Design of a hand-held automatic focus digital microscope by using CMOS image sensor

Abstract The purpose of this paper was to realize a hand-held, auto-focus digital microscope system in order to observe and record microscopic images. Based on the Gauss optical theorem, we designed the algorithm and implemented it into the proposed digital microscope system. Compared with conventional optical microscopes, our digital microscope system significantly reduces the volume to only 40 mm × 35 mm × 105 mm, and achieves hand-held convenience. In order to increase the stability and convenience of the usage, we apply the discrete cosine transform (DCT) method and MathWorks MATLAB to realize the automatic focus function – it takes only 4 s for the system to complete a single time auto-focus. Therefore, in addition to the advantages of small size, low price and high convenience, our system has much room for further development and usage in medical, scientific and industrial fields in the near future.

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