1. A method for detecting a pattern-like image, which comprises: obtaining a histogram h&lsqb;x&rsqb; of an input image; dividing the histogram h&lsqb;x&rsqb; into at least a first subset of samples and a second subset of samples; and determining whether the input image is a pattern-like image based on a relationship between a number n 1 of samples in the first subset of samples and a number n 2 of samples in the second subset of samples.