1. An object-tracking method in an environment of multiple non-overlapping cameras, comprising: dividing color rendering values required to represent colors into a plurality of sub-color regions; converting Red, Green, Blue (RGB) pixels of objects present in a first image and a second image acquired by cameras into first hue values and second hue values, respectively; assigning the first hue values to corresponding sub-color regions, and then generating a first color histogram; assigning the second hue values to corresponding sub-color regions, and then generating a second color histogram; extending an area of the first color histogram to a predetermined width; determining whether the second color histogram is included in the extended area of the first color histogram; and determining that the object in the first image is identical to the object in the second image if the second color histogram is included in the extended area of the first color histogram.