JPH0685563B2 - Image processing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention detects a high density portion of an original image,
The present invention relates to an image processing device capable of reproducing an image corresponding to this.

[Prior art]

A digital color copying machine has been proposed in which a color original image is subjected to digital signal processing to obtain a reproduced image. In this type of copying machine, processing such as dither processing, gamma processing, and undercolor removal processing is performed.

However, in such a digital color copying machine, a technique for forming a line image in color by performing line image processing according to the magnitude of the density change of the image has not been considered.

Therefore, for example, it was not possible to obtain an image of only a portion of the original image in which the density change is large, such as a contour image.

[Object] Therefore, according to the present invention, when a color image is reproduced by superimposing images of a plurality of reproduced colors based on reproduced color component signals which are sequentially output for each reproduced color, the present invention responds to changes in image density with a simple configuration. It is an object of the present invention to provide an image processing apparatus capable of performing a line drawing process and forming a color line image.

In order to achieve such an object, the image processing apparatus of the present invention includes a signal generating unit (corresponding to the CCD light receiving units 56, 57 and 58 in the embodiment) that reads a color original and generates a plurality of color component signals, Signal output means for processing a plurality of color component signals generated by the signal generating means and sequentially outputting reproduced color component signals for each reproduced color (also shading unit 59, γ correction unit 60, masking processing unit 61, UCR processing unit 6
2), and a line drawing processing unit (also a line drawing processing circuit 123) that detects a portion having a large density change for each reproduction color of the reproduction color component signal output by the signal processing unit and outputs it as a line drawing signal.
Based on the line drawing signal output by the line drawing processing means,
Image forming means for forming reproduced color images (also laser 23
And the like), the signal generating means repeatedly generates the plurality of color component signals each time the reproduced color component signal is output by the signal processing means, and the signal processing means repeatedly uses the signal generating means. The generated plurality of color component signals are processed, and the reproduced color component signals are sequentially output for each reproduced color, and the line drawing processing unit is commonly used for forming images of a plurality of reproduced colors by the image forming unit. Further, each time the reproduced color component signal is output by the signal processing means, a portion having a large density change is repeatedly detected and sequentially output as a line drawing signal, and the image forming means, for each reproduced color by the line drawing processing means. It is characterized in that a color image is reproduced by superimposing a plurality of reproduced color images based on the line drawing signal repeatedly output.

[First Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 13. The same or equivalent parts in the drawings are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a sectional view of an image processing apparatus to which the present invention can be applied.
Reference numeral 1 is an original, 2 is a transparent plate for placing the original 1, 3 is an original mat for holding the original 1 from above, 4 and 5 are illumination lamps, and 6 and 7 are reflections. Mirror, 8 is a main body control section for controlling each section, 9 and 10 are the main body control section 8
The moving reflection mirrors that move at different speeds (V, 1 / 2V) under the control of 11), 11 is a lens that collects the light reflected by the moving reflection mirrors 9 and 10, and 12 is the light that has passed through the lens 11. Dichroic mirror for splitting light of blue wavelengths, light of green wavelengths and light of red wavelengths, 13 is a blue filter that passes the decomposed light of blue wavelengths among the respective decomposed light, 14 is the blue A solid-state imaging device such as a CCD for receiving light passing through the filter, 15 is a green filter that similarly passes a green wavelength, 16 is a solid-state imaging device that receives light from the green filter 15, and 17 is red. A red filter that passes light of a wavelength, 18 is a solid-state image sensor that receives the light from the red filter 17,
Reference numeral 19 is a white calibration plate, 20 and 21 are cooling fans provided in the optical system to dissipate heat from the illumination system, 22 is an image processing unit as image processing means described later, 23 is a semiconductor laser, and 24 is a semiconductor laser.
Is a polygon mirror irradiated with the laser light La from the semiconductor laser 23, 25 is a scanner motor for rotating the polygon mirror 24, and 26 is a laser light La that is scanned perpendicularly to the rotation direction to be exposed. 27 is a photosensitive drum, 27 is a sensor for detecting the light scanning the photosensitive drum 26 to generate a beam detector (BD) signal, 28 is a high voltage power source for generating a negative high voltage, 28a Is a negative charging device, 29 is an exposure unit, 30 to 33 are developing units for four colors of B, G, R, and BK, 34 is a ghost lamp for erasing an electrostatic latent image, and 35 is the negative The post electrode of the minor to which a high voltage is supplied from the high voltage power supply 28, 36 and 37 are cassettes selected by the operation unit, 38 and 39 are paper feed rollers, and 40 is a copy paper sent by the paper feed rollers 38 and 39, 41 and 42 are upper and lower first registration rollers, 43 is a conveyance roller, and 44 is a second Gist roller, 45 is a transfer drum for transferring the toner on the photoconductor to the copy paper 40, 46 is a transfer power source for transferring the toner on the photoconductor to the copy paper 40, and 47 is a transfer for cleaning the transfer drum 45 A drum cleaner, 48 is supplied with a high voltage from the high-voltage power supply 28, and a static elimination electrode 49 for removing static electricity from the copy paper 40 is a gripper, 50 is a transport fan, and 51 is a transport for suctioning and transporting the copy paper. A belt, 52 is a fixing unit, 53 is a pre-cleaner charge eliminator for discharging the potential remaining on the photosensitive drum 26, 54 is a cleaner unit for removing toner on the photosensitive drum 26, and 55 is the photosensitive drum. It is a pre-AC static eliminator that removes the potential of 26.

