JP3347550B2 - Image processing apparatus and method - Google Patents

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 method for performing scaling, filtering, and the like on image data.

[0002]

2. Description of the Related Art There is known a digital copying machine which optically reads a document image by a CCD line sensor or the like and records an image based on image data obtained thereby.
In such a digital copying machine, magnification, deformation, or correction of an image can be performed by performing electrical image processing on image data.

The magnification of an image in the sub-scanning direction of the image (the direction perpendicular to the scanning direction of the CCD line sensor) depends on the sub-scanning speed (movement speed of the optical system and the original) of the CCD line sensor. It is executed by changing according to the magnification.

[0004]

By the way, the moving speed of the optical system and the original has been increased by improving the resolution and processing speed of the image. In this situation, in order to reduce the image at a high reduction ratio or to read the image at a low resolution, it is necessary to make the moving speed of the optical system and the document considerably high. However, the speeding up is limited by problems such as the motor capacity and the transport system mechanism, and it is not possible to obtain image data with desired magnification and resolution only with such a moving speed.

[0005] Therefore, scaling of the image in the sub-scanning direction,
It is conceivable to achieve the resolution conversion by electrical processing. However, when other image processing such as edge enhancement or smoothing is continuously performed on image data that has been scaled or converted in resolution, the image processing must be adaptive to the previous scale or resolution conversion processing. , Good image processing cannot be performed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to execute good image processing by matching processing such as image scaling, resolution conversion, and the subsequent image processing. More specifically, a scaling unit for inputting image data for each line and outputting image data together with an identification signal indicating whether or not the line is valid according to a line thinning rate; and the scaling unit. Output from
And a memory for storing the image data.
Processing unit for performing predetermined processing on stored image data
And the processing unit is provided from the scaling unit.
Valid in the output image data by the identification signal
The image data of the determined line is written into the memory,
The image data of the line invalidated by the identification signal is
By not writing to the memory, the line thinning rate
The image data thinned out based on the
And performs the predetermined processing on the generated image data.
It is intended to provide an image processing apparatus characterized by applying physical, also zooming unit and its subsequent processing unit
The image processing method according to
There are inputs image data for each line, depending on the line-thinning rate, and outputting the image data together with the identification signal indicating whether the line is valid or said processing uni
The image data output from the scaling unit.
Data in the memory, and the image data stored in the memory.
And a processing step of performing predetermined processing on the data.
The image data output from the scaling unit.
Of the lines validated by the identification signal
Write image data to the memory, and
Write the image data of the invalidated line to the memory.
The thinning process based on the line thinning rate
Generating the generated image data on the memory,
The present invention provides an image processing method characterized in that the predetermined processing is performed on the obtained image data .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments.

FIG. 1 shows the configuration of a digital copying machine to which the present invention is applied, and will be described below with reference to the drawings.

The exposure lamp 201 is composed of a fluorescent lamp, a halogen lamp, etc., and irradiates an original on an original placing glass (original table) 200 while moving in a direction perpendicular to the longitudinal direction. The scattered light from the original due to the irradiation of the exposure lamp 201 is reflected by first, second, and third mirrors 202, 204, and 2.
05, and reaches the lens 207. At this time, a first mirror 202 including an exposure lamp 201 and a first mirror 202 is provided.
Movement of the movable body 203, the second movable body 206 including the second mirror 204 and the third mirror 205
Moves at half speed, and from the irradiated original surface,
The distance to the lens 207 is always kept constant. The images on the original are mirrors 202, 204, 205 and lens 20.
7, a CC in which thousands of light receiving elements are line-arranged
An image is formed on the light receiving portion of the D line sensor 208, and is photoelectrically converted by the CCD line sensor 208 sequentially line by line. The photoelectrically converted signal is processed by a signal processing unit (not shown), PWM-modulated, and output.

The exposure control section 210 drives a semiconductor laser based on the PWM-modulated image signal output from the signal processing section, and irradiates a light beam onto the surface of the photoconductor 240 rotating at a constant speed. At this time, the light beam is deflected and scanned using a polygon mirror in parallel with the axial direction of the drum-shaped photoconductor 240. The exposure control unit 210 is cooled by the cooling fan 209.

Before the light beam is irradiated with the light beam, the remaining charge on the drum is removed by a pre-exposure lamp (not shown), and the surface of the photosensitive member 240 is uniformly charged by the primary charger 228. . Therefore, the photosensitive member 240 receives the light beam while rotating, so that an electrostatic latent image is formed on the drum surface. Then, the electrostatic latent image on the drum surface is visualized with a developer (toner) of a predetermined color by the developing device 211.

On the other hand, reference numerals 223 and 224 denote transfer paper loading sections, on which transfer paper of a fixed size is loaded and stored.

The lift-ups 225 and 226 operate to lift the transfer sheet stored in the transfer sheet stacking sections 223 and 224 to the position of the pair of feed rollers 229 and 232. The feed roller pairs 229 and 232 are driven by the same motor (not shown), and selectively feed the transfer paper from one of the transfer paper stacking units 223 or 224 by switching the roller rotation direction. Each pair of the feed roller pairs 229 and 232 is applied with torque in the reverse rotation direction to the sheet feeding, thereby preventing double feeding of the recording medium.

Feed rollers 230, 233, 234, 2
35 feeds the transfer paper from the transfer paper stacking units 223 and 224 to the registration roller 238. In the present embodiment, the third and fourth transfer paper stacking sections can be further connected downward to expand the transfer paper stack, and 231 transfers the transfer paper from the transfer paper stacking section connected below. This is a pair of feeding rollers that perform a sheet feeding operation leading to a feeding roller. When the manual paper feed mode is selected on the operation unit, the manual
When the transfer paper is manually fed by opening 7, the feed roller 236 feeds the manually fed transfer paper to the registration roller 238.

