JP3039673B2 - Image processing apparatus and method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image processing apparatus and an image processing method.

[Conventional technology]

2. Description of the Related Art Conventionally, a digital color copying machine separates a document into three primary colors of R, G, and B, converts the three-color signals into recording material color signals of C, M, Y, and K colors, and records the signals. At this time, the achromatic region of the original is not represented by only a single black signal, but is expressed by a maximum of two or three colors including other color signals C, M, and Y in order to represent blacker black. It is known that recording materials are expressed in layers.

[Problems to be solved by the invention]

However, in the above-described conventional example, in order to represent a black thin line, if recording of four colors does not completely match in position in a recording apparatus, a color ghost will occur. For example, computer graphics and page description language However, there is a drawback that black characters and fine lines input by the R, G, B three color signals generated by the above method cannot be clearly recorded and expressed.

Accordingly, an object of the present invention is to provide an image processing apparatus and method capable of favorably determining both a specific color image edge portion in image data generated by an external computer and image data obtained by an image sensor.

[Means and Actions for Solving the Problems]

In order to solve the above-mentioned problem, the invention according to claim 1 is an input unit for inputting image data generated by an external computer and image data obtained by an image sensor, and a specific image in the image data input by the input unit. An image processing apparatus comprising: a determination unit for determining an edge portion, wherein when image data generated by an external computer is input from the input unit, a determination method for image data generated by the external computer is used. The determination unit determines the specific color image edge portion,
When image data obtained by an image sensor is input from the input means, the edge of the specific color image is determined using a determination method for image data obtained by the image sensor.

According to a second aspect of the present invention, image data generated by an external computer and image data obtained by an image sensor are input, a specific color image edge portion in the input image data is determined, and the image data is generated by the external computer. When the image data is input, the specific color image edge portion is determined using the determination method for image data generated by the external computer, and the image data obtained by the image sensor is input. The edge of the specific color image is determined by using a determination method for image data obtained by the image sensor.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes image data such as binary data of R, G, B, Y, M, C, and K, multi-valued data, character code data, color code data, drawing command data, and the like. The host computer 2 is an interface for exchanging data between the computer and the recording device. For example, an interpreter of a page description language such as PostScript, a memory for developing code data into image data, and the like. It consists of. Reference numeral 3 denotes a black character processing unit for detecting a black pixel from the 8-bit signal of each color of R, G and B outputted from the interface 2 and generating recording control signals KB and KW, and 9 denotes a CCD line of R, G and B. Reader unit such as digital copier including sensors, 10 is a still video camera, 11 is a TV camera, 12 is a still image for one screen of 8 bits each of R, G, B from image data from SV camera 11 or TV camera 12. An input interface 13 for generating an image, a black character processing unit 13 for performing black character processing on the R, G, B signals from the reader 9 and the input interface 12 and generating recording control signals KB, KW; An image processing unit that inputs image signals and recording control signals in parallel from the input means and performs image editing such as inset synthesis, scaling, movement, and the like. It also edits the KW signal.

4 selects the output of the black character processing units 3 and 13 and the output of the editing processing unit 14 and sends the recording signals R, G and B to the logarithmic conversion unit 5 and the recording control signals KB and KW to the binarization control unit 7. It is a selector.

5 is a logarithmic conversion unit for converting an R, G, B 8-bit signal from a luminance signal to a density signal, and 6 is a matrix operation on the C, M, Y, K signals, which are recording colors from logR, logG, logB after logarithmic conversion. A so-called masking UCR processing unit 7 that converts the C, M, Y, and K signals generated by each 8 bits into a binary signal, and based on the recording control signal generated by the black signal processing unit, generates a black thin line pixel. A binarization control section 8 for adaptively controlling the binarization of, and a recording section 8 for performing binary recording based on the binarized image signal.

<Black Character Processing Unit 13> FIG. 2A shows a black character processing unit. In the figure, a maximum value detection unit 61 and a minimum value detection unit 62 each have an RG represented by 8 bits.
The level of the B signal is compared for each pixel, and the largest value and the smallest value of the level are max (RGB) and min (RG
B) get as. The adder 63 calculates the difference max (RGB) −min
(RGB) is calculated, and the result is multiplied by a predetermined constant α in a multiplier 66 and added to max (RGB) in an adder 64. When the addition result exceeds the 8-bit width by a limiter (limiter) 65, the addition result is limited to 255 to obtain a black signal d.

