JP4397898B2 - Digitized drawing photographing apparatus and method - Google Patents

Description

  The present invention is used for digitizing drawing information such as land-register maps. In particular, the present invention relates to a technique for performing digitization of drawing information such as a land register at high speed and efficiency.

  In order to adapt drawing information that has been conventionally stored in paper, such as a cadastral map, to an electronic information society, it is necessary to digitize the drawing information. As a digitization technique, it is common to digitize image data read by a scanner.

  A conventional digitizing procedure for a cadastral map will be described with reference to FIG. FIG. 10 is a diagram schematically showing a conventional digitizing procedure for a cadastral map. There are two types of scanners: an original fixed type in which the CCD unit moves and an original moving type in which the original moves. Conventional digitization of the cadastral map enables high-definition scanning and wears or damages the cadastral map. In order to avoid this, a fixed document type scanner is used.

  Such a fixed-document scanner requires a large document size in the scanner itself, and is made rugged in order to maintain accuracy, and is generally difficult to carry easily. For example, in the drawings stored at the registry office, survey maps such as 40 x 50 cm cadastral maps occupy about half, but the remaining half are mylarized public maps, the size of which is 50 cm x In order to scan this, an A1 size scanner is required. Furthermore, there are about 1% of public figures using Japanese paper, and the size is indefinite (B4-10 tatami mats).

  Therefore, it is difficult to carry out the work by bringing the scanner into a registry office or the like where the cadastral map is placed, and a method of taking a copy of the cadastral map and carrying out the work is taken. Since this copying work is also required to maintain high copy accuracy, the close contact copying method is used.

In general, extremely high accuracy is required for copying and scanning of a cadastral map. For example, in a 1/1000 scale cadastral map, even if the error is 0.1 mm on the drawing, the error is 10 cm locally. Digital reconstruction based on high-precision copying and scanning is also necessary in order to restore the site from drawings in the event of a major disaster such as an earthquake. For example, an error of 10 cm is a big problem in a city center where buildings are densely packed.
Ministry of Justice Chief of Information Management (CIO) decision, “Map management work / system optimization plan”, [online], 2005, Ministry of Justice, [February 2, 2006 search], Internet <URL: http // www. moj. go. jp / PUBLIC / MINJI58 / refer01. pdf>

  As described above, the conventional digitization of a cadastral map requires a work process of close copy → reading image data with a scanner → digitizing, but the work time required for close copy and the read time of image data with a scanner are required. The percentage of the total work time is high, which hinders the speeding up of the digitization work.

  That is, in the contact copying process, as shown in FIG. 10, it takes a long work time to expose and develop the land register on the copy sheet. Further, in the image data reading process by the scanner, since it is necessary to perform high-definition scanning, a long time is required for scanning. For example, the line width of the cadastral map is 0.1 mm. In order to scan such a thin line, an accuracy of at least 200 DPI (the width of one dot is 0.127 mm), preferably about 400 DPI (the width of one dot is 0.0635 mm) is necessary. Further, the accuracy of the scanner depends on the mechanical accuracy of the scanning unit, and the accuracy deteriorates with time due to factors such as wear of the operating unit or running out of oil due to repeated operation.

  Furthermore, in each of these processes, strict accuracy check is required, but conventionally, accuracy check is performed based on the experience of so-called craftsmen, and general workers who are not craftsmen check the accuracy. Is in a difficult situation to do. This is also a factor that hinders the speeding up of the digitization work.

  Furthermore, in order to perform contact copying, it is necessary that the original drawing has a property of transmitting light, such as aluminum Kent paper (aluminum sandwiched between Kent papers to prevent Kent paper expansion and contraction) and Japanese paper. In other words, close copy is impossible, and there is nothing other than scanning the original with great care. In this case, it also takes time for office procedures such as procedures for obtaining permission to take out the original.

  The present invention has been made under such a background, and is a digitized drawing photographing apparatus capable of performing digitization of a drawing such as a cadastral map requiring high accuracy at high speed and efficiently. It aims to provide a method.

  The digitized drawing photographing apparatus of the present invention has a photographed drawing placing means for placing the digitized drawing at a predetermined position in the photographed region, and is placed on the digitized drawing, and a reference point for determination is previously set. A plurality of transparent plates, a digital camera device for photographing the digitized drawing through the transparent plate, and a predetermined correction coefficient applied to the digitized drawing image photographed by the digital camera device. Image correcting means for correcting distortion, and the transparent plate after being corrected using the correction coefficient for the image of the digitized drawing placed at the predetermined position and photographed by the digital camera device The distance between the plurality of determination reference points in the image of the image is compared with a distance that is a determination reference that is held in advance, and it is determined whether or not the distance matches within an allowable range. Characterized by comprising a means.

