Non-invasive blood glucose measurement using near infrared (NIR) spectroscopy relies on wavebands that provide reliable information about spectral absorption. In this study, we investigated wavebands which are informative for blood glucose in the NIR shortwave band (900∼1450 nm) and the first overtone band (1450∼1700 nm) through a specially designed NIR Fourier transform spectrometer (FTS), which featured a test fixture (where a sample or subject’s finger could be placed) and all-reflective optics, except for a Michelson structure. Different concentrations of glucose solution and seven volunteers who had undergone oral glucose tolerance tests (OGTT) were studied to acquire transmission spectra in the shortwave band and the first overtone band. Characteristic peaks of glucose absorption were identified from the spectra of glucose aqueous solution by second-order derivative processing. The wavebands linked to blood glucose were successfully estimated through spectra of the middle fingertip of OGTT participants by a simple linear regression and correlation coefficient. The light intensity difference showed that glucose absorption in the first overtone band was much more prominent than it was in the shortwave band. The results of the SLR model established from seven OGTTs in total on seven participants enabled a positive estimation of the glucose-linked wavelength. It is suggested that wavebands with prominent characteristic peaks, a high correlation coefficient between blood glucose and light intensity difference and a relatively low standard deviation of predicted values will be the most informative wavebands for transmission non-invasive blood glucose measurement methods. This work provides a guidance for waveband selection for the development of non-invasive NIR blood glucose measurement.

How to balance the optical efficiency, illumination uniformity and the size of the illumination system is a challenging task in projector design. In this paper, we present a mathematical model describing the relationship between optical energy of the illumination system and the optical parameters and an optimization design method considering the light intensity distribution of the light source. By using the proposed method, two illumination systems are designed with different types of the digital micromirror device chips. In addition, we also propose a non-coaxial system to solve the deformation problem caused by the large flip angle of the DMD chip and further improve the illumination uniformity based on Scheimpflug principle. The optical efficiency and illumination uniformity of the illumination systems were verified and analyzed. The results indicate that the systems designed by the proposed method can provide a good design scheme and obtain a satisfactory utilization rate of the optical energy and higher uniformity.

A new method is proposed to build up a color reproduction model based on neural networks and visual matching. Training data were obtained from a visual matching experiment and the commonly used CIECAM02 model to set up a link between the device parameters and human color perception. The process of training neural networks is presented. An experiment simulating an office environment was conducted, together with a user study, to verify the performance of the proposed method in identifying and reproducing color.

We propose a new method to detect latent fingerprints and their residues based on Sagnac ultraviolet Fourier transform imaging spectroscopy. The three-dimensional data cube including two-dimensional images and spectrum dimensions can be obtained by the new hyperspectral imaging technique. The method to inhibit the redundancy from the spectra-image data is also presented, which includes the self-adaptive differential filtering, the apodization algorithm, and a fast Fourier transform method. The whole process is also discussed in detail. Not only the latent fingerprint but also its residues’ distribution are provided in experimental results, and the proposed method is demonstrated.