FIG. 2B is an explanatory diagram of this processing. In this embodiment, the greater the value of each of the color signals R, G, and B, the whiter, that is, R
When = G = B = 0, black is assumed. Accordingly, in FIG. 2 (b), the portion A is a thin line having a tint, and the portion B is a black line.

d = max (RGB) + α [max (RGB) −min (RGB)] (max (GRB) is a gray component signal, max (RGB) −min (RG
(B) is a signal indicating tint, α is a color suppression constant. The physical meaning of this processing is that max (RGB) -min (RGB) is regarded as tint and max (RGB) is a gray component (brightness). If max (RGB) -min (RGB) is large, that is, at a point having a color, the value can be converted to a brighter (white) direction by multiplying this value by a constant α and adding it to max (RGB). Therefore, as the value of the constant α increases, α is referred to as a color suppression constant as a value representing the degree to which the tint is suppressed in order to make a point having a tint a whiter point. That is, the degree of black component detection indicated by d can be changed by changing the value of α set in the multiplier 66 by a CPU (not shown). In FIG. 2 (b), α = 1 is shown. However, when max (RGB) is large and max (RGB) −min (RGB) is large, a complete white point is obtained by the limiter 65 of FIG. 2 (a). 25 representing the maximum
It becomes 5. Therefore, it is considered that the change in the generated signal d substantially means a change in the black component.

The black signal d is input to the binarizing unit 7 shown in FIG.

<Binarizing Unit> In FIG. 3, the data for one line of the black signal d is delayed and held by the memory 71 using the memory 71, and the data of five pixels sequentially line-delayed are added by the adder 72. Further, the adder 75 adds the five adder values obtained by delaying the adder by the F / F 73 for each pixel. The output of the adder is delayed by two pixels from the input data, that is, the memory 71-
If the output position of the F / F 73-6 obtained by delaying the two outputs by the F / F 73-5 and 73-6 is set as the target pixel position, it is an integrated value of 25 pixels around the target pixel position. If it is multiplied, the average value m of the black signal near the target pixel can be obtained.

The comparator 79 compares the data d at the pixel position of interest with the average value m as a threshold value to obtain a finer binary signal B.

That is And

Further, the difference between the average values m and d is obtained by the adder 77, converted into the absolute value by the absolute value circuit 78, and compared with the constant δ by the comparator 74 to obtain the binary signal C.

That is And

The physical meaning of both signals is that the former B is a signal obtained by binarizing the black signal with high definition, and the latter C is a signal obtained by binarizing the level change amount at the target pixel. That is, when B = 1 and C = 1, it can be determined that the density change at the target pixel is larger than the constant δ and changes in the black direction. That is, it can be said that there is a high probability that this point is a part of the character thin line.

However, since the pixel of interest may be a halftone image portion represented by a halftone dot, the same two-bit signal is input to the black character identification unit 8 to identify the character portion in order to remove the halftone dot.

<Black Character Recognition Unit> FIG. 4 shows the black character recognition unit. First, the input binary signal B is successively delayed and held line by line using line memories 80-1, 80-2, 80-3, and 80-4, and flip-flops 81-0 to 81-9 are used for each pixel. Hold delayed. Therefore, if the current pixel position is the F / F81-4 output position, the binary data B of eight pixels adjacent to the target pixel is F / F8
1-2, 81-4, 81-6 input position and F / F 81-2, 81-
9, 81-3, 81-5, and 81-7 output terminals, and the nine adjacent pixel data including the target pixel are all gate circuit 83-2.
Is input to

