This transform enhances detail in high-value regions of the image (bright) whilst
decreasing the dynamic range in low-value regions (dark) – the opposite effect to the
logarithmic transform. The choice of base depends on the level of dynamic range
compression required. In general, base numbers just above 1 are suitable for photographic
image enhancement. Thus, we expand our exponential transform notation to include a
variable base and scale to the appropriate output range as before: