JPS59158481A - Method and apparatus for reading optically diagram - Google Patents

Abstract

PURPOSE:To read clearly only an indicating line described by a writing tool by discriminating whether or not a reading a point is point on a ruled line printed by dropout color so as to control the binary-coding of a lightness signal. CONSTITUTION:A scanner 4 has three primary color (red, green and blue) filters and outputs R, G, B signals respectively. A lightness operating circuit 5 outputs a lightness signal W by performing the operatin of W=R+G+B. A chromaticity operating circuit 6 outputs chromaticity coordinate signals X, Y by performing the operation of X=R/W and Y=G/W. A discriminating circuit 7 consists of window comparators 9, 10 and AND gate 11, a binary-coding circuit 12, and an OR gate 13, discriminates from the signals W, X, Y whether or not a reading point on an objective diagram is a point on the indicating line described by a writing tool such as pencil while exluding the effect of dropout color, and outputs 1 when the reading point is on the indicating line and 0 when the point is on the indicating line to an output terminal 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention reliably skips ruled lines printed in dropout colors such as green, red, and blue on drawings, and only reads marked lines marked with a writing instrument such as a pencil. The present invention relates to an optical drawing reading method and apparatus.

Conventionally, in order to automatically recognize drawings such as electrical circuit diagrams, flow charts, artwork drawings, etc. by a computer, there has been a device that scans drawings and inputs them into a computer, an example of which is shown in Fig. 1. Ta. The drawings are made using paper with ruled lines printed in dropout colors such as green, red, and blue to assist in notation of electrical circuit diagrams, flow charts, artwork diagrams, etc. The information was filled out using a writing utensil such as a pencil.

When inputting the drawing into a computer or the like, it is necessary to completely remove the dropout color signal from the input signal and input only the signal of the marking lines drawn with a writing instrument such as a pencil.

In FIG. 1, the scanner 1 is generally a drum scanner that performs main scanning in the rotational direction t and subscanning in the rotational axis direction, or a facsimile type scanner that performs main scanning with a line sensor such as a COD. In this case, optical filters such as colored glass filters and optical interference filters are used to ignore dropout colors in drawings. This optical filter is used depending on the color of the dropout color printed on the drawing paper. For example, if the dropout color is green, use an optical filter that only passes green light. The output signal of the scanner 1 is a signal obtained by photoelectrically converting the intensity of monochromatic light that has passed through such an optical filter into an electrical signal.

The binarization circuit 2 outputs 1 to the output terminal 3 if the output signal of the scanner 1 exceeds a certain value, and outputs 0 if the output signal is below a certain value.

However, the conventional method shown in Fig. 1 has the disadvantage that the L1 optical filter, which changes the printed color of the dropout color, must be replaced, and also when the brightness of the printed color of the dropout color is low (3). The disadvantage is that it becomes difficult to distinguish the marking lines drawn with a writing instrument such as a pencil, and the ability to reliably read the dropout color and the clear reading of the marking lines are contradictory and cannot be compatible. was there.

The purpose of the present invention is to eliminate such conventional drawbacks, to be able to reliably read the dropout colors on the drawing, and to clearly read only the marking lines marked with a writing instrument such as a pencil. It is an object of the present invention to provide a method and a device that can easily handle changes in dropout color without changing optical filters.

According to the present invention, a scanner for scanning a drawing to be read and obtaining a plurality of color signals, a brightness calculation circuit for calculating a brightness signal from a plurality of color signals, a chromaticity calculation circuit for calculating a chromaticity signal, An optical drawing reading method and apparatus are provided, comprising a determination circuit that determines whether a chromaticity signal is within a rectangular area on chromaticity coordinates and controls binarization of a brightness signal. It will be done.

(4) Hereinafter, the present invention will be described with reference to drawings showing embodiments.

FIG. 2 is a block diagram showing one embodiment. Scanner 4, unlike scanner 1, has filters for the three primary colors of red, green, and blue, and outputs them as RSG and B signals, respectively. The brightness calculation circuit 5 outputs chromaticity coordinate signals X and Y based on W=R+G-)-B. The determination circuit 7 includes window comparators 9, 10, AND gates 11. Binarization circuit 12. It consists of an OR gate 13, and determines from the w, x, and y signals whether or not a reading point on the target drawing is on a marking line marked with a marking tool such as a pencil, eliminating the influence of dropout colors. 1 if there is no notation, 0 if it is on the notation line
is output to output terminal 8.

The window comparator 9 outputs 1 only when the input signal is in the range of X, <X<. Window comparator 1
0 outputs 1 only when the input signal is in the range of Yl<Y<Y2. In response to these outputs, (5) AND gate 11 outputs 1 only when the chromaticity coordinates X and Y satisfy X, <X< and y, < y < y. That is, the AND gate 11 outputs 1 only in the shaded range on the chromaticity coordinate shown in FIG.

The binarization circuit 12 sets 1 when the brightness signal W exceeds a certain value.
If it is less than a certain value, output O. The OR gate 13 receives this signal, and if the output of the binarization circuit 12 is 0 and A
Only when the output of the ND gate 11 is 0, the output terminal 8 is
Output.

The third problem is the variation in the hue of the print color of the dropout color.
If all the distribution is within the diagonal lines in the figure, even if it is difficult to determine whether it is a dropout color or a marking line by looking only at the brightness signal W, the chromaticity coordinate signals X and Y will be as shown in Figure 3. If the color is within the diagonal line, it is determined that the color is a dropout color and not a marking line. As a result, the threshold value of the threshold circuit 12 can be set with a margin, which makes it possible to reliably skip dropout colors and mark lines, which are contradictory to each other and difficult to achieve with conventional methods. It is possible to achieve clear reading without contradicting (6). Also, for changing the dropout color, simply use Xl, Yt, X2. This can be handled by changing the value of Yt.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an example of a conventional optical drawing reading device, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG.
The figure is a chromaticity coordinate diagram, 1 and 4 are scanners, 2.12 are binarization circuits, 3 and 8 are output terminals, 5 is brightness calculation circuit, 6 is chromaticity calculation circuit, 7 is judgment circuit, 9 and 10 is a window comparator, 11 is an AND gate, and 13 is an OR gate. (7) Pavilion 1 Diagram 2 Diagram XlX2 X

Claims (1)

[Claims] 1. A brightness signal and a chromaticity signal are detected from a plurality of color signals obtained by scanning a drawing to be read, and a reading point in the drawing to be read is determined based on the chromaticity coordinates indicated by the chromaticity signal. , an optical drawing reading method characterized by determining whether or not the point is on a ruled line printed in a dropout color, and controlling binarization of the brightness signal based on this. 2. A scanner for scanning a drawing to be read and obtaining a plurality of color signals, a brightness calculation circuit for calculating a brightness signal from the plurality of color signals, and a chromaticity for calculating a chromaticity signal from the plurality of color signals. An optical drawing characterized in that it includes an arithmetic circuit and a determination circuit that determines whether the chromaticity signal is within a rectangular area on chromaticity coordinates and controls binarization of the brightness signal. reader.