DRAWING ASSISTANCE DEVICE AND DRAWING ASSISTANCE METHOD

A drawing assistance device acquires image data of a design diagram to detect dimensional information drawn on the image data, detects arrows drawn on the image data, detects a line drawn on the image data, combines the arrows and the line based on positions of the arrows and a position of the line to generate a dimension line, detects a dimension value corresponding to a position of the dimension line from the dimensional information so as to assign the detected dimension value to the dimension line, generates guidelines indicating positions of ends of the dimension line, superposes the guidelines on the image data to display the guidelines on an editing screen, and outputs digital data of the design diagram drawn by the operator on the editing screen on which the guidelines are displayed.

TECHNICAL FIELD

The present invention relates to a drawing assistance device and a drawing assistance method.

BACKGROUND ART

Patent Literature 1 discloses a service regarding drawing by use of computer aided design (CAD) that converts raster data into vector data. The conventional CAD data converting method disclosed in Patent Literature 1 stores various kinds of CAD data conversion soft in a server, and converts the raster data into the vector data by use of the stored CAD data conversion soft.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

When a design diagram is converted from the raster data to the vector data, the conventional method requires an operator to read to manually input dimension values and dimension lines drawn on the raster data to a computer system.

The manual inputting operation made by the operator has a problem taking a long operating time and increasing a probability of causing operational errors accordingly.

Solution to Problem

A drawing assistance device and a drawing assistance method according to one aspect of the present invention include a controller configured to assist an operator with a drawing operation of converting image data of a design diagram into digital data, the controller being configured to acquire the image data of the design diagram to detect dimensional information drawn on the image data, detect an arrow drawn on the image data, detect a line drawn on the image data, combine the arrow and the line based on a position of the arrow and a position of the line to generate a dimension line, detect a dimension value corresponding to a position of the dimension line from the dimensional information so as to assign the detected dimension value to the dimension line, generate guidelines indicating positions of ends of the dimension line, superpose the guidelines on the image data to display the guidelines on an editing screen, and output the digital data of the design diagram drawn by the operator on the editing screen on which the guidelines are displayed.

The drawing assistance device and the drawing assistance method having the above configuration are configured to generate the dimension line from the image data, assign the dimension value corresponding to the position of the dimension line to the dimension line, and generate the guidelines indicating the positions of the ends of the dimension line. This configuration enables the operator to draw the design diagram by use of the guidelines, so as to decrease the operating time, and reduce the probability of causing the operational errors accordingly.

Advantageous Effects of Invention

The drawing assistance device and the drawing assistance method according to the aspect of the present invention can reduce the operating time taken by the operator, so as to reduce the probability of causing the operational errors.

DESCRIPTION OF EMBODIMENTS

An embodiment to which the present invention is applied is described below with reference to the drawings. The same elements illustrated in the drawings are denoted by the same reference numerals, and overlapping explanations are not made below.

FIG.1is a block diagram illustrating a configuration of a drawing assistance device according to the present embodiment. The drawing assistance device1illustrated inFIG.1includes a controller100, an input unit200, and a display device300. The drawing assistance device1is a device for assisting an operator with a drawing operation, and in particular, assists the operator with a drawing operation of converting image data of a design diagram such as raster data into digital data such as vector data.

The controller100executes drawing assistance processing of assisting the operator with the drawing operation of converting the image data of the design diagram such as a computer aided design (CAD) diagram into the digital data. The controller100includes a dimensional information detection unit11, an arrow detection unit13, a symbol detection unit15, a line detection unit17, a dimension line generation unit19, a guideline generation unit21, and an editor23, as illustrated inFIG.1.

The input unit200acquires the image data of the design diagram such as a CAD diagram to store the image data to a database (not illustrated). For example, the input unit200reads the design diagram with a scanner, and stores the acquired image data such as raster data to the database (not illustrated).

The display unit300is a device for displaying the information output from the controller100, and displays an editing screen and the like displayed by the editor23.

The respective elements of the controller100are described below. The dimensional information detection unit11acquires the image data of the design diagram to detect dimensional information drawn on the image data. In particular, the dimensional information detection unit11acquires the raster data of the design diagram from the database, and detects the dimensional information drawn on the raster data by use of an Optical Character Recognition (OCR) machine learning algorithm.