Next, FIG. 2 shows a block diagram of the image processing unit 22.

In the figure, 56, 57 and 58 are the solid-state image pickup devices (CCD) 14, 1
CCD light receiving unit as a density detecting means for A / D converting the light received by 6,18 and detecting the density change of the original 1, 59 is a constant output level of the CCD light receiving unit 56,57,58 A calibrating unit for calibrating as described above, 60 is a γ (gamma) correction unit for switching the input sensitivity of the CCD by receiving a signal from the main body control section 8, and 61 is a signal from the γ correction unit 60, respectively. , A masking processing unit for performing G, R color correction, 62 is a U for obtaining a black level signal from the B, G, R signals by a signal from the main body control section 8.
CR processing unit, 63, 64, 65 are each the CCD light receiving unit 5
Buffer circuits arranged on the CCD substrate P constituting 6,57,58, 66,67,68 are CLK drivers, 69,70,71 are signals obtained from the solid-state imaging device (CCD) 14,16,18 Amplifier for amplifying, 72, 73, 74 are A / D converters for converting the analog signals from the amplifiers 69, 70, 71 into digital signals, 75,
76 and 77 are for shading correction corresponding to B, G, and R, respectively.
ROM, 78, 79, 80 are RAMs as memories connected to the ROMs 75, 76, 77, 81, 82, 83 are gamma correction ROMs corresponding to B, G, R colors, 84, 85 , 86 are latches for holding the γ-corrected signal, 87-95 are ROMs for coefficient multiplication, 96, 97, 98 are ROMs for addition / subtraction, and 99, 100, 101 correspond to B, G, R colors respectively. ,
A latch for holding the signal from the masking processing unit 61, 102 constitutes the UCR processing unit 62, and the latch 10
A comparator for comparing the B color data of 0, 101 and the G color data; 103 is a comparator for comparing the G color and R color data of the latches 99, 101; 104 is a B comparator for the latches 99, 100. Comparators for comparing color data and R color data, 105, 106 and 107 are comparators 102 and 10 respectively.
NOT circuits arranged on the output side of 3,104, 108, 109, 110 are AND circuits for ANDing the comparators 102, 103, 104 and NOT circuits 105, 106, 107, and 111, 112, 113 are AND circuits 108, 109, 1
Latches that hold the minimum values of the blue, green, and red color signals using the output of 10 as an enable signal, 114, 115, and 116 correspond to the B, G, and R colors, respectively, and the output side of the above-mentioned latches 99, 100, and 101. 117, 118, 119, and 120 are ROMs for UCR correction that are separately driven by the enable signal (E), 121 is a latch connected to the output side of the UCR correction ROM 120, 122
Is a gate circuit.

