JPH09224155A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set the range to perform optimum density converting processing for each original image by setting the density converting object range respectively individually from an operating part to plural density converting means. SOLUTION: As for image data inputted from an image input part, at density converting parts, density conversion is performed based on density conversion curves to which density conversion 1(401)-3(403) is respectively set. Besides, concerning input images from the image input part, density range detecting means 1(405)-3(407) respectively detect whether the density is within the set density conversion range or not and when the density is within the set range, signals a1-a3 corresponding to the respective images are outputted. A priority discriminating means 408 finds the priority of signals from the density range detecting means 1(405)-3(407) and sends it to a selector 404. Based on the signal from the priority discriminating means 408, the selector 404 selectively outputs only one signal having the highest priority among three input signals a1-a3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus which is used in various devices such as a copying machine, a facsimile, a scanner and a printer, and which digitally processes image data input from the scanner or the like. Regarding

[0002]

2. Description of the Related Art A digital copying machine which processes image data input from a scanner or the like and outputs it from a printer has a density converting means such as γ correction for controlling the density of an original image. As an invention for improving the image quality by determining the setting of the density converting means from the density range of the entire document, Japanese Patent Laid-Open No. 5-14730 (image forming apparatus, Canon), the image quality is improved by removing the background density range. As an invention to be improved, there is JP-A-2-265276 (background removal method of image reading device, Fuji Xerox).

However, one original contains images of different properties, and it is detected that the density differs depending on the type of the image, and the density converter is selected according to the density distribution. I can't find anything that took such a method.

[0004]

As described above, there are manuscripts having various characteristics in the world. For example, there may be a document with a dark background, a document with lightly written characters, a graph on a graph paper, a photograph or a drawing, and a document in which these are mixed. 2. Description of the Related Art Conventionally, a γ-correction unit has been considered which performs density conversion on image data obtained by reading an original to obtain easily-viewable output image data.

However, there is no density conversion means that can cope well with all kinds of originals. For this reason, there are problems that characters of light density that are desired to appear in the output image data disappear, or that the density of the background that does not want to appear in the output image data appears and the output image becomes dirty.

As a method for satisfactorily reproducing such an original, there is considered an image processing which has a plurality of density converting means and can select which density converting means to use each density converting means. By doing so, it is possible to associate various types of image data included in the document image data with a density conversion unit suitable for each type of image data.

However, even in such a case, the number of density converting means to be used differs depending on the type of original. Some image data is composed of relatively uniform types of elements, and some is image data in which many types of elements are mixed.

In order to deal with this, an ON / OFF control means is provided for each of the plurality of density conversion means described above, and it is set by selecting an object to be used and an object not to be used from the plurality of density conversion means prepared. Will be easier.

By having a plurality of density converting means and selecting the density converting means according to the density distribution of the image data,
It is possible to make the density conversion means suitable for each type of image data. However, since the density distribution varies depending on the type of original, it is necessary to set the density conversion target range individually for each original image in order to perform the optimum density conversion processing.

Therefore, if a register for storing the density conversion target range is provided for each of the plurality of density conversion means so that the density conversion target range can be set, the optimum density conversion processing for each original image can be performed. The range can be set.

Further, by having a plurality of density converting means and selecting the density converting means according to the density distribution of the image data, it is possible to make the density converting means suitable for each type of image data. Further, the density conversion target range can be set by having a register for individually storing the density conversion target range. However, since the type of document is often undetermined until it is actually used, it is desirable that the density conversion target range corresponding thereto can be easily changed.

Therefore, the density conversion target range can be individually set for each of the plurality of density conversion means from the operation unit. As a result, it is possible to easily set the range for performing the optimum density conversion process for each original image.

It is an object of the present invention to meet such a problem of the density conversion method and to make the image processing apparatus easier to use. For example, eliminating the need to reset the concentration range once set, eliminating the need to reset multiple concentration range items, and resetting the concentration range automatically when the device is turned on again. thing,
It is an object of the invention to eliminate the trouble of resetting the density range for a specific original document and to easily perform the setting suitable for the original document.

[0014]

In order to achieve the above object, the present invention provides an image processing apparatus for converting image data into a digital signal and processing the image data according to different conversion methods for the density of the image data. A plurality of density converting means for converting into digital signals, a density distribution range detecting means for detecting a density distribution range of the image data, and the density converting means according to a density distribution range detection result of the density distribution range detecting means. And a density conversion selecting means.

Here, the density conversion selecting means includes a plurality of switch means provided for each of the density converting means and a switch selecting means for selecting one of the switch means.

Further, the density distribution range detecting means includes a density upper limit value comparing means and a density lower limit value comparing means, respectively.

