JP5304465B2 - Mosaic image generation method, apparatus and program - Google Patents

Description

  The present invention relates to a mosaic image generating method, apparatus, and program for generating a mosaic image by combining partially overlapping ortho images.

  The ground can be precisely photographed from an airplane or satellite. These aerial photographs or satellite images are projected on a certain horizontal plane by a plotter after eliminating distortion due to the shooting direction. By synthesizing or joining orthographic images (ortho images) obtained by the plotter, one mosaic image showing a vast area can be obtained. Patent Document 1 describes a method of joining raster image data such as a map or aerial photograph data that displays adjacent regions partially overlapping at the partially overlapping portions.

  For the purpose of such composition or joining, usually, in photographing from an airplane or a satellite, the subject is photographed so as to overlap more than a certain amount. In the case of aerial photographs, it is prescribed that images should be taken so as to overlap 60% or more in the vertical direction (flight direction) and 30% or more in the horizontal direction. FIG. 5 shows an example of overlapping ortho images from which photographs or the like taken partially overlapping in this way are obtained. In general, each ortho image partially overlaps a plurality of other ortho images.

  Even in an ortho image generated from a photograph taken from the vertically upward direction, a slight fall occurs at the edge of a building or an elevated part. Of course, when shooting from an oblique direction, most buildings fall down. In order to reduce such a fall, it is preferable to shoot from directly above as much as possible, and it is also preferable to synthesize an ortho image in a building unit or a narrow area during the synthesis. That is, when a mosaic image is formed, only a part of the ortho image (or aerial photograph) is used for composition.

JP 2001-351113 A

  In order to be able to clearly identify individual buildings after synthesis, it is necessary to use a high-resolution camera at the stage of shooting, and the aerial photograph has a considerably high resolution of about 10,000 × 10000 pixels. Become.

  For mosaic composition, basically an orthographic transformation process that forms an ortho image from an aerial photograph by orthographic projection, a joint line search process that searches for a joint line from a plurality of ortho images including the same region, and a decision However, if the resolution is high at the aerial photography stage, computer processing for each processing becomes very heavy, so the processing burden is high. It is desirable to reduce this.

  Also, when scanning a target area having a size of about 2.0 km × 2.0 km to take an aerial image, about 500 aerial photographs (about 10,000 × 10000 pixels) are taken at a shooting scale of 1/10000. It takes one night with normal workstation computing power to orthorectify about 500 aerial photographs. Therefore, if there is an input error or setting error of the orientation element, the calculation is completely wasted and cannot be overlooked.

  An object of this invention is to show the mosaic image generation method, apparatus, and program which can produce | generate a high-quality mosaic image efficiently from several ortho images.

A mosaic image generating method according to the present invention is a mosaic image generating method for generating a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting that scans the target area, and is lower than the aerial image. Preparing a plurality of low-resolution images having the same area as each of the plurality of aerial images and a coordinate conversion function of the computer from each of the plurality of low-resolution images A low-resolution orthoimage generating step for generating a low-resolution orthoimage by orthogonal transformation according to the orientation element of the image, and a temporary joint-line searching step for searching for a temporary joint line from the low-resolution orthoimage by the computer's joint line search function When, the mosaic synthetic functions of the computer, in accordance with the provisional joining line which is searched by the provisional bonding line searching step The low-resolution mosaic synthesis step for generating a low-resolution mosaic image from the resolution ortho-image and the tone correction coefficient determination function of the computer according to the instruction of the operator of the computer, the tone correction for each mosaic piece constituting the low-resolution mosaic image A step of determining a coefficient, and the coordinate transformation function of the computer, for each of the plurality of aerial images, from a synthesis candidate area according to the provisional joint line, by orthonormal transformation according to the orientation element, to obtain a high-resolution ortho image A high-resolution ortho image generation step for generating the color tone correction function of the computer according to the color tone correction coefficient, and a color tone correction step for correcting the color tone of the high-resolution ortho image, and the junction line search function of the computer Search for joint line from high-resolution ortho image And the mosaic composition function of the computer includes a high-resolution mosaic composition step for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched in the joint line search step. And
A mosaic image generating method according to the present invention is a mosaic image generating method for generating a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting that scans the target area, and is lower than the aerial image. Preparing a plurality of low-resolution images having the same area as each of the plurality of aerial images and a coordinate conversion function of the computer from each of the plurality of low-resolution images A low-resolution orthoimage generating step for generating a low-resolution orthoimage by orthogonal transformation according to the orientation element of the image, and a temporary joint-line searching step for searching for a temporary joint line from the low-resolution orthoimage by the computer's joint line search function And the coordinate conversion function of the computer, for each of the plurality of aerial images, In addition, a high-resolution orthoimage generation step for generating a high-resolution orthoimage by orthogonal transformation according to the orientation element, and a joint-line search in which the joint-line search function of the computer searches for a joint line from the high-resolution orthoimage A high-resolution mosaic composition step for generating a high-resolution mosaic image from the high-resolution orthoimage according to the joint line searched in the joint line search step, and a correction function of the computer. And a correction step of overwriting the image portion specified by the computer operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image.