A line drawing processing circuit 123 as a line drawing processing means is shown in FIG.
Shows the details of. In the figure, 124 is a latch for holding the signal from the image processing unit 22, 125, 126, 127 are shift registers, 128 is a data selector for selecting each input port P1 to P3 by a select signal (CS), P4 is an output port, 129 Is a subtraction circuit, 130 is a two-input EX-OR circuit which constitutes the subtraction circuit 129, and 131 is a latch which holds the output of the subtraction circuit 129. 132 is a dither processing unit, 133, 134 and 135 are dither processing ROMs, and 136, 137 and 138 are data of the latch 131 of the line drawing processing circuit 123 and ROMs 133 and 13
Comparator to compare 4,135 data, 139,140,141
Is a latch for holding the outputs of the comparators 136, 137, 138, 142, 143, 144 are R / W line memories for storing the data held in the latches 139, 140, 141, 145 is a multi-value processing unit, and 146 is the multi-value processing unit 145. Latches, 147, 148, 149 are AND circuits connected to the output side of the latch 146, 150 is a sync counter for gates the AND circuits 147, 148, 149, 151 is connected to the sync counter 148 and sends out B / D signals as sync signals B for
D signal generator, 152 is an OR circuit arranged on the output side of the AND circuits 147, 148, 149, 153 is a blanking circuit arranged at the latter stage of the OR circuit 152, and 154 is a pattern signal to be sent to the blanking circuit 153. A pattern generator for 155, a laser driver 155 for receiving the signal from the blanking circuit 153 to drive the semiconductor laser 23, and 156 a laser beam La from the semiconductor laser 23.
Is a scanner unit for scanning.

First, the copying process will be outlined. The original 1 is placed on the transparent plate 1 and pressed by the original mat 3 from above. Then, when the apparatus is started, light is emitted from the illumination lamps 4,5 and is combined with the light from the reflecting mirrors 6 and 7 to irradiate the original 1, and the reflected light from the original 1 is moved and reflected by the moving mirror 9. Then, the light is reflected by 10 and passes through the lens 11 and the dichroic mirror 12. Then, the dichroic mirror
The light passing through 12 is split into blue light, green light, and red light, and the decomposed light having a blue wavelength of each decomposed light is passed through a blue filter 13 to the solid-state image sensor.
Similarly, light having a wavelength of green is received by the solid-state image sensor 16 via the green filter 15, and light having a wavelength of red is received by the solid-state image sensor 18 via the red filter 17. Received light. The manuscript 1 is moved along with the illumination lamps 4 and 5, and is moved by a reflecting mirror 9 which moves.
Then, while the optical path length is kept constant by another moving reflection mirror 10, images are formed on the solid-state imaging devices 14, 16, 18 of each color via the lens 11 and the dichroic filter 12. Further, a white end plate 19 is provided in front of the original 1 for correcting the amount of light when the illumination lamp 4 moves along the original 1. At this time, in the optical system, heat is released from the illumination system by the cooling fans 20 and 21, and the prescribed temperature is maintained.

Further, the outputs of the respective solid-state image pickup devices 14, 16 and 18 are passed through an image processing unit 22 as an image processing means to a semiconductor laser.
ON / OFF control 23, and the laser light is polygon mirror 24
However, since the polygon mirror 24 is rotated by the scanner motor 25, the laser beam La is scanned perpendicularly to the rotation direction of the photosensitive drum 26.

