1. A method for detecting the number and/or location particles comprising: imaging a plurality of particles using an imaging system having a point spread function, wherein the imaging returns an image; estimating a plurality of point spread function dictionary coefficients of the image using a point spread function dictionary, wherein the point spread function dictionary includes a plurality of point spread function responses that each correspond with a different particle position; and determining the number and/or location of the particles in the image from the point spread function dictionary coefficients.