A mosaic image generating method according to the present invention is a mosaic image generating method for generating a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting that scans the target area, and is lower than the aerial image. Preparing a plurality of low-resolution images having the same area as each of the plurality of aerial images and a coordinate conversion function of the computer from each of the plurality of low-resolution images A low-resolution orthoimage generating step for generating a low-resolution orthoimage by orthogonal transformation according to the orientation element of the image, and a temporary joint-line searching step for searching for a temporary joint line from the low-resolution orthoimage by the computer's joint line search function The mosaic compositing function of the computer from the low-resolution ortho image to the low-resolution mosaic image according to the provisional joint line A step of generating a low-resolution mosaic composition, a tone correction coefficient determination function of the computer, a step of determining a tone correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image, and the coordinate conversion function of the computer A high-resolution ortho image generation step for generating a high-resolution ortho image from a plurality of aerial images by orthogonal transformation according to the orientation element, and a color correction function of the computer according to the color correction coefficient, the high-resolution ortho image A tone correction step for correcting the color tone of the computer, a junction line search function of the computer for searching for a junction line from the high-resolution ortho image, and a mosaic synthesis function of the computer for searching for the junction line From the high-resolution ortho image according to the joint line searched by the step, High resolution mosaic synthesis step of generating a Zodo mosaic image, correction function of the computer is, of the high-resolution mosaic image, the image portion specified by the operator of the computer, of the high-resolution orthorectified image, by the operator And a correction step of overwriting with a designated image portion .

A mosaic image generating apparatus according to the present invention is a mosaic image generating apparatus that generates a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting that scans the target area, and the plurality of aerial images A plurality of low-resolution images that are lower in resolution than the aerial images and indicate the same area as each of the aerial images, and a storage device that stores orientation elements of the aerial images, and the plurality Low-resolution orthoimage generation means for generating a low-resolution orthoimage from each of the low-resolution images by orthogonal transformation according to the corresponding orientation element, and a temporary joint search for searching for a temporary joint line from the low-resolution orthoimage A high-resolution ortho image is generated for each of the plurality of aerial images by orthogonal transformation according to the orientation element from the synthesis candidate area according to the provisional joint line. High resolution orthoimage generating unit that, a joining line searching unit for searching for a joint line from the high-resolution orthorectified images, and high-resolution mosaic synthesizing means for generating a high-resolution mosaic image from the high resolution orthorectified images according the junction line, A tone correction coefficient determining means for determining a tone correction coefficient for each mosaic piece constituting the low-resolution mosaic image, and the high-resolution ortho image according to the tone correction coefficient before or after the joint line search by the joint line search means. And a color tone correcting means for correcting the color tone .
A mosaic image generating apparatus according to the present invention is a mosaic image generating apparatus that generates a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting that scans the target area, and the plurality of aerial images A plurality of low-resolution images that are lower in resolution than the aerial images and indicate the same area as each of the aerial images, and a storage device that stores orientation elements of the aerial images, and the plurality Low-resolution orthoimage generation means for generating a low-resolution orthoimage from each of the low-resolution images by orthogonal transformation according to the corresponding orientation element, and a temporary joint search for searching for a temporary joint line from the low-resolution orthoimage A high-resolution ortho image is generated for each of the plurality of aerial images by orthogonal transformation according to the orientation element from the synthesis candidate area according to the provisional joint line. A high-resolution ortho image generating means, a joint line searching means for searching for a joint line from the high-resolution ortho image, a high-resolution mosaic synthesis means for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line, A correction means for overwriting the image portion specified by the operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image according to an operation of the operator. To do.

A mosaic image generating apparatus according to the present invention is a mosaic image generating apparatus that generates a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting that scans the target area, and the plurality of aerial images A plurality of low-resolution images that are lower in resolution than the aerial images and indicate the same area as each of the aerial images, and a storage device that stores orientation elements of the aerial images, and the plurality Low-resolution orthoimage generation means for generating a low-resolution orthoimage from each of the low-resolution images by orthogonal transformation according to the corresponding orientation element, and a temporary joint search for searching for a temporary joint line from the low-resolution orthoimage Means, a low-resolution mosaic synthesizing means for generating a low-resolution mosaic image from the low-resolution orthoimage according to the provisional joint line, and the low-resolution mosaic image A tone correction coefficient determining means for determining a tone correction coefficient for each mosaic piece to be formed, and a high-resolution ortho image generating means for generating a high-resolution ortho image from the plurality of aerial images by orthogonal transformation according to the orientation element, The color correction means for correcting the color tone of the high-resolution ortho image according to the color correction coefficient, the joint line search means for searching for a joint line from the high-resolution ortho image, and the joint searched by the joint line search means A high-resolution mosaic synthesizing means for generating a high-resolution mosaic image from the high-resolution orthoimage according to the line, and an image portion specified by the operator of the high-resolution mosaic image according to the operation of the operator. And correction means for overwriting the image portion designated by the operator .

A mosaic image generation program according to the present invention is a mosaic image generation program that causes a computer to generate a mosaic image indicating a target area from a plurality of aerial images obtained by aerial photography that scans the target area. The storage means of the computer stores the plurality of aerial images, a plurality of low resolution images that are lower in resolution than the aerial images, and indicate the same area as each of the plurality of aerial images, and the aerial images. a function that stores orientation parameters of the image shooting, from each of the plurality of low-resolution images, the orthographic conversion according corresponding the orientation parameters, the low-resolution orthoimage generating function that generates a low-resolution orthorectified images, the a provisional bonding line searching function to search a provisional joint line from the low-resolution orthorectified images, on the provisional joining line which is searched by the provisional bonding line searching function Low resolution mosaic synthesis function for generating a low-resolution mosaic image from have the low-resolution orthorectified images, and color correction coefficient determination function for determining a color correction factor mosaic piece units constituting the low-resolution mosaic image, the plurality of air for each shooting images, a synthetic candidate region according the provisional joining line, the orthographic conversion according the orientation parameters, the high-resolution orthoimage generating function to generate a high-resolution orthorectified image, joint line from the high-resolution orthoimage a bonding line searching function to explore, and a high-resolution mosaic synthesis function that generates a high-resolution mosaic image from the high resolution orthorectified image in accordance with the joining line which is searched by the bonding line searching function, bonding by the bonding line searching function before or after the line search in accordance with the color correction coefficient, realizing a color correction function for color correction of the high-resolution orthoimage And characterized in that.
A mosaic image generation program according to the present invention is a mosaic image generation program that causes a computer to generate a mosaic image indicating a target area from a plurality of aerial images obtained by aerial photography that scans the target area. The storage means of the computer stores the plurality of aerial images, a plurality of low resolution images that are lower in resolution than the aerial images, and indicate the same area as each of the plurality of aerial images, and the aerial images. A function for storing orientation elements of captured images, a low-resolution orthoimage generation function for generating a low-resolution orthoimage from each of the plurality of low-resolution images by orthogonal transformation according to the corresponding orientation element, and the low-resolution A provisional joint line search function that searches for a provisional joint line from an ortho image and the provisional joint line for each of the plurality of aerial images. A high-resolution ortho-image generation function that generates a high-resolution ortho image from the synthesis candidate area by orthogonal transformation according to the orientation element, a joint line search function that searches for a joint line from the high-resolution ortho image, and the joint line search A high-resolution mosaic synthesis function for generating a high-resolution mosaic image from the high-resolution orthoimage according to the joint line searched by the function, and an image portion of the high-resolution mosaic image designated by the computer operator A correction function for overwriting the ortho image with an image portion designated by the operator is realized.

