JPH045304B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an image processing apparatus that converts a plurality of optical hue input data into respective printing hue output data and outputs a printing pattern.

Technical Background of the Invention Generally, a plurality of optical hue input data R (red),
Hue output data C for each printing from G (green) and B (blue)
(cyan), M (magenta), Y (yellow) or C,
Convert to M, Y, BK (black), C, M, Y
Alternatively, the algorithm for determining the number of dots for each pixel of each color (C, M, Y, BK) may be determined by various methods depending on the optical input device such as an image pickup tube or image sensor, the output device such as a color printer, the characteristics of the ink, etc. is possible. On the other hand, once C, M, Y or C,
By determining the number of print dots for each color such as M, Y, BK, etc., a print image can be obtained by determining the arrangement of color dots within a unit picture element.

Various printing methods can be considered for image processing, but in general, data from an input device such as an image pickup tube or image sensor is divided into many parts and sampled, and each of these is processed individually. It is processed using picture elements to create an output image. The configuration of the unit picture element at the time of output is 2×2, 3×3, 4×
A 4th order dot matrix has been proposed. In addition, the output printing colors are C, M, Y, or BK.
In some cases, there are four colors including . Furthermore, there are methods that print by overlapping each color within a unit pixel, and there are methods called area gradation methods that do not overlap multiple colors.
There is also a method in which only one color is printed at one dot position.

Problems with the background technology However, in the past, everything up to the creation of dot patterns for printing, which is the print image, was processed by a program, so this type of image processing, which handles a huge amount of data, requires a considerable amount of processing time. It takes time. Furthermore, in the case of unit picture elements of the same color, their dot patterns for printing are exactly the same, so when viewed as a whole, the dots may appear streak-like due to the unevenness of the dots.

Purpose of the Invention The present invention was made in view of the above points, and it is possible to perform processing up to the creation of dot patterns for printing at high speed by using hardware, and even when the same color tone is continuous, a more natural gradation can be achieved. An object of the present invention is to obtain an image processing device capable of expressing a sharp image without forming streaks.

Summary of the Invention The present invention calculates the cumulative value of the number of dots of each printing hue output data and the number of dots of each printing hue output data that circulates with the maximum value of {(total number of dots per unit picture element) - 1}. By providing a dot pattern generator that receives an address as an input and outputs a preset printing dot pattern in accordance with this address, once the address is determined, the printing dot pattern can be output using hardware. High-speed processing is possible, and in this case, the address input includes the cumulative value of the number of dots of each printing hue output data that circulates with the maximum value of {(total number of dots per unit picture element) - 1}. Therefore, even if the color tone is the same, the dot pattern for printing will be different for each unit pixel, and the dot arrangement is averaged so that an image with natural gradation can be expressed. .

Embodiment of the Invention An embodiment of the present invention will be described based on the drawings.
In this embodiment, as shown in FIG _. 2, ₃
A unit picture element 1 is a ×3 dot matrix. FIG. 1 shows a control processing system for such a unit pixel 1. First, data from an input device such as an image pickup tube or an image sensor is sent to a control device 2.
The control device 2 outputs the number of dots for each printing hue output data C, M, Y, BK and is latched by a latch A3. This number of dots is outputted in the order of C, M, Y, BK, accumulated by the accumulating circuit 4, and the accumulated value is latched in the latch B5. The output of this latch B5 is input to the accumulation circuit 4, and the output of the previous unit picture element 1
The number of dots corresponding to the number of dots is also sequentially added to the cumulative value. Here, this accumulated value is a variable, {(total number of dots per unit number of pictures) - 1}, that is, in this example, it cycles from 0 to this 8 with 8 as the maximum value. .

Thus, a dot pattern generator 6 is provided which receives the number of dots from latch A3 and the cumulative value from latch B5 as 4-bit address inputs. This dot pattern generator 6 is
It is composed of ROM, and a printing dot pattern for each address is written in advance, and in response to address input, the printing dot pattern of that address is output for each C, M, Y, and BK buffer 7. This is what is output to. The printing dot pattern is constructed by writing 9-bit data corresponding to the total number of dots P ₀ to P ₈ per unit picture element per address.

