Image processing method

Abstract

To provide a method for setting an appropriate threshold value for extracting a main groove cross section from a CT image.SOLUTION: An image processing method for binarizing a CT image obtained by photographing a cross section of a tire including a plurality of main grooves with a CT apparatus using a threshold value, includes: binarizing the CT image with each of a plurality of threshold values to generate a plurality of binarized images; obtaining a plurality of temporary main groove widths which are widths of the respective main grooves in the respective binarized images; obtaining, for each of the binarized images, a ratio of the temporary main groove width of the second or subsequent main groove to the temporary main groove width of the first main groove; and setting, for each of the second or subsequent main grooves, a threshold value in a range in which the ratio does not change even which the threshold value is changed as an optimum threshold value for binarizing the CT image.SELECTED DRAWING: Figure 4

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