In order to perform document image denoising more efficiently and rapidly, we proposed a hybrid method which used the Otsu's method to initial binary quantization, used two dimensional median filters to reduce the left pepper & salt noises, and performed open and close operators to eliminate the remained noises. Besides, a fast calculation strategy was proposed based on packed binary (PB) format and source word accumulation (SWA). The PB format uses a uint32 word to represent 32 binary pixels, and SWA is capable of directly performing erosion and dilation processes on this format. Experiments demonstrate that the computation time using acceleration is only 18.92% and 18.57% of those not using acceleration for erosion and dilation, respectively. Besides, the denoising method using acceleration is efficient on denoising while keep the quality of thin strokes, and it results in a 17.68% reduction in computation time.