Further, it is characterized by further comprising density distribution range setting means capable of setting the density upper limit value of the density upper limit value comparing means and the density lower limit value of the density lower limit value comparing means.

[0018]

DETAILED DESCRIPTION OF THE INVENTION An image processing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. For the sake of explanation, an embodiment in which the present invention is applied to a digital copying machine will be described here.

FIG. 1 shows an example of a block diagram of the entire apparatus for carrying out the present invention. The image input unit 101 corresponds to a scanner for digital copy and digital facsimile, and reads a document and sends it as input image data to the density conversion unit 102. The density conversion unit 102 detects the density distribution of the input image data, performs density conversion corresponding to the density range of the image,
The converted image data is sent to the image processing unit 103.

The image processing unit 103 performs various kinds of image processing such as filter processing, scaling processing, and gradation processing on the input image data, and sends the processing result to the image output unit 104. The image output unit 104 corresponds to a printer of a digital copying machine and prints out the processed bitmap image data on paper.

The control unit 105 controls the entire apparatus when performing a copy operation. For the image input unit 101,
The scanner operation is controlled, the density range is set for the density conversion unit 102, and various image processes such as filter processing, scaling processing, and gradation processing are selected for the image processing unit 103. The parameters used for the processing are set, and the operation unit 106 is subjected to display control of operation setting conditions and input control of operation mode and level setting.

The operation unit 106 is used for designation / input / display when the user inputs an operation mode, a copy operation, an operation start instruction, and a density setting range change.

A more detailed block diagram of the present invention is shown in FIG. The present invention relates to a scanner unit 201 that reads a document image,
Density conversion 202 having a plurality of conversion means, filter processing,
An image processing unit 203 that performs scaling processing and gradation processing, a printer unit 204 that outputs an image as a copy, a CPU 206 that controls the entire apparatus, a ROM 207 that stores a control program, and a temporary use by the control program. RAM 208, internal system bus 205 for exchanging data between each device, operation unit 20 for giving instructions such as operation mode selection, start and stop, and displaying recognition
9.

The correspondence between FIG. 1 and FIG. 2 will be described below. The scanner unit 201 corresponds to the image input unit 101. The density converter 202 corresponds to the density converter 102. The image processing unit 103 corresponds to filter processing, scaling processing, and gradation processing 203. The printer unit 204 corresponds to the image output unit 104. CPU 206 and ROM 2 in the control unit 105
07 and RAM 208 correspond.

FIG. 3 is an explanatory diagram showing a schematic configuration inside the scanner unit 201 and the printer unit 204. The contact glass 301 for placing a document on the scanner unit 201 is illuminated by the light sources 302a and 302b,
The reflected light from the read document is imaged on the light receiving surface of the CCD image sensor 309 via the mirrors 303 to 307 and the lens 308.

The light source 302 (302a, 302b) and the mirror 303 are mounted on a traveling body 310 which moves the lower surface of the contact glass 301 parallel to the contact glass 301 in the sub scanning direction, and the mirrors 304, 305 are mounted on the traveling body 310. It is mounted on the traveling body 311 that moves in the sub-scanning direction at a speed of 1/2 in conjunction with it.

Scanning in the main scanning direction is performed by individual scanning of the CCD image sensor 309, and the original image is C
The entire original is scanned by being read by the CD image sensor 309 and moving the optical system as described above. Incidentally, reference numeral 339 in the drawing denotes a pressure plate for pressing the original.

Next, the printer section 204 comprises a laser writing system, an image reproducing system and a paper feeding system. The laser writing system includes a laser output unit 321, an imaging lens 322, and a mirror 323. Inside the laser output unit 321, a laser diode as a laser light source and a polygon mirror (polygon mirror) rotated at high speed by an electric motor are provided. The laser beam output from the laser writing system is applied to the photosensitive drum 324 of the image reproducing system.

Around the photosensitive drum 324, a charging charger 325, an eraser 326, and a developing unit 32 are provided.
7, a transfer charger 328, a separation charger 329, a separation claw 330, a cleaning unit 331, and the like. The laser beam is emitted near one end of the photosensitive drum 324.

The image reproducing process in the printer unit 204 will be briefly described. The peripheral surface of the photosensitive drum 324 is uniformly charged to a high potential by the charging charger 325. When the peripheral surface is irradiated with the laser beam, the irradiated portion has a lower potential. Since the laser light is ON / OFF controlled according to black / white of recording / reproducing, the potential distribution corresponding to the recorded image, that is, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 324 by the irradiation of the laser light. It The portion on which the electrostatic latent image is formed passes through the developing unit 327, and toner adheres according to the level of the potential, and the electrostatic latent image becomes a visualized toner image.