The registration roller 238 is connected to the photosensitive member 240.
The paper to be transferred is fed to the transfer position by adjusting the timing of the leading edge of the image formed on the paper and the leading edge of the paper to be transferred. A transfer charger 239 transfers the developed toner image on the photoconductor 240 to the fed paper. After transfer, photoconductor 240
The remaining toner is removed by the cleaner 227. The transfer target paper after the transfer is easily separated from the photoconductor 240 because the curvature of the photoconductor 240 is large.
The adsorbing force between the paper and the receiving paper is weakened to facilitate separation.

The separated transfer paper is fed to a conveyor belt 241.
Are sent to the fixing units 212 and 213 to fix the toner. 212 is a ceramic heater and film,
Composed of two rollers, the heat of the ceramic heater is efficiently transmitted through the thin film. The cooling roller 214 radiates heat from the fixing unit roller 213. The feed roller 215 is configured by one large roller and two small rollers, and feeds the paper to be transferred from the fixing unit.
Correct the curl of the paper to be transferred.

The direction flapper 222 switches the transfer direction of the transfer sheet according to the operation mode. In a mode in which a single transfer is performed on one side of the transfer target paper (during single-sided recording), a path from the feed roller 215 to the discharge port is selected. A discharge roller pair 216 stacks and discharges the transfer-receiving sheet on which the image formation has been completed on the discharge tray 242.

At the time of double-sided recording, the discharge roller pair 216 is rotated in the reverse direction while the rear end of the transfer-receiving sheet is left during the discharge operation by the discharge roller pair 216 after the development on one side is completed. At the same time, the direction of the directional flapper 222 is switched so as to pass below the directional flapper 222, and the paper to be transferred is sent to the feed roller 217 from the paper discharge port. The feed roller 217 has the same configuration as the feed roller 215,
The curl of the transfer paper is corrected, and the transfer paper is placed in the intermediate tray 24.
Send to 3. Thereafter, the transfer paper is fed from the intermediate tray 243 to the feed rollers 218, 219, 221 and 235 in this order.
The paper is fed to the above-described transfer position, the toner is transferred to the back surface of the transfer-receiving paper, and further discharged to the discharge tray 242.

During multiplex recording, the feed roller 215
Is passed through the right side of the direction flapper 222 in the drawing and is sent to the feed roller 217 by switching the direction of the direction flapper 222. The feed roller 217 sends the transfer sheet to the intermediate tray 243. Thereafter, the transfer paper is fed from the intermediate tray 243 to the feeding roller 21.
8, 219, 221 and 235 are fed to the above-described transfer position, and toner transfer is performed on the same surface as the previous transfer.
The paper is further discharged to a paper discharge tray 242.

At the time of double-sided recording or multiple recording,
When recording a plurality of sheets, the first transfer sheet is fixed by the stopped feeding roller 218 and the intermediate tray 24 is fixed.
3 is loaded. When the second transfer paper arrives, the feed roller 218 starts rotating and sandwiches the two transfer papers between the rollers. The two transfer sheets are stacked on the intermediate tray 243 while being fixed by the stopped feeding roller 218. The third and subsequent transfer sheets are similarly stacked on the intermediate tray 243. At this time, the leading end of the transfer paper stacked later is shifted backward and stacked in the feeding direction as shown in FIG.

When the desired number of sheets is stacked on the intermediate tray 243, the feeding operation from the intermediate tray 243 starts. The feed rollers 218 and 219 are
During the transfer of the transfer sheet to the transfer sheet 21, the separation lever 220 moves down between the leading ends of the first and second transfer sheets, and the first transfer sheet is sent to the feed roller 221 as it is. The paper is fed by the feed roller 235 and guided to the transfer position to perform the transfer. Further, the second and subsequent sheets are transferred to the separation lever 2.
20 and then feed rollers 218, 219
Is rotated backward and returned to the intermediate tray 243. The same operation is repeated to feed all the sheets to be transferred from the intermediate tray 243.

A paper detection sensor is arranged in the transfer path of the paper to be transferred, and is used for detecting an error such as a paper jam and measuring the operation timing of each unit. The first sensor 250 is located before the feed roller 235, the second sensor 251 is located before the registration roller 238, the third sensor 252 is located before the feed roller 215, and the fourth sensor 253 is located at the discharge side. Between the roller pair 216 and the paper exit,
The fifth sensor 254 is provided immediately after the feed roller 217,
The sixth sensor 255 is arranged before the separation lever 220.

Reference numeral 260 denotes a standard white plate, which is a shading correction data for correcting a variation (shading distortion) of an output level of an image signal caused by unevenness of sensitivity of the CCD line sensor 208, unevenness of light source and light amount, and the like. It is for obtaining. Prior to scanning the manuscript,
The standard white plate 260 is scanned several times by the CCD line sensor 208, and the white image data obtained thereby is used as shading correction data. Performs uniform correction (shading correction).

FIG. 3 is a sectional view of an automatic document feeder (hereinafter, ADF) of the present invention.

The ADF has a lid-like structure that is detachable from the main body and that can be opened and closed with respect to the document table.
FIG. 3 shows a closed state, in which the ADF can operate at this time. Reference numeral 1515 denotes a platen glass (corresponding to the platen 200 in FIG. 1), and reference numeral 1516 denotes an attachment plate, which is a member belonging to the main body. A cable (not shown)
The DF and the main body are electrically connected to enable the joint operation with the main body.

The side regulating member 1501 is a member that is movable in a direction perpendicular to the document feeding direction, that is, in the front and back directions in the drawing, and adjusts the width and position of the document. When the operator places a document on the document stacking tray unit 1517 with the document face down, sets the side regulating member 1501 and operates the copy start key 305 to start a copy operation or the like, a document feed start signal is output. The document is transmitted from the main body via the cable, and the document feeding operation starts.

