KR20050063992A - Mapping method of satellite overlay image map using landsat-7 image with slc-off - Google Patents

Abstract

The present invention relates to a satellite image mapping method using the SLC-off Landsat-7 image. The present invention relates to a satellite image map using the Landsat-7 satellite image. In addition to using the satellite images taken periodically, the time required for mapping the rapidly changing land can be greatly reduced.

Accordingly, the present invention is to retrieve a satellite image received from the pre-stored database image of the same time and region as the image photographed by Landsat-7, and that the Landsat-7 is already in the image of the same region retrieved from the database Correcting the unphotographed image by matching the image of the photographed portion, removing brightness and discontinuous characteristics appearing at the boundary between the matched image and the image captured by the Landsat-7, and The calibrated image is generated as an image for cartography and transmitted to the satellite image mapping process.

Description

Mapping Method of Satellite Overlay Image Map using Landsat-7 Image with SLC-off

The present invention relates to a satellite image mapping device and method using SLC-off Landsat-7 image, and more particularly, to Landsat satellite image, which is the most common and widely used medium / resolution satellite image for the past 30 years. The three-dimensional map is produced by compensating for defects in the Landsat-7 satellites currently in use.

Satellite image production using the conventional Landsat satellite image is processed through geometric correction and orthodontic correction of image and outputting graphic image satellite map by overlapping with digital map.

Recently, Landsat-7 satellite, which is the latest model of the Landsat satellite, is used. In the case of the Landsat-7 satellite, SLC (Scan Line Corrector), which is essentially used to photograph the ground surface horizontally, is mechanically used. There was a case where the operation failed due to a defect.

However, since there are no other satellites to replace Landsat images among mid- and low resolution satellite images, there is a need for a method capable of maximizing Landsat-7 satellite images photographed while the SLC is inactive.

Therefore, until now, Landsat-based satellite imagery mapping technology is limited to images received in the past. For satellite imagery using Landsat-7 satellites, which are being photographed continuously, the SLC problem has to be solved before applying existing techniques. There is a need for a pretreatment technique to solve the problem.

Accordingly, the present invention is to solve the above-mentioned conventional problems, an object of the present invention is to supplement the unphotographed portion of the Landsat-7 satellite image received while the SLC is not operated from the Landsat image database received in the past. In addition, the present invention provides a satellite image mapping apparatus and method using Landsat-7 image which can be used for satellite image mapping through image processing such as color adjustment and border line processing.

Satellite image mapping method using a Landsat-7 image to achieve the object of the present invention as described above, the satellite image is received from the pre-stored database retrieves the image of the same time and region as the image taken by Landsat-7 And matching an image of a portion of the landsat-7 that is not already photographed by the image of the same region retrieved from the database, and adjusting brightness and a boundary between the matched image and the image captured by the landsat-7. Compensating the unphotographed image by removing the discontinuous characteristics appearing, and generating the matched and corrected image as an image for mapping to pass to the satellite image mapping process.

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

1 is a view showing the processing of the satellite image mapping method according to the present invention.

As shown in FIG. 1, as a pre-processing step for producing a map using the Landsat-7 satellite image that has been SLC-off, first, an acquisition time of an input image in a lost form in a fitting part And basic information about the lost part, etc., search for the image acquired at the most similar time from the pre-established Landsat image database, and perform fitting to compensate for the lost part (S100). Since the image obtained through the matching unit is an image obtained at different times, the government part corrects the image to the same brightness as the current image so that the brightness or the color of the image is not different from each other (S200).

In addition, the correction unit removes not only the brightness of the image and the correction of the missing portion, but also the step phenomenon appearing in the boundary portion (S210).

The images created by the matching unit have no difficulty in areas with small changes over time, but for areas where roads are newly opened or active in development, only the correction of existing images Since it is impossible to construct an accurate image corresponding to the situation, the road information and the forest part are separated from the recently produced digital map and inserted into the satellite image in reverse.

Through the above method, when an image for mapping is generated (S300), the matched and corrected image is transferred to an existing satellite image mapping process (S400).

