ULTRASONIC OBSERVATION APPARATUS, METHOD FOR OPERATING ULTRASONIC OBSERVATION APPARATUS, AND COMPUTER-READABLE RECORDING MEDIUM

An ultrasonic observation apparatus includes: a frequency analysis unit configured to analyze a frequency of a received ultrasonic wave to calculate a frequency spectrum; a feature-data extraction unit configured to approximate the frequency spectrum calculated by the frequency analysis unit to extract at least one piece of feature data from the frequency spectrum; and a feature-data image data generation unit configured to generate feature-data image data for displaying information corresponding to the feature data in accordance with one of a color display method in which hue varies depending on a value of the feature data, and a gray scale display method in which hue is constant regardless of the value of the feature data, depending on a relationship between the feature data extracted by the feature-data extraction unit and a threshold in the feature data, the threshold being constant regardless of a value of a display parameter of image data.