Auto-focusing method which uses a different focus determining method according to a type of corresponding focus graph, recording medium recording the method, and auto-focusing apparatus performing the method

An auto-focusing apparatus comprising:

• a focus value creating unit for creating focus values for an image, each focus value corresponding to a distance between a lens and a subject;
• a focus graph generating unit for generating a focus graph of the focus values;
• a first comparison unit for comparing the focus graph with at least one of a point light source reference graph and a non-point light source reference graph;
• a first determining unit for determining whether the focus graph corresponds to a point light source reference graph or a non-point light source reference graph based on comparison result and,
• if the focus graph corresponds to the point light source reference graph, determining a minimum point on the focus graph as a focus value of a focused image, and
• if the focus graph corresponds to the non-point light source reference graph, determining a maximum point on the focus graph as the focus value of the focused image.

A method for focusing an image comprising:

• creating a focus graph based on focus values for the image, each focus value corresponding to a distance between a lens and a subject;
• comparing the focus graph to at least one of a point light source reference graph and a non-point light source reference graph and determining whether the focus graph corresponds to a point light source reference graph and,
• determining whether the focus graph corresponds to a point light source reference graph or a non-point light source reference graph based on comparison result;
• focusing the image based on a minimum point of the focus graph if the focus graph corresponds to the point light source reference graph;
• and
• focusing the image based on the maximum point of the focus graph if the focus graph corresponds to the non-point light source reference graph.

An auto-focusing method comprising:

• creating focus values for an image, each focus value corresponding to a distance between a lens and a subject, and generating a focus graph of the focus values;
• comparing the focus graph with at least one of a point light source reference graph and a non-point light source reference graph by creating a difference between a sample of the focus graph and a sample of one of the point light source reference graph and the non-point light source reference graph;
• if the focus graph corresponds to the point light source reference graph, determining a minimum point on the focus graph as a focus value of a focused image;
• and
• if the focus graph corresponds to the non-point light source reference graph, determining a maximum point on the focus graph as the focus value of the focused image.

An auto-focusing apparatus comprising:

• a focus value creating unit for creating focus values for an image, each focus value corresponding to a distance between a lens and a subject, and generating a focus graph of the focus values;
• a focus graph generating unit for comparing the focus graph with at least one of a point light source reference graph having a minimum point and a non-point light source reference graph having a maximum point;
• a first comparison unit for, if the focus graph corresponds to the point light source reference graph, determining a minimum point on the focus graph as a focus value of a focused image;
• and
• a first determining unit for, if the focus graph corresponds to the non-point light source reference graph, determining a maximum point on the focus graph as the focus value of the focused image.