Establishment of the Fourier transform image analysis and the three-dimensional development to the tropical wood species.

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For the quantitative evaluation of wood cell structures using Fourier transform image analysis(FTIA), which has been developed by the authous, general procedures and their backgrounds were examined. The FTIA was constructed by three main procedures, namely, pre-FFT step on the image domain, two dimensional FFT and post-FFT step on the frequency domain. Mapping procedures in the pre-FFT extracting structural elements and shape factors are proposed. Some new problems in the post-FFT such as frequency scale, frequency errors, direction problem and so on were verified. Especially, relations between contrast on the image domain and power level on the frequency domain were inspected in detail, and then some simulations were proposed to evaluate the degree of errors and to overcome them. A peculiar nature of FFT that one pixel or line of one pixel width is recognized as the δfunction was found out, and the peculiarity is shown to be effective for the application of the convolution techniques which is useful to control power level.Succeedingly, the stereology for the three dimensional analysis, which have long history but has been rarely applied in practical view, is challenged to some tropical timbers such as Acacia mangium