A mosaic image generation program according to the present invention is a mosaic image generation program that causes a computer to generate a mosaic image indicating a target area from a plurality of aerial images obtained by aerial photography that scans the target area. The storage means of the computer stores the plurality of aerial images, a plurality of low resolution images that are lower in resolution than the aerial images, and indicate the same area as each of the plurality of aerial images, and the aerial images. a function that stores orientation parameters of the image shooting, from each of the plurality of low-resolution images, the orthographic conversion according corresponding the orientation parameters, the low-resolution orthoimage generating function for generating a low-resolution orthorectified image, the low a provisional bonding line searching function of searching a provisional joint line from the resolution orthorectified images, low resolution from the low resolution orthoimage according the provisional joining line Low resolution mosaic synthesis function for generating a mosaic image, a color correction coefficient determination function for determining a color correction factor mosaic piece units constituting the low-resolution mosaic image, from the plurality of aerial images, positive according the orientation elements A high-resolution orthoimage generation function that generates a high-resolution orthoimage by recursive conversion, a color correction function that corrects the color tone of the high-resolution orthoimage according to the color correction coefficient, and a search for a joint line from the high-resolution orthoimage Connecting line search function, a high-resolution mosaic composition function for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search function, and an operator of the computer of the high-resolution mosaic image Specified by the operator of the high-resolution ortho image. Characterized in that to realize a correction function to overwrite the image portion was.

  In the present invention, the provisional joint line is determined from the low-resolution image, and the range including the provisional joint line of the aerial image is subjected to orthographic transformation, thereby obtaining a mosaic image from the high-resolution aerial image. The processing burden can be greatly reduced.

  Since a low-resolution mosaic image is generated from the low-resolution image, the color tone is confirmed, and the color tone correction coefficient is determined, the processing load until obtaining a mosaic image with a matching color tone from the aerial image can be greatly reduced.

  Further, by trying from the low resolution image to the generation of the low resolution mosaic image, it is possible to confirm whether the orientation element itself or the correspondence between the orientation element and the aerial image is correct.

It is a general | schematic functional block diagram of one Example of this invention. It is a flowchart of the pre-processing of a present Example. It is a flowchart of this process of a present Example. It is a schematic diagram which shows the relationship between an ortho image, a mosaic image, a mosaic piece, and a synthetic | combination candidate area. It is a schematic diagram which shows the example of an orthoimage overlap by an aerial photograph.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic block diagram of an embodiment of the present invention. Some functions of the mosaic image generating apparatus 20 are implemented as a computer program on a computer or a workstation. Of course, each function can be implemented by a dedicated device.

  The helicopter 10 (or light aircraft) is equipped with a high-resolution digital camera 12 and a GPS-IMU device 14 that detects the flight position and orientation of the helicopter 10 (and thus the shooting direction of the camera 12).

  The digital camera 12 is generally a still camera, but may be a movie camera when a desired resolution can be realized. In this embodiment, in addition to a high-definition still image, the digital camera 12 also outputs a low-resolution still image in which the number of pixels is reduced to 1/256 (1/16 horizontally and 1/16 vertically). To do. When a camera that does not output a low-resolution still image is used, a low-resolution still image may be generated from a high-resolution still image in advance on the ground device.

  The GPS-IMU device 14 includes a receiver of a global positioning system (GPS) and an inertial measurement unit (IMU), and the GPS receiver determines the flight position of the helicopter 10 for 1 second ( 3D measurement can be performed at a time interval of about 1 Hz), and the relative change in the position and posture of the helicopter 10 can be measured at a time interval of about 0.005 seconds (200 Hz) by the inertial attitude measurement device. By integrating the measurement result of the GPS receiver and the measurement result of the inertial attitude measurement device, continuous and highly accurate positioning can be realized. Since such a technique is well known, further explanation is omitted.

  While the helicopter 10 is flying in the designated direction over the target area, the digital camera 12 continuously photographs the ground. Next, the ground is photographed with the camera 12 while the helicopter 10 is flying in the opposite direction at a certain distance in the lateral direction. This is repeated, and the whole area is imaged by scanning the target area. As described above, it is specified that images are taken so as to overlap 60% or more in the vertical direction (flight direction) and 30% or more in the horizontal direction (horizontal direction). Shooting is performed at a higher overlap rate, such as 80% or more in the direction and 60% or more in the horizontal direction. Thus, by increasing the duplication rate at the time of shooting, it is possible to reduce the collapse of the building on the mosaic image.