Similarly, the gate circuit 83-1 has pixel data one line after the target pixel, that is, nine points adjacent to the F / F81-2 output position, and the gate circuit 83-4 has one line before the target pixel. Data of 9 points adjacent to the F / F81-6 output position is input. In the gate circuit 83, whether or not the center point is inverted from the eight binary levels (0 or 1) of the eight adjacent points, that is, the center point is isolated from the periphery and "0" Alternatively, a value S of 0 to 4 is assigned to each pixel depending on whether or not the pixel has the level of “1”. As the value S increases, the possibility of a halftone pixel increases as the value increases. Conversely, if the value S is 0, it is highly likely that the value is a part of a character or the like. This is because characters and lines are a set of one-dimensionally continuous dots. However, it is not always 1
Since it cannot be determined in terms of points, the value S indicating the isolation assigned to each pixel is integrated two-dimensionally and determined. That is, multi-value data indicating the degree of isolation is used for the determination. First, three pixels in the line direction of the adder 85-1 are added, and the result is delayed and held by the F / Fs 84-1 to 84-6 for six pixels and added by the adder 85-2 to obtain input image data. B
If a pixel delayed by 2 lines and 4 pixels is used as the target pixel position, an adder Pf for data S of 3 × 7 pixels centered on the target pixel is obtained. The feature amount Pf means a two-dimensional spatial frequency. In other words, the larger the Pf value is, the more the value of the binary data B is inverted from “0” to “1” in the vicinity of the target pixel.
This means that there are many points where the spatial frequency is high and therefore the dots are two-dimensionally isolated.

Therefore, the Pf value is set to a predetermined constant K (about 4 to 5) and the comparator 86.
And the target pixel position, that is, the memories 80-5 and 80-5
-7, the binary signal C and the binary signal B at the same position delayed by 4 pixels at the F / Fs 82-1 to 82-4 and the binary signal B at the same position are 87 output values E = 1. Some points.

One line from the signal E and the pixel position of interest and F / F89-1 to
The signal B delayed by two pixels by 2 is input to the black character signal generator 88 to generate black character signals KB and KW which are final outputs.

Now, the inside of the gate circuit 83 will be described in detail. FIG. 5 is a diagram showing the gate circuit 83, and a, b, c, d, e, f, g, and h adjacent to the central pixel i are the input / output signals B of the F / F 81 described above. EX-OR gate 831−
1, 831-2 detects whether or not the target pixel i is inverted in the a, i, and h directions. That is, if both EX-OR gate outputs are “1”, the output of the AND gate 832-1 becomes 1, and
The target pixel i is isolated in the aih direction. Similarly, the EX-OR gates 831-3 and 831-4, and the AND gate 832-2 are in the cif direction, E
X-OR gates 831-5 and 831-6, AND gate 832-3 are big
Direction, EX-OR gates 831-7, 831-8, AND gate 832-
Reference numeral 4 detects the isolation in the die direction. Here AND gate 833
-1, 833-2, and the OR gate 834 detect the case where the target pixel i is continuously at the same level "0" or "1" in the big direction or the die direction. 0 ". The signal is ANDed with the outputs of the AND gates 832-1 to 832-4 by AND gates 83-1 to 835-4, and the output effect is added by an adder 836 to obtain S indicating a value of 0 to 4. .

The physical meaning of the condition by the AND gate 833 and the OR gate 834 is likely to be a part of a character because its continuity is a line segment orthogonal to the paper surface (document or recording paper surface). Therefore, in this case, S = 0 is uniquely set, and as a result, a very small amount
Lower Pf. The area to be integrated as the Pf value is desirably a square of about 7 × 7, and a wider area than in the present embodiment can identify characters with higher definition. However, the block size and the block shape are not limited to the above-described example, and can be appropriately set according to the detection accuracy and the like.

Next, the inside of the black character signal generator 88 will be described in detail with reference to FIG. The part of the processing is KB = 1 (1 bit) indicating a part of black characters
An object is to generate a signal and a pixel position signal KW = 1 (1 bit) adjacent to the signal and adjacent to a black character having B = 0. If the above-mentioned 1-bit signals E and B are input, the E signal is line-delayed, and the target pixel position is set to the F / F880-3 output position by further delaying each pixel by F / F880-1 to 880-5. The OR gate 881 has one of eight pixels adjacent to the pixel of interest.
When = 1, "1" is obtained at the output. Therefore, the B signal is changed to F / F8
Delayed at 80-7, adjusted to the target pixel position, then inverted and AND
When input to the gate 882, a KW signal is obtained.

<Another Embodiment (1) of Black Signal Generation Unit> FIG. 2 (c) shows another embodiment of the black signal generation. In the previous embodiment, the tint suppression constant is a constant value α irrespective of the gray component max (RGB). However, in general, the gray component is large, that is, the lighter the gray component is, the more the tint is suppressed. Increase the lighter. By doing so, a black signal d having higher contrast can be generated.