  The digitized drawing photographing apparatus of the present invention configured as described above can save the scan time required for the conventional scanner, and is lighter and more portable than the conventional fixed document scanner. . Therefore, it is possible to work by bringing the equipment into a registry office where the cadastral map is stored.

  As a result, it is possible to capture the image data in a non-contact manner with respect to the original drawing without requiring copying at the original storage location, thereby eliminating the conventionally required copying process. This not only saves the work time required for close copy, but also supports drawings of any material, and further eliminates the need for duplicate drawings to be discarded after work, so from the viewpoint of environmental issues. Is also desirable. In addition, the time required for office procedures such as a procedure for taking out a land register that was necessary in the past can be omitted. Further, in the digitized drawing photographing apparatus of the present invention, since there is no operating part such as a scanner, there is no deterioration over time unlike a scanner.

  Further, by performing the photographing accuracy determination using the determination reference point, it is possible to omit the accuracy confirmation work based on the experience of a craftsman, which has been conventionally required. This not only shortens the work time for accuracy check, but also speeds up the digitization work by allowing more general workers than craftsmen to work simultaneously in many places in parallel. It leads to.

  Such shooting accuracy determination is performed, for example, when the digitized drawing placement means is subjected to minute vibrations due to the placement of the digitized drawing, and the positional relationship between the digital camera device and the digitized drawing is shifted. In order to detect this, it is performed every time shooting is performed. In addition, at the time of initial setting when the digitized drawing imaging apparatus of the present invention is brought into the shooting site, the accuracy of shooting is determined using the determination reference point. By determining, an accurate setting can be performed. Thereby, even if it is not an operator with special experience, all the operations including the initial setting can be performed accurately and efficiently.

  In addition, the image correction means includes a plurality of correction reference point positions in an image of a reference drawing placed at the predetermined position and provided with a plurality of correction reference points previously captured by the digital camera device. Reference drawing correction means for correcting the reference drawing coordinates to be known, and means for applying the correction coefficient used by the reference drawing correction means for the correction as the predetermined correction coefficient.

  Thereby, even if it is not an operator who has special experience, an appropriate correction coefficient can be acquired easily in a short time. For example, as described above, when the digitized drawing placement means is subjected to minute vibration due to the placement of the digitized drawing, and the positional relationship between the digital camera device and the digitized drawing is shifted, This misalignment can be found by photographing accuracy determination using the determination reference point. In this case, since it can be seen that correct correction cannot be performed with correction using the correction coefficient that has been applied so far, it is necessary to acquire a new correction coefficient. A new correction coefficient can be easily acquired in a short time even if the operator is not experienced.

  Using the digitized drawing photographing apparatus of the present invention, the digitized drawing photographing method of the present invention is executed. That is, the digitized drawing photographing method using the digitized drawing photographing apparatus of the present invention includes a step of placing the digitized drawing at a predetermined position on the photographed drawing placing means, and the transparent plate. The step of covering the digitized drawing, the step of photographing the digitized drawing through the transparent plate by the digital camera device, and the digital camera device using the image correcting means Applying a correction coefficient to the image to correct distortion; and using the photographing accuracy determination means, a plurality of images in the image of the transparent plate corrected by applying the correction coefficient by the image correction means Comparing the distance between the reference points for determination with a distance serving as a determination reference, and determining whether the distance matches within an allowable range; and When the determination result of the step of the constant is negative, and executes the steps to restart the process from the acquisition of the correction coefficient by the image correction means said correction factor as invalid.

  As described above, when the final shooting accuracy determination using the determination reference point on the transparent plate does not satisfy the predetermined condition, the current correction coefficient is continuously applied for the reason described above. Since it is understood that it is not appropriate to perform the processing from the generation and acquisition of the correction coefficient again, the imaging accuracy can be maintained efficiently and strictly high.

  According to the present invention, it is possible to omit a copying process and a scanning process that have been conventionally required. Moreover, it can respond to drawings of any material. In addition, it is also desirable from the viewpoint of environmental problems because there is no need for duplicate drawings to be discarded after work. In addition, the time required for administrative procedures such as taking out land registers can be omitted. Moreover, the accuracy check work by the craftsman's experience can be omitted. Thereby, digitization of a drawing such as a cadastral map requiring high accuracy can be performed at high speed and efficiently.

  The configuration of the digitized drawing photographing apparatus of the embodiment of the present invention will be described with reference to FIG. FIG. 1 is an overall configuration diagram of a digitized drawing photographing apparatus of the present embodiment.