  The mosaic image generating apparatus 20 prepared on the ground is composed of a computer or a workstation, and a part of the function is implemented as a computer program. Of course, each function can be implemented by a dedicated device.

  High resolution aerial photograph data 24 and low resolution aerial photograph data 26 from the camera 12 are stored in the hard disk 22 of the mosaic image generating device 20. The operator of the mosaic image generating apparatus 20 stores the shooting direction and position data of the camera 12 obtained from the flight position and attitude data measured by the GPS-IMU apparatus 14 as the external orientation element 28 in the hard disk 22, and The size of the 12 image sensors and the focal length of the photographic lens are stored in the hard disk 22 as the internal orientation element 30. The external orientation element 28 and the internal orientation element 30 may be collectively stored in the hard disk 22 as orientation elements. The high-resolution aerial photograph data 24, the low-resolution aerial photograph data 26, and the external orientation element 28 may be automatically stored in the hard disk 22 from the camera 12 and the GPS-IMU device 14 via the communication line. Needless to say.

  The hard disk 22 further stores low resolution (50 m mesh) numerical terrain model data (DEM data) 32 issued by the Geographical Survey Institute for the target area. The Geographical Survey Institute has issued a numerical map 250m mesh and a volcanic altitude 10m mesh in addition to the numerical map 50m mesh as a numerical terrain model, and these can also be used. In addition, when the undulation is small, a USGS (US Geographical Survey) 30 second mesh (corresponding to about 1 km mesh) can be used. Similar numerical terrain model data is provided by private companies. These numerical terrain model data can also be used as the DEM data 32.

  The CPU 36 of the computer constituting the mosaic image generating apparatus 20 can access the hard disk 22 via the bus 34. The CPU 36 has a plurality of functions 38 to 52 according to the installed computer program.

  The orthographic transformation function 38 generates an ortho image of the ground coordinate system or a coordinate system equivalent thereto from the aerial photograph, and the inverse orthographic transformation function 40 is a point on the aerial photograph corresponding to an arbitrary point on the ortho image. Is calculated. The inverse orthographic transformation function 40 is specified so that it is easy to understand the coordinate transformation from the ortho image (ground coordinate system) to the coordinate system of the aerial photograph in this embodiment, and the orthographic transformation function 38 is used as the coordinate transformation function. Can be substituted. The joining line search function 42 searches for joining lines from overlapping portions of a plurality of ortho images. The mosaic synthesizing function 44 synthesizes an ortho image according to the joining line searched by the joining line search function 42.

  The color correction coefficient determination function 46 determines a color correction coefficient or a color correction parameter for matching the color tones between the orthoimages. The color correction function 48 determines each orthorectification according to the color correction coefficient determined by the color correction coefficient determination function 46. Correct the color tone of the image. The correction function 50 corrects the mosaic image at the designated position using the original ortho image in accordance with the correction operation of the operator.

  The resolution conversion function 52 generates low-resolution aerial photograph data 26 from the high-resolution aerial photograph data 24 and stores it in the hard disk 22. As described above, when the camera 12 itself generates and outputs the low-resolution aerial photograph data 26, the resolution conversion function 52 is not necessary.

  The RAM 54 is used as a work area for operations by the CPU 36, and temporarily stores intermediate data and result data. The display device 56 displays an intermediate result image or an image after mosaic synthesis, and is also used for fine adjustment of a color tone correction coefficient for color tone correction and confirmation of an adjustment result. The display device 56 also simultaneously displays the mosaic composite image and the ortho image before the mosaic composite when the correction function 50 corrects the image. The operator can input various numerical values using the keyboard 58 and the mouse 60, and can specify the position of the display device 56 on the display screen. The RAM 54, the display device 56, the keyboard 58 and the mouse 60 are connected to the bus 34.

  2 and 3 show operation flowcharts of the composition processing by the mosaic image generating apparatus 20. FIG. 2 shows an operation flow of the preprocessing portion using the low-resolution aerial photograph data 26, and FIG. 3 shows an operation flow of the main processing using the high-resolution aerial photograph data 24.

  In this embodiment, the low-resolution aerial photograph data 26 is used to check and correct the color tone, to confirm the setting values in advance such as ortho-rectification, and to narrow down the ortho-rectification target of the high-resolution aerial photograph data 24. Due to the prior confirmation of the setting value, a setting error of the internal orientation element 30, an error in correspondence between the aerial photograph data 24 and 26 and the external orientation element 28 or the internal orientation element 30, or a numerical value that does not correspond to the aerial photograph data 24 and 26 It is possible to prevent mosaic synthesis accompanied by an input error of the terrain model data 32 or the like. By checking and correcting the color tone, a color correction coefficient for preventing the appearance of an unnatural region having a different color tone on the mosaic image can be determined in advance and with simple processing. In addition, the calculation time can be greatly shortened by narrowing down the orthographic conversion target of high-resolution aerial photographs.

  First, the mosaic image generating device 20 is initialized (S1). This initial setting includes file designation of the aerial photograph data 24 and 26, the external orientation element 28, the internal orientation element 30 and the numerical terrain model data 32 of the area to be synthesized. Note that the high-resolution aerial photograph data 24 and the low-resolution aerial photograph data 26 for the same region have different file names according to certain rules, so that the high-resolution aerial photograph data can be processed for high-resolution aerial photographs. It is not necessary to designate the file name of the photo data 24 again.