The value of max (RGB) -min (RGB) obtained by the adder 63 is multiplied by the output max (RGB) of the maximum value detector 61 by the multiplier 661, and the result is divided by the constant β by the divider 662. The value of β is, for example, 128
Good degree. Further, the result is max (R
(GB) and clamp to 255 with limiter 65.

<Another Embodiment (2) of Black Signal Generating Unit> In the previous embodiment, the color was defined by the difference between max (RGB) and min (RGB), and the suppression was performed by an addition operation. (RG
B) and min (RGB) may be defined, and the suppression may be defined by a multiplication operation on max (RGB). I mean Here, the constant γ is preferably about 63. According to the above expression, the larger the gray component, that is, the brighter the lighter, the more effective the suppression of the tint is.
Since both max (RGB) and min (RGB) are alleviated when they are small, the value of d does not increase even when the color is slightly shaded from the black component.
Can be generated. In the embodiment shown in FIG. 2 (d), a constant γ is first added to the output of the minimum value detector 62 by an adder 663, and a divider 664 is added.
Divides the maximum value detection unit 61 output by. Then the multiplier 665 sets max
(RGB).

As described above, the algorithm for generating the multi-valued data in which the tint is suppressed from each of the R, G, and B data is not limited to the present invention, and is not particularly limited to the primary color RGB. Needless to say, the same effect can be obtained by using other color component signals.

<Black Character Processing Unit 3> FIG. 2 shows the contents of the black signal processing unit 1 based on the present invention. First, R, G, B8 input from the host computer 1
After the bit signal is added by the adder 100, the comparator 101 performs a threshold process with a constant α1 by the following equation to determine whether or not the signal is black.
Generate a 1-bit signal a.

Now, considering the black determination, pure black is R = G
= B = 0. Normally, leaders of copying machines, SV
In the case of an input from a camera, a TV camera, or the like, R = G = B = 0 is not often satisfied even when the target image is pure black due to reading characteristics and reading errors. Therefore, as described above, the black character processing unit 13 determines black if a pixel that does not satisfy R = G = B = 0 at the time of black determination is within a predetermined standard. I have. However, in the case of computer graphics, in the case of pure black, data of R = G = B = 0 is sent. Therefore, even if the above α1 is set to 0, it is necessary to perform the black determination with high accuracy. Can be. If it is desired to detect not only pure black but also a color in a certain range close to black at the same time, α1 may be set to a value close to 0.

The 1-bit black signal a extracted in this manner is stored in the memories 102 and 103, each of which holds a delay of one line, and data of the past two lines delayed by the F / Fs 105, 106, 107 and 10 respectively.
8 holds a delay of several pixels. Then, after setting the output position of the F / F 106 as the target pixel position, the black determination binary data a at the four pixel positions adjacent in the orthogonal direction can be simultaneously detected. That is, if the binary data a at the four pixel positions adjacent to the pixel of interest is input to the OR gate 109, at the output end, any one of the four pixels has a = 0, that is, "1" if not a black pixel. . The AND gate 110 determines that the target pixel is a “black pixel” from the OR gate output and the “a” data at the target pixel position, and if any one of the four adjacent pixels is “not a black pixel”, the target pixel is an edge of a black image. It determines that there is, and outputs a 1-bit recording control signal KB = 1. In the black character processing unit 3, the determination signal KW using the black determination result of the pixels around the target pixel is always set to 0. That is, since it is considered that the error of the black color determination is extremely small for the CG image, it is not necessary to perform the adaptive processing using the determination result of the peripheral pixels.

FIG. 15 shows an example of a KB signal (b in the figure) when a black pattern of R = G = B = α1 is input (a in the figure).

The input R, G, B signals are delayed by about one line in the memory 104 in order to synchronize with the KB signal, and the logarithmic conversion unit 2
To enter.

