JPH0581952B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for extracting core patterns from image patterns such as figures and characters. [Prior Art] When performing processing such as character recognition or typeface conversion of a character pattern read from a form, there are cases where it is desired to extract the core pattern of the original character pattern. Conventionally, extraction of the core pattern of such character or other graphic patterns has been achieved by simply subjecting the original pattern to a thinning process. In addition, as a typical thinning method of this type,
Hildich method is known. However, when using the Hildich method, there are problems such as a) core lines are distorted due to irregularities on the boundaries of the lines,) core lines are distorted due to rotation of the original image pattern, and) core lines are distorted at intersections of the lines. Further, even when using other wire thinning methods, there is a similar problem in that the core wires are disturbed due to noise. [Purpose] The purpose of the present invention is to solve the above problems,
It is an object of the present invention to provide a method for extracting a fiber pattern without disturbance due to noise or the like. [Example] In the present invention, after performing smoothing processing, line thinning-shaping/thickening-thinning processing is performed, and by further applying smoothing processing to the result,
Extract the core pattern of the original image pattern. Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a flow chart of core pattern extraction processing according to the present invention. Each processing step will be explained in turn. Smoothing process Observe the original image pattern with a 3 x 3 pixel window, and compare the patterns a to h in Figure 2 to a' to a' in the same figure, respectively.
By converting to the h′ pattern, unevenness on the boundary of the line is removed. Thinning Process The image pattern after the step is subjected to a thinning process such as the Hildich method to extract core lines. A direction code shown in Table 1 is added to this thinned image pattern.

〔effect〕

As explained above, in the cord pattern extraction method of the present invention, the original image pattern is subjected to smoothing processing to remove noise (removal of irregularities on line boundaries), and then thinning processing (cord extraction). After shaping, the line width is uniformly thickened, the line is thinned again, and the result is further smoothed, so the intersections of strokes, decorations such as splashes, and other noise are removed. It is possible to extract an extremely natural fiber pattern with no disturbance caused by

[Brief explanation of the drawing]

FIG. 1 is a processing flow diagram showing an embodiment of the present invention;
Figure 2 is an explanatory diagram of the pre-smoothing process, Figure 3a
~e are diagrams showing examples of image patterns at each processing stage, Figures 4 to 7 are explanatory diagrams of the shaping process, Figure 8 is an explanatory diagram of the thick line processing, and Figure 9 is an explanatory diagram of the post-smoothing process. , FIG. 10 is a schematic block diagram showing an example of an apparatus for extracting a core pattern according to the present invention. 50... Sukiyana, 51... Character cutting device, 5
2, 54...Storage device, 53...General-purpose computer.

Claims (1)

[Claims] 1. In a method for extracting a core pattern from an original image pattern, the first step is to perform smoothing processing on the original image pattern.
a second step of performing thinning processing for core pattern extraction on the pattern resulting from the smoothing process performed in the first step; and a third step performing shaping processing on the pattern resulting from the thinning process performed in the second step. , a fourth step in which the pattern resulting from the shaping process in the third step is subjected to thick line processing with uniform line width; and a fifth step in which the pattern resulting from the thick line processing in the fourth step is again subjected to thin line processing. , a sixth step of subjecting the pattern resulting from the thinning process in the fifth step again to smoothing processing;