When feeding paper, the lever 1518 pushes down the roller presser 1502, raises the stopper 1519 upward, and feeds paper by rotating the paper feed roller 1503. Separation roller 1505 and roller holder 150
Reference numeral 4 separates and feeds the originals received from the paper feed roller 1503 one by one. Registration roller pair 1508, 1509
Sends the document received from the separation roller 1505 between the document holder 1510 and the document glass 1515. The document holding unit 1510 includes a pair of registration rollers 1508 and 150
The document fed from the document 9 is guided on a platen glass. Further, the original is appropriately pressed by a spring member (not shown) so that the original comes into close contact with the original table glass 1515.

At this time, the first movable body 203 of the digital copying machine main body has moved below the position 1520 where the original comes into close contact with the platen glass 1515 and stopped. This scans the original sent by the ADF (CC
The photoelectric conversion is performed by the D line sensor 208). The discharge roller pairs 1511 and 1512 discharge the scanned document onto a discharge tray 1514.

Note that 1506, 1507, and 1513 are:
An error such as a paper jam is determined at ON / OFF timing by a lever switch for detecting a passing state of a document during a document feeding operation.

FIG. 4 shows the key arrangement of the operation unit of the digital copying machine, which will be described below with reference to the drawings.

Reference numeral 315 denotes a main power lamp, which is turned on when the power is turned on. A power switch (not shown) is disposed on a side surface of the main body, and controls power supply to the main body. Reference numeral 301 denotes a preheating key, which is used to turn ON / OFF a preheating mode.

A copy mode key 304 is used to select a copy mode from a plurality of functions. A fax mode key 303 is used to select a fax mode from a plurality of functions. An option mode key 302 is used to select an option mode from a plurality of functions when an optional device such as a printer is mounted.
Reference numerals 317 to 322 denote status display lamps.
During the copying operation, lamps 317 and 318 are used.
And 320 are ramps 321 and 3 during facsimile operation.
Reference numeral 22 denotes a state in which the option is being operated. Lamp 3
17, 319 and 321 indicate a normal operation state, and lamps 318, 320 and 322 indicate an error state. Further, the lamp 317 indicates that the image is being copied if it is blinking, and that the image memory is being used if it is lit. Lamp 319 is
Blinking indicates that a fax is being transmitted or received, while lit indicates that the image memory is being used. If the lamp 321 blinks, it indicates that data is being received, and if it is lit, it indicates that data is being transmitted. If the lamps 318, 320, and 322 blink in each mode, they indicate a paper jam, no paper, and no toner, and if lit, indicate a failure state.

Reference numeral 305 denotes a copy start key which is used to instruct the start of copying. 306
Is a stop key which is used to interrupt or stop copying.

A reset key 308 operates as a key for returning to the standard mode during standby. 309
Is a guide key, which is used when one wants to know each function. Reference numeral 311 denotes an interrupt key, which is used when the user wants to interrupt and copy during copying. 312
Is a numeric keypad, which is used to input numerical values. A clear key 313 is used to clear a numerical value. A user mode key 310 is used when the user changes the basic settings of the system.

Reference numeral 314 denotes twenty one-touch dial keys, which are used for one-touch dialing in facsimile transmission. Reference numeral 316 denotes a set of two lids. Each key part of the one-touch dial key 314 is hollowed out to form a double lid. A first switch in which two lids are closed by a sensor switch (not shown)
State, the second state in which only the first cover is opened, and 2
A third state in which the lids are open is detected. The operation of the key of the one-touch dial key 314 is determined in combination with the open / closed state of these three types of lids. Therefore, in the present embodiment, the same effect as when there are 20 × 3 = 60 keys is provided. .

Reference numeral 307 denotes a touch panel comprising a combination of a liquid crystal screen and a touch sensor. An individual setting screen is displayed for each mode, and various detailed settings can be made by touching drawn keys. Is possible.

FIG. 5 is a block diagram of the signal processing of the digital copying machine, which will be described below with reference to the drawings.

The CCD line sensor 401 (corresponding to the CCD line sensor 208 in FIG. 1) composed of thousands of light receiving elements outputs an electric signal for one line in two systems of an odd pixel and an even pixel. The A / D conversion unit 402 calculates C
An analog signal output from the CD line sensor 401 is received, converted into a digital signal, and output.

FIG. 6 shows the details of the A / D converter 402. The analog processing circuit 901 receives signals of two systems of the CCD line sensor, performs clamping, gain adjustment, and sample hold for each system, and then integrates and outputs one system by switching processing. The A / D converter 902 inputs an output signal of the analog processing circuit 901 to a signal input, and outputs an 8-bit digital signal based on a voltage of a reference voltage input from the analog switch 903.

The AE circuit 904 controls the reference voltage of the A / D converter 902 to perform an operation of bringing the output of the A / D converter at the original portion of the document closer to the white level (FFhex). The analog switch 903 selects one of the constant reference voltage from the analog processing circuit 901 and the reference voltage from the AE circuit 904 according to a control signal from the CPU 423, and outputs the selected voltage to the A / D converter 902.

A drive signal generating circuit (not shown) is provided to supply a line signal such as a synchronization signal and a drive clock to the CCD line sensor, analog processing circuit 901 and A / D converter 902.

The AE circuit 904 controls the reference voltage value of the A / D converter based on the output of the A / D converter 902. That is, if the output of the A / D converter 902 is FFhex, the AE circuit 904 determines the first resistance determined by the first capacitor (not shown) connected to the AE circuit 904 and the first resistance.
The reference voltage output is increased as shown in FIG. The output of the A / D converter 902 is FF
If it is not hex, the second not-shown second connected to the AE circuit
In accordance with a second time constant determined by the capacitor and the second resistor, the reference voltage output is decreased as shown in FIG. Each of the above time constants is set to several tens of lines so that the reference voltage output does not suddenly change due to a change in the image signal.

