Method and apparatus using a zero-point crossing of quadratically differentiated intensity data in a histogram to determine a threshold for detecting a component from background

摘要

In a component detecting method and apparatus, intensity data stored in an intensity data storing device are rearranged in order of increasing intensity data. An intensity data quadratic differential table is formed by quadratically differentiating the intensity data of an intensity profile with respect to a data number of the intensity data. The data number at a zero-crossing point at which a quadratic differential data obtained by quadratically differentiating the intensity data is changed between positive and negative through zero from the intensity data quadratic differential table is detected. A threshold value is determined according to the intensity data of the intensity profile corresponding to the data number at the zero-crossing point. So, the component detect method and apparatus can detecting an image of the component from a background with the appropriate threshold value even when the component to be recognized is dirty or the intensity of the background fluctuates