<Another Embodiment of Black Character Processing Unit 3> In the above-described embodiment, the control signal KB is generated without detecting the amount of density change from around the point of R + G + B ≦ α1, but in FIG. 8, a so-called Laplacian is obtained. Thus, KB = 1 may be generated only when a predetermined amount of edge component is detected. In FIG. 5, the addition is performed by an adder 100, and 8bi is added.
Rounded to the width t, the line delay memories 102 and 103
And the F / Fs 105, 106, and 107 are used to simultaneously detect the amount of blackness of a pixel adjacent to the target pixel F / F 106 output X, that is, R + G + B. If the data are A, B, C, D, and X, respectively, the adder 11
The Laplacian 4X− (A + B + C + D) of the target pixel X is obtained by using the multipliers 112 and 116 and the comparator 114.
Then, threshold processing is performed with a constant α2, and the presence or absence of an edge is input to the AND gate 115. On the other hand, if the comparator 113 processes the threshold value of the black component of the pixel of interest with the constant α3 and inputs the threshold value to the AND gate 115, a KB signal can be obtained with higher accuracy than in the above embodiment.

<Logarithmic Conversion Unit 5, Masking / UCR Unit 6> Next, an outline of the logarithmic conversion unit 5 and the masking / UCR6 will be described. Here, the following equation is used.

First, the logarithmic converter 5 converts the luminance data R, G, B quantized to 8 bits into 8-bit density data r, g, b according to the equation. Further masking · UCR part 6 of the following the r, g, the minimum value in the b data and black k ₁ is extracted to obtain the black k ₂ signal squaring the k ₁ as terms of non-linear UCR. The formula is a masking calculation formula by a 4 × 5 matrix calculation for generating the recording signals C, M, Y, K based on the black component k ₁ , k ₂ terms and r, g, b terms. When a black signal with R = G = B = 0 is input from the coefficients used in the embodiment, r = g = b = 255 from the equation, and as a result, (C, M, Y, K) becomes (111, 127, 95, 255). Therefore, in addition to the K signal, the C, M, and Y signals overlap the input signal by about 1.3 colors as an integrated value.

<Binarization control unit 7> In FIG. 9, reference numerals 39-1 to 39-4 denote C, M, Y, and K of 8 bi each.
This is a binarization unit that binarizes the data of t, and uses a dither method, an average density storage method, error diffusion, and the like. Reference numerals 40-1 to 40-4 denote timing adjustment memories for delaying the binarized data to match the positions of the KB and KW signals.

Also, each of the binary recording signals KB and KW is when KB = 1 When KW = 1, control as C, M, Y = 0. That is, the black recording signal is 2K signal and KB =
In addition, when the color recording signal is recorded at the same position with the OR with 1, the color recording is stopped and suppressed in order to avoid color mixture. Also KW
= 1 signal pixel can be recorded more clearly by suppressing the color recording signal and stopping the recording dot around the black character.

 The relationship between KB, 2K, KW and dot recording is shown in Table 1 below.

<Another Embodiment (1) of Binarization Control Unit 7> In the above-described embodiment, an example in which print data is controlled after binarization has been disclosed. However, multivalued data before binarization will be described with reference to FIG. Is shown below.

The masking / UCR unit 62 converts the data converted into C, M, Y, and K4 color signals into 2-bit signals output from the black character signal generation units 3 and 13 described above.
After controlling by KW and KB, binarization is performed by a binarization unit and recorded.
In the case of the present embodiment, in the case where the recording element 8 is a thermal recording element capable of density recording of dots such as an LBP or a piezo-type ink jet printer or a thermal transfer printer in which the dot size can be modulated in multiple steps by pulse width modulation. The binarizing unit 3 is not always necessary, and the controlled multi-value data may be used for recording as it is.

Now, the inside of the recording signal control unit will be described in detail with reference to FIG. In FIG. 10 (a), memories 91, 92, 93 and 94 constitute a delay circuit for timing adjustment.
Multi-value data is directly converted by LUT of ROM95,96,97,98 according to B and KW.

In the case of the black signal K, when KB = 1, the input data is emphasized in the black direction as shown in FIG. 10 (c), and the color signals C, M and Y are reversed as shown in FIG. 10 (b). A γ table that emphasizes in the white direction is selected and used.

When KW = 1, the degree of enhancement of the color signals C, M, Y is slightly reduced as compared with the case of KB = 1. In the present embodiment, in order to control the multi-value level, especially when KW = 1, the periphery of a black character having a ground color can be controlled to a light color as natural as possible, so that a higher quality recorded image can be obtained.

When KB = 1, it goes without saying that CK = 255 and CM, CC, CY = 0 may be set regardless of the input data.

