In accordance with an embodiment, a method of adjusting quality of an image of patterns common in shape includes acquiring a first gray value and a first waveform within a reference image, acquiring a sample image, acquiring a second gray value and a second waveform from third and fourth regions within a sample image, respectively, and adjusting the brightness and contrast of the sample image. The first gray value is a standard for the brightness of the image from a first region within a reference image. The first and second waveforms represent a luminance profile of second and fourth regions including edges, respectively. The third and fourth regions correspond to the first and second regions. The brightness and contrast of the sample image are adjusted by matching the first gray value and the first waveform with the second gray value and the second waveform.