
The image data obtained in the preview is temporarily stored in the working memory 81 from the interface 80 via the data bus 82, and then transferred to the video memory 84, where the display device 85
Will be displayed. Based on the displayed screen, a trimming range is designated using a pointing device such as a mouse (not shown), and a reading resolution and other reading conditions are further designated using a keyboard or the like. (Referred to as scanning) to control the image reading apparatus 1 to obtain image data. The image data obtained by the main scan is transferred from the interface 80 to the work memory 81 via the data bus 82, and then predetermined image processing is performed on the work memory 81 to obtain final image data. This image data is also transferred to the video memory 84 and displayed on the display device 85. The image data thus obtained can be stored and stored in the storage 83, or can be transferred to another device via the interface 80.

The procedure for reading an image in the image reading system will be described below in detail with reference to FIGS. 5, 16, 17 and 30.

FIG. 30 is a flowchart showing an image reading procedure according to the fifth embodiment.

First, the whole document is previewed at a coarse resolution (step 701). The preview resolution in the fifth embodiment is set to 30 dpi. The host computer 2 receives the MODE SEL via the interface 80.
The ECT command and the SETWINDOW command are output, the full-size area is read at 30 dpi, and the image reading apparatus 1 is controlled to output only the image data (see FIG. 16 for the SCSI command). When the image reading device 1 receives these commands, the image reading device 1
Read at 5 dpi resolution (Table 2), 30-75d
The resolution is described as being 75 dpi, and the first resolution conversion unit 27 (see FIG. 5) described above converts the resolution to 30 dpi and outputs it to the host computer 2.

Next, the host computer 2 displays the received image data (Step 702).

The reading area to be main-scanned is designated for the preview image displayed by indicating a rectangular trimming range with a pointing device (not shown) (step 703), and a keyboard (not shown) The reading resolution may be selected using a pull-down menu (step 70).
4). Further, another reading mode is designated as necessary (step 705). The designation in step 605 includes, for example, color / monochrome designation for designating whether an image is read in color or monochrome, bit precision designation for designating how many bits per pixel read accuracy, tone curve setting, brightness and brightness. Setting the contrast,
Specify negative / positive to specify whether to perform negative reading or positive reading, specify magnification when transferring the read image data directly to a printer to operate like a copier, remove moiré, and emphasize edges This includes specifying the type of filter to perform.

Next, part of the image reading conditions set in steps 703, 704, and 705 are as follows.
MODE SELECT command or SET WINDO
It is transferred from the host computer 2 to the image reading device 1 via the interface 80 as a W command. In the main scan, a command is output so as to output both the image data and the local feature amount of the image.

The image reading device 1 executes the main scan according to the designated image reading conditions (step 60).
6) Output image data. Also, the image reading device 1
In accordance with an instruction from the host computer 2, every time a predetermined amount of image data is output, the local feature of the image is output. Until the output of all the image data and the local feature of the image is completed, Output data alternately.

Upon receiving the image data, the host computer 2 stores the image data in the work memory 81 and, when receiving the local feature of the image, stores the image data in the work memory 81 arranged in an area different from the image data.

The local feature values of the images stored in the work memory 81 are interpreted by the CPU 86 in the order of input, and the specific image is included in the input image data according to the procedure already described in detail in the first embodiment. Detect whether or not it is

If it is determined that the specific image is included in the main scan image (step 707), predetermined specific forgery prevention image processing is performed (step 7).
08) On the other hand, if the specific image is not included in the main scan image, the image processing designated in step 705 is executed (step 709). If the specific image is not included in the main scan image, the host computer 2 converts the transferred image data according to the reading mode designated in step 705, for example, image level conversion according to a tone curve, Perform image processing such as adjustment of brightness and contrast.

The image data on which the image processing has been completed is displayed on the image display device 85 (step 710), and a series of processing ends.

The image processing for preventing forgery performed in step 708 is the same as the contents described in detail in the fourth embodiment, and a description thereof will not be repeated. However, it is determined whether or not a specific image is included in the original at the time of the main scan. If it is determined that the specific image is included in the main scan image, specific processing is performed on the obtained image. This makes it difficult to obtain a normal image even if the obtained image data is printed, thereby preventing forgery. Further, by embedding a specific pattern in the image data, it is possible to indirectly suppress counterfeiting.

