The flood fill operation fills the connected components with a given color. Starting from a seed point, the neighboring pixels are colored with a uniform color. The neighboring pixels can be within a specified range of the current pixel. The flood fill function is int floodFill(InputOutputArray image, Point seedPoint, Scalar newVal, Rect* rect=0, Scalar loDiff=Scalar(), Scalar upDiff=Scalar(),int flags=4). The parameters loDiff and upDiff represent the range to check for every neighboring pixel (note that 3-channel difference thresholds can be specified). The parameter newVal is the color to apply to the pixels that are in range. The lower part of the parameter flags contains the pixel's connectivity value to use (4 or 8). The upper part defines the mode of the operation.

Depending on this mode, the flood fill function will color a neighboring pixel in the input image if it is within the specified range (given by loDiff and upDiff) of either the current pixel or if the neighboring...