  Ortho image data (hereinafter referred to as low resolution ortho image data) is generated from each low resolution aerial photograph data 26. The CPU 36 captures the first low-resolution aerial photo data 26 and its external orientation element 28 (S2), and the orthographic transformation function 38 generates low-resolution ortho image data from the low-resolution aerial photo data 26 by orthographic projection. (S3). Specifically, the orthographic transformation function 38 calculates ground coordinates from the numerical terrain model data 32, and uses the internal orientation element 30 and the external orientation element 28 captured in step S2 to obtain the low resolution captured in step S2. The aerial photograph data 26 is projected onto an orthographic projection screen corresponding to the ground coordinates. By generating and synthesizing the ortho image data for each color component of the low resolution aerial photo data 26, it is possible to obtain color low resolution ortho image data.

  The next low-resolution aerial photograph data 26 and its external orientation element 28 are captured (S5), and similarly, the orthographic conversion function 38 generates low-resolution ortho image data by orthographic conversion (S3). The generated low-resolution ortho image data is temporarily stored in the hard disk 22.

  When the low-resolution orthoimage data is generated from all the low-resolution aerial photo data 26 (S6), the joint line search function 42 uses the low-resolution orthoimage data to linearly search the pixel portion that is closest to the overlapping portion. Then, a joining line between the ortho images is set (S6). The joint line searched here is a provisional line for limiting the orthogonal transformation range of the high-resolution aerial photograph data 24, that is, a provisional joint line.

  In order to confirm and correct the overall color tone, the mosaic composition function 44 joins the low-resolution ortho image using the searched joint line to generate low-resolution mosaic image data (S7). The generated low resolution mosaic image data is temporarily stored in the hard disk 22.

  FIG. 4 shows an example of the correspondence between the ortho image and the mosaic image. 4A shows an ortho image 70, and FIG. 4B shows an ortho image 72. FIG. 4C shows a mosaic image 74 using the ortho images 70 and 72. A part 70a of the ortho image 70 is incorporated into the mosaic image 74 as a mosaic piece (or mosaic piece image). Similarly, a part 72a of the ortho image 72 is incorporated into the mosaic image 74 as a mosaic piece.

  The CPU 36 displays the generated low resolution mosaic image on the display device 56. The color correction coefficient determination function 46 determines a color correction coefficient (or color correction parameter) for adjusting the color tone of the low-resolution mosaic image, and the color correction function 48 corrects the color (S8). In this color tone correction, the tone correction coefficient is determined automatically or manually for each area in consideration of the ground conditions, for example, distinction between forests, fields, and urban areas. In this case, the standard color tone of the region is designated by the file indicating the color tone for each region or the designation of the operator, and the color correction coefficient to be adjusted to such a standard color tone is determined.

  Specifically, the color correction coefficient determination function 46 spatially samples the color components of the low-resolution mosaic image data, and automatically determines the color correction coefficient so that the standard color tone (or its range) is obtained on average. Alternatively, it may be determined according to the operation of the operator. Since the color correction using the color correction coefficient may be a global one that the unnaturalness is not clear on the mosaic image, the operator visually recognizes the low-resolution mosaic image displayed on the display device 56, and the operator's Even a method of manually adjusting the color tone for each designated area is sufficient in accuracy. In this case, the color correction function 48 corrects the color tone of the low-resolution ortho image data according to the color tone adjustment operation input by the operator using the keyboard 58 or the mouse 60, and the color correction coefficient determination function 46 performs the color correction operation by the operator. You may make it take in the numerical value of the corresponding color correction coefficient.

  The CPU 36 displays the low-resolution mosaic image generated using the low-resolution aerial photograph data 26 on the display device 56 (S9). The operator observes the displayed low-resolution mosaic image and confirms whether the image composition setting is correct (S10). If it is not correct (S10), the setting is corrected and step S2 and subsequent steps are repeated.

  In this way, by performing trials with the low-resolution aerial photograph data 26, the correctness of the settings for mosaic composition can be confirmed in advance. In addition, when trying to adjust the color tone of the high-resolution mosaic image generated from the high-resolution aerial photograph data 24, a large load is imposed on the computer due to the large number of pixels. Since the tone correction coefficient is acquired from the low-resolution mosaic image data obtained as a result, simple processing is required, and a computer with a relatively low capability can be used.

  As shown in FIG. 4, the joint line search by the joint line search function 42 (step S6) is a process of cutting out regions (mosaic pieces 70a and 72a) used for mosaic composition from the respective ortho image data 70 and 72. In step S6, the joint line search function 42 performs orthogonal orthographic transformation on the coordinate values on the ortho image of a region (combination candidate regions 70b and 72b) wider than the rectangular region circumscribing the composition target region by a predetermined margin in the horizontal plane. Supply to function 40. The inverse orthographic conversion function 40 converts the composite candidate area coordinate value on the ortho image from the joint line search function 42 into the composite candidate area coordinate value on the aerial photograph by inverse orthonormal conversion (S12). Even if the joint line search function 42 supplies the coordinate value of the synthesis target area to the inverse orthogonal transformation function 40, the inverse orthogonal transformation function 40 calculates the coordinate value of the synthesis candidate area from the coordinate value of the synthesis target area. Needless to say, it is good.

  As described above, in the present embodiment, the joint line search process (S6) for the low-resolution ortho image data is used to check roughly which part of each aerial photograph is to be used for the mosaic image in advance. Thus, the portion of the high-resolution aerial photograph data 24 that is the target of orthographic projection (the portion corresponding to the combination candidate areas 70b and 72b) is determined. Can be reduced.

  After such preprocessing, a high-resolution ortho image is created from the high-resolution aerial photograph data 24 (S13 to S19). Specifically, the CPU 36 takes in the first high-resolution aerial photograph data 24 and its external orientation element 28 (S13). From the result of the inverse orthogonal transformation function 40 (step S12), it is checked whether or not the combined candidate area is included in the captured high-resolution aerial photograph data 24 (S14).

