JPH0865526A - Top secret image storage device / top secret image transmission device and top secret image storage / transmission device - Google Patents

Abstract

(57) [Summary] [Purpose] To store confidential images with highly confidential data. [Structure] A confidential document is read by a reading device 1001 as pixel data, special density conversion is performed by a density conversion device 1003, and stored in a storage medium by a storage device 1006.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a confidential image storage device, a confidential image transmission device, and a confidential image storage transmission device.

A "confidential image storage device" is a device capable of reading a document image and storing it as confidential data, and a "confidential image transmitting device" is a device capable of reading a document image and transmitting it as confidential data to an external device.

A "confidential image storage / transmission device" is a device capable of reading a document image, storing it as confidential data, and transmitting it as external data to an external device.

[0004]

2. Description of the Related Art With the widespread use of copying machines, word processors, computer communications, etc., the handling of confidential information has become a problem in connection with these.

The confidential information can be stored in various storage media. In this case, it is desirable to store such that "the original confidential information cannot be easily reproduced from the stored information".

For example, as a method for storing confidential information as a confidential copy image on a recording sheet which is a storage medium, Japanese Patent Laid-Open No. HEI-2 is disclosed.
As disclosed in Japanese Patent Laid-Open No. 214264/1994, there is a method in which image data obtained by reading an original having confidential information is deformed by shifting in line units in the main scanning direction by an amount according to a random number and is written on a recording sheet. Are known.

With this method, since the image stored on the recording paper is deformed, the original confidential information cannot be reproduced visually.

This method is excellent as a method of storing confidential information, but if necessary, from the stored confidential copy image,
To reproduce the original confidential information, it is necessary to read the confidential copy image and restore the shift amount for each line. Therefore, when reading the confidential copy image, the image for each line at the time of writing, Since it is necessary to read each line accurately, there is a problem that accurate restoration is difficult.

In addition, if a random number is stored and an amount corresponding to the random number is shifted in real time in the main scanning direction to perform image deformation / restoration, the circuit configuration must be complicated.

In order to "transmit" the confidential information stored as described above, the recording paper itself storing the confidential copy image is sent, or the confidential copy image recorded on the recording paper is read and transmitted. There is also a problem that when a confidential copy image is read and transmitted, the image for each line at the time of writing cannot be reproduced unless the image is accurately read line by line.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to store confidential image information on a document while maintaining confidentiality and in a state where it can be surely reproduced. It is intended to provide a highly confidential image storage device (claims 1 to 5).

Another object of the present invention is to provide a novel confidential image transmission device capable of transmitting confidential image information on a document while maintaining confidentiality and in a state where it can be reliably reproduced. 9).

Another object of the present invention is to provide a new confidential image in which confidential image information on a document can be stored in a state where the confidentiality is maintained and can be surely reproduced and transmitted while being surely reproduced. A storage and transmission device is provided (claim 10).

[0014]

The "image storage device" of the present invention is a device capable of reading a document image and storing it as confidential data, and includes a pixel reading device, a confidential mode storage instruction means, a density conversion device, and It has a storage device and a writing means (claim 1).

The "pixel reading device" is a device for reading image information in pixel units as density data.

The "confidential mode storage instruction means" is means for instructing image data storage in the confidential mode.

The "density conversion device" is a device for performing density conversion for a confidential image in the case of storage in the confidential mode. That is, when storing in the confidential mode, the image data (density data in pixel units) read by the pixel reading device is subjected to "density conversion for confidential image" by the density converting device.

The "storage device" is a device for storing "density data for a confidential image" whose density is converted by the density conversion device.

Although the storage device can be configured as a "memory" provided in the image storage device, the density data for the confidential image, which is the density-converted digital information such as a floppy disk or an optical disk, is stored. Any medium that can be reliably stored can be used without particular limitation. In particular, a floppy disk is one suitable as a storage device.

The "writing means" is means for writing the density data after density conversion by the density converter into the storage device.

In the density conversion by the density converter, the original confidential image is not reproduced when the converted density data is reproduced as it is, and the original confidential image can be reproduced by a certain image processing. Any conversion is possible and various conversions are possible, but a very suitable conversion is conversion for converting image data of a confidential document into density data of "a level not visualized when output in the general image mode" (claim 2). ).

The "density conversion device" is capable of performing plural kinds of conversion for density conversion of a confidential image, and can specify any one of them.

In this case, the "plurality of types of conversion" may be "unique density conversion" by each of a plurality of conversion means which form an independent circuit structure and constitute a density conversion device. It is to specify the conversion means. Alternatively, a plurality of types of conversion may be conversion software, and one of them may be arbitrarily selected and executed.