In FIG. 5, the shading correction unit 40
Reference numeral 3 inputs an A / D-converted digital signal, and digitally corrects mainly a variation in an output value between pixels of an optical system and a sensor with respect to a black level and a gain.

The pattern generator 404 generates various image patterns such as a vertical ruled line, a horizontal ruled line, a lattice pattern, a gray scale, and the like, for checking functions after the scanner unit. The selector A 405 includes a shading correction unit 40.
3 or one of the outputs of the pattern generator 404 is selected and output according to the control signal of the CPU 423.

The connector A 406 includes image input signal, image output signal, pixel clock signal, image enable signal, and synchronization signal terminals. The output of the selector A 405 is connected to the terminal of the image output signal, and the function can be extended by connecting a new signal processing circuit to the connector A 406. The function can be expanded by connecting the selector B circuit to the connector A 406. Selector B407
Is the output signal of the selector A 405 and the connector A 406
Is selected according to the control signal of the CPU 423 and output.

The scaling unit 408 has the functions of thinning processing in the main scanning direction, linear interpolation processing, thinning processing in the sub-scanning direction, italic processing, mirror image processing, repeat processing, and loopback processing.

The scaling in the main scanning direction is realized by inputting a signal from the selector B 407 and calculating a pixel value from two adjacent pixels by a linear interpolation process. However, when the magnification in the main scanning direction is 50% or less, the main scanning direction thinning process is performed as a pre-process in order to prevent moiré and interruption of fine lines. In the pre-processing, adjacent n pixels (n = 2, 4,
Regarding 8), (a) the maximum value or (b) the average value is output. The value of n and the selection of processes (a) and (b)
23.

The magnification in the sub-scanning direction is changed by changing the scanning speed of an optical system such as an exposure lamp or a mirror, or by changing the speed of feeding the document to the document table 200 when using an automatic document feeder. Realize zooming. However, in the case of a small magnification that exceeds the limit of increasing the scanning speed of the optical system or the speed of paper feeding, the magnification is realized in conjunction with the electrical thinning processing in the sub-scanning direction by the magnification processing unit 408c. I do. In the thinning process in the sub-scanning direction, a line buffer including an SRAM memory A409 is provided, and (a) the maximum value or (a) is obtained for n pixels (n = 2, 4, 8) adjacent between lines.
(B) Output the average value. n and the processing (a),
The selection of (b) is performed by the CPU 423.

The functions of the italic processing, the mirror image processing, the repeat processing, and the return processing are performed by the SRAM memory A40.
This is realized by reading control of a line buffer consisting of nine lines.

The histogram is created by receiving the output of the selector B 407 and receiving the output from the SRAM memory A of the scaling unit 408.
409 is used to create a histogram. A signal that determines a sampling interval and a sampling range in creating a histogram is controlled by a timing signal generator 424. The timing signal generator 424 is connected to the CPU 4
23. The created histogram data is used to determine a table for luminance / density conversion in the AE mode when using the prescan.

The filter processing unit 410 has a line buffer 411, receives the signal after the scaling process, and
Filter processing is performed with a mask size of. As shown in FIG. 8, the coefficients constituting the filter of the filter processing unit 410 are six types of a to f, and the coefficients at the point-symmetric positions are set to the same value. A to f have the following relational expressions. a + 4 * (b + c + d + f) + 8 * e = 1

By adjusting the coefficient of the filter processing unit 410, correction of the optical system and output system and adjustment of sharpness by the user are realized.

The image processing unit 412 includes the filter processing unit 4
10 signals are input, and a masking process or an inversion process is performed. The connector B413 includes terminals for an image input signal, an image output signal, an image clock signal, an image input enable signal, and a synchronization signal. The output of the filter processing unit 410 is connected to the terminal of the image output signal, and the function can be extended by connecting a new signal processing circuit to the connector B413.

The selector C 414 selects and outputs one of the output signal from the image processing unit 412 and the output signal from the connector B 413 according to the control signal of the CPU 423.

The connector C415 includes terminals for an image input signal, an image output signal, a pixel clock signal, an image enable signal, a synchronization signal, an address bus, a data bus, and an interrupt signal. A selector C4 is connected to the terminal of the image output signal.
14 outputs are connected and the new system is connected to connector C4.
15 enables expansion of functions.

The synthesis processing section 416 inputs the output signal of the selector C414 to one input A, inputs the output signal from the connector C415 to the other input B, performs synthesis processing, and outputs the result. The types of output are (1) inset synthesis, (2) multiplex synthesis, (3) halftone overlay, (4) watermark synthesis, (5) input A through, and (6) input B through.
3 is selected by the control signal.

Each composition will be described with reference to FIG. Inset synthesis is a process in which a part of an image is extracted and inserted into another image. (D) is an example of the process, in which a rectangular area around the rectangle of (b) is extracted and inserted into (a). It is an image. Multiple synthesis is a process of selecting and combining the two images with the higher density, and FIG.
9A and 9B are images synthesized from FIGS. In the watermark synthesis, a pixel whose density of one image is equal to or lower than a predetermined threshold value is replaced with another image. At this time, the image to be replaced is multiplied by a predetermined coefficient to reduce the density, and has an effect like a watermark. (F) is an example of this, in which the image of (b) is synthesized with the watermark of (a). The halftone overlay replaces pixels in which the density of one image is equal to or higher than a predetermined threshold value with the other image. (G) is an example of this, in which the dark circle of the image of (a) is replaced by the pattern of (c).

The table conversion processing section 417 receives the output signal of the synthesis processing section 416, performs table conversion processing according to the data of the connected SRAM memory B 418, and outputs the result.

The binarization processing unit 419 receives the output signal of the table conversion processing unit 417 and selects whether to process the data by a predetermined binarization method or to output the data in a through manner in accordance with the control signal of the CPU 423. Output.