  When the composite candidate area is included (S14), the orthographic transformation function 38 refers to the numerical terrain model data 32, the internal orientation element 30 and the external orientation element 28, and images within the composite candidate area of the high-resolution aerial photograph data 24 are displayed. The data is orthogonally transformed to generate high resolution ortho image data (S15). Although it consists only of image data within the synthesis candidate area of the high-resolution aerial photo data 24, it originally has a high resolution, so it still has a large amount of data and may require a lot of computer resources. In such a case, in the present embodiment, the image data in the synthesis candidate area of the high-resolution aerial photograph data is separated for each color component, orthorectified for each color component, and the obtained ortho image for each color component. Combine the data into one. In this way, by performing orthogonal transformation separately for each component, an ortho image can be obtained from high-resolution aerial photograph data with a small amount of computer resources. If an infrared image is included, the infrared component image is also orthogonally converted, and the obtained ortho image is combined into one file together with the ortho image of each color component, if necessary. Put together.

  The color tone correction function 48 refers to the color tone correction coefficient determined in step S8 and corrects the color tone of the high-resolution ortho image data generated in step S15 (S16). Calculation time can be reduced by correcting the color tone of the image data in the synthesis candidate area of the high-resolution ortho image. Of course, when color tone correction is unnecessary, the color tone correction function 48 outputs the high-resolution ortho image data generated in step S15 as it is. The CPU 36 stores the high-resolution ortho image data 62 output by the color tone correction function 48 in the hard disk 22 (S17).

  If the captured high-resolution aerial photograph data 24 does not include a composition candidate area (S14), steps S15, S16, and S17 are passed.

  The next high-resolution aerial photograph data 24 and its external orientation element 28 are taken in (S19), and when the high-resolution aerial photograph data 24 includes a synthesis candidate area (S14), orthorectification and color tone correction are performed (S15, S16). ), And stores the high-resolution ortho image data 62 (S17).

  In this manner, the above-described processing S14 to S17 is executed for all the high-resolution aerial photograph data 24 (S18), and thereby necessary high-resolution ortho image data 62 is obtained.

  Next, the joint line search function 42 uses the high-resolution orthoimage data 62 to search for a pixel portion that is closest to the overlapped portion in a line, and sets it as a joint line between the high-resolution orthoimages (S20). The joint line searched here generally does not coincide with the joint line searched in step S6. Appropriate joint lines can be determined by appropriately setting the margin when determining the synthesis candidate area. The tone correction (S16) may be performed after the joint line search (S20), but it is necessary to identify the mosaic pieces separated by the joint lines, and the timing shown in FIG. .

  The mosaic compositing function 44 joins the high-resolution ortho image data using the joining line searched in step S20, and generates high-resolution mosaic image data (S21). The generated high resolution mosaic image data 64 is stored in the hard disk 22.

  Since the ortho image data to be subjected to the mosaic composition is composed only of the image data within the composition candidate area, the area is small. However, since the resolution is originally high, the amount of data is still large and a lot of computer resources may be required. In such a case, in this embodiment, the image data in the synthesis area of each high-resolution ortho image data determined in the joint line search (S20) is separated for each color component, and mosaic synthesis is performed for each color component. Then, the mosaic image data for each color component is finally combined into one. By separating mosaic components separately for each component in this way, it becomes possible to mosaic combine high-resolution ortho image data with a small amount of computer resources. The obtained high resolution mosaic image data 64 is stored in the hard disk 22.

  Since the joining line is automatically determined, there is a possibility that an erroneous joining line that cuts a building or the like is employed. In order to correct such a mistake, a high-resolution mosaic image is displayed on the display device 56 (S22). Then, the operator visually confirms, in particular, the joining line portion, and corrects it using the high-resolution ortho image data (S23).

  For example, it is assumed that the ortho image is joined so as to cut out a part of a building. The high-resolution ortho image data 62 including a building that is partially missing is displayed on the screen of the display device 56 simultaneously with the high-resolution mosaic image data 64. Then, with respect to a building in which a part of the high-resolution orthoimage data 62 is missing, the periphery of the complete building of the high-resolution orthoimage data is specified, and the image data of the building is cut. The image data 62 is pasted on the image of the building that is partially missing. In this way, it is possible to correct a mosaic synthesis error caused by automatically generated joining lines.

  The high-resolution mosaic image data on the hard disk 22 is overwritten and saved with the corrected high-resolution mosaic image data (S24), and the process ends.

  Although the example which forms a ground mosaic image from an aerial photograph was demonstrated, an aerial photograph is an example of the aerial image by aerial photography. In addition to helicopters, the present invention can also be applied to aerial images obtained by photographing from light aircraft, satellites, radio-controlled aircrafts, etc., and the mosaic image generating device 20 performs processing similar to the above-described aerial photograph. A mosaic image can be formed from these aerial images. The orthographic transformation function 38 and the inverse orthographic transformation function 40 both convert coordinates from one coordinate system in the three-dimensional space to the other coordinate system. When converting to an ortho image of the ground coordinate system or a coordinate system conforming thereto, it functions as an orthophoto conversion function 38, and conversely, when returning an ortho image to the coordinate system to an aerial photograph or the like, an inverse orthophoto image is used. It functions as a conversion function 40.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

10: Helicopter 12: Digital camera 14: GPS-IMU device 20: Mosaic image generating device 22: Hard disk 24: High resolution aerial photograph data 26: Low resolution aerial photograph data 28: External orientation element 30: Internal orientation element 32: Low resolution Numerical terrain model data (DEM data)
34: Bus 36: CPU
38: Orthogonal conversion function 40: Inverse orthogonal conversion function 42: Join line search function 44: Mosaic composition function 46: Color tone correction coefficient determination function 48: Color tone correction function 60: Correction function 52: Resolution conversion function 54: RAM
56: Display device 58: Keyboard 60: Mouse