The recording sheet 332 is fed from the cassette to the portion where the toner image is formed at a predetermined timing,
It overlaps the toner image. This toner image is transferred to the transfer charger 32.
8 is transferred onto the recording sheet 332 by the recording sheet 332, and then separated from the photosensitive drum 324 by the separation charger 329 and the separation claw 330. Separated recording sheet 3
The sheet 32 is conveyed by a conveying belt 334, heated and fixed by a fixing roller 335 having a built-in heater, and then discharged onto a sheet discharge tray 336.

Further, in this embodiment, as shown in FIG.
The printer unit 206 has two paper feeding systems. One of the paper feed systems is provided with an upper paper feed cassette 333a and a manual paper feed tray 333c.
The recording sheet 332a set on the manual feed tray 333c is fed by the feed roller 337a.

The other paper feeding system has a lower paper feeding cassette 3
33b, and the recording sheet 332b in the lower paper feed cassette 333b is fed by the paper feed roller 337b. Then, the recording sheet 332 fed from any one of the sheet feeding rollers is temporarily stopped while being in contact with the registration roller 338, and is fed to the photosensitive drum 324 at a timing synchronized with the progress of the recording process.

Next, the actual operation of the embodiment of the present invention will be described by taking the operation of the digital copying machine as an example. FIG. 4 shows only the portion related to the density conversion unit 102 or 202. In the density conversion unit 102 or 202, the density conversion unit 1 (401), the density conversion 2 (402), and the density conversion 3 (4) are applied to the image data input from the image input unit 101.
03) performs density conversion based on the density conversion curves set respectively.

The density conversion curve is set for each density conversion device as shown in FIG. 7, for example. Here, the density conversion unit 1
Then, the conversion that gives a dark output is
It is assumed that the conversion that obtains a thin output is performed by the density conversion unit 3 so that an output that is equal to the input density is obtained.

For the image data input from the image input unit 101, the density range detecting means 1 (405), the density range detecting means 2 (406), and the density range detecting means 3 (40).
It is detected whether or not 7) is within the set density range. Density range detecting means 1 (405), density range detecting means 2 (406), density range detecting means 3 (407)
If the input image data is within the set density range, signals a1, a2,
Output a3.

The priority determination 408 determines the priority of the signals from the density range detecting means 1 (405), the density range detecting means 2 (406), and the density range detecting means 3 (407) and sends them to the selector 404. That is, even if a plurality of signals among the three signals a1, a2, and a3 are input, only one of them is determined and sent to the selector 404. Here, as an example, it is assumed that a1 has the highest priority and a3 has the lowest priority, that is, the priority is a1>a2> a3.

The selector 404 selects and outputs only one of the three input signals a1, a2, and a3 based on the signal from the priority determination 408. For example, when the signal of the density range detection a1 is output, the output of the corresponding density conversion unit 1 is selected and output. With the above configuration,
The density conversion method is selected according to the density distribution of the image data.

FIG. 5 shows a detailed internal structure of the priority order judgment 408. Concentration range detecting means 1 (405), concentration range detecting means 2 (406), concentration range detecting means 3 (40
Signals a1, a2, a3 from 7) are individually turned on / off by gates (501, 502, 503).
F control. When the gate is ON, the detection signals a1 and a
Although the signals 2 and a3 are transmitted to the priority encoder 504, when the gate is OFF, the detection signals a1, a2 and a3 are not transmitted to the priority encoder 504 even within the detection concentration range. Therefore, the priority determination 408 is ON
The control is performed only on the basis of the output from the detection of the density range. With the above configuration, the plurality of density conversion means are individually ON / OFF controlled.

FIG. 6 shows the density range detecting means 1 (405),
Concentration range detecting means 2 (406), concentration range detecting means 3
It is a detailed configuration inside (407). Register 60
1, 602, comparators 607, 608, gate 61
3 is a register 603 in the concentration range detecting means 1 (405),
604, the comparators 609 and 610, and the gate 614 are connected to the concentration range detecting means 2 (406) by the registers 605 and 60.
6, the comparators 611 and 612, and the gate 615 correspond to the density range detecting means 3 (407), respectively.

The operation of the concentration range detecting means 1 (405) will be described. The same applies to the density range detecting means 2 (406) and the density range detecting means 3 (407). Register S1
Reference numeral (601) is a register that stores the density at the beginning of the set density range. Also, register E1 (6
02) is a register that stores the density at the end of the set density range. The comparator 607 outputs the image data from the image input unit 101 to the register S1 (60
It is determined whether the value is equal to or larger than the set value of 1).

Further, the comparator 608 determines whether the image data from the image input unit 101 is less than the set value of the register E1 (602). When the image data from the image input unit is equal to or more than the set value of the register S1 (601) and less than the set value of the register E1 (602), the AND gate 61
The output a1 of 3 is output. Here, the setting of each register (601 to 606) can be changed by the CPU 206 through the system bus 205. With the above configuration, the density distribution range corresponding to each of the plurality of density conversion units 401 to 403 is set individually.

FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG.
2 shows a display example of the operation unit 106 or 209. The operation unit 106 or 209 is composed of a liquid crystal display and a touch panel, and can display and input. Initially, the display of the operation unit 106 or 209 is as shown in FIG. The "concentration conversion" display in FIG.
Determine N / OFF. When using the density conversion function,
Press the "Concentration conversion" display. When the density conversion function is selected, the function is selected as shown in FIG. When the density conversion function is selected, the density conversion setting screen to be used is displayed as shown in FIG. In the embodiment, it is set whether or not to use each of the three different density conversions.

FIG. 10 shows a display example when the density conversion 3 is not used. "use"
For the density conversion for which is selected, the density range to be converted is set on the screen as shown in FIG. Set the beginning and end of the density range to be converted by pressing the arrow keys. FIG. 12 shows a display in a state in which the density range to be converted is set to the second level from the lighter start to the fifth level from the lighter end.

The CPU 206 sets the start level of the density range to be converted, which is set here, by the system bus 205.
Through the register S1 (601). The level at the end of the concentration range is set in the same manner in the register E1.
Set to (602). With the above configuration, the user sets the concentration distribution range based on the instruction from the operation unit (209).

As can be seen from the above description, an image processing apparatus capable of selecting the density conversion method according to the density distribution of image data can be realized by such a method.

[0047]

As described above, according to the present invention, a plurality of density conversion methods can be set and selected for each corresponding type of original, so that various types of originals can be selected. Can respond well. Further, in the present invention, since the plurality of density conversion means can be individually ON / OFF controlled, the density conversion means can be easily set when a plurality of density conversion methods are selected for each corresponding document type. It can be carried out. Further, according to the present invention, even if the density distribution varies depending on the type of the original document, since each of the plurality of density conversion means has a register for storing the density conversion target range, the density conversion target range is individually set for each original image. Can be set. Further, according to the present invention, since the density distribution range can be set based on the instruction from the operation unit, it is possible to provide the image processing apparatus in which the optimum density conversion process for each document image can be easily set from the operation unit.

[Brief description of drawings]

FIG. 1 is a block diagram of a digital copying machine according to an embodiment of the present invention.

FIG. 2 is a specific block diagram of one embodiment of the present invention shown in FIG.

FIG. 3 is a configuration diagram of a digital copying machine according to an embodiment of the present invention shown in FIG.

FIG. 4 is an internal block diagram of density conversion means.

FIG. 5 is an internal block diagram of a priority order determination unit.

FIG. 6 is an internal block diagram of a concentration range detecting means.

FIG. 7 is an explanatory diagram showing a display example of the operation unit of the digital copying machine.

FIG. 8 is an explanatory diagram showing a display example of the operation unit of the digital copying machine when the density conversion function is turned on.

FIG. 9 is an explanatory diagram showing a display example of the operation unit of the digital copying machine when individually setting a switch for a plurality of density conversions.

FIG. 10 is an explanatory diagram showing a display example of an operation unit of a digital copying machine when individually setting a switch for a plurality of density conversions.

FIG. 11 is an explanatory diagram showing a display example of the operation unit of the digital copying machine when setting the density conversion target range.

FIG. 12 is an explanatory diagram showing a display example of the operation unit of the digital copying machine when setting the density conversion target range.

FIG. 13 is a graph showing an example of a conversion curve showing the correspondence between input density and output density set for density conversion.

[Explanation of symbols]

 Reference Signs List 101 image input unit 102 density conversion unit 103 image processing unit 104 image output unit 105 control unit 106 operating unit 401 to 403 density conversion unit 405 to 407 density range detection unit 404 selector 408 priority order determination unit

Claims (4)

[Claims] 1. An image processing apparatus for converting image data into a digital signal for processing, and a plurality of density converting means for converting the density of the image data into a digital signal according to different conversion methods, and the image data. Image processing, which comprises: a density distribution range detecting means for detecting the density distribution range; and a density conversion selecting means for selecting the density converting means according to the density distribution range detection result of the density distribution range detecting means. apparatus. 2. The density conversion selecting means includes a plurality of switch means provided for each of the density converting means, and a switch selecting means for selecting one of the switch means. 1. The image processing device according to 1. 3. The image processing apparatus according to claim 1, wherein the density distribution range detecting means includes a density upper limit value comparing means and a density lower limit value comparing means, respectively. 4. The image processing according to claim 3, further comprising density distribution range setting means capable of setting a density upper limit value of said density upper limit value comparing means and a density lower limit value of said density lower limit value comparing means. apparatus.