Hard to tell from the laptop screen shot but it looks a little like parasitic noise, especially if it is erratic in nature.
Try running the laptop on internal battery only for a short while while acquiring images, the laptop mains supply/charger unit should be completely disconnected for this test.
If the noise disappears when on internal battery then the source is the laptop charger.
If the noise is still present when running on internal battery only then possibly there is some RF leakage from the laptop CPU/RAM modules that is being picked up in the USB cable shield or the power supply lines to the camera and the addition of some anti-parasitic ferrite clamps to either ends of the USB cable and the SX power supply cable might be sufficient to deal with this source of parasitic noise.
William.