In the binarization of this embodiment, one pixel is divided into two in the main scanning direction, and the divided small pixels are represented by binary values, thereby improving the resolution in the main scanning direction. Buffer 4
Reference numeral 20 inputs the output signal of the binarization processing unit 419, and adjusts the processing speed before and after the buffer 420 and the reading start time of the image signal.

The PWM circuit 421 receives the digital signal from the buffer 420, modulates the pulse width, and outputs it. Further, the PWM circuit 421 has three types of modulation schemes, and an appropriate modulation scheme is determined according to the system mode by the CPU.
The processing is performed by selection at 423.

The first modulation method is a resolution priority mode. As shown in FIG. 10A, the pixel data represented by 8 bits is D / A converted, sampled and held, and
The signal is compared with a triangular wave signal of one pixel cycle to output PWM.

The second modulation method is a gradation priority mode. As shown in FIG. 10B, the pixel data represented by 8 bits is D / A converted and sampled and held.
The signal is compared with a triangular wave signal having a cycle of three pixels, and is output as PWM. FIG. 10 (e) shows a modulation method in which both the sample-and-hold cycle and the triangular wave signal have a 3-pixel cycle. A low-frequency modulation signal is obtained, and stable gradation characteristics are obtained. In the second modulation method, the same characteristics as shown in FIG. 10E can be obtained for low-frequency image data, but as shown in FIG. It also has the feature of modulating while preserving the components.

The third modulation method is a binary image mode, and outputs a binary modulation signal in which one pixel is divided into four in the main scanning direction, as shown in FIG. The values of the four divided small pixels are calculated by using the rising and falling edges of the first pixel clock and the rising and falling edges of the second pixel clock that is delayed by 1/4 phase from the first pixel clock. Are obtained by latching bit 7, bit 5, bit 6, and bit 4, respectively. In the binarization method of this embodiment, one small pixel is formed by combining bits 7 and 6 and bits 5 and 4 respectively, and one pixel is used in a form divided into two in the main scanning direction.

The laser section 422 receives the output of the PWM circuit 420 and controls the laser lighting operation.

The timing generator 424 and the control signal generator 425 provide the CP before starting the scanner operation.
It is set by U423. Timing generator 424
Generates a timing signal for each part of the system. Also,
The control signal generator 425 operates as an extension port of the CPU 423, and is used as a control signal for each part of the system. Further, a system address bus and a system data bus, which are buses of the CPU 423, are connected to the respective connectors, and the CPU 423 controls a system connected to the connectors.

An operation unit 426 shown in FIG.
423 also controls key input and display. Also, CPU
Reference numeral 423 performs control of the ADF 42 in FIG. 3 and drive control of the driver 42 that drives the polygon mirror.

FIGS. 11 and 12 show the configuration of the system, which will be described below with reference to the drawings.

FIG. 11 shows a system in which a facsimile function, a printer function, and an electronic sorter function are added to a basic copy function, and FIG. 12 shows a system in which a facsimile function is added.

In FIGS. 11 and 12, the signal processing unit 5
01 executes the processing related to the basic copy function shown in FIG.
5. The image storage unit 504 has a facsimile function,
Performs processing related to the printer function and electronic sorter function. The image storage unit 504 further has an external connector, and can add functions such as an external scanner and an electronic file.

Since the resolution and the number of gradations are different for each function, the resolution / gradation number conversion unit 502
And an operation of converting the number of gradations into an optimum image quality. The resolution / gradation number conversion unit 502 is connected to the signal processing unit 5
01, it is possible to expand the system as needed. The connection between the signal processing unit 501 and the resolution / gradation number conversion unit 502 is performed by the connector C415 in FIG.
Done through.

The connectors for connecting the resolution / gradation number conversion unit 502 and the signal processing unit 501, the facsimile unit 503, the image storage unit 504, and the printer unit 505 are provided with an address bus, a data bus, and a synchronization signal of the system. , A pixel clock signal, an interrupt signal, and other terminals.

The address bus and the data bus are buses of the CPU 423 in FIG. The synchronization signal is generated from the timing generator 424. The pixel clock signal is generated from an oscillator (not shown) of the signal processing unit. The interrupt signal is prepared for transmitting a request for processing, an end of processing, occurrence of an error, and the like to the CPU 423 in FIG. 5 from the facsimile unit 503, the image storage unit 504, and the printer unit 505.

FIG. 13 is a block diagram showing the inside of the resolution / gradation number conversion unit 502. Multiplexer A 601
Receives output signals from the signal processing unit 501, the facsimile unit 503, the printer unit 505, and the image storage unit 504,
The signal is distributed to the first, second, third, and fourth signal paths. First
Is a through path, and the second signal path is a path that receives a binary image signal, performs processing to make a contour of a curve look smooth, and outputs the processed signal.
A binary image signal 602 is received from the multiplexer A 601, and one bit is assigned to each of the small pixels obtained by dividing one pixel into four in the main scanning direction, and is output with four bits per pixel.

The third signal path is a path for binarizing the multi-level signal. The table conversion processing section 603 receives the multi-level signal from the multiplexer A 601 and converts the table, and the binarization processing section 604 further converts the table. Upon receiving the output signal from the table conversion processing unit 603, the output signal is binarized using the average density method. At this time, one bit is assigned to each of the small pixels obtained by dividing one pixel into two in the main scanning direction, and two bits are output per pixel.

The fourth signal path is a path that receives binary images of various resolutions, performs a process of making the contour of the curve look smooth, and outputs 8-bit multi-values. The contour smoothing processing unit B6
05 receives the binary signal from the multiplexer A 601, performs a process of making the contour of the curve look smooth, outputs an 8-bit multi-level signal, and furthermore, the scaling unit 606 includes a contour smoothing unit. Upon receiving the multi-level output 605, it performs linear interpolation and outputs an 8-bit multi-level signal.

