An image processing apparatus includes a first halftone processor, a first filtering processor, a second filtering processor, and an evaluator. The first halftone processor generates first halftone image data from input image data using thresholds. The first filtering processor smoothes the first halftone image data using a first filter having a size corresponding to a cycle of the thresholds. The second filtering processor smoothes the input image data using a second filter having a characteristic corresponding to the first filter. The evaluator evaluates a moiré caused in the first halftone image data based on a difference between the first halftone image data smoothed by the first filtering processor and the image data smoothed by the second filtering processor.