topic Re: Color Model Conversion from RGB to HSV in ArcGIS Spatial Analyst Questions

Color Model Conversion from RGB to HSV

CaroFoehn — Tue, 16 Nov 2010 19:05:15 GMT

Hello,
I have a Tiff-file containing several bands, three of them beeing RGB. I like to convert them to HSV color model.

In 9.3 spatial analyst used to have the Color Model tools. I searched toolbox, resource centre, internet, but I coudn't find similar tools for ArcGIS 10. Did anyone find color model tools (that do not only apply to mosaic datasets) ?

Apreciate every help!
bye, lila

Re: Color Model Conversion from RGB to HSV

CaroFoehn — Sat, 11 Dec 2021 20:21:37 GMT

In the meantime I implemented a python script to do the color conversion manually, but it is very very slow. How can I make things more efficient? I won't have a chance to convert my final raster.

import arcpy
from arcpy import sa
import string
import numpy
import colorsys

arcpy.env.workspace = r"U:\path" # internal drive

inRast = r"U:\path\multiple_bands.tif"
outRast = r"U:\path\hsv"

Ymin = float(str(arcpy.GetRasterProperties_management(inRast, "BOTTOM")))
Xmin = float(str(arcpy.GetRasterProperties_management(inRast, "LEFT")))
Ymax = float(str(arcpy.GetRasterProperties_management(inRast, "TOP")))
rows = float(str(arcpy.GetRasterProperties_management(inRast, "ROWCOUNT")))
cols = float(str(arcpy.GetRasterProperties_management(inRast, "COLUMNCOUNT")))

# create numpy arrays
shape = rows, cols
hueArray = numpy.empty(shape)
satArray = numpy.empty(shape)
valArray = numpy.empty(shape)

x = 0
while x < cols:
    y = 0
    while y < rows:
        #Get the Cell values of the three bands
        values = arcpy.GetCellValue_management(inRast, str(Xmin + 5 + 10*x) + " " + str(Ymax - 5 - 10*y), "1;2;3")
        # save values in list
        slist = string.split(str(values), "\\", 3)
        b = float(slist[0])/255 # 1. Band Green equals blue in RGB
        nlist = string.split(slist[1], "n", 2)
        g = float(nlist[1])/255 # 2. Band Red equals green in RGB
        nnlist = string.split(slist[2], "n", 2)
        r = float(nnlist[1])/255 # 3. Band NIR equals red in RGB
        # convert ot HSV
        result = colorsys.rgb_to_hsv(r, g, b)
        hueArray[y,x] = result[0]*360
        satArray[y,x] = result[1]*100
        valArray[y,x] = result[2]*100
        
        y = y + 1
    x = x + 1

xymin = arcpy.Point(Xmin, Ymin)
hueRast = arcpy.NumPyArrayToRaster(hueArray, xymin, 10, 10)
satRast = arcpy.NumPyArrayToRaster(satArray, xymin, 10, 10)
valRast = arcpy.NumPyArrayToRaster(valArray, xymin, 10, 10)

satRast.save(outRast+"_sat.tif")
valRast.save(outRast+"_val.tif")
hueRast.save(outRast+"_hue.tif")

Re: Color Model Conversion from RGB to HSV

LouisZachos — Tue, 04 Oct 2011 21:00:17 GMT

This may help others who come across this:

The conversion tools for RGB to IHS and IHS to RGB are in the Toolbox : ERDAS Image Analysis Tools : Spectral Enhancement.

I have no clue where the old RGB to HSV, etc. tools went.

Re: Color Model Conversion from RGB to HSV

JeffreySwain — Thu, 06 Oct 2011 10:44:24 GMT

You mean the color model conversion function within Mosaic Datasets? To complete the described process, you could use the mosaic dataset to create the look and then export it, or just utilize the mosaic dataset. That would be the recommended way to create the color model change. The mosaic dataset should be fairly fast, if your script is causing performance problems.

Re: Color Model Conversion from RGB to HSV

dsffdsdf — Mon, 10 Feb 2014 04:46:54 GMT

really help a lot if you use color conversion tool. it is easy to convert RGB color mode to HSV color model. but i can't tell whether it is fit for ArcGIS. hope it is the right image sdk control for you.

best luck
Lily

Re: Color Model Conversion from RGB to HSV

FionaGregory — Mon, 27 Oct 2014 18:57:54 GMT

I finally found Color Model Conversion under the Image Analysis window in ArcMap (10.2.2). Highlight your image name at top of window ->Processing->fx->Right click on Identity Function -> Insert->choose Color Model Conversion from list.

However it would not run on my 4 band Tiff. I don't know if this is because it is 4 bands (no option is given to select which bands to use for the color model) or because of its format. No useful error message, it just says the inputs are inappropriate.