Then, since the B / D sensor 27 is located 1 (mm) before the laser beam La starts optical scanning on the photosensitive drum 26, when the laser beam La is received, a B / D signal is emitted and each part is sent. Are synchronized. At this time, the photosensitive drum 26 is negatively charged by the negative charger 28a to which a high negative voltage is supplied from the high voltage power source 28. On the other hand, since the original 1 on the transparent plate 2 is illuminated by the illumination lamps 4 and 5, the moving reflection mirrors 9 and 10 are provided.
The image of the original 1 is formed on the respective solid-state image pickup devices 14, 16 and 18 via the lens 11, the dichroic mirror 12, the blue filter 13, the green filter 15 and the red filter 17. The image output thus obtained is subjected to the shading correction for each color as shown in each block diagram of the image processing unit 22 in FIG. 2, that is, the shading correction by the shading unit 59, the gamma correction by the gamma correction unit 60, and the masking processing. Color correction is performed by the unit 61, and the next
Undercolor adjustment is performed by the UCR processing unit 62, and a signal corresponding to the shading of the original 1 is obtained by the dither processing unit 132 and the multi-value processing unit 145. This signal is sent to the laser driver bar 155, the semiconductor laser 23 is driven, laser light La is emitted, and the photosensitive drum 26 is irradiated through the polygon mirror 24. Then, an electrostatic latent image is formed, and as the photosensitive drum 26 rotates, the electrostatic latent image enters the four-color developing devices 30 to 33.

Here, when one color is selected based on a signal from the main body control unit 8 via the line drawing processing unit 123 among the three color separation light by one exposure scan, one corresponding developing device (for example, 3
1) is selected. Then, powder development by the magnetic blade method is performed by the selected developing device 31, and the electrostatic latent image is visualized. Then, the ghost miniature lamp 34 for erasing the electrostatic latent image and the post electrode 35 to which a negative high voltage is applied from the high voltage power source 28 are charged to remove the electrostatic latent image on the drum.

Next, the upper and lower cassettes 36 and 37 are selected by the operation unit and either of the paper feed rollers 38 and 39 is rotated to send the copy paper 40 which is the upper or lower first registration rollers 41 and 42. The toner of the image formed on the photosensitive drum 26 by being caught in the gripper 49 and wound around the transfer drum 45 is transferred to the copy paper 40 by the transfer electrode 46. This transfer is performed the number of times of the selected color, and each time the charge is removed from the copy paper 40 by the charge removing electrode 48 to which a high voltage is supplied from the high voltage power supply 28. When the transfer is completed the selected number of times, the copy paper 40 is peeled off from the gripper 49, adsorbed on the conveyor belt 51 by the conveyor fan 50, and guided to the fixing section 52. On the other hand, the potential remaining on the photosensitive drum 26 is further neutralized by the pre-cleaner static elimination 53 to remove the toner on the photosensitive drum 26 by the cleaner unit 54. The potential on the photosensitive drum 26 is eliminated by the AC pre-eliminating device 55.

The image signal processing in the copying process will be described below in detail with reference to the circuit diagram.