The multiplexer B 607 receives signals from the first, second, third, and fourth signal paths, and receives a signal from the signal processing unit 501, the facsimile unit 503, the printer unit 505,
Assigned to the image storage unit 504.

In the facsimile transmission operation, the image signal is sent from the signal processing unit 501 to the facsimile unit 503 via the resolution / gradation number conversion unit 502. At this time, the multiplexer A 601 in FIG. 13 selects 1...> C, the image signal passes through the third signal path, and the multiplexer B 607 selects 3.
U controls. In the facsimile receiving operation,
Facsimile unit 503 to resolution / gradation number conversion unit 502
, The image signal is sent to the signal processing unit 501. At this time, the multiplexer A 601 in FIG.
D is selected and passed through the fourth signal path, and multiplexer B 607 is controlled by the CPU so that 4...> A is selected.
Controls.

In the printer operation, the printer unit 50
From 5, the image signal is sent to the signal processing unit 501 via the resolution / gradation number conversion unit 502. At this time, the multiplexer A 601 in FIG. 13 selects 2...> B, the image signal passes through the second signal path, and the multiplexer B
607 is controlled by the CPU so that 2...> A is selected.

In the printer operation, when performing fixed-size scaling to a different paper size, an image signal is sent from the printer unit 505 to the signal processing unit 501 via the resolution / gradation number conversion unit 502. At this time, the multiplexer A 601 in FIG. 13 selects 2...> D, the image signal passes through the fourth signal path, and the multiplexer B 60
7 is controlled by the CPU so that 4...> A is selected.

When the electronic sorter function or the like is used, the image signal is sent from the signal processing unit 501 to the image storage unit 504 via the resolution / gradation number conversion unit 502. At this time, FIG.
..> A is selected, the image signal passes through the first signal path, and the multiplexer B 607 selects the CPU so that 1.
Controls.

In the printer function, when image data is sorted and output in the reverse order, the image signal is sent from the printer unit 505 to the image storage unit 504 via the resolution / gradation number conversion unit 502 once. At this time, the multiplexer A 601 in FIG. 13 selects 1...> A, the image signal passes through the first signal path, and the multiplexer B 60
7 is controlled by the CPU so that 1 ...> C is selected.
The image storage unit 504 writes an image to the hard disk 1909 and reads the image in the reverse order when reading the image. The read image signal is sent from the image storage unit 504 to the signal processing unit 501 via the resolution / gradation number conversion unit 502. At this time, the multiplexer A 601 in FIG.
B is selected, the image signal passes through the second signal path, and the multiplexer B 607 is controlled by the CPU so that 2...> A is selected.

FIG. 14 is a block diagram of the facsimile unit 503, which will be described below with reference to FIG.

The connector C 701 includes terminals for a system address bus, data bus, video input signal, video output signal, synchronization signal, pixel clock signal, interrupt signal, and the like. The connector C 701 connects the facsimile unit 503 and the resolution / gradation number conversion unit 502.

In the facsimile transmission operation, the memory control unit 703 receives a video input signal from the connector C 701 and stores image data in the image memory 704.

The encode / decode processing section 702 is connected to the memory control section 703 via an image address bus and a data bus. The encode / decode processing unit 702 has a built-in DMA controller, fetches image data at high speed by DMA transfer from the image memory 704 through communication with the memory control unit 703, and encodes the fetched image data.
The encoded code is transferred to the code memory 7 by DMA transfer.
05. The code memory 705 is provided with a data protection measure by a backup power supply 706 in order to cope with a power supply trouble such as a power failure.

The encoding / decoding processing unit 702, the memory control unit 703, the modem unit 710 and the voice synthesizing unit 711 connected to the address bus and the data bus of the system are controlled by the CPU 423 connected via the connector C 701. Controlled.

When the encoding / decoding processing unit 702 finishes encoding the image in the image memory 704,
An interrupt signal to the CPU 423 for notifying the end is generated. Upon receiving the interrupt signal, the CPU 423 sends the code memory 705 via the memory control unit 703.
And reads the encoded code from the
Write as transmission data to. The transmission data is modulated into an analog signal by a modem unit 710 and transmitted from an external connector 709 via an NCU (network control unit) unit 708. Speaker section 707
Is connected to the modem unit 710 and can monitor the communication state of the modem by voice.

In the facsimile receiving operation, when an analog signal received from the external connector 709 is received by the modem unit 710 via the NCU unit 708, an interrupt signal to the CPU 423 notifying of data reception is generated. The CPU 423 that has received the interrupt signal reads data from the modem unit 710 and writes a code to the code memory 705 via the memory control unit 703. When the writing to the encoding memory 705 ends, the CPU 423 sends a write end signal to the encoding / decoding processing unit 702 via the system bus.
The encoding / decoding processing unit 702 fetches data at high speed by DMA transfer from the coding memory 705 by communication with the memory control unit 703, decodes the fetched code data, and decodes the decoded image data by DMA transfer. Is stored in the memory 704.
When the decoding of the code in the code memory 705 is completed, the encode / decode processing unit 702 generates an interrupt signal to the CPU 423 notifying the end.

The memory control unit 703 outputs a video signal from the image memory 704 to the connector C 701 according to the timing signal from the connector C 701. The memory control unit 703 also stores an image in the image memory 704 using an internal buffer.
It has a function of rotating at degrees, 180 degrees, and 270 degrees, and rotates and outputs received or transmitted images as necessary.

The voice synthesizing unit 711 synthesizes a response message by voice at the time of an incoming call based on the data set via the bus of the system, and transmits the message via the NCU unit 708.

The connector D 712 is connected to the system bus and the image bus.
Be prepared for system expansion to improve performance.

Next, the shading correction unit 403 shown in FIG.
Will be described in detail.

