There is described a method comprising: capturing an image of a drip chamber using an image sensor； identifying a plurality of pixels of interest within the image； determining a subset of pixels within the plurality of pixels of interest, wherein each pixel of the plurality of pixels of interest is determined to be within the subset of pixels when there is a path to a baseline corresponding to the drip chamber； performing a rotation operation on the subset of pixels； and estimating a volume of a drop within the drip chamber by counting a number of pixels within the rotated subset of pixels. There is also described a flow meter.
