Charged particle beam apparatus

A full-focused image composing apparatus comprising:

• a plurality of full-focused image composing means including:
• noise reducing means for reducing noise of a plurality of input images each read with a different focus to generate noise-reduced images;
• noise amount evaluating means for evaluating noise amounts of said noise-reduced images to calculate noise amount evaluation values;
• signal change amount evaluating means for calculating said noise amount evaluation values, and evaluating in-focus degrees of said noise-reduced images to calculate signal change amount evaluation values;
• focus determination means for evaluating said signal change amount evaluation values to generate a maximum signal change amount evaluation value and composition information;
• and
• noise determination means for determining a noise influence degree using said maximum signal change amount evaluation value and said noise amount evaluation values to generate favorableness degree information;
• and
• composing means for generating a composite image based on a plurality of pieces of said favorableness degree information and a plurality of pieces of said composition information generated by said plurality of full-focused image composing means.