1 Introduction

The letter develops as the means that a human being takes the communication and becomes the important element characterizing the racial culture. A variety of letters exist in the world, but it becomes two big flows of a phonogram and the ideograph at the present. The kanji is a representative of the ideographs. Kanji was born in China and has the history of 4,000 years. Japan is known as a specific race in the world using the kanji of the ideograph and the hiragana letter of the phonogram at the same time. The Japanese improved a kanji and devised a hiragana letter originally.

The culture to catch the form of the letter as an art object other than a function to perform communication exists in the world. The history of the calligraphy to express a kanji and a hiragana letter with a writing brush style is very old.

An impression to receive from a writing brush style, namely the sensitivity evaluation is subjective and is hard to quantify it.

In late years, with development of the sensitivity engineering including the handwriting study by the sensitivity evaluation, the study for the quantification is advancing [1–3]. However, the study that pursued the characteristic of the shape of the writing brush style in detail from a quantitative point of view is not found.

Therefore, in this study, we suggest technique to evaluate the characteristic of the shape of the writing brush style quantitatively.

This study is classified into three parts. Part1 treats the analytical method with computer technology. Part2 treats one character of calligraphy Letter “kanji” and “hiragana”. Part3 treats the writing paper with calligraphy letter works.

2 The Establishing of Brush Letter Evaluated System

2.1 The Synopsis of Brush Letter Evaluated System

The new brush letter evaluated system was proposed and designed to quantitative the calligraphy product, which was written on paper.

As always, the quality of calligraphy product was evaluated and judged by experienced masters according to their experience and intuition, which is a very subjective relied on the evaluators’ status and reputation. The new brush letter evaluated system was used to establish an evaluation index of synthesis quantify method by numerical method.

The calligraphy is a visual art related to writing. It is the design and execution of lettering with a broad tip instrument or brush form to signs in an “expressive, harmonious, and skillful manner”, which was created and developed on Asia, especially in China and Japan. The Japanese character was originated from China, adopted and used Chinese characters. However, during this long period, Japanese have formulated some native characteristic forms. Therefore, current brush letter evaluated system was focused on the Chinese “Kanji” and Japanese “Hiragana”, which was designed to obtain a quantified analysis of this evolution. The three types of Chinese “Kanji” of “Kaisho”, “Gyosho”, “Sousho” and Japanese “Hiragana” were paid attention to compare according to the order of calligraphy development. The characteristic of “sumi” length distribution and the stability index were calculated and used to analysis the length of the line and balance index in order to establish a quantitative evaluated benchmark.

2.2 The Proposed of Brush Letter Evaluated System

Writing brush works is expressed with characters by writing brush on paper. Character by writing brush is style written by writing brush. When the writing brush is lowered and strongly pushed to the writing paper, width of the line of character grows big. When the tip of the writing brush completely leaves the writing paper, line disappears. Digitizing construction of written paper is done as preprocessing of proposed system. Next, the length of the line and balance index of writing brush characters were carried out by using numeric written paper.

The program’s analysis process of brush letter evaluated system was shown as following:

  1. 1.

    Written paper is regarded as two dimensional plane and is divided into many square elements. The image of written paper was produced by scan machine, all the image data was changed into the same designed size.

  2. 2.

    The data of RGB color image was changed to gray image data. The density of “sumi” was digitized in numerical value from 1 to 255 and is substituted for each element as the property value of the element.

  3. 3.

    In order to examine the distribution of section length of “sumi” line (black ink) at any incline angle, new software program is proposed.

  4. 4.

    The outline is taken out from “sumi” line by linking the element between “sumi” part and blank part. And the data of gray image was changed into write and black colors by binaryzation method (“Sumi” area is 0, the blank is 255).

  5. 5.

    Writing brush character was inclined angle θ (θ = 0, 15, 30…150, 165). Section length at any angle θ was by using new program as shown in Fig. 1.

    Fig. 1.
    figure 1

    The scanning and calculation method of brush letter evaluated system

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  6. 6.

    New software program was proposed in order to obtain the breadth distribution of “sumi” line in writing brush character. The breadth distribution was summarized by two methods. The “Method-1” was applied to analysis the single character in part-2, which was calculated based on interval “sumi”. And the “Method-2” was used to analysis the whole writing paper of “Hiragana” in part-3, which was calculated based on continued “sumi” on one line as shown in Table 1.

    Table 1. The example of calculated method for “Method-1” and “Method-2”
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  7. 7.

    The degree of stability S of writing brush character also was an important element for new soft ware program, which was calculated according to Eq. 1.

  8. 8.

    Additionally, full situation of “sumi” is examined by “sumi” area in block cell.

  9. 9.

    Finally, Writing brush character is evaluated from viewpoint of 5 items, that is, ①Stability index, ②Sumi area, ③Vertical/horizontal ratio, ④Diagonal to right/Horizontal ratio, ⑤Diagonal to left/Horizontal ratio (Table 1).

Equation

SI ::

Stability Index

(IG,JG) : :

Coordinate of center of figure

V : :

“sumi” area of character

3 The Verification of Brush Letter Evaluated System

3.1 The Verification of the Breadth Distribution of “Sumi”

The four different types of images separated into two basic types, quadrate and empty circle, had been calculated by new program in order to prove the program’s validity, which were illustrated in Figs. 2, 3, 4 and 5. According to the Fig. 2, the results of solid quadrate shape by “Method-1” and “Method-2” were presented the same distribution. In case of separate quadrated shape as show in Fig. 3, the breadth of “sumi” by “Method-1” was concentrated distribution on the short parts. But, the breadth of “sumi” by “Method-2” was concentrated on longer parts, and all distribution was similar with the “Method-2” of solid quadrate. The empty circle shape calculated results based on two methods were shown in Fig. 4. The separated empty circle of two methods also was shown in Fig. 5. As shown in Figs. 4 and 5, the continued empty circle and the separated empty circle were presented a similar distribution. It is can confirm that the program was correct based on four graphic verification for Figs. 2, 3, and 4.

Fig. 2.
figure 2

The graphic verification of solid quadrate shape

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Fig. 3.
figure 3

The graphic verification of separate quadrated shape

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Fig. 4.
figure 4

The graphic verification of empty circle shape

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Fig. 5.
figure 5

The graphic verification of separated empty circle shape

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3.2 The Verification of Stability Index (S)

Nine “sumi” types with the same area at different location were applied to verify the stability index program as shown in Fig. 6. According to Fig. 6, the “sumi” for nine types were consist of three layers, the “sumi” areas were located at three location of left, right, and middle side among each layer. The total size of graphic verification was 10*10, and the background was white color with the value of 255. And each “sumi” area made up by four pixels with black color with the value of 0, which were marked with yellow color as shown in Fig. 6. The verification result of stability index (S) was shown in Fig. 7. The upper layer was shown smaller stability value than middle and lower layers. And the lower layer was presented largest stability value. Therefore, the result of program was met the original design. The stability index was considered as a degree that the calligraphy was not easy to move under gravity force.

Fig. 6.
figure 6

Nine “sumi” types with the same area at different location (Color figure online)

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Fig. 7.
figure 7

The stability index result of nice types’ graphic verification

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4 Conclusion

In this research, the program of brush letter evaluated system was proposed. The characteristic of breadth distribution and stability index were calculated by program. Afterwards, the proposed program was verified by graphic verification tests. The program will be applied to characterize the Part-2 Case of one Character of Calligraphy Letter “Kanji” and “Hiragana” and Part-3 Case of the writing paper with Calligraphy Letter works.