(Embodiment 6) Hereinafter, Embodiment 6 of the present invention will be described with reference to the drawings.

(Overview of Image Reading System)
FIG. 31 is a diagram showing an entire image reading system to which the present invention is applied in the sixth embodiment.

In FIG. 1, reference numeral 1 denotes an image reading device which reads a document and outputs digital color image data and local feature amounts of an image for recognizing a specific image included in the image. An image forming apparatus 95 is an apparatus for forming an image on recording paper, such as a color laser beam printer. 3 is, for example, a bidirectional parallel interface or SCSI (Small Computer S).
The image reading apparatus 1 is connected to the image forming apparatus 95 via the cable 3. Reference numeral 96 denotes a controller built in the image forming apparatus 95, which outputs a plurality of types of commands to the image reading apparatus 1 via the interface cable 3 and obtains image data and local feature amounts of the image.

The configuration and operation of the image reading device 1, the details of the optical system of the image reading device 1, the hardware configuration of the image reading device 1, and the image processing and feature amount extraction process performed by the image reading device 1 are described in the embodiments. 1 has already been described in detail, and a description thereof will be omitted.

FIG. 32 shows the structure of the controller 96.

In FIG. 32, reference numeral 97 denotes a scanner interface, which outputs a command to the image reading device 1, receives image data, and receives local feature amounts of an image. A page memory 98 temporarily stores image data received via the scanner interface 97. An image processing unit 99 processes the image data stored in the page memory 98 to make it printable. Reference numeral 100 denotes an engine interface which outputs data on which image processing has been completed to the image forming apparatus 95. 10
1 is a data bus, and each module in the controller transmits and receives data using this bus. Reference numeral 102 denotes a working memory in which local feature values of an image received via a scanner interface are temporarily stored. 10
Reference numeral 3 denotes a CPU which controls each module via the data bus 101 and detects whether or not a specific image is included in the image data based on local feature amounts of the image stored in the working memory 102. . Reference numeral 104 denotes a ROM,
U103 is all operated by the program stored in the ROM.

Next, the operation of the controller according to the sixth embodiment will be described with reference to FIG.

[0279] The local feature amount of the image output by the image reading device 1 is taken into the controller via the scanner interface 98, and then stored in the working memory 102 via the data bus 101. Every time data is stored, the CPU 103 checks the feature amount and detects whether or not the input image includes a specific image. This detection process is the same as the process performed by the host computer in the first embodiment, and a detailed description will be omitted.

On the other hand, the image data output from the image reading device 1 is taken into the controller via the scanner interface 98, and then temporarily stored in the page memory 98 via the data bus 101. When the CPU 103 confirms that at least one page of images has been stored in the page memory, the CPU 103 waits for the detection result of the specific image described above.

If the input image does not include a specific image, the image data in the page memory 98 is transferred to the image processing section 99, and after performing predetermined image processing, transferred to the engine interface 100. The document image read by the image reading device 1 is printed and output by the image forming device 95.

On the other hand, if it is determined that the specific image is included in the input image, the image data in the page memory 98 is transferred to the image processing unit 99, and after the image processing for preventing forgery is performed, the image data is transmitted to the engine interface 100. The document image transferred and read by the image reading device 1 is printed and output by the image forming device 95. With such a configuration, the image data is temporarily stored in the page memory 98,
Thereafter, the image processing can be changed based on whether or not the specific image is included in the image. Image processing for preventing forgery will be described later in detail.

FIG. 33 is a diagram showing the processing contents of the image processing section 99.

Hereinafter, the image processing of the controller according to the sixth embodiment will be described with reference to FIG.