FIG. 15 is a block diagram of the shading correction unit 403 in this embodiment. In FIG.
Reference numerals 801, 802, 706, and 812 are selectors, and the A side is selected when the select terminal is “L”. A counter 803 clears a count value by a horizontal synchronization signal HSYNC signal synchronized with reading of each line of the CCD line sensor 401 and counts up in synchronization with an RCLK signal corresponding to each pixel of the image signal. This count value becomes an address of a memory for storing shading correction data. Reference numerals 804 and 805 denote JK flip-flops, each of which has an RCLK signal and an HSYN signal.
Divide the C signal. Reference numerals 807 and 808 denote D flip props, which latch data input to the D terminal at the rising edge of the input clock (here, RCLK2).

The digital image data from the A / D converter 402 is input to the flip-flop 807 and the selector 806. A memory 809 stores shading correction data, and stores data input to the Di terminal at an address specified by an address (VA) input to the A terminal. From the Do terminal, data stored at the address specified by the A terminal is output. Here, designation of writing to and reading from the memory 809 and an instruction to switch the selector are performed using control signals from the CPU 423. 810 is an addition circuit,
The result of adding the two input data is output. Reference numeral 811 denotes a division circuit, which calculates an average value by dividing by the number of times the input data is added. Reference numeral 813 denotes an arithmetic circuit which performs an operation for shading correction.

In FIG. 15, the CCD line sensor 4
01, when inputting the shading data obtained by reading the reference white plate into the memory 809, the input signals of the select terminals of the selectors 802 and 806 are set to “H”.
And all data in the memory 809 is set to 0. Further, the select terminal of the selector 812 is set to “H”, and the output of the adder circuit 810 is connected to the Di terminal of the memory.

When the rising edge of the HSYNC signal after the clear signal of the flip-flop 805 becomes "H" is set to the 0th line, the Q output of the flip-flop 805 becomes "H", so that the selector 801 selects the B side. Therefore, the Q output of the flip-flop 804 is
, Ie, RCLK2. At this time, the memory 8
09 at the rising edge of RCLK2 in the output value of the counter 803.
There are only even values latched at 8. At this time, the selector 806 selects the B side, so that only the even-numbered data latched by the flip-flop 807 at the rising edge of RCLK2 is transmitted to the next stage as the image data. At the same time, the data (here, 0) stored in the memory address latched by the flip-flop 808 is read from the memory 809,
This data and the even-numbered image data from the selector 806 are added by the adder circuit 810 and written again to the same memory address. Therefore, in the 0th line, the memory 80
The even-numbered image data for one line is stored in the even-numbered address 9.

In the next first line, the flip-flop 80
5 becomes "L" and the selector 801 selects the A side, so that RCLK2 is supplied to the flip-flop 804.
, That is, a clock having a phase opposite to that of RCLK2 on the 0th line, the address VA of the memory 809 latched by the flip-flop 808 has only an odd value. At this time, only odd-numbered image data latched by the flip-flop 807 at the rising edge of RCLK2 is transmitted to the next stage as image data.
At the same time, the data (here, 0) stored in the memory address latched here is read, and the read data and the odd-numbered image data from the selector 806 are added by the adder circuit 810. The addition result is written to the memory address latched by the flip-flop 808. Therefore, in the first line, the odd-numbered image data for one line is stored in the odd address of the memory 809.

In the next second line, the operation is the same as that of the above-mentioned zeroth line. However, since the image data of the zeroth line is stored in the even address of the memory 809, the value written to the memory 809 again is 0. The sum of the even-numbered image data on the line and the (even-numbered) image data at the same position on the second line.

When the same processing is performed up to the fifteenth line (for 16 lines), the addition result of eight lines of the even-numbered image data is stored in the even address of the memory 809, and the odd-numbered image data is stored in the odd address. The result of addition for eight lines of image data is stored. (The 16 lines are read while moving the reading position of the standard white plate.) After the above addition processing is completed, the select terminal of the selector 812 is set to “L”, and the image data is read from the memory 809. The division circuit 811 divides the data of all the addresses in the memory 809 by 8, thereby obtaining an average value of the data of 8 lines for each pixel, and stores the average value in the memory 809 again as shading correction data. This completes the shading data averaging process.

In calculating the average value, the average value of the even-numbered image data is obtained first, and then the average value of the odd-numbered image data is calculated. Can be executed in two clocks.

After the creation of the shading correction data is completed,
When the select terminal of the selector 806 is set to "L" and the original is read by the CCD line sensor 401, the A / D converter 4
02 is continuously input to the shading correction operation circuit 813 (image data Vi
And). Then, the shading correction data Dn stored in the memory 809 is read out in accordance with the input of the image data, and the calculation of Vi and Dn (Vo = C / Dn · Vo) is performed by the calculation circuit 913. As a result, the shading correction data Vo is output. Here, C is a constant. The image data that has been subjected to the shading correction is input to the next scaling unit 408.

In the present embodiment, even-numbered lines represent even-numbered pixels,
In the odd-numbered line, the sample of the odd-numbered pixels is used. However, the present invention is not limited to this combination. The same effect can be obtained by alternately sampling the pixels of the even-numbered line and the odd-numbered line. Further, by increasing the interval between the pixels to be sampled to, for example, two pixels, three pixels, or the like, it is easy to increase the calculation time per pixel.

According to this embodiment, in the addition processing for averaging the shading correction data, the time corresponding to two reference clocks per pixel can be used. Even
Shading correction data in high-speed image processing can be created.

Next, the scaling section 408 and the filter section 410 of FIG. 5 will be described in detail.

In the image processing described above, the sub-scanning thinning-out processing is performed by the scaling processing section 408 simultaneously with the reduction processing in the main scanning direction.