This is possible because the resolution of the satellite image of the present invention is relatively low (30m) because it is only to describe the degree of difficulty to identify with the eyes rather than to express a specific object.

FIG. 2 is a view illustrating the processing of the matching unit shown in FIG. 1 in more detail. As shown in FIG. 2, the matching unit is first stored in a current Landsat-7 from a database in which satellite images acquired by Landsat in the past are stored. Similar to the image obtained by the time, the image corresponding to the same region is extracted (S101).

Of course, since the trajectory of the satellite image does not coincide exactly each time, a slight left and right error appears, but it is easy to find the omitted portion through a very simple region matching method.

The image matching method can obtain a result through a two-stage search method. First, by dividing the search area into blocks having a predetermined size (S102 and S103), measuring the activity of the block (S104), and comparing the area with the matched area. The primary candidate area is obtained (S105).

This is not a pixel unit comparison but an area unit comparison, and thus there is no sensitive response even if there is some change in brightness in the image.

Next, the final candidate region can be obtained by wavelet transforming the primary candidate region (S106) and measuring the energy in the transform band (S107) (S108).

This is based on the fact that the energy value in the conversion band is almost unchanged even when there is a change in brightness or slight edge change in the spatial domain.

3 is a view illustrating in detail the processing of the corrector shown in FIG. 1, and as illustrated in FIG. 3, the corrector is matched by the matcher to artificially restore an unphotographed area and is currently received. In order to prevent the Landsat-7 image from being displayed differently, a histogram and statistical values are calculated (S211).

 Then, the calculated value is applied to the compensated area to adjust the brightness (S212), and since the matching is performed from the past image, the latest terrain or artifacts may not be completely reflected, and thus the same as recently produced Using the numerical map of the area (S213), the changed terrain is artificially restored (S214).

Subsequently, even if the brightness of the reconstructed image and the currently received Landsat-7 image are adjusted, the boundary portions of the different images may remain unobtrusive, so that the boundary portion is determined by the average value between the two regions of the boundary line. By smoothing the processing (S215, S216), one completed image can be obtained.

The corrected image can be processed according to the existing satellite image mapping process.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described embodiments, and the present invention is not limited to the above-described embodiments without departing from the spirit of the present invention as claimed in the claims. Of course, any person skilled in the art can make various modifications, and such changes are within the scope of the claims.

As described above, according to the present invention, it is possible to provide more accurate images by utilizing Landsat-7 satellite images, which are received at high cost, in fields that do not require precise processing such as satellite image mapping. have.

1 is a view showing the processing of the satellite image mapping method according to the present invention,

2 is a view showing in detail the processing of the matching unit shown in FIG.

3 is a view illustrating in detail the processing of the correction unit shown in FIG. 1.

Claims (3)

(a) receiving a satellite image and retrieving an image having the same time and region as the image photographed by Landsat-7 from a previously stored database; (b) matching images of portions of the landsat-7 that are not already photographed from images of the same region retrieved from the database; (c) correcting the unphotographed image by removing brightness and discontinuous characteristics appearing at the boundary between the matched image and the image photographed by the Landsat-7; And (d) a satellite image mapping method using Landsat-7 image which comprises the step of generating the matched and corrected image as an image for mapping and transmitting the image to a satellite imagery mapping process. The method of claim 1, wherein step (b) Dividing a search region into detailed blocks in an image of the same region searched from the database; Setting a relationship between the divided blocks, measuring the activity of the blocks, and determining a primary matching candidate region by comparing with the regions to be matched; Performing wavelet transformation of each region to determine a final candidate region in the first matching candidate region; And And analyzing the relationship of energy in the conversion area, measuring the energy, and comparing the area with the area to be matched to determine a final matching area. The method of claim 1, wherein step (c) Calculating histogram analysis and statistical values for the image obtained by reconstructing the artificially photographed area and the image received from Landsat-7 in step (b); Adjusting the brightness by applying the calculated value to the restored area and restoring the changed terrain of the same area; And Compensating the boundary line between the reconstructed image and the image received from the Landsat-7 satellite map mapping method using a Landsat-7 image.