In FIG. 33, reference numeral 105 denotes a density conversion unit which performs logarithmic conversion on the luminance data R, G, and B transferred from the page memory 98 to obtain density data Dr, Dg, Gb.
To A lookup table is used for this conversion. Reference numeral 106 denotes a UCR / black generation unit, and density data D
UCR (Und) in which a minimum value is obtained from r, Dg, and Gb, and a value obtained by multiplying the minimum value by a predetermined ratio is subtracted from the density data of each color.
er Color Removal) processing, and further multiplies the minimum value of the density data Dr, Dg, and Gb by a predetermined ratio to generate black = K (Black) data.

Reference numeral 107 denotes a color correction unit which removes an unnecessary absorption component of a recording color material of the image forming apparatus 95 from chromatic components other than K in the image data for which UCR / black generation has been completed, and has no turbidity. The colors are corrected to vivid colors, and C (Cyan), M (Magenta), and Y (Ye)
lllow). 108 is a selector, UC
R / K (Black) output from the black generation unit 106,
C (Cyan), M (M
agent) and Y (Yellow). Reference numeral 109 denotes a magnification conversion unit.
The image data is subjected to scaling processing such as enlargement / reduction based on the designation from step 3. Numeral 110 denotes a gamma correction unit that corrects a non-linear component of gradation characteristics caused by an image forming process of the image forming apparatus using a look-up table. Reference numeral 111 denotes a gradation processing unit which performs a binarization process or the like on image data.

If the specific image is not included in the input image, the above-described image processing is sequentially performed, and printing is performed by the image forming apparatus. FIG. 32 shows the processing contents of the processing unit 99.
This will be described with reference to FIG.

When the CPU 103 determines that the specific image is included in the input image data, the CPU 103 discards the setting contents for the magnification conversion unit 109 if any setting has already been made, and The image is set to be reduced to a size of 90%. The algorithm for reducing the image is described in detail in the first embodiment, taking the processing of the image reading apparatus as an example, and therefore will not be described. However, briefly, pixels are arranged in the reduced image. A power position is obtained, and a weighting operation is performed on surrounding pixel values according to the pixel position after the conversion. The image is reduced by performing this processing in both the main scanning direction and the sub-scanning direction.

By performing the reduction process on the specific image in this way, the image actually copied is printed smaller than the actual image. If the real object is zoomed by 90%, it can be seen at first glance that it is a fake. Of course, the reduction ratio may be other than the value shown here, and it is also possible to enlarge instead of reducing. In short, it is significant to prohibit 1: 1 copying in size when a specific image is detected.

As described in detail in the first embodiment, in the present invention, the color information is used for recognizing a specific image. It is impossible to prove that "is not present." In other words, there is always a risk of erroneous determination that a non-specific image is determined to be a specific image, and it is not possible to copy an image that can be copied originally, or the image is modified and cannot be used for its intended purpose. Problems can occur.

However, this problem can be solved by employing the scaling process described above. In general, the entire image of a color image is important, and there are very few cases where the copy size is particularly important. As a manuscript requiring an accurate size, for example, a drafting drawing is typical, but a monochrome copy is sufficient for this copy. However, certain images, such as banknotes, fall into this exception, and if they are not color and accurate dimensions, they can be construed as counterfeits, and with a certain magnification, counterfeits can be easily identified. it can.

That is, when the specific image is recognized, the image is scaled and copied so that the specific image can be completely recognized as a forgery, and the general image is mistaken for the specific image. Even if it is determined, damage to the user can be minimized and stopped.

Of course, as the image processing when a specific image is detected, image level conversion described in detail in Embodiment 4 may be performed, or image scaling and image level conversion may be combined. . This level conversion is performed by the γ correction unit 1
Since it can be easily performed by using the ten lookup tables and does not affect the processing contents of the magnification conversion unit 109 at all,
Each can be processed independently.

(Transfer of Image Data and Feature Amount)
Next, transmission and reception of data by a SCSI command will be described in detail with reference to FIG.

FIG. 34 is a diagram showing a procedure for commands exchanged between the controller 96 and the image reading apparatus 1 and data to be transferred. A solid arrow in the drawing indicates that a command has occurred in that direction, and a broken arrow indicates that data is sent in that direction.

In the following description, SCSI will be described as an example for the sake of simplicity. Of course, the same procedure is adopted for other interfaces if the host computer and the image reading apparatus can communicate bidirectionally. be able to.

