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Orthophoto Production Services

Gworld is expert in the processes of generating ortho products, such as an image mosaic, a digital terrain model (DTM), and a digital surface model (DSM), from a set of remote-sensing images.
When many images are required to fully cover your study area, you need to mosaic these images together into an orthomosaic dataset. These satellite and aerial images come with geometric errors, as well as misalignments between adjacent image scenes due to systematic and nonsystematic factors. To improve geometric accuracy and reduce the misalignment, bundle block adjustment, also known as image triangulation, needs to be performed on these images.

  • Ortho-mosaicing.
  • Color Balancing.
  • Seamline editing.

Orthomosaic Generation

The orthomosaic generation is based on orthorectification. This method removes the perspective distortions from the images using the 3D model. A high number of matches/keypoints (more than 1000) is required to generate the 3D model.
This method handles all types of terrain, as well as large datasets. Distances are preserved and therefore the orthomosaic can be used for measurements.

Color Balancing

After the mosaic dataset’s geometric correction is finished, there are two additional techniques that can be used to improve its visual appearance: color balance the images, and compute the seamlines in the mosaic dataset.
Color balancing is often needed for satellite images because the cross-strip images are often taken on different days. Before you can perform color balancing, the statistics and histograms first need to be computed for each image in the mosaic dataset using the Build Pyramids and Statistics tool. Once the statistics and histograms have been built, run the Color Balance Mosaic Dataset tool to balance the image colors. In general, the Dodging method with the Second Order color surface produces a good result.

Seamline editing

Seamlines are polygons that are used for defining mosaicking boundaries and resolving the image overlaps. The Build Seamlines tool provides some common algorithms to automatically compute seamlines:

  • Radiometry—Derives seamlines based on the pixel values using the best path algorithm on a cost surface.
  • Voronoi—Partitions image footprints based on an area Voronoi diagram.
  • Disparity—Determines the seamlines by leveraging the disparity images of the stereo pairs and is useful for large-scale mosaicking where the mosaic area has buildings.

Our Service

  • Photogrammetry
  • LiDAR
  • Mobile LiDAR
  • GIS services
  • Ortho Photo Production

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Green World Soft Tech
25 B, Sri Seenivasa Nagar , Mel Raghunadhapuram , Mangadu
Chennai- 600 122, India
Phone:   +91-8148615794

Email: info@gworldsoft.in
hr@gworldsoft.in
Link:    www.gworldsoft.in

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