The "density converter" can have a function of converting the pixel data read as the density data of each pixel into "secret image data of density data of 3 or more" (claim 4).

When it is possible to specify any one of a plurality of types of conversions that can be performed by the density conversion device, as in the confidential image storage device according to the third aspect, information about the conversion type, that is, which one Information regarding whether or not the type conversion is specified is stored in the nonvolatile memory other than the storage device in the apparatus main body together with the content of the user ID for restricting the use of the confidential image storage device or the user ID for restricting the use of the confidential mode. It can be stored in a backup memory of the sex (claim 5).

The "confidential image transmission device" of the present invention is a device capable of reading a document image and transmitting it as confidential data to an external device, and includes a pixel reading device, a confidential mode transmission instruction means, a density conversion device, and image data. And a transmission means (claim 6).

The "pixel reading device" is a device that reads image information in units of pixels as density data. The "secret communication mode transmission instructing means" is means for instructing transmission of image data in the confidential mode.

The "density conversion means" is a device for performing density conversion for confidential transmission in the case of transmission in the confidential mode.

The "image data transmitting means" is means for transmitting the density data after density conversion by the density conversion device.

In the density conversion by the density conversion device, the original confidential image is not reproduced when the converted density data is reproduced as it is, and the original confidential image can be reproduced by a certain image processing. Any conversion is possible, and various conversions are possible, but a very suitable conversion is a conversion for converting the density data of a confidential document into the density data of "a level that is not visualized when output in the general image mode" (Claims). 7).

The "density conversion device" in the confidential image transmission device according to the invention of claim 6 is capable of performing plural kinds of conversion as density conversion for confidential transmission, and can specify any one of them. Yes (claim 8).

As in the case of the third aspect of the invention, also in this case, the "plurality of types of conversion" is the "inherent density conversion" by a plurality of conversion means having an independent circuit configuration and constituting the density conversion device. Alternatively, the conversion means may be conversion software, and one of them may be arbitrarily selected and executed.

Similarly to the fourth aspect of the invention, the "density converter" also has a function of converting the pixel data read as the density data for each pixel into "secret image data of three or more density data". It can have (claim 9).

As described above, the confidential image storage device according to claims 1 to 5 and the confidential image transmission device according to claims 6 to 9 both have the pixel reading device and the density conversion device,
The functions of the pixel reading device and the density converting device are common to the confidential image storage device and the confidential image transmitting device.

Therefore, the "confidential image storage / transmission device" according to claim 10 is the confidential image storage device according to claim 1 or 2 or 3 or 4 or 5 and the confidential information according to claim 6 or 7 or 8 or 9. The image transmission device is characterized in that "the pixel reading device and the density conversion device are common and configured as the same device".

[0036]

As described above, in the "secret image storage device" of the present invention, the pixel information is read by the pixel reading device as the density data of each pixel, and in the confidential mode, the read pixel data has a density exclusive for the confidential mode. Apply conversion.

The converted density data is written and stored in the storage device.

The "confidential image transmitting device" of the present invention reads the density data in pixel units by the pixel reading device, and in the case of transmission in the confidential mode, the read pixel data is subjected to the density conversion dedicated to the confidential mode to obtain the confidential information. Is transmitted to the external device as “image data”.

Particularly, in the invention according to claim 2 or 7,
The density conversion is performed at a level that cannot be visualized when output in the general image mode, that is, a low efficiency level that cannot be visualized.

The "secret image storage / transmission device" of the present invention is
Image information is read by the pixel reading device as density data in pixel units, and in the confidential mode, the read pixel data is subjected to density conversion dedicated to the confidential mode. The converted density data is written and stored in a storage device, or is transmitted to an external device as confidential image data.

Particularly, in the invention according to claim 2 or 7,
The density conversion is performed so that the level is not visualized even when output in the general image mode.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a top view of the apparatus of one embodiment in which the confidential image storage / transmission apparatus of the invention of claim 10 is implemented as an "image forming apparatus" having a storage function and a transmission function. Show.

In FIG. 1A, the original pressure plate 101 is
This is a plate-shaped member that applies pressure to the original placed on the contact glass to bring it into close contact with the contact glass. An editing device (editor) is provided on the upper surface of the original to specify the area and coordinates on the original. ing.

In FIG. 1A, the portion following the document pressure plate 101 is an "operation portion". The operation unit is an input / output device for designating the operation of the image forming apparatus and man / machine I / F with the user, and is provided with a hard key 102, a display 103, and an application key 106. That is, the operation unit constitutes "secret mode storage instruction means" and "secret mode transmission instruction means".