A method of detecting the dimensional information is described in detail below with reference toFIG.2. The OCR machine learning algorithm40has learned the design diagram by use of teaching data41preliminarily prepared, as illustrated inFIG.2. For example, the OCR machine learning algorithm to be used is a deep learning model called Fast Oriented Text Spotting (FOTS), and a set of data in which the CAD diagram is divided into 512×512 image patches is prepared as the teaching data41. The FOTS is then caused to learn the design diagram by use of the teaching data41so as to detect the dimensional information such as dimension values drawn on the CAD diagram.

The dimensional information is detected by use of the OCR machine learning algorithm having learned. When the dimensional information is actually detected from the raster data, the raster data42of the input CAD diagram is divided into the 512×512 image patches (43), and the divided raster data44is input to the OCR machine learning algorithm (FOTS)45having learned. The divided image patches overlap with each other by 256 pixels.

The OCR machine learning algorithm recognizes the dimension values per divided image to determine the recognized dimension values as a detection result (45). The OCR machine learning algorithm merges and outputs the detection result of each divided image (46). The output is a Comma Separated Value (CSV) file in which the numerical values and the positions of the dimensions are stored. For example, as illustrated inFIG.2, the CSV file stores the dimensional numerical values such as “25” and “12.5”, and the positions of bounding boxes surrounding the numerical values.

The arrow detection unit13detects arrows drawn on the image data. In particular, the arrow detection unit13acquires the raster data of the design diagram from the database, and detects the positions of the tips and the directions of the arrows drawn on the raster data by use of an object recognition algorithm.

A method of detecting the arrows is described in detail below with reference toFIG.3. The object recognition algorithm50has learned the design diagram by use of teaching data51preliminarily prepared, as illustrated inFIG.3. For example, the object recognition algorithm to be used is an object recognition deep learning model called YOLO, and a set of data in which the CAD diagram is divided into 512×512 image patches is prepared as the teaching data51. The YOLO is then caused to learn the design diagram by use of the teaching data51so as to detect the arrows drawn on the CAD diagram.

The arrows are detected by use of the object recognition algorithm having learned. When the arrows are actually detected from the raster data, the raster data52of the input CAD diagram is divided into the 512×512 image patches (53), and the divided raster data54is input to the object recognition algorithm (YOLO)55having learned. The divided image patches overlap with each other by 400 pixels.

The object recognition algorithm recognizes the arrows per divided image, and calculates the positions of the tips and the directions of the recognized arrows to determine them as a detection result (55). The object recognition algorithm merges and outputs the detection result of each divided image (56). The output is a CSV file in which the positions of the tips and the directions of the recognized arrows are stored. For example, as illustrated inFIG.3, the CSV file stores a label “0” indicating the arrows, the positions of the bounding boxes surrounding the arrows, and the directions (the angles) of the arrows.

The symbol detection unit15detects symbols drawn on the image data. In particular, the symbol detection unit15acquires the raster data of the design diagram from the database, and detects the positions of the symbols drawn on the raster data by use of the object recognition algorithm. Example of the symbols to be detected include a hole and a screw.

A method of detection the symbols is described in detail below with reference toFIG.4. The object recognition algorithm60has learned the design diagram by use of teaching data61preliminarily prepared, as illustrated inFIG.4. For example, the object recognition algorithm to be used is an object recognition deep learning model called YOLO, and a set of data in which the CAD diagram is divided into 512×512 image patches is prepared as the teaching data61. The YOLO is then caused to learn the design diagram by use of the teaching data61so as to detect the symbols drawn on the CAD diagram.

The symbols are detected by use of the object recognition algorithm having learned. When the symbols are actually detected from the raster data, the raster data62of the input CAD diagram is divided into the 512×512 image patches (63), and the divided raster data64is input to the object recognition algorithm (YOLO)65having learned. The divided image patches overlap with each other by 400 pixels.

The object recognition algorithm recognizes the symbols per divided image to determine the recognized symbols as a detection result (65). The object recognition algorithm merges and outputs the detection result of each divided image (66). The output is a CSV file in which the types and the positions of the recognized symbols are stored. For example, as illustrated inFIG.4, the CSV file stores a label “3” or “4” indicating the type of the symbol, and the position of the bounding box surrounding the symbol. The label “3” indicates a screw, and the label “4” indicates a hole.