FIG. 3 shows such a dot pattern generator 6.
This is an explanatory diagram showing part of the contents preset in the address input, and the upper 4 bits A ₇ to
A ₄ is assigned the number of dots, and the lower 4 bits A ₃
~A ₀ is assigned an accumulated value. Here, this FIG. 3 is based on the premise of the dot arrangement order shown in FIG. For example, if the number of dots is 1 and the cumulative value is 2, the third
The dots _P2 in (c) constitute a printing dot pattern. Also, if the number of dots is 3 and the cumulative value is 0, it starts from the first (A) → A → B →
The three dots P ₀ , P ₇ , and P ₂ in this order become the selected dot pattern for printing. In other words, the cumulative value determines the starting point of the required number of dots according to the order of dot arrangement. Here, in order to determine the dot pattern for printing, the dot arrangement order is arbitrary, but in this embodiment, the dot patterns for printing are arranged in a scattered pattern so that they do not adjoin each other as much as possible within the unit picture element 1. The order is as shown in FIG. Note that the scattered state of the patterns can also be seen from the image output in FIG.

FIG. 4a shows a case where such a dot pattern generator 6 is used to print four colors of C, M, Y, and BK for one unit pixel. Each printing hue output data is input in the order of C, M, Y, BK,
Now, the number of dots is C=2, M=1, Y=3, BK
=1. First, if the cumulative value is 6 when C (cyan) is input, the address is determined by the number of dots 2 and the cumulative value 6, and the printing dot pattern for C is generated from the ROM of the dot pattern generator 6. (dots P ₅ and P ₆ are selected) is output. Next, in the case of M (magenta) input, the address is determined by the number of dots 1 and the changed cumulative value 8, and the printing dot pattern for M (dot P ₄₎ is selected from the ROM of the dot pattern generator 6. ) is output. The same is true for Y (yellow) and BK (black); processing for unit picture elements is completed with BK, and the bottom image of the image output becomes the final image. In the image output, dot positions where color symbols C, M, Y, and BK are not written are areas where nothing is printed.

Next, consider the case of an image in which the same color tone continues. Figure 4b is a process diagram for this purpose, and following the printing on a certain picture element in Figure 4a, the same number of dots (C = 2, M = 1, Y = 3, BK =
This is the case where the next unit picture element is printed in 1). The processing procedure is the same as in Figure 4a, but since the accumulated value from the previous time is also required for address input, even if the number of dots is the same, the final image obtained by Figure 4b is It can be seen that this is different from the final image obtained in Figure (a).

Therefore, according to this embodiment, since the dot pattern for printing is written in advance in the ROM of the dot pattern generator 6 for each address and converted into hardware, the dot pattern for printing is immediately generated when an address is input. Patterns can be output, which greatly reduces processing time. In addition, even in the case of an image in which the same color tone is continuous, the dot pattern for printing is determined by taking into account the cumulative value.
The image differs for each unit picture element and is averaged as a whole. Therefore, there is no deviation of dots of the same color, such as C being fixed at the same dot position, and therefore an image with more natural gradation can be expressed without appearing streaky. This point becomes even more effective when the dot arrangement is averaged by the dot arrangement order shown in FIG.

Effects of the Invention Since the present invention is configured as described above, processing up to the creation of dot patterns for printing can be performed at high speed by using hardware. (Total number of dots per unit pixel) - 1} is used as the maximum value, and the accumulated value of the number of dots of each print hue output data is used, so the image output is random and has a more natural gradation. It is possible to express a sharp image without creating streaks.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram, FIG. 2 is a plan view showing the dot arrangement and order of unit picture elements, and FIG. 3 is a correspondence between address input and image output. An explanatory diagram partially showing the relationship,
FIGS. 4a and 4b are process diagrams showing the process of setting image output. 1...Unit picture element, 6...Dot pattern generator.

Claims (1)

[Scope of Claims] 1. In an image processing device that converts a plurality of optical hue input data into each printing hue output data and outputs a printing pattern, calculation is performed for each unit pixel formed by a plurality of printing dots. The number of dots for each printing hue output data and the cumulative number of dots for each printing hue output data circulated with {(total number of dots per unit picture element) - 1} as the maximum value are input as address inputs. An image processing apparatus comprising a dot pattern generator that outputs a printing dot pattern preset according to an address for each printing hue output data. 2. Claim 1, characterized in that the dot pattern for printing is a pattern that is set so as to be scattered within a unit picture element so that they do not adjoin each other as much as possible.
The image processing device described in Section 1.