The hard key 102 is a key for key input. The display device 103 is a dot matrix display device of an LCD, and displays a setting state, gives a setting instruction to a user, and informs of an abnormality of the device.

Since the circled portion of the hard key 102 is a key group which is important for the following description, these are enlarged and shown in FIG. 1 (b).

Reference position mark 104 on the upper surface of the pressure plate 101
Is a mark indicating the coordinate reference on the editor, and can be used, for example, for designating an image portion that is a target for storing or transmitting a confidential image.

The connector 105 is a connection terminal for connecting the image forming apparatus and an external device (application), and transmits image data read by an “image reading section” described later to an application and transmits / receives (transmits) a control signal. Function), a connection cable for receiving image data from an application by the “image output device” described later, transmitting and receiving control signals, etc., and constitutes a part of “image data transmitting means”. To do.

The application key 106 is the display 1
A display key 03 is a switching key for switching between the image formation mode display and the application mode display.

FIG. 2 schematically shows the structure of the "image forming apparatus" whose upper surface is shown in FIG. 1 (a), as viewed from the front side of the apparatus.

Reference numerals 101 and 202 to 211 denote constituent elements of an "image reading section" for inputting an image, and reference numeral 2
Reference numerals 12 to 234 denote constituent elements of a "printer unit" that performs image processing on the image data obtained from the image reading unit and outputs digital image data on a recording sheet.

The contact glass 202 provided under the pressure plate 101 is used to set the original to be read flatly.

The fluorescent lamp 204 is the contact glass 202.
It is a light source for irradiating a document placed above for reading, and a reflector is provided along the longitudinal direction (direction orthogonal to the drawing).

The reading element 205 has a CCD which is a line sensor and an image forming element which forms an image of an original on the CCD, and changes the light reflected from the original into a reading charge amount in pixel units. The photoelectric conversion elements of the CCD are arranged in a direction perpendicular to the drawing (main scanning direction), and the document is read by the reading element 205 line by line.

The fluorescent lamp 204 and the reading element 205 are integrated as a carriage 203, move in the direction of the arrow (sub-scanning direction) in the figure, and two-dimensionally read the original by main / sub-scanning and convert it into "digital data". To do. In other words, the image information of the original is read by reading the image information as density data in units of pixels.

The scanner controller 210 includes the carriage 2
In addition to the control of No. 03, it exchanges control signals with the printer unit and external devices. That is, the carriage 20
3 and the scanner control device 210 form the main part of the “pixel reading device”.

The image processing device 209 performs image processing such as color conversion and density conversion on the pixel data obtained by reading. Therefore, the image processing apparatus 209 includes a “density converter” as a function.

The interface board 208 is an interface with a storage device and an external device, and sends pixel data from the “pixel reading device” to the storage device or the external device or receives image data from the storage device or the external device. To do. Therefore, the interface board 208 and the above-mentioned connector 105 (FIG. 1A) constitute the main part of the "image data transmitting means".

The storage device 207 is a device for writing image data to and reading image data from a "recording device" such as a floppy disk. The storage device 207 constitutes the main part of the “writing means”.

The connector 211 is designated by reference numeral 105 in FIG.
And is a connection device for transmitting and receiving image data and control data to and from an external device.

The system control device 228 is a device that controls the entire system of the image forming apparatus. The image processing device 229 performs image processing for image output on the image data from the image reading unit.

The printer control device 230 is a device for controlling each part of the printer and outputting an image on a recording sheet.

The laser beam emitted from the laser output device 212 is collimated by the collimator lens 213, reflected by the polygon mirror 226, and deflected in the main scanning direction. The deflected light beam is reflected by the mirror 214, the optical path is bent, and the main body scans the photoconductor 216 via the fθ lens 215.

At this time, the photoconductor 216 is rotated clockwise and uniformly charged to a constant potential by the charging device 217, and is optically scanned by the laser beam to form an electrostatic latent image. The electrostatic latent image is reversely developed by the developing device 218, and the toner adheres to the portion of the photoconductor 216 irradiated with the laser beam.

On the other hand, the recording paper is the paper feed tray 224 or 2
25, the paper feed roller 222 or 223 is selected.
The sheet is fed by and is conveyed to the registration roller 220. The registration roller 220 accurately controls the timing of feeding the recording paper to the transfer portion.

The recording paper sent out by the registration rollers 220 is conveyed by the conveyor belt 221 to the transfer position for the photoconductor 216, and the toner image on the photoconductor 216 is transferred onto the recording paper by the transfer device 2311 at the transfer position. .

The surface of the photoconductor 216 after the transfer of the toner image is destaticized by the destaticizer 2313, and the cleaning device 219.
To be cleaned.