The light of the original 1 separated into three colors by the dichroic mirror 12 in the preceding stage of the image processing unit 22 is a solid-state image sensor.
The information signals received by 14, 16 and 18 are received by amplifiers 69, 70,
The signal is amplified by 71, A / D converted by A / D converters 72, 73, and 74, and sent to the next shading unit 59 via the buffer 65. Then, when the optical system, that is, the illumination lamps 5, 6 and the like pass through the white calibration plate 19, a signal is sent from the main body control unit 8 so that the output level becomes constant every one bit of the CCD light receiving units 56, 57, 58. Correction is made by the shading unit 59. Next stage γ correction unit
An appropriate γ curve is selected by the signal from the main body control unit 60, γ correction is performed according to the curve, and then a B, G, R color signal is simultaneously processed by the masking unit 61 in the subsequent stage. , The color correction is performed by changing the mixing ratio of each color component. The mixing ratio of each color of B, G and R is switched by a control signal from the main body control section 8. Further information signals are UCR
The processing unit 62 determines the minimum signal of B, G, and R. A value obtained by multiplying the minimum signal by an arbitrary coefficient written in the ROM 120 selected by the signal from the main body control unit 8 is set as a black level. Whether or not to reduce the value multiplied by the coefficient from each color is selected by a signal from the main body control unit 8.
This is done according to the contents of ROM 117, 118, 119. Therefore, of the signals of B, G, R, and BK of each color, a signal of one color of B, G, and BK is sent to the line drawing processing circuit 123 by the select (CS) signal of the main body control unit. Then, in the line drawing processing circuit 123, each 6-bit color signal is once held by the latch 124, and then branched into two circuits. Then, for example, by the select signal (CS), the input port P of the data selector 128
_{When 3} is selected, one branched signal passes through the shift register 127 and the input port of the data selector 128.
It is sent to the subtraction circuit 129 via P ₃ and the output port P ₄ with a delay of several clocks to 1,000 clocks. The delay time can be switched by selecting _one of the input ports P ₁ , P ₂ , P ₃ by the select signal (CS) of the data selector 128. Since the subtraction circuit 129 is composed of the 2-input EX-OR gate 130 as described above, the value of the 6-bit signal input through the shift registers 125 to 127 is compared with the value of the signal directly input from the latch 124. . When the values of the two signals are equal, the output becomes zero, and when the values of the input 6-bit signals are different, the absolute value of the difference is output. That is, when read by the CCD light receiving unit 56 as shown by the one-dot chain line of the original as shown in FIG. 5, the output signal of the latch 124 becomes as shown in FIG. 6 (1) while the signal passed through the shift register 125. Is as shown in FIG. 6 (2). At this time, if the input port P ₁ of the data selector 128 is selected, the absolute value of the difference between (1) and (2) in FIG. 6 is as shown in (3) in FIG. Let's assume that this Fig. 6 (1), (2),
If the image is reproduced based on the signal shown in (3), the images shown in FIGS. 7, 8 and 9 are reproduced. As can be seen from the reproduced image in FIG. 9, the vertical line is reproduced, but the horizontal line has disappeared.
Therefore, take a large delay time in the line drawing processing circuit 123,
If the original image shown in FIG. 5 is read by the CCD light receiving unit 56 described above and reproduced by the processing signal of the latch 124, the reproduced image as shown in FIG. 11 is obtained so that it is displaced not only horizontally but also vertically. To be

Further, if the image is reproduced by a signal passing through the shift registers 125, 126 and 127, an image is reproduced as shown in FIG. The output of the subtraction circuit 129 thus obtained is held in the latch 131 and sent to the dither processing unit 132.

The dither processing unit 132 compares each signal having a deep signal, for example, a 6-bit signal, using a ROM for table reference, and converts it into a digital signal of 1 or 0 to modulate the semiconductor laser 23. I do. The dither processing is performed by the dither processing blocks existing in parallel inside the dither processing unit 132, and the data obtained by the processing is sent to the multi-value processing unit 145, and the main body control unit 8
By this, select control is performed and signal processing is performed. When the semiconductor laser 23 is driven through the laser driver 155 based on the obtained processed data and the image is reproduced, a line image as shown in FIG. 13 is obtained.

In the above description, one of the colors has been described, but a full-color reproduced image can be obtained by repeating the above operation four times and superimposing the colors B, G, R, and BK.

(1) B, G, R, obtained by signal processing the image information of the original 1
By reproducing an image with only one or two signals of each of BK, it is possible to create a line drawing of only a specific color of the original image.

(2) Then, by reproducing the image of R color by the signal of B color, for example, a line image subjected to color conversion can be created. That is, after processing the B color signal, laser modulation is performed, and at this time, the developing device having the R color toner is selected and development is performed.

(3) Also, select signal (CS) to the line drawing processing unit
Switch the delay time of the line drawing processing unit by appropriately selecting the input ports P ₁ , P ₂ , P ₃ of the data selector 128. For example, a thicker line can be obtained by increasing the delay time. An image is obtained.

