Question

Rastermosaicker adds data (0,0,0)

  • 3 October 2017
  • 2 replies
  • 3 views

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My workspace created this QR code with a description below it was created by a rastermoasaicker from two png files - one for the QR and another one for the text below it.

The blue section with text extends by about 300 pixels more than the QR code - string length is up to 50 characters. When the raster mosaicker merges the two pictures together the nodata section of the merge is now replaced with black pixels. On RasterMosaicker, I tried "Overlapping Values: Last with Nodata Overwriting Data to No" and Overlapping Values: Maximum (255) and netheir one worked.

I prefer to have it white or no data. So far every thing I've tried has not worked yet. Any suggestions?


2 replies

Userlevel 2
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Hi @salvaleonrp,

In the ImageRasterizer that creates the text image, set Interpretation Type to RGBA32.

Use a RasterInterpretationCoercer to coerce QR image to RGBA32 before mosaicking.

In RasterMosaicker, set Overlapping Values to 'Composite Using Alpha Band'.

This will make all the extra pixels transparent.

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@DaveAtSafe, after trying what you suggested, the pixels became transparent but the rasters did not merge. I'm back to where I was yesterday.

When rasters were merging, the QR code starts off as UINT8 with Band 0 and palette 0 (RGB24). The second PNG is 3 bands - Red8, Green8, Blue8) all with the value of 255 on the color black. I used the PaletteResolver on the QR code and the QR Code changed to 3 bands (Red8, Green8, Blue8) with Value 0 on black. This translation produced the merged but with the black square next to the QR code.

It's almost there. What else can I try?

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