FIG. 16 is a block diagram of the scaling unit 408 and the filter unit 410 of this embodiment. Reference numeral 408 denotes a scaling unit, and 410 denotes a filter unit. 1
Reference numeral 01 denotes a circuit for performing a reduction process in the main scanning direction. 102
Reference numeral denotes a sub-scanning thinning circuit, which generates valid data for only one of predetermined lines in accordance with a thinning rate such as a resolution or a magnification ratio while referring to image data subjected to reduction processing in the main scanning direction. Here it is reduced by 25% for simplicity, ie
An example in which valid data for one line is created will be described. Reference numerals 103, 104, 105, and 106 denote line memories, each of which is an element for storing one line of image data input for each pixel in synchronization with a pixel clock. The address in each line memory is reset by the RST signal. In the case of this embodiment, an HSYNC signal indicating the head of one line is connected to the RST terminal, so that one line of image data from the head of one line can be stored. The writing and reading of the line memory are controlled by the WE and RE signals, respectively, and the respective operations are performed only when the WE and RE signals are "L". When the WE and RE signals are "H", the previous state is maintained without overwriting new data.

Reference numeral 107 denotes an arithmetic operation circuit for filter processing, which outputs image data for one line of the sub-scanning thinning circuit 102 and line memories 103, 104, 105, and 106.
A 5 × 5 pixel matrix as shown in FIG. 8 is created from the four lines of image data stored in the image processing unit, and a predetermined operation is performed to perform a filter process such as an edge enhancement process.

Here, when the sub-scanning thinning circuit 102 performs a sub-scanning thinning process of 25% in the sub-scanning direction, only one line out of four lines becomes a valid image, and the remaining three lines are output as invalid images. At this time, the sub-scanning thinning circuit 102
Therefore, the signal VE which becomes "L" during the output of the effective image line and becomes "H" during the output of the invalid image line is simultaneously output. By inputting this VE signal to the WE and RE terminals of the line memories 103, 104, 105 and 106 in the filter processing unit 410, image data is written into each line memory only for valid image lines. Therefore, since the invalid image is not transmitted to the line memory and thereafter, the image data used for the filter processing in the arithmetic circuit 107 is only the valid image.

In this embodiment, the case where only one of the four lines is an effective line has been described as an example. However, even when the sub-scanning thinning interval is changed, the arithmetic circuit 107 uses the VE signal indicating the effective image line. Can be easily applied. For example, at the time of 50% reduction, a VE signal is output once to input two lines of image data.

As described above, the sub-scanning thinning circuit 1
02, a VE signal indicating an effective image line output from
The line memories 103 and 1 of the next-stage filter processing unit 410
Since the write enable control of the write operations 04, 105, and 106 can be performed, the filter processing can be performed only on the effective image lines.

In the above description, a digital copying machine is used. However, it is needless to say that the present invention is not limited to this and can be applied to a facsimile, an electronic file, and the like.

[0113]

As described above, according to the present invention, according to the line thinning rate, image data is output together with an identification signal indicating whether or not the line is valid, and the image data validated by the identification signal is output. Since image processing is performed by taking in the image, image processing suitable for scaling of the image and resolution conversion can be executed, and the image processing can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a digital copying machine to which the present invention is applied.

FIG. 2 is a diagram showing a transfer sheet on an intermediate tray.

FIG. 3 is a diagram showing a configuration of an ADF.

FIG. 4 is a diagram illustrating an appearance of an operation unit.

FIG. 5 is a block diagram of a signal processing unit.

FIG. 6 is a block diagram of an A / D converter.

FIG. 7 is a diagram showing an AE operation.

FIG. 8 is a diagram showing a filter matrix.

FIG. 9 is a diagram illustrating an example of an image combining process.

FIG. 10 is a diagram showing types of PWM modulation.

FIG. 11 is a diagram showing a system configuration.

FIG. 12 is a diagram showing a system configuration.

FIG. 13 is a block diagram of a resolution / gradation number conversion unit.

FIG. 14 is a block diagram of a facsimile unit.

FIG. 15 is a block diagram of a shading correction unit.

FIG. 16 is a block diagram of a scaling unit and a filter unit.

[Explanation of symbols]

 102 Sub-scanning thinning circuit 401 CCD line sensor 403 Shading correction unit 408 Zoom processing unit 410 Filter processing unit 809 Memory

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/38-1/409

Claims (5)

(57) [Claims] 1. A variable power unit for inputting image data for each line and outputting image data together with an identification signal indicating whether or not the line is valid according to a line thinning rate, and an output from the variable power unit . Store image data
A memory for storing image data stored in the memory.
A processing unit for performing a predetermined process , wherein the processing unit is output from the scaling unit.
In the image data, the line that has been validated by the identification signal
Write the image data of the
The image data of the line invalidated by the
Is not written in the
Generating, on the memory,
An image processing apparatus , wherein the predetermined processing is performed on generated image data . 2. The image processing apparatus according to claim 1, wherein the processing unit has a line memory for storing the image data of a plurality of lines taken. 3. The image processing apparatus according to claim 2, wherein the processing unit performs a filtering process on a plurality of lines of image data stored in the line memory . 4. The image processing apparatus according to claim 1, wherein the scaling unit outputs an identification signal indicating whether or not the line is valid according to a scaling factor. 5. A scaling unit and a subsequent processing unit
In the image processing method in the above, in the scaling unit, inputting image data for each line, according to a line thinning rate, an output step of outputting image data together with an identification signal indicating whether the line is valid, Output from the scaling unit in the processing unit
And stores the image data in the memory.
And a processing step of performing predetermined processing on the obtained image data.
A, wherein the processing step, output from the variable power unit
In the image data, the line that has been validated by the identification signal
Writing the image data in-the memory, before Symbol identification signal
The image data of the line invalidated by the
Is not written in the
Generating, on the memory,
An image processing method , wherein the predetermined processing is performed on generated image data .