When reading image data, first, the controller 96 sends the image reading device 1 a TEST.
Issue a UNIT READY command. When the image reading device 1 receives this command, the BUSY or RE
The status of the image reading device such as ADY is returned to the controller 96 (step 800). The controller 96 waits until the returned status becomes READY to execute TEST UNI.
Issue a T READY command periodically.

When the image reading device 1 returns READY in response to the TEST UNIT READY command, the controller 96 determines that the image reading device 1 is in a readable state, and issues a MODE SENSE command (step 801). Upon receiving this command, the image reading apparatus 1 operates the operation panel (not shown), that is, whether or not a copy start instruction has been issued (hereinafter referred to as copy start key information), or what read mode has been selected. The information about the user operation, such as whether the user is, is output to the controller 96. Controller 9
6 periodically outputs a MODE SENSE command until a copy start is instructed by the copy start key information;
The information of the operation panel is continuously obtained from the image reading device 1.

When it is determined that the copy start is instructed by the copy start key information, the controller 96 sets the MOD
Issue an E SELECT command. With this command, the controller 96 passes control parameters to the image reading device 1. The control parameters include a parameter for selecting data output from the image reading device in a scanning operation to be performed. That is,
The user selects whether to read the document and output the image data, read the document and output the local feature amount, or output both (step 802). Embodiment 6
In, the selection is made so as to output both the image data and the local feature amount of the image.

Next, the controller 96 issues a SET WINDOW command to the image reading device 1.
Following this command, the controller 96 passes the image reading conditions to the image reading device 1. The image reading conditions include information such as an image reading start position, a reading range (image size), and an image reading resolution (step 803). On the image reading device side, based on the resolution information passed by this command,
The setting of the second resolution conversion unit (see FIG. 11) is performed.
In the sixth embodiment, as the image reading conditions, the reading resolution is set to 600 dpi, and the reading range is set to, for example, the entire LETTER size from the head of the readable position.

If it is determined in step 802 that at least the local feature of the image is to be output, the controller 96 issues a SEND command to the image reading device 1, and subsequently, in the first embodiment, The described characteristic color count range and template are transferred (step 804).

Next, the controller 96 issues a SCAN command to the image reading device 1. Thereby, the image reading apparatus 1 starts the rotation of the driving source (the driving source 8 in FIG. 2) and prepares for image reading (step 805).

Next, the controller 96 issues a GET PIXEL NUMBER command to the image reading device 1. Upon receiving this command, the image reading device 1 calculates the actual number of pixels per line, the amount of data, and the like from the image size and the reading resolution received in step 803, and returns the result to the controller 96 (step 806). . In this way, SET WINDOWS
The reading device returns the actual setting value for the reading condition specified by the command, so that the reading range specified by the controller 96 is higher than the accuracy handled by the image reading device. (The controller 96 follows the value returned from the image reading device 1).

Next, the controller 96 sends a GET DATA BUFFER STAT to the image reading device 1.
Issue a US command. Upon receiving this command, the image reading device 1 returns the amount of image data and the amount of feature not yet transferred to the controller 96 (step 8).
07).

Next, the controller 96 determines in step 80
If an instruction has been issued to the image reading device 1 to output at least the image data in step 2, a READ (1) command is issued, and a predetermined amount of image data is received from the image reading device 1 (step 808).

Next, the controller 96 proceeds to step 80.
If the image reading device 1 is instructed to output at least the local feature amount of the image in step 2,
(2) A command is issued, and a predetermined amount of image data is received from the image reading device 1 (step 809).

The processing from step 807 to step 809 is repeated until it is determined in step 807 that there is no remaining data to be transferred.