In this embodiment, the laser output device 212, the collimator lens 213, the polygon mirror 226, the mirror 214, the fθ lens 215 and the photoconductor 21 are used.
6, charging device 217, developing device 218, transfer device 2311,
The static eliminator 2313 and the cleaning device 219 constitute the above-mentioned "imaging unit", and the same constitution as the above-mentioned image forming unit (polygon mirrors 226, 227).
Have three image forming units 21, 22 and 23 each of which is shared by two image forming units, and a total of four image forming units are sequentially arranged in yellow, magenta, cyan and black. An image corresponding to each color is formed as a toner image.

The formed toner images corresponding to the respective colors are sequentially superposed on the same recording paper conveyed by the conveyor belt 221 to form a "full color image". After the transfer of each toner image, the conveyor belt 22 is separated by the separation charger 231.
The recording paper separated from No. 1 has the full-color image fixed by the fixing device 232, and is discharged onto the paper discharge tray 233.

The toner removed from the photoconductor by the cleaning device in each image forming unit is collectively collected in the waste toner tank 234.

FIG. 3 shows, from the front side of the apparatus, the structure of another embodiment in which the confidential image storage / transmission apparatus according to the tenth aspect of the present invention is implemented as an “image forming apparatus” having a storage function and a transmission function. The state as seen is schematically shown.

In FIG. 3, the "image reading section" indicated by reference numeral 300 is exactly the same as in the example of FIG.

The system controller 314 controls the entire system of the image forming apparatus. The image processing device 315
Image processing is performed on the image data from the image reading unit.

The printer controller 316 controls each part of the printer. Reference numerals 301 to 326 represent constituent elements of a "full color printer section" of a surface sequential time system having a single photoconductor structure.

The laser beam emitted from the laser output device 301 is collimated by the collimator lens 306 and is deflected in the main scanning direction by the rotation of the polygon mirror 302. The deflected laser light flux passes through the fθ lens 303 and the mirror 304, and scans the photosensitive member 317 as the main scanning.

At this time, the photoconductor 317 rotates clockwise, is uniformly charged by the charging device 305, and is optically scanned by the laser beam to form an electrostatic latent image. The electrostatic latent image is reversely developed by the developing device 318 to form a toner image. The toner image is transferred onto the transfer belt 309.

Developing devices 318, 319, 320, 321
Have toners of yellow, magenta, cyan, and black, respectively, and the yellow, magenta, cyan, and black color data sent from the image reading unit are
The electrostatic latent images are sequentially formed as described above, and the developing devices 318, 31
9, 320, 321 are sequentially developed.

Each color toner image formed by development is
The “full color image” is formed by sequentially superimposing on the transfer belt 309. The photoconductor 304 is cleaned by the cleaning device 307 and recharged by the charging device 305 each time the toner image is transferred.

On the other hand, the recording paper fed from the paper feed trays 324 and 325 by the paper feed rollers 312 and 313 is controlled by the registration roller 311 in the positional relationship with the image on the transfer belt 309, and on the conveyance belt 310. A full-color image with toner is transferred. After that, the recording paper is fixed with a full-color image by the fixing device 323, and is discharged to the paper discharge tray 322.

As described above, the image forming apparatus shown in FIGS. 1 and 2 and the image forming apparatus shown in FIG. 3 have exactly the same configuration of the image reading section, and are different only in the printer section. Since the reproduction of images by image output has been described above, the storage and transmission of the images described below is as follows.
The image forming apparatus described with reference to FIGS. 1 and 2 will be described as an example. Of course, the following description is also applicable to the image forming apparatus of FIG.

FIG. 10 shows a simplified block diagram of the above-mentioned "image reading section (common to the apparatus examples of FIGS. 2 and 3)".

In the figure, a pixel reading device 1001
Is a device for reading image information as density data on a pixel-by-pixel basis. As described above, the carriage 203 and the scanner control device 210 of FIG.

The color conversion device 10012 and the density conversion device 1003 form the image processing device 209 of FIG. The image processing apparatus 1004 in FIG. 11 corresponds to the image processing apparatus 229 in FIG.
Reference numeral 5 corresponds to a printer unit.

The storage device 1006 of FIG. 10 corresponds to the storage device 207 of FIG. 2, and the external interface device 1007 is the interface board 20 of FIG.
Equivalent to 8.

First, the case of the "normal mode" in which the original image is normally read and "image formation" is performed as it is as a copied image will be described.

In this case, the original is placed flat on the contact glass 202 of FIG. 2 and the start key 109 shown in FIG. 1B is pressed.

