Panchromatic merge of rasters (Pansharpening)

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ic_8673   Dialog allows to increase the spatial resolution of a color raster using a panchromatic raster of higher-resolution. Both rasters must have the same coordinate system and be located in a space with overlap.

To recalculate the brightness of pixels, one of three methods is used:

1.        Averaging of values over the channels, the new value is calculated as:

 

where – a new value of the multispectral channel, – value of the panchromatic channel, – the old value of RGB channels.

2.        IHS transformation (Intensity-Hue-Saturation Transformation). The values of the RGB channels are converted to the IHS color space. The component of brightness (Intensity) is replaced by the value of the PAN channel and is recalculated into RGB space. The calculations are performed using the following formulas:

where – the intensity replaced with the value of PAN channel, and – components of the tone (Hue) and saturations (Saturation), – the old values of channels, – the calculated values.

3.        Transformation of Brovey (BroveyTransform, BT). Increases visual contrast, but greatly degrades spectral characteristics. Formula:

where – the calculated values of channels, – the old values of channels, – average value of RGB channels.