As described above, in the sixth embodiment, acquisition of image data and local feature amounts of an image is alternately repeated. For example, considering a LETTER size document, the local feature amount of an image is about 600 bytes, and if the image is to be transferred all at once, it is necessary to store the image in a buffer of the image reading device until reading of the image is completed. Also, if the document size increases, it must be expanded to the maximum document size. However, by alternately outputting the image data and the local feature amount of the image, the buffer on the image reading device side needs only about 40 bytes. This is a capacity that can be called a register rather than a memory, and hardware can be easily realized. Further, by alternately acquiring the image data and the local feature amount of the image, the controller 96 can sequentially process the acquired local feature amount of the image. There is also an effect that the required time until the determination is made can be substantially reduced.

According to the procedure described above, the image data and the local feature amount of the image are transferred from the image reading device 1 to the controller 96.

(Regarding Image Reading Procedure by Image Reading System in Embodiment 6) Next, the image reading procedure in Embodiment 6 will be described in detail.

First, the outline will be described with reference to FIG. The following procedures are all executed by the CPU 103 by activating a program stored in the ROM 104.

In the sixth embodiment, as described above,
Copying of an image is started by an operation panel (not shown) of the image reading device 1. Therefore, the entire image area of the original is directly read without using the pre-scan mode used in the first to fifth embodiments.

The following describes in detail the image reading procedure in the image reading system with reference to FIGS. 5, 32, 34 and 35.

FIG. 35 is a flowchart showing an image reading procedure according to the sixth embodiment.

First, the controller 96 sets the MODE SEN
An SE command is output to the image reading apparatus 1 to receive operation panel information of the image reading apparatus 1, and waits until a copy start is instructed (step 900).

Next, a predetermined reading area, such as the LETTER size, is specified from the top of the readable range of the image reading apparatus (step 901), and the reading resolution is specified as 600 dpi (step 902). . Further, another reading mode specified by an operation panel (not shown) of the image reading apparatus is specified (step 903).

The designation in step 903 includes, for example, color / monochrome designation for designating whether an image is read in color or monochrome, bit precision designation for designating how many bits of the reading accuracy per pixel, and setting of a tone curve. , Setting of brightness and contrast, negative / positive designation to specify whether to perform negative reading or positive reading, magnification designation when the read image data is directly transferred to the printer to perform an operation like a copying machine, moiré And the designation of a filter type for removing edges and enhancing edges.

Next, part of the image reading conditions set in steps 901, 902, and 903 are as follows.
MODE SELECT command or SET WINDO
The W command is transferred from the controller 96 to the image reading device 1 via SCSI.

[0319] The image reading apparatus 1 executes a scan for copying in accordance with the designated image reading conditions (step 904) and outputs image data. Further, the image reading device 1 outputs a local feature amount of the image every time a predetermined amount of image data is output in accordance with an instruction from the controller 96, and the output of all the image data and the local feature amount of the image is completed. Until the above, these data output are performed alternately.

Upon receiving the image data, the controller 96 stores the image data in the page memory 98 and, when receiving the local feature of the image, stores it in the working memory 102.

The local feature amounts of the images stored in the work memory 102 are interpreted by the CPU 103 in the order of input, and according to the procedure already described in detail in the first embodiment.
It is determined whether or not a specific image is included in the input image data.

If it is determined that the specific image is included in the image obtained by the copy scan (step 9).
05), a predetermined specific forgery prevention image process is performed (step 906), and if the specific image is not included in the image obtained by the copy scan, the image specified in step 903 Execute processing (step 9
07). If the specific image is not included in the image obtained by the copy scan, the controller 96 applies an image corresponding to the transferred image data in accordance with the reading mode specified in step 903, for example, according to the tone curve. Image processing such as level conversion, brightness and contrast adjustment, and scaling.

The image data on which the image processing has been completed is sequentially transmitted to the image forming apparatus 95 via the engine interface.
And print is executed (step 908).

The image processing for preventing forgery performed in step 906 is as already described in detail, and it is determined whether or not a specific image is included in the image obtained by the scan for copying.
If a specific image is included, the obtained image scaling processing is performed. Even if the image data obtained in this way is printed, the size of the image data is different, so that the image data can be distinguished at a glance from a counterfeit, so that the counterfeit does not hold.