The line detection unit17detects lines drawn on the image data. In particular the line detection unit17acquires the raster data of the design diagram from the database, and executes image processing such as Hough transform so as to detect the positions of the lines or circular arcs drawn on the raster data. For example, in the design diagram illustrated inFIG.5, all of the positions of the lines drawn on the raster data are detected.

The dimension line generation unit19combines the arrows and the lines based on the positions of the arrows detected by the arrow detection unit13and the positions of the lines detected by the line detection unit17and generates the dimension lines. For example, in the case in which arrows A1and A2and a line L1are detected, as illustrated inFIG.5, the positions of the arrows A1and A2and the position of the line L1overlap with each other, these are thus combined together to generate the dimension line DL1.

The dimension line generation unit19also detects the dimension value corresponding to the position of the generated dimension line from the dimensional information, and assigns the detected dimension value to the dimension line. For example, as illustrated inFIG.5, the dimension line generation unit19detects “25” as a dimension value corresponding to the position of the generated dimension line DL1, and assigns the dimension value to the dimension line DL1. As a specific example of the detecting method, the present embodiment may detect the dimension value indicated above the middle point of the dimension line DL1. When the dimension line is a vertical line, the present embodiment may detect the dimension value indicated on the left of the middle point of the dimension line. Alternatively, the present embodiment may detect the dimension value indicated closest to the dimension line.

The dimension line generation unit19, after assigning the dimension value to the dimension line, sets a length of the dimension line to the dimension value assigned to the dimension line. For example, as illustrated inFIG.5, when the dimension value “25” is assigned to the dimension line DL1, the length of the dimensional line DL1is set to 25 mm. The dimension line generation unit19generates all of the dimension lines drawn on the raster data in the same manner as described above.

The guideline generation unit21generates guidelines indicating the positions of the ends of the dimension line generated by the dimension line generation unit19. In particular, the guideline generation unit21generates guidelines perpendicular to the dimension line and passing through the tips of the arrows of the generated dimension line. For example, as illustrated inFIG.5, the guideline generation unit21generates guidelines GL1and GL2perpendicular to the dimension line DL1and passing through the tips of the arrows A1and A2of the generated dimension line DL1. The guidelines GL1and GL2indicated by the dotted lines inFIG.5partly overlap with and are thus hidden by the lines on the raster image, but continuously extend in the upper-lower direction. The guideline generation unit21generates the guidelines for all of the dimension lines generated by the dimension line generation unit19in the same manner as described above.

The editor23, which is an editing function enabling the operator to draw the design diagram, superposes the guidelines generated by the guideline generation unit21on the raster data of the input CAD diagram, and displays the guidelines on the editing screen. For example, as illustrated inFIG.6, a front view V1, a top view V2, and a side view V3of the input raster data are displayed on the editing screen displayed by the editor23. A plurality of guidelines GL are superposed on the raster data and are displayed on the editing screen in the vertical direction and in the horizontal direction.

The operator draws the diagram by use of the guidelines GL in accordance with the raster data on the editing screen on which the guidelines GL are displayed. When the operator finishes to draw all of the figures drawn on the raster data on the editing screen, the CAD diagram input as the raster data can be converted into the digital data such as vector data. The editor23outputs the converted vector data.

The controller100is composed of a general-purpose electronic circuit including a microcomputer, a microprocessor, and a CUP, and a peripheral device such as a memory, and has a function of assisting the operator with the drawing operation of converting the image data of the design diagram into the digital data. The respective functions of the controller100can be implemented by one or plural processing circuits. The respective processing circuits include a programed processing device, such as a processing circuit including an electrical circuit, and include an application-specific integrated circuit (ASIC) arranged to execute the functions described in the present embodiment and a device such as a conventional circuit component.

<Drawing Assistance Method of Drawing Design Diagram>

A drawing assistance method of drawing the design diagram by the drawing assistance device1according to the present embodiment is described below.FIG.7is a flowchart showing a process procedure of drawing assistance processing executed by the drawing assistance device1according to the present embodiment.