Referring to FIG. 10, reading of the original image is started by pressing the start key, and the image data read by the pixel reading device 1001 is converted into cyan, magenta, yellow, and black data by the color conversion device 1002. After being converted by color separation, it is sent to the density converter 1003.

The density conversion device 1003 performs density conversion according to the "normal γ curve" shown in FIG. 5A, and the image processing device 1004 (image processing device 209 of FIG. 2) and the image output device 1005 of FIG. The original image is reproduced as faithfully as possible.

In the figure showing the γ curve, generally, “ID” on the horizontal axis represents density data (density level) for each input pixel, and “OD” on the vertical axis represents image output after density / density conversion. Represents the concentration data for. The density level is "0" at the lowest and "255" at the highest.

When the "image data read in the normal mode" is stored in the "storage medium" such as a floppy disk as described above, that is, when the image information to be stored is "not confidential", FIG. The data subjected to the density conversion according to the “normal memory γ curve” in (d) is stored in the storage device 10 of FIG.
06 (storage device 207 in FIG. 2) is recorded in the storage medium.

When the image data recorded in this way is reproduced, the data in the storage medium is read by the storage device 1006, the density is converted according to the "normal γ curve" in FIG. 5A, and the image is output. By changing the shape of this γ curve, it is possible to reproduce an image according to the characteristics of the pixel input device or the image output device or a user's preference.

Selection of these density conversion curves (γ curves) is performed by the system controller 228 of FIG.

On the other hand, the storage of the confidential image, that is, the "memory in the confidential mode" is performed as follows. A manuscript having a top secret image (hereinafter referred to as a top secret manuscript) is placed on the contact glass 202 of FIG. 2, and the mode clear key 108 and the clear stop key 107 shown in FIG. 1B are simultaneously pressed for 3 seconds. This is because the confidential mode is not released to general users. By this operation, the image forming apparatus enters the "secret mode".

That is, pressing and holding the mode clear key 108 and the clear stop key 107 for 3 seconds at the same time "instructs the storage of image data in the confidential mode".

By this operation, the display on the display panel 103 of FIG. 1A becomes the "confidential mode permission screen (displayed as" confidential image mode ") shown in FIG. 11A. According to the displayed contents, if the "user ID" registered in advance is input, the use of the confidential mode is permitted.

After the permission, the display panel 103 is displayed as shown in FIG.
The “confidential mode selection screen” shown in (b) is displayed.

To store an image of a confidential document in a storage medium (floppy disk), press the "store" key in the state of FIG. 11B, and press the "send" key to send it to an external device. .

The flow at this time is shown in FIG.

When the "memorize" key is pressed, the "secret image memory mode" in the flow of FIG.
The screen of No. 3 becomes the "storage mode screen" shown in FIG.

In this state, the start key 1 shown in FIG.
When the user presses 09, the confidential document placed on the contact glass is read by the carriage 203 (pixel reading device 1001 in FIG. 10).

The read image data is color-converted by the color conversion device 1002 in FIG. 10 into four color data of cyan, magenta, yellow and black for each pixel as in the normal image mode.

The color-converted data is processed by the density conversion device 1003 shown in FIG.
Density conversion according to "Curve 1" is performed.

That is, in this density conversion, the density level of each pixel (horizontal axis in FIG. 5B) of the read image data is 1
When the density is 50 or less, the pixel data is changed to "0" (vertical axis in FIG. 5B), and when the density level exceeds 150, it is changed to "1".

FIG. 7A shows a part of a confidential document in relation to pixels (shown by squares). FIG.7 (b) is
The “image data” obtained by reading the portion (a) is shown. The data is represented by hexadecimal numbers (0 to F) in 255 steps, where "0" corresponds to the lowest density and "FF" corresponds to the highest density 255.

Such density data is converted as shown in FIG. 8A by the density conversion according to the above-mentioned "secret memory γ curve 1".

Returning to FIG. 10, the pixel data subjected to the density conversion is recorded on the recording medium by the storage device 1006.

The flow at this time is shown in FIG. The storage mode 1 means a storage process using the confidential memory γ curve 1 for density conversion.

When reproducing the confidential image from the data stored in the storage medium after the density conversion according to the "secret memory γ curve 1", the same operation as "when storing in the confidential mode" is performed and the operation shown in FIG. Call up the "confidential mode selection screen" in (b) and press the "play" key. As a result, the display screen becomes the "reproduction mode screen" shown in FIG.

Hereinafter, the flow of FIG. 14 will be referred to.

