The invention relates to an apparatus and method for providing a modifiable headspace for measuring a concentration of volatile releases from a sample. Incidentally, the image processing system is configured by an imaging device and a computer recording an image processing program, in which the imaging device includes the image pickup device, the obtaining unit, and the creating unit, and the image processing program may make the computer function as the detecting unit and the estimating unit. Thereby, it becomes easy to manufacture magnetic detection devices which detect three-axis components of terrestrial magnetism vector.