As illustrated inFIG.7, in step S101, the editor23opens the editing screen, and displays the raster data of the CAD diagram input through the input unit200by the operator. The editor23at this point erases title information drawn on the raster data. For example, as illustrated inFIG.8, the title information81including a name of a company, a name of a person in charge, a name of an article and the like is preliminarily erased when displayed on the lower side of the raster image. In particular, the editor23detects a region having a rectangular shape located in contact with an outer circumference83of the raster image, and determines that the region is presumed to include the title information81and erases the region. This step can eliminate unnecessary information drawn on the raster data, so as to reduce the processing load to enhance the processing speed accordingly.

In step S103, the dimensional information detection unit11acquires the raster data of the CAD diagram, and detects the dimensional information drawn on the raster data. In particular, the dimensional information detection unit11inputs the raster data to the OCR machine learning algorithm having learned, and detects the values of the dimensions and the positions of the dimensions drawn on the raster image.

In step S105, the arrow detection unit13acquires the raster data of the CAD diagram, and detects the arrows drawn on the raster data. In particular, the arrow detection unit13inputs the raster data to the object recognition algorithm having learned, and detects the positions of the tips and the directions of the arrows drawn on the raster image.

In step S107, the symbol detection unit15acquires the raster data of the CAD diagram, and detects the symbols such as a hole and a screw drawn on the raster data. In particular, the symbol detection unit15inputs the raster data to the object recognition algorithm having learned, and detects the types and the positions of the symbols drawn on the raster image.

In step S109, the line detection unit17acquires the raster data of the CAD diagram, and detects the lines drawn on the raster data. In particular, the line detection unit17performs the image processing such as Hough transform on the raster data, and detects the lines or circular arcs drawn on the raster image.

When the respective detected lines are not a horizontal or vertical line, the line detection unit17rotates the lines and corrects the lines so as to be oriented horizontally or vertically. The processing of correcting the lines by the line detection unit17is described in detail below.FIG.9is a flowchart showing a process procedure of the line correction processing.

As illustrated inFIG.9, the line detection unit17executes the Hough transform to detect the lines drawn on the raster image in step S201, and chooses the two longest lines from the detected lines in each of the horizontal direction and the vertical direction in step S203. For example, as illustratedFIG.10A, when the detected lines are leaned, the line detection unit17chooses the two lines L11and L12longest in the horizontal direction and the two lines L13and L14longest in the vertical direction.

In step S205, the line detection unit17detects the intersecting points of the lines chosen in step S203. For example, as illustrated inFIG.10B, the line detection unit17extends the lines L11to L14chosen in step S203, and detects the intersecting points P1to P4of the respective lines L11to L14.

In step S207, the line detection unit17detects the angle of the respective lines with respect to the horizontal direction or the vertical direction, and rotates the respective lines by the detected angle in the opposite direction so as to detect the intersecting points of the lines. For example, as illustrated inFIG.10C, the line detection unit17detects the angle of the line L11leaned with respect to the horizontal direction, and rotates the line L11by the detected angle in the direction opposite to the leaned direction. The line detection unit17also rotates the other lines L12to L14in the same manner as described above to calculate the intersecting points P11to P14after the rotation.

In step S209, the line detection unit17calculates a perspective transformation matrix for converting the intersecting points P1to P4detected in step S205into the intersecting points P11to P14calculated in step S207. The line detection unit17performs affine transformation on the image by use of the calculated perspective transformation matrix so as to correct the leaned lines. In particular, as illustrated inFIG.10D, the lines are rotated about the middle point in the direction opposite to the leaned direction so as to correct the lines L11to L14to be oriented horizontally or vertically. As a result, even if the lines of the input raster image are leaned, the lines can be corrected horizontally or vertically.

Returning to the flowchart shown inFIG.7, in step S111, the dimension line generation unit19combines the arrows and the lines based on the positions of the arrows detected in step S105and the positions of the lines detected in step S109and generates the dimension lines. For example, when the arrows A1and A2and the line L1are detected, these are combined together to generate the dimension line DL1, as illustrated inFIG.5.

In step S113, the dimension line generation unit19detects the dimension value corresponding to the position of the dimension line generated in step S111from the dimensional information, and assigns the detected dimension value to the dimension line. For example, as illustrated inFIG.5, the dimension line generation unit19detects “25” as the dimension value corresponding to the position of the generated dimension line DL1from the dimensional information detected in step S103, and assigns the value to the dimension line DL1.