When the start button 109 shown in FIG. 1B is pressed in the above state, the density conversion device 1003
“Confidential reproduction γ curve 1” shown in FIG. 6B is selected (therefore, the process of the flow in FIG. 14 is the reproduction mode 1).
Called). On the other hand, the confidential image data stored in the storage medium is read by the storage device 1006 of FIG. 10 and input to the density conversion device 1003.

In the density converter 1003, the density conversion is performed according to the "secret reproduction γ curve 1" selected as described above. That is, in this density conversion, the density level of input data (image data): 0 is output density level: 0 (image data = 0), and the density level: 1 is output density level: 255.
(Image data = FF).

If the density data thus converted is output as image data to the image output device 1005, the original image is reproduced.

Pixels having a density level of 0 to 150 in the image data at the time of image reading are reproduced as pixels having a density level of 0 in the reproduced image, and pixels having a density level of 151 to 255 in the image data at the time of reading are , In the reproduced image, it is reproduced as a pixel having a density level of 255. Therefore, although the reproduced image has "no halftone", the confidential information is mostly character information,
Even with such a reproducing method, the character information is effectively reproduced in an image with high contrast.

If a user who does not know the procedure for shifting to the "confidential mode permission screen" in FIG. 11 or a user who has not registered a user ID outputs the confidential image data in the storage medium in the normal mode, in that case The density conversion according to the "normal γ curve" shown in FIG. 6A is performed, and the image is output according to the result.

However, since the data of the confidential image in the storage medium is composed of the density levels 1 and 0, even if this is converted by the above-mentioned "density conversion according to the normal γ curve", the converted density The level is still close to "0 level".
Therefore, a visible image cannot be formed even if an image is output with such low density image data.

In a general situation (when a confidential image is drawn on a white paper), the density level is about 15 to 20 even in the white part of the background of the image, so the image data obtained by reading the image data has a density. Level: There will be no extremely low concentration data around 1.

Therefore, as the density conversion during reproduction, FIG.
By using the density conversion according to the “secret / normal reproduction γ curve” shown in (d), it is possible to reproduce the confidential image or the normal “non-secret image” in this density conversion. That is, since the reproduction of the confidential image and the reproduction of the normal image can be realized by the same density conversion, the software and hardware design becomes easy.

When the confidential image is stored, the density level is set to 0 or 1 according to the "secret memory γ curve 2" shown in FIG. 5 (c).
Alternatively, FIG. 15 shows a flow in which the density is converted into 10 and stored in the storage medium (claim 4) (referred to as storage mode 2 because the density conversion using the confidential memory γ curve 2 is performed).
Shown in

Pixel data having density levels from 0 to 150 (threshold value) in the read image data is
When the density level is converted to 0 (image data = 0) and the density level is pixel data from 151 to 255 (valid data), the number is counted by the valid counter for each pixel, and the count number of the valid counter Depending on whether is even or odd,
The density level is converted to 1 or A (10: image data = A in the example described).

For example, the image data as shown in FIG. 7B, which is the result of reading the image as shown in FIG.
The density is converted as shown in FIG.

In this case, since the high density portion (density level: 151 or higher) of the confidential document is converted into the density levels: 1 and 10, when the data is stored in the storage medium, the data of the stored image is as described above. More complex and more sensitive.

In this case, the density conversion when reproducing the data of the confidential image is as shown in FIG.
The curve 2 "or the" secret / normal reproduction γ curve 2 "shown in FIG. 6 (e) can be used.

The flow during reproduction is shown in FIG. 16 (reproduction mode 2).
Is.

When storing the confidential image, the OD value for the ID in the "secret memory γ curve 1" of FIG. 5B is set to "1".
Instead of, “n (integer of 2 or more)” can be used. This is just a conversion promise.

At this time, a value of 2 or more can be set in advance as the "OD value", and an arbitrary value can be designated from the values. That is, a plurality of types of density conversion can be performed according to the type of OD value that can be set (claim 3).

In this case, the density conversion device 1003 shown in FIG.
May be configured by a circuit set for each of the above-mentioned two or more setting values, and the circuit may be designated according to the selection of the setting value. You may be allowed to run change software.

As described above, the procedure for designating the set value of the density conversion is the operation of the operation unit to display the "density conversion level input screen" for storing the confidential image as shown in FIG.
Is displayed on the display panel 103 (FIG. 1), and the operator inputs the "density conversion level" as an appropriate numerical value.

Then, for example, the remainder when the input density conversion level is divided by 10 is set to "n (<10)". Of course, n is "a level that is not visualized even when output in the normal mode".

At the time of reproduction, the operator inputs the density conversion level at the time of storage and "n" is selected. As a result, the density conversion is performed at the density conversion level originally set by the operator, so that the confidentiality is further enhanced.

