PROBLEM TO BE SOLVED: To provide a technique for carrying out male and female identification of fertilized eggs at a high identification rate and at high speed based on image data obtained by photographing the outline of an egg. That is, a fertilized egg sex determination method for determining a sex with a contour of a fertilized egg by a computer, wherein the contour is determined based on image data obtained by photographing the fertilized egg at different angles. Extraction, calculating the minor axis from the contour, calculating the phase difference of the minor axis corresponding to imaging at each angle, fertilized egg sex determination method to determine the sex using the phase difference of the minor axis Is. [Selection diagram] Fig. 25【課題】本発明では、卵の輪郭を撮影した画像データに基づいて、高い鑑定率で、且つ高速に有精卵の雌雄鑑定を行う技術を提供する。【解決手段】即ち、コンピュータにより有精卵の輪郭で雌雄を判定する有精卵の雌雄鑑定方法であって、前記有精卵を角度を変えて撮影して得た画像データに基づいて輪郭を抽出し、前記輪郭から短径を算出し、各角度での撮影に対応した前記短径の位相差を算出し、前記短径の位相差を用いて雌雄の判定を行う有精卵雌雄鑑定方法である。【選択図】図２５