The dimension line generation unit19sets the length of the dimension line to the dimension value assigned to the dimension line after assigning the dimension value to the dimension line. For example, in the case illustrated inFIG.5, the length of the dimension line DL1is set to 25 mm that is the assigned dimension value. Setting the length of the dimension line DL1to the assigned dimension value enables the drawing of the dimension line having an accurate length.

The type of the dimension lines generated by the dimension line generation unit19includes a dimension line DL21interposed between the two arrows, and a dimension line DL22drawn in parallel to a diagonal structural line, as illustrated inFIG.11A, in addition to the typical straight dimension line DL20. The dimension line generation unit19may generate a dimension line DL23including a plurality of dimension lines each indicating a distance from a black-dot point P23, as illustrated inFIG.11B. The dimension line DL23includes the dimension lines having the lengths from the point P23ranging from 12 mm to 310 mm. The arrow detection unit13thus can detect the black dot, in addition to the arrows. In this case, the arrow detection unit13may be caused to learn in advance so as to detect the black dot as an end of the dimension line. The arrow detection unit13may be caused to learn so as to detect a white circle that could be indicated as the end of the dimension line instead of the black dot.

In step S115, the guideline generation unit21generates the guidelines indicating the positions of the ends of the dimension line generated in step S111. In particular, the guideline generation unit21generates the guidelines perpendicular to the dimension line and passing through the tips of the arrows of the generated dimension line. For example, as illustrated inFIG.5, the guide line generation unit21generates the guidelines GL1and GL2perpendicular to the dimension line DL1and passing through the tips of the arrows A1and A2of the generated dimension line DL1.

In step S117, the editor23instructs the operator to input the plate thickness information that is the numerical value of the plate thickness necessary for drawing the CAD diagram.

In step S119, the editor23causes the operator to select the area of the front view from the raster image displayed on the editing screen. For example, as illustrated inFIG.6, the operator selects the area71of the front view V1from the editing screen showing the front view V1, the top view V2, and the side view V3.

In step S121, the editor23superposes the guidelines generated in step S115on the raster image displayed on the editing screen so as to display the guidelines on the editing screen. For example, as illustrated inFIG.6, the editor23superposes the plural guidelines GL on the raster image on the editing screen so as to display the respective guidelines GL on the editing screen in the vertical direction and in the lateral direction.

In step S123, the editor23causes the operator to designate the correspondence between the guidelines drawn on the two areas other than the front view. For example, when the operator moves a cursor of a pointing device onto the line L3in the side view V3illustrated inFIG.6, the editor23generates the guideline GL3corresponding to the line L3. When the operator selects the guideline GL3and the guideline GL4in the top view V2, the correspondence between the guideline GL3in the side view V3and the guideline GL4in the top view V2is designated. This designation connects a plurality of guidelines GL20extending in the lateral direction in the top view V2with a plurality of guidelines GL25extending in the perpendicular direction in the side view V3, as illustrated inFIG.12.

In step S125, the editor23causes the dimension values to conform to each other drawn on the two areas in which the correspondence is designated in step S123. For example, when the correspondence between the top view V2and the side view V3is designated, as illustrated inFIG.12, the dimension values in the top view V2are transferred to the side view V3so as to cause the dimension values in the side view V3to conform to the dimension values in the top view V2. This correspondence enables the accurate drawing of the side view V3by use of the dimension values in the top view V2even if the dimension values are not indicated in the side view V3.

In step S127, the operator performs the drawing operation on the editing screen. In particular, the operator performs the drawing operation by use of the guidelines while seeing the raster image displayed on the editing screen. For example, when the operator moves the cursor of the pointing device onto the guide line on the editing screen, the guideline GL30on which the cursor is positioned is highlighted, as illustrated inFIG.13. The other guideline GL32intersecting with the guideline GL30is then highlighted, and the intersecting point P34between the guide lines GL30and GL32is also highlighted. When the operator selects the intersecting point P34, the guidelines GL30and the GL32intersecting at the intersecting point P34are selected. This enables the operator to trace and draw the selected guidelines GL30and GL32with a solid line or a broken line, so as to easily draw the shapes drawn on the raster image.

The operator can change the dimension value assigned to the dimension line so as to change the length of the dimension line. For example, when the operator changes the dimension value “84” shown inFIG.13to “60”, the length of the dimension line DL36can be changed to 60 mm. The operator thus can easily draw up the parts having similar shapes but different sizes. The operator also draws a cut part or an R part at each corner drawn on the raster image, and designates a plate-thickness surface as necessary.