Claims (12)

A mosaic image generating method for generating a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting for scanning the target area,
Preparing a plurality of low resolution images having a lower resolution than the aerial image and indicating the same area as each of the plurality of aerial images;
A low-resolution orthoimage generating step in which a coordinate conversion function of the computer generates a low-resolution orthoimage from each of the plurality of low-resolution images by orthogonal transformation according to the orientation element at the time of the aerial shooting;
A provisional joint line search step in which the joint line search function of the computer searches for a provisional joint line from the low-resolution ortho image;
A mosaic synthesis function of the computer, a low-resolution mosaic synthesis step for generating a low-resolution mosaic image from the low-resolution ortho image according to the provisional joint line searched by the provisional joint line search step;
The color tone correction coefficient determination function of the computer, according to an instruction of the computer operator, determining a color correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image;
The coordinate conversion function of the computer generates a high-resolution ortho image for each of the plurality of aerial images from a synthesis candidate area according to the provisional joint line by orthonormal conversion according to the orientation element. Generation step;
A color correction step of correcting a color tone of the high-resolution ortho image according to the color correction coefficient;
The junction line search function of the computer searches for the junction line from the high-resolution ortho image,
A mosaic image characterized in that the mosaic composition function of the computer includes a high-resolution mosaic composition step for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search step. Generation method. Furthermore, the correction function of the computer includes a correction step of overwriting the image portion specified by the computer operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image. The mosaic image generating method according to claim 1 , wherein: A mosaic image generating method for generating a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting for scanning the target area,
Preparing a plurality of low resolution images having a lower resolution than the aerial image and indicating the same area as each of the plurality of aerial images;
A low-resolution orthoimage generating step in which a coordinate conversion function of the computer generates a low-resolution orthoimage from each of the plurality of low-resolution images by orthogonal transformation according to the orientation element at the time of the aerial shooting;
A provisional joint line search step in which the joint line search function of the computer searches for a provisional joint line from the low-resolution ortho image;
The coordinate conversion function of the computer generates a high-resolution ortho image for each of the plurality of aerial images from a synthesis candidate area according to the provisional joint line by orthonormal conversion according to the orientation element. Generation step;
The junction line search function of the computer searches for the junction line from the high-resolution ortho image,
The mosaic composition function of the computer generates a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search step;
A correction step in which the correction function of the computer overwrites the image portion specified by the computer operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image.
A mosaic image generating method comprising: A mosaic image generating method for generating a mosaic image indicating a target area from a plurality of aerial images obtained by aerial shooting for scanning the target area,
Preparing a plurality of low resolution images having a lower resolution than the aerial image and indicating the same area as each of the plurality of aerial images;
A low-resolution orthoimage generating step in which a coordinate conversion function of the computer generates a low-resolution orthoimage from each of the plurality of low-resolution images by orthogonal transformation according to the orientation element at the time of the aerial shooting;
A provisional joint line search step in which the joint line search function of the computer searches for a provisional joint line from the low-resolution ortho image;
A low-resolution mosaic synthesis step in which the mosaic synthesis function of the computer generates a low-resolution mosaic image from the low-resolution orthoimage according to the provisional joint line;
The color correction coefficient determination function of the computer determines a color correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image;
The coordinate conversion function of the computer is a high-resolution orthoimage generation step for generating a high-resolution orthoimage from the plurality of aerial images by orthogonal transformation according to the orientation element;
A color tone correction function in which the color tone correction function of the computer corrects the color tone of the high-resolution ortho image according to the color tone correction coefficient;
The junction line search function of the computer searches for the junction line from the high-resolution ortho image,
The mosaic composition function of the computer generates a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search step ;
A correction step in which the correction function of the computer overwrites the image portion specified by the computer operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image. A mosaic image generating method comprising: A mosaic image generating device that generates a mosaic image indicating a target area from a plurality of aerial images obtained by aerial imaging for scanning the target area,
The plurality of aerial images, a plurality of low resolution images that are lower in resolution than the aerial images and indicate the same region as each of the plurality of aerial images, and orientation factors of the aerial images are stored. A storage device;
A low-resolution ortho image generating means for generating a low-resolution ortho image from each of the plurality of low-resolution images by orthogonal transformation according to the corresponding orientation element;
Provisional joint line search means for searching for provisional joint lines from the low-resolution ortho image;
For each of the plurality of aerial images, a high-resolution orthoimage generating means for generating a high-resolution orthoimage by orthographic conversion according to the orientation element from the synthesis candidate area according to the provisional joint line;
A joining line searching means for searching for a joining line from the high-resolution ortho image;
High-resolution mosaic synthesizing means for generating a high-resolution mosaic image from the high-resolution orthoimage according to the joint line ;
A color correction coefficient determining means for determining a color correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image;
A mosaic image generating apparatus comprising: a color tone correcting unit that corrects the color tone of the high-resolution ortho image according to the color tone correction coefficient before or after the junction line search by the junction line searching unit. According to an operator's operation, the image processing apparatus includes correction means for overwriting the image portion specified by the operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image. The mosaic image generating apparatus according to claim 5. A mosaic image generating device that generates a mosaic image indicating a target area from a plurality of aerial images obtained by aerial imaging for scanning the target area,
The plurality of aerial images, a plurality of low resolution images that are lower in resolution than the aerial images and indicate the same region as each of the plurality of aerial images, and orientation factors of the aerial images are stored. A storage device;
A low-resolution ortho image generating means for generating a low-resolution ortho image from each of the plurality of low-resolution images by orthogonal transformation according to the corresponding orientation element;
Provisional joint line search means for searching for provisional joint lines from the low-resolution ortho image;