As described above in the first to sixth embodiments, in the present image reading system, reading of a specific image for which copying is prohibited or copying can be effectively prohibited. In the description of each of the embodiments, the processing is divided into the preview and the main scan, but the processing of detecting the specific image from the preview image and the processing of detecting the specific image in the main scan may be performed together. In this way, for example, a malicious action such as reading a non-specific image during a preview, replacing a document with a specific image, and specifying a large area to perform a main scan also prevents a specific image from being read. be able to. In addition, if control is performed such that a preview is always required before the main scan, it becomes impossible to read the entire image of the specific image.

Further, the present invention can be applied to any environment in which an image reading system is incorporated. For example, FIG. 36 is a diagram showing a configuration when the image reading system of the present invention is connected to a network.

[0327] As shown in FIG.
Even in an environment in which an image forming apparatus and a plurality of host computers are connected via a network, the present invention can be applied, of course, since image data and local feature amounts of an image can be easily transferred through the network.

In all the embodiments, the description has been made on the assumption that the data is transferred by SCSI. However, this may be extended to a network to transfer the command by the TCP / IP protocol.

[0329]

As described above, according to the present invention,
The image reading device outputs at least one of the read image data and the local feature amount of the image in accordance with an instruction from the control device, so that the image reading device side performs a local feature amount extraction process that requires high speed. Thus, the load on a control device such as a host computer or a printer controller can be reduced without significantly increasing the hardware scale of the image reading device, and the specific image can be determined at high speed.

The control device controls the image reading device to obtain a local feature of the image, and determines whether or not a specific image exists in the obtained image data based on the local feature. The determination does not require a special device, and the control device such as a host computer can determine the presence or absence of the specific image.

Further, the image reading device is controlled so as to alternately repeat the transfer of the image data and the transfer of the local feature value by the time the transfer of all the image data is completed in accordance with the instruction of the control device. Therefore, the image reading device side can output the local feature amount using a small amount of memory resources, and the control device side such as the host computer can receive the local feature amount in a divided manner. The time for determining whether or not a specific image exists in image data can be substantially shortened.

A pre-scan mode for reading a document roughly at a predetermined resolution, a reading area for an image obtained in the pre-scan mode, and a main scan mode for reading by specifying a reading resolution are provided. Since it is determined whether or not the specific image is included in the image data obtained in the scan mode, the specific image can be determined before the main scan for reading the image data with high resolution.
For this reason, it becomes difficult to read a specific image at a resolution necessary for establishing forgery.

If it is determined that the specific image is included in the image data obtained in the prescan mode, reading in the main scan mode is prohibited. Thereby, reading of the image data of the specific image at high resolution can be prohibited.

When it is determined that a specific image is included in the image data obtained in the pre-scan mode, reading of an image at a higher resolution in the main scan mode than in the pre-scan mode is prohibited. As a result, image reading at a resolution sufficient for image formation can be prohibited.

When it is determined that a specific image is included in the image data obtained in the prescan mode, reading of an image in a predetermined resolution range in the main scan mode is prohibited. As a result, it is possible to prohibit only reading in a resolution range in which a specific image can be sufficiently reproduced when printed.

If it is determined that a specific image is included in the image data obtained in the prescan mode, reading of a color image in the main scan mode is prohibited. As a result, it is possible to effectively prohibit only reading of a color specific image represented by a bill or the like.

When it is determined that a specific image is included in the image data obtained in the prescan mode, predetermined image processing is performed on the image data read in the main scan mode. As a result, it is possible to clearly recognize that the print is a forgery even when printed.

A pre-scan mode for reading a document roughly at a predetermined resolution, a read area for reading an image obtained in the pre-scan mode, and a main scan mode for reading by specifying a read resolution are provided. It is determined whether or not a specific image is included in the image data obtained in the scan mode. Thus, it is possible to prevent a malicious act of reading a non-specific image in the pre-scan and reading a specific image in the main scan.

When it is determined that a specific image is included in the image data obtained in the main scan mode, predetermined image processing is performed on the read image data. As a result, it is possible to clearly recognize that the print is a forgery even when printed.

