Converting RGB to greyscale

[JamesSaunders3]

Hi there

I can't seem to find a thread on this topic, although I would think it to be a fairly common task.

I want to convert some images that I have from 3 band RGB's to greyscale. They are historical aerial photographs that are in black and white, but have been mistakenly scanned in colour. I have them both with and without spacial data, so retaining that spatial data would be ideal, but is not absolutely necessary.

The images are JPEGs that I convert to IMGs.

Thanks
James

[EricRice]

James,

You can add the bands together, then take the average to get a single band grayscale image.  Basicaly its R+G+B/3.  You can do this quite easily with the raster calculator.  If you want to get fancy, you can use the grayscale function so the conversion to grayscale happens on the fly.

Regards,
Eric

[BuckleLEE]

For common prople, Converting RGB to greyscale is not a common topic, but im a image programmer, i think i can answer your question in this robust image dealing site, RGB, CMYK and grayscle is its most common info.