<Another Embodiment (2) of Binarization Control Unit 7> In the above-described embodiment, black character processing is performed after masking UCR. However, the same applies when the R, G, and B signals that are primary colors are directly controlled. The effect of is obtained.

In FIG. 11 (a), a delay memory similar to the above-described embodiment is used.
101, 102, 103 are 91, 92, 93, 94 in the embodiment shown in FIG.
Although the memory has the same capacity as that of the first embodiment, a memory for one color is not required in the present embodiment, so that the memory can be realized with a simpler configuration. Data conversion is performed by LUT conversion using ROMs 104, 105, and 106 for each color.

When KW = 1 as shown in FIG. 10 (c), each color is emphasized in the white direction, and when KB = 1 as shown in FIG. 10 (d), it is enhanced in the black direction. Normal masking, UCR
When KW = 1, both Y, M, C, and K are emphasized in the white direction. Conversely, when KB = 1, the K signal is emphasized in the black direction, whereas the C, M, and Y signals are white. Emphasized in the direction. In both of the above embodiments, the conversion characteristic is not limited to a linear characteristic. If a non-linear characteristic is provided, the input signal becomes blacker when KB = 1 and KW =
In the case of 1, the color signal can be controlled to be whiter.

As described above, if α1 = 0 in the input image shown in FIG. 15 (a), the edge portion of the black image indicated by KB = 1 in FIG. 15 (b) or a thin line having a line width of 2 pixels or less. The portion is recorded in black and single color, and the recording device 8 uses the ink jet recording that requires registration of the resist for each color recording.
Even electrophotographic records can be clearly expressed. In the same figure, in a region having a large line width, since KB = 0, it is possible to record two or three colors including black dots on average, so that a high reflection density (black) can be recorded. In addition, it is possible to perform recording while achieving both high-resolution recording of fine line portions and high gradation by multiplex recording.

<Recording Unit 8> Next, the configuration of the recording unit 8 in FIG. 1 will be described.

The present invention provides ink jet recording, thermal transfer recording,
It is applicable to various recording methods such as electrostatic recording. Here, an example in the case of using for ink jet recording will be described.

FIG. 12 is a perspective view around the head of an ink jet recording apparatus using a heating element.

In the figure, reference numeral 51 denotes a head unit, which is a total of four nozzles 52.
Have a book. That is, the head unit 51 is a black ink discharge nozzle.
52K, a yellow ink discharge nozzle 52Y, a magenta ink discharge nozzle 52M, and a cyan ink discharge nozzle 52C. 53 is an ink supply tube, and 54 is a main tank provided with four main tanks corresponding to each nozzle.

The configuration of the nozzle 52 will be described with reference to the cross-sectional view of FIG.
55 is an upper plate, 56 is a bottom plate, 57 is a heating element, 58 is an orifice portion, and 59 is ink.

When a voltage is applied to the heating element 57, heat is generated, and bubbles are formed around the element 57. When the application of the voltage is completed, the bubbles shrink. The ink near the orifice portion 58 is ejected from the orifice portion 58 in accordance with the formation and contraction of the bubble.

The recording head causes a state change such as film boiling in the ink by thermal energy to generate air bubbles (bubbles), and the ink is discharged from the discharge ports (nozzles) toward the recording material using the bubbles. This is a so-called bubble jet recording head for recording characters, images and the like.
In this recording head, the size of a heating resistor (heater) provided in each nozzle is much smaller than that of a piezoelectric element used for conventional ink jet recording, and high-density multiple nozzles are possible. High quality recorded images can be obtained, and it has characteristics such as high speed and low noise.

A recording device having a number of heads for one type of coloring material may be used.

In FIG. 14, reference numeral 101 denotes a head unit in which a number of ink jet heads are arranged in the sub-scanning direction for one type of coloring material, and has black, yellow, cyan, and magenta units. 107 is an ink tank for each head unit, 109 is a signal line, and 104 is a carriage drive motor for moving a carriage 105 with the head unit attached along a rail 103 in cooperation with a transport belt 105. 106 is a recording paper, 120 is a platen, 111 and 112 are recording paper transport rollers, 113 is a recording paper roll, and 114 is a guide roller. The head unit 101 is composed of a plurality of ink jet heads using the heating elements shown in FIG. 13, but an ink jet head using electromechanical conversion means such as a piezo element can of course be used.

