Bentley Descartes - Mosaic Rasters

Pascal Cloutier — Thu, 19 Mar 2020 12:41:37 GMT

Current Revision posted to ContextCapture | Descartes | Pointools | Orbit Wiki by Pascal Cloutier on 3/19/2020 12:41:37 PM

Mosaic

With Bentley Descartes it is possible to create a seamless mosaic from a group of overlapping images representing different part of the a region. The Mosaic tool box contains two tools that will help you create mosaics, making all images look alike by changing the color and by cutting the overlapping sections and applying the feathering tool to hide the seam of the cut.

Balance Tone

The Balance Tone tool is used to balance the tone of colors between all images of a mosaic and offers two modes to select from:

Average ‐ Averages a unique color table to selected images and is a good choice when the images look good but are not perfectly balanced.
From Reference ‐ Utilizes a source image for the color table to apply to the selected images. Use this mode when one image of the mosaic looks particularly good and the remaining images should be similar.

In addition to the two modes, the Balance Tone tool also allows you to define the Source Area by selecting the Entire Image, Overlap, Block, Oriented Block, Element or Fence.

Define Seam

The Define Seam tool is used to define the position of a seam between two overlapping images of a mosaic.

Seam Type ‐ Defines linear junction between the overlapping area of two images. The seam can be defined using one of the following methods: Quick, User-Defined, Element, and Smart.
Save Seam ‐ When enabled, the seam line is saved to the design file as a vector element.
Feathering ‐ Feathering is a camouflage technique that allows the seam to fade into the image. Feathering options are: None, Active Width, and by Input Point
Width ‐ Used to specify the width of the feathering and is applied on both sides of the seam.

And example of this tools usage is shown below.

The following illustrates two overlapping images.

When using the Define Seam tool, dashed lines are drawn to indicate the following:

The boundaries of the selected images.
The seam location which connects the diagonal corners of the overlapped area.
The width of the feathering shown on either side of the seam.

When processed, the top image is modified to create a seamless mosaic.

Tags: Descartes, Raster, Mosaic