Abstract：One important step for detecting quantified information from image of full-hole mi-croresistivity scan imaging log (FMI) is division of FMI image、that sub-image mainly refleeting fracture and pore can be detected from raw FMI image,whether the effectiveness of image division directly related to accuracy of calculating FMI parameters.The paper gave two cluster marks-gray approximate level and increment of error rule f unction in accordance with feature of FMI image and with insufficiency of common-used threshold division algorithm and applied these two cluster marks gradationally to cluster division of FMI image.Test results show that the method has good division effect and noise suppression effect on FMI image.
