An image processing apparatus according to an embodiment includes a first frequency image generating circuitry, a second frequency image generating circuitry, a signal detecting circuitry, and a display image generating circuitry. The first frequency image generating circuitry performs, on an object pixel of processing, processing based on a pixel value of a neighboring pixel positioned close to the pixel to generate first frequency image data including a specific contrast component and a first frequency component on image data. The second frequency image generating circuitry performs processing of subtracting the first frequency image data from the image data to generate second frequency image data including a second frequency component. The signal detecting circuitry detects a linear signal derived from a linear structural object from the second frequency image data. The display image generating circuitry generates a display image according to the linear signal detected.