  As shown in FIG. 1, the digitized drawing photographing apparatus of this embodiment includes a photographed drawing placing unit 1 for placing the digitized drawing at a predetermined position in the photographed region, and a digitized drawing. A transparent plate 2 which is covered with a plurality of reference points for determination in advance, a digital camera device 3 for photographing a digitized drawing through the transparent plate 2, and a digital image photographed by the digital camera device 3 An image correction unit 4 that corrects distortion by applying a predetermined correction coefficient to the image of the digitized drawing, and the image of the digitized drawing placed at the predetermined position and photographed by the digital camera device 3 The distance between the plurality of determination reference points in the image of the transparent plate 2 after correction using the correction coefficient is compared with a distance that is a determination criterion that is held in advance, and the distances match within an allowable range. Or Or characterized in that a shooting accuracy determination unit 5 determines.

  The image correcting unit 4 is placed on the drawing drawing mounting unit 1 and the positions of the plurality of correction reference points in the image of the reference drawing provided with a plurality of correction reference points previously captured by the digital camera device 3. Includes a reference drawing correction unit 42 for correcting the reference drawing coordinates so as to become known reference drawing coordinates, and the correction coefficient used by the reference drawing correction unit 42 for the correction is held in the correction coefficient holding unit 43 as the predetermined correction coefficient. Then, the distortion correction unit 40 performs correction by applying this correction coefficient.

  Next, the procedure of the digitized drawing photographing method using the digitized drawing photographing apparatus of the present embodiment will be described with reference to FIGS. FIG. 2 is a flowchart showing the procedure of the digitized drawing photographing method using the digitized drawing photographing apparatus of this embodiment. FIG. 3 is a schematic diagram showing the procedure of a digitized drawing photographing method using the digitized drawing photographing apparatus of this embodiment.

  A reference drawing is placed on the photographed drawing placement portion 1 shown in FIG. 1 (S1), and a transparent plate 2 is placed on the placed reference drawing (S2). Since the preparation for photographing is thus completed, photographing is performed using the digital camera device 3 (S3). Here, the reference image correction unit 42 of the image correction unit 4 corrects the captured image of the reference drawing by a method (FIGS. 6 and 7) described later (S4). The correction coefficient holding unit 43 acquires and holds the correction coefficient used by the reference drawing correction unit 42 for correction (S5). The shooting accuracy determination unit 5 pays attention to the image of the transparent plate 2 in the image corrected by the reference drawing correction unit 42, and determines the shooting accuracy by a method (FIGS. 8 and 9) described later (S6). If the photographing accuracy does not satisfy the predetermined condition (S7), the procedure is repeated from step S1.

  In the shooting accuracy determination in step S6, if the shooting accuracy satisfies a predetermined condition (S7), the reference drawing is removed from the shooting drawing placement unit 1 (S8), and instead, the cadastral map or the like is covered. A digitized drawing is placed (S9). The transparent plate 2 is put on the placed digitized drawing (S10). As a result, the preparation for photographing is completed, and photographing is performed using the digital camera device 3 (S11). Here, the distortion correction unit 40 of the image correction unit 4 performs correction by applying the correction coefficient held in the correction coefficient holding unit 43 to the captured image of the digitized drawing (S12). The imaging accuracy determination unit 5 pays attention to the image of the transparent plate 2 in the image corrected by the distortion correction unit 40, and determines the imaging accuracy by a method (FIGS. 8 and 9) described later (S13). If the photographing accuracy does not satisfy the predetermined condition (S14), the current correction coefficient held in the correction coefficient holding unit 43 is invalidated (S15), and the procedure is restarted from step S1.

  In the shooting accuracy determination in step S13, if the shooting accuracy satisfies a predetermined condition (S14), the process proceeds to the next shooting target (S16). That is, the digitized drawing placed on the photographed drawing placement unit 1 is removed and the digitized drawing to be photographed next is placed, and the procedure from step S9 is executed.

  Next, distortion in digitized drawing shooting will be described with reference to FIG. FIG. 4 is a diagram for explaining the cause of distortion in digitized drawing photography. As shown in FIG. 4A, when the digitized drawing is accurately photographed from the front, only image distortion due to lens characteristics occurs. Further, as shown in FIG. 4B, when the digitized drawing is photographed from an oblique direction, an image resulting from the deviation of the photographing position in addition to the image distortion caused by the lens characteristics shown in FIG. Distortion occurs. The image correction unit 4 corrects distortion caused by these multiple factors.

