Standard 3x3

Standard event processing is based on 3x3 pixel neighborhood event detection and extraction. A local maximum is specifically defined as any pixel, p₀, that meets the following comparison rules.

p₀ > p₆ p₀ > p₇ p₀ > p₈

$$p_0 \geq p_4 p_0 \geq$$ p₀ > p₅

$$p_0 \geq p_1 p_0 \geq p_2 p_0 \geq p_3$$

where the pixels are in READX and READY coordinates. Note: This may be different than the flight software. Any event that meets the above comparison rules is written into the event list as a 9 pixel vector with the pixels arranged from p₀ to p₈ as illustrated above.

Events are not detected at quadrant boundaries (i.e. the boundaries between regions read by a single output node). Therefore there will always be a 2 pixel gap in images where nodes meet (one pixel on each side of the node). Events are also not detected at the edges of windows or full-frames. Note that events are detected at quadrant boundaries for the flight instrument (but no effect is made to adjust for diffential gain between output nodes).