AN IMAGING SUPPER-RESOLUTION PROCESSING METHOD FOR EFFECTIVE APERTURE CHECK OF THICK PINHOLE
DOI:
https://doi.org/10.14738/aivp.11.4Keywords:
Image super resolution, Thick pinhole, Lucy-Richardson, Neutron imagingAbstract
The Lucy-Richardson super resolution image processing technique, combined with the introduced virtual point spread function(PSF), was used to develop a measurement method of the processing precision of the superfine thick pinhole aperture. The principles of the technique were based on the known ideal image and degraded image. After the restoration and reconstruction of the degraded image with the introduced virtual point spread function (PSF)，the comparison is made between the reconstructed image and the ideal image to judge the correctness of the virtual point spread function (PSF). During this process, the simulation of the effects of the point spread function (PSF) upon the image reconstruction was carried out at first. As indicated by the simulation, the ideal point spread function (PSF) used in the image restoration and reconstruction could provide ideal results of the image reconstruction. However, in the case of relatively bigger size of the point spread function (PSF), the reconstructed image would be obtained smaller than the ideal image. Besides, related experiments were carried out on the cobalt radiation sources. In the experiments, the aperture of the shielded collimator to restrict and align the radiation source was known to be 1.0mm, the thick pinholes respectively 0.7mm and 0.45mm in aperture were used for the imaging of the F1mm radiation source, and the radiation image was recorded in imaging plates 0.05mm´0.05mm in spatial resolution. Based on the hypothesis that the processing precision of the thick pinhole fulfill the experiment requirements, the point spread function obtained from the simulated computation was introduced into the restoration and reconstruction of the recorded images. At the area with an intensity of 50%, the thick pinhole with 0.7mm aperture could provide homogenous image of the radiation source. However, the thick pinhole with 0.45mm aperture provided an elliptical image with a major-minor axis ratio of 5:3. The relatively big difference between the measurement results with the actual known object size indicates the relatively big gap between the virtual point spread function with the actual or real point spread function. This could be considered to be another indirect evidence of the relatively big difference between the actual processing precision of the 0.45mm aperture with the designed requirements.
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