<Other Embodiments> Although input signals from an external computer are implemented by R, G, and B, it is sufficient if they are independent three-dimensional color coordinate system signals.
L ^* , a ^* , b ^* and L of the color space coordinate system determined by E
^* , U ^* , v ^* can be similarly implemented. For example, if α1 = 0 in the embodiment shown in FIG.
When G = B = 0, L ^* = a ^* = b ^* = 0 due to the coordinate conversion, and L ^* , | a ^* |, | b is required to perform more accurately using L ^* , a ^* , b ^{*. * Replace} | with R, G, B for good results. Similarly, the present invention can be implemented using the XYZ color system.

7 and 8, blackness is determined after adding the R, G, B signals by the adder 100. 1) If min (R, G, B) is smaller than a predetermined value, A similar effect can be obtained by using black or 2) max (R, G, B) + α × (max (R, G, B) −min (R, G, B)).

As described above, according to the above embodiment of the present invention,
A plurality of input means for inputting image data; and a determination means for determining a specific color line drawing part of the image data input from the input means, wherein the determination means determines the type of the input means according to the type of the input means. By using different standards, the configuration of the black character processing circuit can be simplified for images where the detection of black characters is relatively easy, such as computer graphics, and the image is read by a CCD sensor or the like. By performing a follow-up on an image when an erroneous determination occurs, it is possible to maintain good image quality.

Therefore, even if the registration accuracy for each color is not good, high-quality image recording can be performed.

Further, since a signal for controlling the recording signal is generated in the black character processing unit, even when input means having different input characteristics are provided, without changing the image processing such as masking and UCR, the recording unit is processed as described above. It is possible to control the immediately preceding recording signal. Therefore, the circuit configuration is simplified.

As a printer for outputting the recording signal generated as described above, a printer capable of color recording, such as a color ink jet printer, a color thermal transfer printer, a color dot printer, and a color laser beam printer, can be used.

Particularly suitable for high-speed processing, USP4723129, USP4740793
This is effective for a printer using a head of a type that discharges droplets using film boiling due to thermal energy as shown in FIG.

Further, the above-described arithmetic circuit may be configured using a ROM, a RAM, or the like, or may be realized by software of a computer capable of performing the above-described arithmetic.

〔The invention's effect〕

As described above, according to the first and second aspects of the present invention, when image data generated by an external computer having almost no noise is input, identification is performed using the determination method for image data generated by the external computer. When a color image edge portion is determined, and image data obtained by an image sensor having noise is input, a specific color image edge portion is determined using a determination method for image data obtained by the image sensor. In addition, accurate determination can be realized even for image data generated by an external computer, and good determination can be realized for image data obtained by a noisy imaging device.

[Brief description of the drawings]

 FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention, FIG. 2 is a diagram showing black signal generation, FIG. 3 is a diagram showing a binarization unit, FIG. FIG. 5 is a diagram showing a circuit for determining a halftone dot, FIG. 6 is a diagram showing a black character signal generator, FIGS. 7 and 8 are diagrams showing a black character processing unit 3, FIGS. 11 is a diagram illustrating a binarization control unit, FIGS. 12, 13, and 14 are diagrams illustrating a recording unit 8, and FIG. 15 is a diagram illustrating black character determination. 3, 13: Black character processing unit 7: Binarization control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04N 1/40-1/409 H04N 1/46-1/62 G06T 1/00

Claims (2)

(57) [Claims] An input means for inputting image data generated by an external computer and image data obtained by an image sensor, and a determination means for determining a specific color image edge portion in the image data input by the input means. An image processing apparatus comprising: when image data generated by an external computer is input from the input unit, using a determination method for image data generated by the external computer, the determination unit determines the specific color. An image edge portion is determined, and when image data obtained by an image sensor is input from the input means, the specific color image edge portion is determined using a determination method for image data obtained by the image sensor. An image processing apparatus characterized by the above-mentioned. 2. An image data generated by an external computer and image data obtained by an image sensor are input, a specific color image edge portion in the input image data is determined, and an edge portion is determined. When image data generated by a computer is input, the specific color image edge portion is determined using a determination method for image data generated by the external computer, and image data obtained by the image sensor is obtained. An image processing method, wherein, when input, an edge portion of the specific color image is determined using a determination method for image data obtained by the image sensor.