Patent Document ID: 20130068001
Application ID: 13471745
Patent Status: 0

Claim One:
1. A hardness tester for determining hardness of a sample by measuring a size of an impression formed on a surface of the sample, placed on a sample stage, by impressing an indenter with predetermined test load, comprising: an image capture control portion for obtaining an image data of the surface of the sample by controlling an image capture portion and making the image capture portion capture an image of the surface; an impression region extracting portion for extracting an impression region formed on the surface of the sample based on the image data obtained by the image capture control portion; an impression vertex extracting portion for extracting a vertex for measuring the impression to measure a size of the impression based on the impression region extracted by the impression region extracting portion; and a hardness calculating portion for calculating hardness of the sample based on the vertexes for measuring the impression extracted by the impression vertex extracting portion; wherein the impression region extracting portion binarizes the image data of the surface of the sample, applies a reduction processing and an expansion processing to the binarized image data, applies a distance conversion processing to the reduction/expansion processed image data, and extracts a closed region corresponding to a contour of the indenter by using the distance-converted image data, and the impression vertex extracting portion estimates the vertex for measuring the impression based on a profile of the closed region extracted by the impression region extracting portion, and extracts a point in the binarized image data, as the vertex for measuring the impression, that agrees with a predetermined condition based on the estimated vertex.