The symbol such as a screw or a hole may be drawn by the operator, or the symbol detected by the symbol detection unit15may be used. For example, when the operator draws the symbol, the operator determines the middle of the symbol by using the guideline, so as to arrange the shape corresponding to the symbol such as a screw or a hole in the middle of the symbol.

When the symbol detected by the symbol detection unit15is used, the symbol detection unit15generates the symbol on the editing screen.FIG.14is a flowchart showing a process procedure of the symbol generation processing.

As shown inFIG.14, the symbol detection unit15detects the guidelines passing through the position of the symbol in step S301, and detects the dimension value corresponding to the position of the symbol from the dimensional information in step S303.

In step S305, the symbol detection unit15sets the intersecting point of the guidelines detected in step S301to a middle position of the symbol.

In step S307, the symbol detection unit15assigns the dimension value detected in step S303to the symbol, and sets a size of the symbol to the assigned dimension value. The symbol detection unit15then arranges the set symbol in the middle position set in step S305. As a result, the symbol having an accurate dimension value can be easily drawn, and the symbol generated by the symbol detection unit15can be used to display the symbol on the editing screen.

When the operator performing the drawing operation on the editing screen finishes drawing all of the figures on the raster image, the operator ends the drawing operation after inspecting the dimensions by use of an automatic dimension recognition function.

In step S129, the editor23exports the vector data drawn on the editing screen, and completes the drawing assistance processing of the design diagram according to the present embodiment.

As described above, the drawing assistance device1according to the present embodiment combines the arrows and the lines drawn on the image data to generate the dimension lines, detects the dimension values corresponding to the positions of the dimension lines from the dimensional information, and assigns the detected dimension values to the dimension lines. The drawing assistance device1generates the guidelines indicating the positions of the ends of the dimension lines, superposes the guidelines on the image data to display the guidelines on the editing screen, and outputs the digital data of the design diagram drawn by the operator on the editing screen on which the guidelines are displayed. This enables the operator to draw the design diagram by use of the guidelines on the editing screen, thus, the operating time can be decreased, and a probability of causing operational errors can be reduced.

The drawing assistance device1according to the present embodiment sets the length of the dimension line to the dimension value assigned to the dimension line. Setting the length of the dimension line to the assigned dimension value can draw the dimension line having an accurate length.

In the drawing assistance device1according to the present embodiment, when the operator moves the cursor of the pointing device onto the guideline on the editing screen, the controller highlights the intersecting point at which the guideline intersects with the other guideline. When the operator selects the intersecting point, the guidelines intersecting at the intersecting point are selected. This allows the operator to easily draw the shapes drawn on the raster image by tracing and drawing the selected guidelines.

In the drawing assistance device1according to the present embodiment, when the operator selects the area of the front view on the editing screen, and designates the correspondence between the guidelines drawn on the two areas other than the front view, the dimension values on the two areas other than the front view is caused to conform to each other. This allows the operator to draw the accurate side view by use of the dimension values in the top view even if the dimension values are not indicated in the side view.

In the drawing assistance device1according to the present embodiment, when the detected lines are not a horizontal or vertical line, the lines are rotated to be corrected so as to be oriented horizontally or vertically. This enables the horizontal or vertical correction of the lines if the lines on the input raster image are leaned.

The drawing assistance device1according to the present embodiment erases the title information drawn on the image data. Erasing the unnecessary information drawn on the image data can reduce the processing load to enhance the processing speed accordingly.

The drawing assistance device1according to the present embodiment changes the dimension value assigned to the dimension line so as to change the length of the dimension line. This enables the operator to easily draw up the parts having similar shapes but different sizes.

The drawing assistance device1according to the present embodiment detects the symbol drawn on the image data, detects the dimension value corresponding to the position of the symbol from the dimensional information, assigns the detected dimension value to the symbol, and sets the size of the symbol to the dimension value assigned to the symbol. As a result, the symbol having an accurate dimension value can be easily drawn.

The embodiment described above is an example of the present invention. It should be understood that the present invention is not intended to be limited to the embodiment described above, and various modifications can be made depending on the design, in addition to the present embodiment, within the range not departing from the technical idea of the present invention.

REFERENCE SIGNS LIST