1. An image signal processing system comprising: an image processing pipeline configured to detect and correct a defective image pixel by: receiving an input pixel of image data acquired using an image sensor; identifying a set of neighboring pixels having the same color component as the input pixel; removing two neighboring pixels from the set of neighboring pixels thereby generating a modified set of neighboring pixels, wherein the two neighboring pixels correspond to a maximum pixel value and a minimum pixel value of the set of neighboring pixels; determining a gradient for each neighboring pixel in the modified set of neighboring pixels; and determining whether the input pixel comprises a dynamic defect or a speckle based at least in part on the gradient for each neighboring pixel in the modified set of neighboring pixels.