Final answer:
Pattern vision influences luminance summation and can be observed in phenomena such as Mach bands, Purkinje shift, and Troxler's fading.
Step-by-step explanation:
Pattern vision influences luminance summation and can be observed in phenomena such as Mach bands, Purkinje shift, and Troxler's fading. Mach bands are broad and brighter bands that occur in visual perception when there is a sudden change in luminance across a border. Purkinje shift refers to the phenomenon where colors that are more saturated are perceived as darker under dim lighting conditions. Troxler's fading occurs when a stationary stimulus gradually disappears from perception if it is fixated for a prolonged period of time. All of these phenomena demonstrate how our perception of brightness and color can be influenced by different patterns and lighting conditions.