  Next, the correction coefficient acquisition procedure will be described with reference to FIG. FIG. 5 is a diagram for explaining the correction coefficient acquisition procedure in detail. The procedure of steps S1 to S6 shown in FIG. The reference drawing shown in FIG. 5A is placed on the to-be-photographed drawing placing portion 1, and the transparent plate 2 shown in FIG. 5B is placed thereon. An image A shown in FIG. 5C is obtained by photographing this with the digital camera device 3.

  The correction reference point position detection unit 41 extracts the image of the reference drawing from the image A as shown in FIG. 5D, and detects the correction reference point position as shown in FIG. For example, a template matching method is used to detect the correction reference point position. Since this method is a known method, detailed description is omitted. Further, the distortion to be corrected here is fine, and the correction reference point position can be sufficiently detected using the template matching technique even from the image of the reference drawing before correction including the distortion.

  As shown in FIG. 5 (f), the reference drawing correction unit 42 has the position of the reference point for correction on the taken reference drawing as the known reference drawing coordinates held in advance in the reference drawing correction unit 42. Perform correction as follows. The correction coefficient used for the current correction is held by the correction coefficient holding unit 43. In this embodiment, the interval between the correction reference points is 10 cm. As a result, the required accuracy can be ensured. However, the shorter the interval between the correction reference points, the higher the accuracy can be ensured.

  As shown in FIG. 5G, an image B is obtained as a result of executing correction on the image A. The imaging accuracy determination unit 5 confirms the distance between the determination reference points on the transparent plate 2 detected by the determination reference point position detection unit 50, as shown in FIG. For this confirmation, information on the distance between the reference points for determination, which is a determination reference previously stored in the determination unit 51, is used. As shown in FIG. 5 (i), as a result of confirming the distance between the reference points for determination on the transparent plate 2, it is determined to be acceptable if it is within the allowable range, and is rejected if outside the allowable range.

  Here, the correction coefficient acquisition procedure in the reference drawing correction unit 42 will be described with reference to FIGS. FIG. 6 is a diagram for explaining the correction coefficient acquisition principle performed using the correction reference points given to the reference drawing. FIG. 7 is a flowchart showing a correction coefficient acquisition procedure in the reference screen correction unit 42.

  As shown in FIG. 6, the reference drawing is provided with a plurality of correction reference points (+) at equal intervals. A square frame (□) is provided as a reference scale. The correction reference point position detection unit 41 monitors an image taken by the digital camera device 3 and, when a reference scale (□) is detected, recognizes that the image is an image of a reference drawing and acquires it. (Extract) (S21). Further, the correction reference point position detection unit 41 detects the correction reference point position from the acquired image of the reference drawing (S22). As described above, the template matching method is used to detect the correction reference point position. The reference drawing correction unit 42 collates the detected reference point for correction with known reference drawing coordinates held in advance (S23). The correction reference point intervals on the reference drawing before correction in the example of FIG. 6 are not equal intervals due to the influence of distortion. If the position of the correction reference point on the photographed reference drawing is not a known reference drawing coordinate, the reference drawing correction unit 42 performs correction so that the position of the correction reference point becomes the known reference drawing coordinate. Execute (S24). In the example of FIG. 6 (before correction), the correction reference point interval tends to become wider toward the right of the reference drawing due to the influence of the deviation of the photographing position of the lens, and the upper and lower opposite sides are not parallel. As a result of the correction by the reference drawing correction unit 42, as shown in FIG. 6 (after correction), the correction reference points are equally spaced, and the opposite sides of the reference drawing are parallel. When the correction is completed in this way, the correction coefficient holding unit 43 acquires and holds the correction coefficient used for the current correction (S25).

  Next, a procedure for determining the shooting accuracy in the shooting accuracy determination unit 5 will be described with reference to FIGS. FIG. 8 is a diagram for explaining the imaging accuracy determination principle performed using the determination reference points given to the transparent plate 2. FIG. 9 is a flowchart showing a procedure for determining the shooting accuracy in the shooting accuracy determination unit 5.

  As shown in FIG. 8, the transparent plate 2 is provided with a plurality of determination reference points (+). The determination unit 51 of the imaging accuracy determination unit 5 holds in advance distance information between determination reference points serving as determination criteria. As shown in FIG. 9, the determination reference point position detection unit 50 acquires an image photographed by the digital camera device 3 and corrected by the image correction unit 4 from the image correction unit 4 (S31). The determination reference point position detection unit 50 detects the determination reference point position from the acquired image of the reference drawing (S32). As described above, the template matching method is used to detect the determination reference point position. Subsequently, the distance between the reference points for determination is correct by comparing the distance between the reference points for determination of the transparent plate 2 in the corrected image with the distance serving as the determination reference held by the determination unit 51. (S33). In the example of FIG. 8, since the deviation of the determination reference point is recognized, the distance between the determination reference points does not coincide with the distance used as the determination reference. When the deviation of the distance between the reference points for determination is recognized exceeding the allowable range (S34), an output to that effect is output (S36). Further, if the deviation of the distance between the reference points for determination is within the allowable range, an output to that effect is made (S35). These outputs can be used, for example, by capturing them in a personal computer and displaying characters such as “pass” or “fail” on the display. Also, the direction of deviation (vertical, horizontal, diagonal, etc.) may be displayed together.

  In the stage where the digitized drawing has already been taken, in the case of “fail”, as described above, the procedure is restarted from the step of reacquiring the correction coefficient. At the initial setting stage when the digitized drawing photographing apparatus is brought into the photographing site, the “pass” is performed while adjusting the positional relationship between the digitized drawing placing unit 1 and the digital camera device 3 together. ".

  According to the present invention, since it is possible to digitize a drawing such as a cadastral map that requires high accuracy at high speed and efficiently, it contributes to promptly providing useful information to the electronic information society. Can do.

1 is an overall configuration diagram of a digitized drawing photographing apparatus of the present embodiment. The flowchart which shows the procedure of the digitized drawing imaging | photography method using the digitized drawing imaging device of a present Example. The schematic diagram which shows the procedure of the digitized drawing imaging | photography method using the digitized drawing imaging device of a present Example. The figure for demonstrating the generation | occurrence | production cause of distortion in digitized drawing photography. The figure for demonstrating in detail the correction coefficient acquisition procedure. The figure for demonstrating the correction coefficient acquisition principle performed using the reference | standard point provided to the reference | standard drawing. The flowchart which shows the correction coefficient acquisition procedure in a reference | standard screen correction | amendment part. The figure for demonstrating the imaging | photography precision determination principle performed using the reference | standard point provided to the transparent plate. The flowchart which shows the imaging accuracy determination procedure in an imaging accuracy determination part. The figure which shows typically the digitization procedure of the conventional land register.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting drawing mounting part 2 Transparent board 3 Digital camera apparatus 4 Image correction part 5 Shooting accuracy determination part 40 Distortion correction part 41 Correction reference point position detection part 42 Reference drawing correction part 43 Correction coefficient holding part 50 Reference point for determination Position detection unit 51 determination unit

Claims (2)

A digital camera device for photographing a drawing placed at a predetermined position;
Means for photographing a reference drawing to which a plurality of correction reference points are given in advance with the digital camera device and obtaining correction coefficients at which the positions of the plurality of correction reference points in the image become known reference drawing coordinates;
A to-be-photographed drawing placing means for placing the digitized drawing at a predetermined position in the to-be-photographed area;
A transparent plate overlaid on the digitized drawing and provided with a plurality of judgment reference points in advance;
Image correction means for correcting distortion by applying a correction coefficient obtained by photographing the reference drawing to the digitized drawing image taken by the digital camera device through the transparent plate;
A plurality of the determination criteria in the image of the transparent plate after correction using the correction coefficient for the image of the digitized drawing placed at the predetermined position and photographed by the digital camera device An imaging accuracy determination unit that compares a distance between points and a distance that is a determination criterion that is stored in advance and determines whether or not the distance is within an allowable range;
Equipped with a,
The photographing accuracy determining means, when it is determined that the distance of the determination reference point on the transparent plate is not within an allowable range, captures the reference drawing and newly acquires a correction coefficient. Chemical drawing device. A digitized drawing photographing method using a digitized drawing photographing apparatus,
A reference drawing to which a plurality of correction reference points are assigned in advance is placed and photographed on the photographing drawing placing means, and distortion of the digitized drawing photographed based on the correction reference point of the photographed reference drawing is corrected. Obtaining a correction coefficient for correction ;
Placing the digitized drawing at a predetermined position on the photographed drawing placing means;
Placing the transparent plate over the digitized drawing;
Photographing the digitized drawing with the digital camera device through the transparent plate;
An image correcting unit correcting distortion of an image of the digitized drawing taken by the digital camera device based on the correction coefficient acquired in advance ;
The photographing accuracy determination unit compares the distance between the plurality of reference points for determination in the image of the transparent plate that has been corrected by applying the correction coefficient by the image correction unit, and a distance serving as a determination reference, Determining whether the distances match within an acceptable range;
And a step of performing a process of acquiring the correction coefficient by photographing the reference drawing while invalidating the correction coefficient when the determination result of the determination step is negative. Digitized drawing photography method.

Images