Calculate Redness Index after Hurst (1977) "Visual estimation of iron in saprolite" DOI: 10.1130/0016-7606(1977)88<174:VEOIIS>2.0.CO;2. Accepts vectorized inputs for hue, value and chroma, produces vector output.
Calculate Redness Index after Hurst (1977) "Visual estimation of iron in saprolite" DOI: 10.1130/0016-7606(1977)88<174:VEOIIS>2.0.CO;2. Accepts vectorized inputs for hue, value and chroma, produces vector output.