Ghosting means some LEDs illuminate unintentionally. Ghosting is primarily attributed to the charging or discharging of lumped parasitic capacitance in row or column of the LED matrix, during the row or column changing process, which causes some LEDs to illuminate unintentionally. This issue is easier to be identified in low grayscale images.

The ghosting is even more pronounced using the left or right slash grid test pattern shown in Figure 3-1 and Figure 3-2. LEDs in green slash are the normal display, we don’t see any LEDs are lighted up between 2 slash. Figure 3-2 is the abnormal display with ghosting. Figure 3-2 has unwanted LEDs lit up between the normal slashes. If the unwanted LEDs are in the upside of the normal slash, this is known as upside ghosting. The opposite is named as downside ghosting.

Figure 3-1 Normal Display without Ghosting

Figure 3-2 Abnormal Display with Ghosting