At this time, the density conversion level or "n" input by the operator, that is, the information regarding the specified conversion type is stored in the system controller 228 (see FIG. 2) together with the user ID input when the confidential image mode is entered. ) Is registered in the non-volatile memory and the system controller sets “n” from the user ID at the time of reproduction, and the γ curve for reproducing the confidential image is automatically set.

As a result, when the confidential image is stored in the confidential mode, the confidential image can be reproduced and the confidentiality can be maintained without inputting the information about "the conversion type designated by the operator" again. improves. The flow of storage and reproduction in this case is shown in FIG. 18 (storage mode 3) and FIG. 19 (reproduction mode 3).

The above is the description of the storage and reproduction of the confidential image by the image forming apparatus shown in FIGS.

The transmission of confidential image data by the image forming apparatus shown in FIGS. 1 and 2 will be briefly described below.

When the "send" key is pressed on the "confidential mode selection screen" shown in FIG. 11B, "send in confidential mode" is selected and the display on the display panel screen 103 is shown in FIG.
It becomes the "transmission mode" of (b).

In this "transmission mode", output of image data to the external interface device 1007 of FIG. 11 (interface board 208 of FIG. 2) is instructed by the system control device 228 (FIG. 2).

As in the storage mode, the pixel reading device 1001, the color conversion device 1002, and the density conversion device 1003.
The image data is transmitted through the external interface device 100.
Input to 7.

At this time, the density converter 1003 performs density conversion according to the "secret memory γ curve 1" of FIG. 5B or the "secret memory γ curve 2" of FIG. 5C, as in the storage mode. As shown in FIG. 17 (transmission mode), the flow at this time is a process of outputting to the interface device 1007 instead of storing in a storage medium in “storage mode 1” of FIG. 13 or “storage mode 2” of FIG. Become.

As a result, the same data as the pixel data stored in the storage mode is transmitted to the external device via the external interface. Since this image data is data of extremely low density as it is in the storage mode, it is not visualized even if it is output in the normal mode by the external device (claim 7).

Also in the transmission mode, FIG.
By specifying the density conversion level on the "density conversion level input screen", the operator can perform density conversion unique to the operator, and it becomes possible to transmit highly confidential image data.

In order to allow the external device to reproduce these confidential image data in the transmission mode, as in the reproduction mode,
It is necessary for the external device to perform density conversion according to the reproduction γ curve as shown in FIG.

On the contrary, if the "proper density conversion" is applied to them, the transmitted confidential image data can be reproduced. Since the confidential image data is reproduced only when the proper density conversion is set in both the transmitting device and the external device, it is possible to transmit and receive highly confidential image data.

In the above description, the embodiment of the image forming apparatus capable of storing, transmitting and reproducing the confidential information has been described. Of course, the image reading unit in the above embodiment is a confidential image storing and transmitting apparatus (claims). 10), the image reading unit without the transmission function is an embodiment of the confidential image storage device, and the image reading unit without the storage device is the confidential image transmission device. It is an example of.

As shown in FIG. 4, a personal computer or a word processor 1, a floppy disk 0 as a storage medium, a confidential image storage / transmission device 3, and another confidential image storage which is connected to this and can transmit / receive data to / from each other. A “secret image management system” that manages the confidential image can be configured with the transmission device 4.

[0144]

As described above, according to the present invention, it is possible to provide a novel confidential image storage device / secret image transmission device and a confidential image storage / transmission device (claims 1 to 1).
0).

According to the first aspect of the present invention, it is possible to surely store the confidential image in a highly confidential state in which the density is converted. According to the second aspect of the present invention, it is possible to store the confidential image in a form in which it is not recognized as an image even if it is output by a device capable of outputting pixel data units.

According to the third aspect of the present invention, the confidential image can be stored in a form capable of reproducing the confidential image only by the operator who has stored the confidential image or only the operator who has been informed of the operation contents at that time.

According to the fourth aspect of the invention, the confidential image can be stored with higher confidentiality. According to the invention described in claim 5, the confidential images are highly confidentially reproduced and stored in a form that can be reproduced only by a specific operator, and the specific operator can reproduce them by an easy method.

According to the sixth aspect of the present invention, it is possible to transmit the confidential image in the highly confidential data state in which the density is converted. According to the seventh aspect of the invention, the data of the confidential image can be transmitted in a form in which it is not recognized as an image even if it is output by a device capable of outputting pixel data units.

According to the invention described in claim 8, the confidential image data capable of reproducing the confidential image can be transmitted only to the person who has been informed of the operation contents. According to the invention described in claim 9, the confidential image can be transmitted. Data can be transmitted with higher confidentiality.