Also, the prescan mode is omitted, a copy scan mode for reading a predetermined area at a predetermined resolution is provided, and it is determined whether or not a specific image is included in the image data obtained in the copy scan mode. I do. This makes it difficult to copy a specific image in a system having a copy function of directly printing image data read using the image reading system.

When it is determined that the specific image is included in the image data obtained in the scan mode for copying, predetermined image processing is performed on the read image data. This makes it possible to recognize that the copy is a counterfeit.

As the predetermined image processing, image scaling processing is performed. Thus, even if a specific image whose copying is prohibited is copied, it can be determined at a glance as a counterfeit, and even if a non-specific image is erroneously determined to be a specific image, actual harm to the user can be minimized.

As the predetermined image processing, level conversion or requantization is performed on the value of each pixel. Since these processes are simple, the process when it is determined that the image is the specific image can be performed at high speed.

In addition, a predetermined pattern signal is superimposed on the image read as the predetermined image processing. As a result, even when the read image data is distributed using a network or the like, it is possible to specify the image reading device that has performed the reading, and it is possible to indirectly prevent forgery.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire image reading system to which the present invention is applied.

FIG. 2 is a diagram showing a structure of an image reading device in the image reading system.

FIG. 3 is a diagram showing an internal structure of a carriage of the image reading apparatus.

FIG. 4 is a perspective view showing details of an optical system of the image reading apparatus.

FIG. 5 is a block configuration diagram of image data processing of the image reading apparatus.

FIG. 6 is a schematic diagram of a side view of a carriage of the image reading apparatus.

FIG. 7 is a view of the image sensor as viewed from a line sensor array side.

FIG. 8 is a diagram illustrating an operation principle of a line correction unit.

FIG. 9 is a diagram illustrating an operation of a line correction unit when reading an image at a resolution of 300 dpi in the sub-scanning direction.

FIG. 10 is a diagram showing a resolution conversion algorithm.

FIG. 11 is a diagram showing the structure of a feature amount extraction unit in detail.

FIG. 12 is a diagram showing a configuration of a characteristic color counter.

FIG. 13 is a diagram showing a data structure of a feature vector passed to a template selection unit.

FIG. 14 is a flowchart showing the operation of a template selection unit.

FIG. 15 is a diagram showing a relationship between a template and a specific image.

FIG. 16 is a diagram showing a procedure for a command exchanged between the host computer and the image reading apparatus 1 and data to be transferred;

FIG. 17 is a diagram showing an overall configuration of a host computer.

FIG. 18 is a diagram showing a data configuration in a working memory.

FIG. 19 is a diagram showing images of TN (n) and D (n) given to each block of an actual specific image.

FIG. 20 is a diagram showing a structure of a frame mask.

FIG. 21 is a flowchart showing processing contents for one frame in frame processing;

FIG. 22 is a diagram showing rotation angle correction in a final determination.

FIG. 23 is a diagram illustrating a relationship between a frame, a block, and a recognition process in a final determination.

FIG. 24 is a flowchart showing an image reading procedure according to the first embodiment;

FIG. 25 is a flowchart illustrating an image reading procedure according to the second embodiment.

FIG. 26 is a flowchart illustrating an image reading procedure according to the third embodiment.

FIG. 27 is a flowchart illustrating an image reading procedure according to the fourth embodiment.

FIG. 28 is a diagram showing first image processing content for forgery prevention;

FIG. 29 is a diagram showing a second image processing content for forgery prevention;

FIG. 30 is a flowchart illustrating an image reading procedure according to the fifth embodiment.

FIG. 31 is a diagram showing an entire image reading system to which the present invention is applied in the sixth embodiment.

FIG. 32 shows a configuration of a controller.

FIG. 33 is a diagram showing processing contents of an image processing unit.

FIG. 34 is a diagram showing a procedure for a command exchanged between the controller and the image reading apparatus and data to be transferred;

FIG. 35 is a flowchart showing an image reading procedure according to the sixth embodiment.

