A reflection heat source including a radiator as well as an aluminum plate is designed, and the temperature
field of the aluminum plate is used as the tested object. The reflection lensless Fourier transform (LFT) digital
holography is performed to measure the temperature field distribution. For the comparison, the temperature
measurement system within the radiator is used to measure the temperature distributions. The results obtained
by these two methods are in good agreement, which demonstrates that the digital holography method is valid
for the measurement of the temperature distribution.
Surface roughness is crucial guideline to the surface quantity of work piece. This paper demonstrates a simple approach
for measurement of surface roughness by using digital holography imaging method based on reflection off-axis lensless
Fourier transform (LFT) holography. The surface profiles of the standard roughness sample plates which have the
different arithmetic average height values are used as the measurement sample. Comparing the arithmetical average
height values of the roughness sample plates obtained from the experiment with the given parameters, the results are in
good agreement. It has shown that the method is reasonable and efficient.
The lensless Fourier transform digital holography has been widely employed in microscopic imaging. It enables
quantitative phase analysis for both reflection and transmission objects. The phase image is obtained in the numerical
reconstruction procedure. The in-focus reconstruction distance could be determined according to the extremum of the
autofocusing criterion function, which is commonly applied in finding the in-focus amplitude image of the object. Then
the reconstruction distance for the phase image is considered to be equal to the one for the amplitude image. When the
object is a pure phase sample, such as the living cell, the minimum value of the autofocusing criterion function should be
found to determine the in-focus reconstruction distance. However, in the experiment, the in-focus amplitude image is
often not an ideal uniform bright field, so this method will result in some deviation. In this contribution, two
derivatives-based criterion functions are applied to the phase image directly to accomplish the in-focus phase contrast
imaging, which is more intuitive and precise. In our experiments, the set-up of the lensless Fourier transform digital
holography is established firstly. Then the living cervical carcinoma cells are detected. The phase aberration is corrected
by two-step algorithm. The final autofocusing results verify the algorithm proposed in this paper.
KEYWORDS: Digital holography, 3D image reconstruction, Holograms, Image segmentation, Fourier transforms, Microscopy, Holography, Digital recording, Reconstruction algorithms, Cervical cancer
The number of cells is commonly employed to describe the cell viability and the status of cell culture in a certain extent.
An automatic and non-invasive detecting method for the status analysis of cell culture is developed based on digital
holography microscopy (DHM) technology. Digital holographic imaging can retrieve quantitative information of object
wavefront by the numerical reconstruction from a single digital hologram recorded by a detector such as CCD or CMOS
camera, which is especially suitable for the morphology detection of the transparent or semi-transparent cells. In this
contribution, the lensless Fourier transform (LFT) based holography configuration is designed for cell imaging without
prestaining, and the amplitude and phase of living cells can be reconstructed by digital reconstruction and phase
unwrapped algorithms. Then the image filtering and segmentation are combined for the automatic evaluation of the level
of confluency. In imaging experiments, the culture status of the cervical cancer cell TZMbl is detected, and the results
demonstrate that digital holography microscopy provides a feasible non-invasive method for monitoring the living cell
culture.
A simple method for measurement of temperature field in the region near to the metal plate of the radiator is
demonstrated by using digital holography in the Lensless Fourier transform configuration (LFT). The temperature is
measured within the boundary layer of the convective flow field. The deviation of the temperature produced by this
method, from that obtained by the thermocouple is rather small. It has shown that the method is reasonable and efficient.
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