[Second Embodiment] FIG. 4 shows a line drawing processing circuit diagram showing another embodiment of the present invention in which the latch 131 and thereafter shown in FIG. 3 are modified.

In the figure, 157 is connected to the output side of the latch 131.
OR gate, 158 is R / W line memory, 159 is latch, 160
Is a blanking circuit, and 161 is a pattern generator connected to the blanking circuit 160 for generating a pattern.

The OR gate 157 connected to the latch 131 is the latch 13
If the output of 1 is a 1-bit high signal, the OR gate 1
57 output goes high. That is, if there is a difference between the output of the latch 131 and the signal passed through the shift register 125, the laser light La is turned on, and if not, it is turned off. In FIG. 3, the density of the reproduced line image changes depending on the magnitude of the signal difference, but in FIG. 4, the density of the line image is always a constant density as described above.

Further, by ignoring the lower-order bits of the 6-bit output of the latch 124 of FIG. 3, it is possible to reproduce as a line drawing only the portion where the difference in density change is greater than a certain value.

As described above, according to this embodiment, the density changing portion of the original image is detected by the density detecting means, the detected original image is subjected to image processing by the image processing means, and the processed image is processed by the line drawing processing means. Since it is configured to reproduce as a line image, it is possible to obtain a simple line image more easily than a complicated original image or an original image with colors because it is possible to reproduce the part where the density of the original image changes with a line image. It produces a working effect.

[Effect] As described above, according to the present invention, a simple configuration is used when reproducing a color image by superimposing a plurality of reproduced color images based on reproduced color component signals that are sequentially output for each reproduced color. It is possible to form a color line image by performing line drawing processing according to a change in image density.

[Brief description of drawings]

FIG. 1 is a sectional view of an image processing apparatus according to the present invention, FIG. 2 is a block diagram of an image processing unit showing the essential parts of the present invention, FIG. 3 is a detailed view of FIG. 2, and FIG. FIG. 5 and FIG. 10 are original image diagrams, FIG. 6 is a signal waveform diagram when an original image according to the present invention is read, FIG. 7 and FIG. Is an explanatory diagram of a line image obtained when the original image according to the present invention is reproduced, and FIGS. 8 and 12 are explanatory diagrams of a line image when the original image according to the present invention is reproduced by delaying a signal, 9 and 13 are line images shown in FIGS. 7 and 8 or FIG. 11 and FIG.
FIG. 13 is an image explanatory diagram when the line images shown in FIG. 12 are combined. 56,57,58 …… CCD light receiving unit (density detection means) 22 …… Image processing unit (image processing means) 123 …… Line drawing processing circuit (line drawing processing means)

Claims (2)

[Claims] 1. A signal generating means for reading a color original to generate a plurality of color component signals, a plurality of color component signals generated by the signal generating means, and sequentially outputting reproduced color component signals for each reproduced color. Signal processing means, a line drawing processing means for detecting a portion having a large density change for each reproduction color of the reproduction color component signal outputted by the signal processing means, and outputting it as a line drawing signal, and the line drawing processing means for outputting. Based on the line drawing signal,
An image forming means for forming an image of reproduced color, wherein the signal generating means repeatedly generates the plurality of color component signals each time the reproduced color component signal is output by the signal processing means, and the signal processing means Is for processing a plurality of color component signals repeatedly generated by the signal generating means and sequentially outputting reproduced color component signals for each reproduced color, and the line drawing processing means is an image of a plurality of reproduced colors by the image forming means. Commonly used for the formation of, and a portion having a large density change is repeatedly detected every time the reproduction color component signal is output by the signal processing means, and sequentially outputs as a line drawing signal, the image forming means, An image processing apparatus for reproducing a color image by superimposing a plurality of reproduction color images based on a line drawing signal repeatedly output for each reproduction color by a line drawing processing means. 2. The image processing apparatus according to any one of claims 1 to 4, wherein the line drawing processing means is a means capable of varying the thickness of the reproduced line image.