FIG. 36 is a diagram showing a configuration when the image reading system of the present invention is connected to a network.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Host computer 4 Network 7 Carriage 6 Original glass 8 Drive source 20 Image sensor 26 Line correction unit 27 First resolution conversion unit 32 CPU 33 Motor control unit 37 Feature amount extraction unit 38 Second resolution conversion unit 39 Feature amount Operation unit 40 Parameter setting signal 55 Feature color counter 56 Template selection unit 57 Template storage memory 58 Buffer 60 Main / sub pixel counter 70_C0 Feature color detection unit 70_C1 Feature color detection unit 70_C2 Feature color detection unit 71 Comparator 77 Final judgment unit 80 Interface 81 working memory 86 CPU 97 scanner interface 98 page memory 99 image processing unit 100 engine interface 102 working memory 103 CPU 109 magnification conversion unit 110 gamma correction unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/387 H04N 1/04 Z 5C077 F term (Reference) 2H027 DB00 FB12 2H034 FA01 5B047 AA01 BC14 CA04 CB10 DC09 5C072 AA05 BA20 RA20 WA04 XA01 5C076 AA21 AA22 BA01 BA02 BA03 BA04 BA05 BA06 5C077 LL14 PP20 PP65 TT02

Claims (16)

[Claims] 1. An image reading system comprising: an image reading device that reads a document and outputs image data; and a control device that controls the image reading device to obtain image data, wherein the image reading device includes the control device. An image reading system that outputs at least one of image data read in accordance with the instruction of (1) and a local feature amount of the image. 2. An image reading system comprising: an image reading device that reads an original and outputs image data; and a control device that controls the image reading device to obtain image data, wherein the control device controls the image reading device. The image reading system according to claim 1, wherein the control unit obtains a local feature amount of the image by controlling, and determines whether or not a specific image exists in the document based on the local feature amount. . 3. The image reading device according to claim 1, wherein the transfer of the image data and the transfer of the local feature are alternately repeated until the transfer of all the image data is completed according to an instruction of the control device. The image reading system according to claim 1, wherein the image reading system performs the image reading. 4. A pre-scan mode in which a document is roughly read at a predetermined resolution, a read area for an image obtained in the pre-scan mode, and a main scan mode in which a read resolution is designated and read. An image reading system for determining whether or not a specific image is included in image data obtained in a prescan mode. 5. The image reading system according to claim 4, wherein when it is determined that the specific image is included in the image data obtained in the pre-scan mode, reading in the main scan mode is prohibited. . 6. When it is determined that a specific image is included in the image data obtained in the prescan mode, it is prohibited to read an image at a higher resolution than in the prescan mode in the main scan mode. The image reading system according to claim 4, wherein: 7. When it is determined that a specific image is included in the image data obtained in the pre-scan mode, reading of an image in a predetermined resolution range is prohibited in the main scan mode. The image reading system according to claim 4, wherein 8. The method according to claim 4, wherein when it is determined that a specific image is included in the image data obtained in the pre-scan mode, reading of a color image in the main scan mode is prohibited. An image reading system as described. 9. When a specific image is determined to be included in the image data obtained in the prescan mode, predetermined image processing is performed on the image data read in the main scan mode. The image reading system according to claim 4, wherein 10. A pre-scan mode in which a document is roughly read at a predetermined resolution, a reading area for an image obtained in the pre-scan mode, and a main scan mode in which a reading resolution is designated and read. An image reading system for determining whether or not a specific image is included in image data obtained in a main scan mode. 11. The apparatus according to claim 10, wherein when it is determined that a specific image is included in the image data obtained in the main scan mode, predetermined image processing is performed on the read image data. An image reading system as described. 12. A copy scan mode for reading a predetermined area at a predetermined resolution by omitting the prescan mode, and determining whether a specific image is included in image data obtained in the copy scan mode. An image reading system characterized by determining: 13. A predetermined image processing is performed on the read image data when it is determined that a specific image is included in the image data obtained in the copy scan mode. An image reading system according to claim 1. 14. An image reading system according to claim 13, wherein said predetermined image processing is an image scaling processing. 15. The image reading system according to claim 9, wherein said predetermined image processing is level conversion or requantization for each pixel value. 16. The image reading system according to claim 9, wherein said predetermined image processing is to superimpose a predetermined pattern signal on a read image.