Posted by
Kenneth R Sloan on
Jun 05, 2015; 11:25am
URL: http://imagej.273.s1.nabble.com/backward-recreatoin-of-an-lut-tp5013041p5013044.html
there was work in the early 80s on rendering images using a restricted set of colors (specifically for frame buffers with 8bits per pixel and a hardware 8->12bits Video Lookup Table. This was often combined with dithering. See, for example , a paper by Paul Heckbert at SIGGRAPH.
These techniques might help.
question: do you require the 8bit image to be a reasonable gray scale rendition of the image, or can the 8bit values be arbitrary?
-Kenneth Sloan
(von meinem iPhone5S gesendet)
> On Jun 5, 2015, at 04:29, Gabriel Landini <
[hidden email]> wrote:
>
>> On Thursday 04 Jun 2015 21:33:12 rustyconc wrote:
>> Is there an easy way to convert the data RGB image to 8 bit gray scale so
>> that the colour scaling in the color scale image is preserved?
>
> You could use the color inspector 3D plugin to investigate this.
>
> The map of one image I loaded has 17187 colours, and the colour scale has 458.
> Most likely there is some smoothing going on at the edges of continents,
> unmapped regions and the superimposed grid which end up blending with the data
> and generating non-LUT colours which need to be dealt with.
>
> I think it will be difficult to know what is going on in the images with any
> certainty and it would be better use the original data, if available.
>
> Cheers
>
> Gabriel
>
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