For each of the plurality of aerial images, a high-resolution orthoimage generating means for generating a high-resolution orthoimage by orthographic conversion according to the orientation element from the synthesis candidate area according to the provisional joint line;
A joining line searching means for searching for a joining line from the high-resolution ortho image;
High-resolution mosaic synthesizing means for generating a high-resolution mosaic image from the high-resolution orthoimage according to the joint line;
Correcting means for overwriting the image portion specified by the operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image according to the operation of the operator
A mosaic image generating apparatus. A mosaic image generating device that generates a mosaic image indicating a target area from a plurality of aerial images obtained by aerial imaging for scanning the target area,
The plurality of aerial images, a plurality of low resolution images that are lower in resolution than the aerial images and indicate the same region as each of the plurality of aerial images, and orientation factors of the aerial images are stored. A storage device;
A low-resolution ortho image generating means for generating a low-resolution ortho image from each of the plurality of low-resolution images by orthogonal transformation according to the corresponding orientation element;
Provisional joint line search means for searching for provisional joint lines from the low-resolution ortho image;
Low-resolution mosaic synthesizing means for generating a low-resolution mosaic image from the low-resolution orthoimage according to the provisional joint line;
A color correction coefficient determining means for determining a color correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image;
A high-resolution orthoimage generating means for generating a high-resolution orthoimage from the plurality of aerial images by orthogonal transformation according to the orientation element;
According to the color correction coefficient, color correction means for correcting the color of the high-resolution ortho image,
A joining line searching means for searching for a joining line from the high-resolution ortho image;
High-resolution mosaic synthesizing means for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search means ;
Correction means for overwriting the image portion specified by the operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image according to the operation of the operator. A mosaic image generating apparatus characterized by that. A mosaic image generation program for causing a computer to generate a mosaic image indicating the target area from a plurality of aerial images obtained by aerial shooting for scanning the target area,
In the storage means of the computer, the plurality of aerial images, the plurality of low-resolution images indicating the same area as each of the plurality of aerial images, and the aerial images a function that stores orientation parameters of the image,
From each of the plurality of low-resolution images, the orthographic conversion according corresponding the orientation parameters, the low-resolution orthoimage generating function that generates a low-resolution orthorectified images,
A provisional bonding line searching function to search a provisional joint line from the low-resolution orthorectified images,
A low-resolution mosaic synthesis function for generating a low-resolution mosaic image from the low-resolution ortho image according to the provisional joint line searched by the provisional joint line search function;
A color correction coefficient determination function for determining a color correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image;
For each of the plurality of aerial images, a synthetic candidate region according the provisional joining line, the orthographic conversion according the orientation parameters, the high-resolution orthoimage generating function to generate a high-resolution orthorectified image,
A bonding line searching function to explore the bonding wire from the high-resolution orthorectified images,
High resolution mosaic synthesis function that generates a high-resolution mosaic image from the high resolution orthorectified image in accordance with the joining line which is searched by the bonding line searching function,
A mosaic image generation program that realizes a color tone correction function for correcting the color tone of the high-resolution ortho image according to the color tone correction coefficient before or after the search for a joint line by the junction line search function . Further to the computer, characterized in the high-resolution mosaic image, the image portion specified by the operator of the computer, of the high resolution orthorectified images, thereby realizing the correction function to override the specified image portion by the operator The mosaic image generating program according to claim 9. A mosaic image generation program for causing a computer to generate a mosaic image indicating the target area from a plurality of aerial images obtained by aerial shooting for scanning the target area,
In the storage means of the computer, the plurality of aerial images, the plurality of low-resolution images indicating the same area as each of the plurality of aerial images, and the aerial images The ability to store image orientation elements;
A low-resolution orthoimage generating function for generating a low-resolution orthoimage from each of the plurality of low-resolution images by orthogonal transformation according to the corresponding orientation element;
A provisional joint line search function for searching a provisional joint line from the low-resolution ortho image;
For each of the plurality of aerial images, a high-resolution orthoimage generation function that generates a high-resolution orthoimage by orthographic conversion according to the orientation element from the synthesis candidate area according to the provisional joint line;
Join line search function for searching for a join line from the high-resolution ortho image,
A high-resolution mosaic composition function for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search function;
A correction function for overwriting the image portion specified by the computer operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image.
A mosaic image generating program characterized by realizing the above. A mosaic image generation program for causing a computer to generate a mosaic image indicating the target area from a plurality of aerial images obtained by aerial shooting for scanning the target area,
In the storage means of the computer, the plurality of aerial images, the plurality of low-resolution images indicating the same area as each of the plurality of aerial images, and the aerial images a function that stores orientation parameters of the image,
A low-resolution orthoimage generating function for generating a low-resolution orthoimage from each of the plurality of low-resolution images by orthogonal transformation according to the corresponding orientation element;
A provisional joint line search function for searching a provisional joint line from the low-resolution ortho image;
A low-resolution mosaic composition function for generating a low-resolution mosaic image from the low-resolution orthoimage according to the provisional joint line;
A color correction coefficient determination function for determining a color correction coefficient in units of mosaic pieces constituting the low-resolution mosaic image;
A high-resolution orthoimage generation function for generating a high-resolution orthoimage from the plurality of aerial images by orthonormal transformation according to the orientation element;
A color correction function for correcting the color tone of the high-resolution ortho image according to the color correction coefficient;
Join line search function for searching for a join line from the high-resolution ortho image,
A high-resolution mosaic composition function for generating a high-resolution mosaic image from the high-resolution ortho image according to the joint line searched by the joint line search function ;
A correction function for overwriting the image portion specified by the computer operator of the high-resolution mosaic image with the image portion specified by the operator of the high-resolution ortho image. A mosaic image generation program.

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