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Converting a multiband image to singleband

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#1
lynx

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Hi,

I've got a problem with an jpg-Image...
I displayed it in ArcView and it contains the RGB band information.

Now I'm stuck with the problem to merge these three bands to one.
Is there a possibility to do that?

As I thought this might be possible using Erdas Imagine, I tried it out (never used Erdas before) but I didn't find a way with this program either.

I use ArcView 10 and Erdas Image 8.4.

Would be glad if anyone had an idea.
Thank you.

#2
DaveB

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I haven't tested this with multi-band rasters, but it should work.
Open just the raster in ArcMap, with no other data. Then use the Export Map command from the File menu. If you do this from data view you can set some options in the output file including writing a world file for jpg or tiff formats or writing a geotiff. I have used this method to "compress" multiple rasters, such as a hillshade and hypsometry, into a single file.
Dave Barnes
Esri
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Map Geek

#3
jrat

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Also at 10 you have access to the Imagery Analysis Window. Menu>windows>Imagery Analysis Window. With this tool you can to a variety of processes some not needing Spatial Analysis.

#4
M.Denil

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You say you want "to merge these three bands to one."

Just what do you mean by that? If the three bands are merged to one, it will no longer be a three color raster, just a single greyscale image. It will also likely be of questionable use, just smouched together (smouched may not be the correct technical term...)

One can go the other way, merging three single band geyscale rasters into an RGB composite using the Arc
CompositeBands_management <in_rasters;in_rasters...> <out_raster>
tool: it puts out .bmp, .img, .jpg, .jp2, .png, .tif, GRID, or geodatabase rasters.

What it sounds like you want, however, begins with splitting the image into individual bands:

Splitting the channels can be done with the Arc tool:
RasterToOtherFormat_conversion <Input_Rasters; Input_Rasters...> <Output_Workspace> {GRID}
Outputting to a GRID with this tool will produce a GRID stack, and three component GRIDs

The three component GRIDs will be one each of the three channels. Each a single band greyscale image.

I suppose you can go on to merge these together, using any of a range of raster tools, if that is what you really wanted to do. Again, just why you needed to do this was unclear.

By the by, one can also split the channels in Photoshop or Corel PhotoPaint, but you will have to georeference the output images after. That, however, is not too hard, since you have the source image for a reference.

Mark Denil
National Ice Center

#5
raj nagi

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You can do this through Image Analysis Window (http://help.arcgis.c...000000m7000000/). Open Image Analysis window by clicking Windows on main menu and then Image Analysis. Now in Image Analysis window click the color aerial imagery and under processing section of Image analysis window, click clip. This will generate a new temporary layer and add to the TOC. Now right click the layer and click properties. In the layer properties window click the ‘Functions’ tab and right click the clip function and insert grayscale function (http://help.arcgis.c...0004w000000.htm). This will open a dialog box where you can give different weight to each band. This will give one band image, which is temporary. You can make this permanent by right clicking the layer and then Data -> Export Data. You would need to provide location, name and format of the file.
Hope this helps!




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