1. A dead pixel detection method, said method comprising: capturing a to-be-tested image, and obtaining a downsampling set formed by a plurality of sample pixels by downsampling said to-be-tested image; computing a moving average for each sample pixel of said downsampling set to determine whether the sample pixel is a dead pixel candidate; determining all pixels of a neighborhood of said dead pixel candidate as to-be-detected pixels; estimating a compensated value and a weighted average value under a mask for each of the to-be-detected pixels; obtaining a hypothetic dead pixel value by comparing an original pixel value of each to-be-detected pixel and the moving average of said dead pixel candidate; and determining whether said to-be-detected pixel is a dead pixel by using the original pixel value, the compensated value, the weighted average value, and the hypothetic dead pixel value.