Methods for determining the exterior points of an object in a background.

(57) In order that access of the outer point of a summary subject may extract the feature useful for subject recognition, when it is important to use the information in the partial outside environment of a subject, it is used in the domain of subject discernment. As an example of the feature of this form important in order to recognize and classify a subject, it is a domain of bacteria detection. An adaptability classification is the 仕 method which carries out analysis to independence from the change on image formation conditions, such as lighting, positioning, and electronic amplification. If the two general methods get to know the circumference point of a subject, they will be used in order to access the partial outside environment of a subject. In the 1st method, form of the surrounding annular outside domain of the target subject is 従わ (ed) by the form of the subject itself. In the 2nd method, circularly, known external shape is used in order to characterize the outside outline domain which approximates the form of a subject.