According to the tenth aspect of the invention, the confidential image can be stored and transmitted with high confidentiality.

[Brief description of drawings]

FIG. 1 is a top view of an embodiment of a device in which the invention according to claim 10 is implemented as an image forming apparatus.

FIG. 2 is a diagram schematically showing a state of the structure of the above embodiment as viewed from the front.

FIG. 3 is a diagram schematically showing a structure of another embodiment of an apparatus in which the invention according to claim 10 is implemented as an image forming apparatus, as viewed from the front.

FIG. 4 is a schematic diagram of a confidential image management system using a confidential information storage / transmission device of the present invention.

FIG. 5 is a diagram showing four types of γ curves used for density conversion for storage and transmission.

FIG. 6 is a diagram showing five types of γ curves used for density conversion for reproduction.

FIG. 7 is a diagram showing an image example (a) and an example of pixel data obtained by reading the image.

FIG. 8 is a diagram showing two examples of data obtained by density-converting the pixel data shown in FIG. 7B.

FIG. 9 is a flow chart diagram when performing storage / reproduction transmission / reception in the confidential image mode.

10 is a block diagram showing an image reading unit in the embodiment of FIGS. 2 and 3. FIG.

FIG. 11 is a diagram showing a screen of a display panel in a confidential mode.

FIG. 12 is a diagram showing a screen of a display panel in a confidential mode.

FIG. 13 is a flowchart diagram of a storage mode (storage mode 1) of a confidential image.

FIG. 14 is a flowchart of a reproduction mode (reproduction mode 1) for reproducing the stored confidential image.

FIG. 15 is a flowchart diagram of a storage mode (storage mode 2) of a confidential image.

FIG. 16 is a flowchart of a reproduction mode (reproduction mode 2) for reproducing the stored confidential image.

FIG. 17 is a flowchart of a transmission mode for transmitting the confidential image data.

FIG. 18 is a flowchart of a storage mode (storage mode 3) for storing a confidential image.

FIG. 19 is a flowchart of a reproduction mode (reproduction mode 3) for reproducing the stored confidential image.

[Explanation of symbols]

 103 Indication device 203 Pixel reading device 1003 Density conversion device 1006 Storage device 1007 External interface device

Claims (10)

[Claims] 1. A pixel reading device for reading image information as density data on a pixel-by-pixel basis, a confidential mode storage instructing means for instructing image data storage in a confidential mode, and a density conversion for a confidential image in the case of storage in a confidential mode. And a storage device for storing the density data for the confidential image, which has been density-converted by the density conversion device, and a writing unit for writing the density data for the confidential image in the storage device. A top secret image storage device. 2. The confidential image storage device according to claim 1, wherein the density data for the confidential image converted by the density conversion device has a level that is not visualized when output in the general image mode. apparatus. 3. The confidential image storage device according to claim 1, wherein the density conversion device can perform plural kinds of conversion for density conversion of the confidential image, and can specify any one of them. A confidential image storage device. 4. The confidential image storage device according to claim 1, wherein the density conversion device has a function of converting pixel data read as density data in pixel units into confidential image data of three or more density data. A confidential image storage device. 5. The confidential image storage device according to claim 3, wherein the information of the designated conversion type is a user ID for limiting the use of the confidential image storage device or a user ID for limiting the use of the confidential mode. The confidential image storage device is stored in a non-volatile backup memory other than the storage device in the main body of the device together with the contents of. 6. A pixel reading device for reading image information as density data on a pixel-by-pixel basis, a confidential mode transmission instruction means for instructing transmission of image data in a confidential mode, and a density conversion for confidential transmission in the case of transmission in a confidential mode. A confidential image transmitting device, comprising: a density converting device for performing the above; and image data transmitting means for transmitting the density data after the density conversion by the density converting device. 7. The confidential image transmission device according to claim 6, wherein the density data for confidential transmission converted by the density conversion device has a level that is not visualized when output in the general image mode. apparatus. 8. The confidential image transmission device according to claim 6, wherein the density conversion device can perform a plurality of types of density conversion for confidential transmission, and can specify any one of them. A confidential image transmission device. 9. The confidential image transmission device according to claim 6, wherein the density conversion device has a function of converting pixel data read as density data in pixel units into confidential image data of three or more density data. A confidential image storage device. 10. The confidential image storage device according to claim 1 or 2 or 3 or 4 or 5 and the confidential image transmission device according to claim 6 or 7 or 8 or 9 are commonly used as a pixel reading device and a density conversion device. The confidential image storage / transmission device is configured as the same device.