Improving the Reconstruction Image Quality of Multiple Small Discrete Targets Using the Phase Coherence Method

Holographic projection is a simple projection as it enlarges or reduces reconstructed images without using a zoom lens. However, one major problem associated with this projection is the deterioration of image quality as the reconstructed image enlarges. In this paper, we propose a time-division holographic projection, in which the original image is divided into blocks and the holograms of each block are calculated. Using a digital micromirror device (DMD), the holograms were projected at high speed to obtain the entire reconstructed image. However, the holograms on the DMD need to be binarized, thereby causing uneven brightness between the divided blocks. We correct this by controlling the displaying time of each hologram. Additionally, combining both the proposed and noise reduction methods, the image quality of the reconstructed image was improved. Results from the simulation and optical reconstructions show we obtained a full-color reconstruction image with reduced noise and uneven brightness.

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Comparative investigation of coherence factor weighting methods for an annular array photoacoustic microscope

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac4684 ◽

2021 ◽

Author(s):

Riku Suzuki ◽

Ryo Shintate ◽

Takuro Ishii ◽

Yoshifumi Saijo

Keyword(s):

Image Quality ◽

Noise Suppression ◽

Contrast Ratio ◽

Comparative Investigation ◽

Phase Coherence ◽

Annular Array ◽

Coherence Factor ◽

Array Transducer ◽

Weighting Methods

Abstract To achieve fine visualization of the peripheral microvascular networks, we have developed a photoacoustic (PA) microscope equipped with a four-channel annular array transducer. The quality of PA images processed with Delay-and-Sum (DAS) method is degraded by off-axis signals. Thus, to achieve higher image quality for the PA microscope, this study evaluated the efficacy of the five coherence factor weighting methods: coherence factor, sign coherence factor, phase coherence factor, circular coherence factor, and vector coherence factor. Using PA signals acquired from a 100 µm microtube and the skin microvessels, we generated PA images with DAS and one of the weighting methods, and quantitatively evaluated the image quality by calculating the sharpness, contrast ratio, and contrast-to-noise ratio. The results showed the phase coherence factor and the vector coherence factor methods were more effective to clearly visualize the microvascular structure, in terms of vessel sharpening and noise suppression performances, than the other methods.

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Use of a speckle reduction technique to improve the reconstruction image quality of CCD-based optical computed tomography scanner

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2014.12.112 ◽

2015 ◽

Vol 784 ◽

pp. 585-589 ◽

Cited By ~ 4

Author(s):

Yuan-Jen Chang

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Reduction Technique ◽

Speckle Reduction ◽

Optical Computed Tomography ◽

Reconstruction Image ◽

Computed Tomography Scanner

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Pengaruh Tegangan Tabung terhadap Kualitas Citra pada Pemeriksaan Computed Tomography Kepala menggunakan Iterative Reconstruction

Jurnal Teori dan Aplikasi Fisika ◽

10.23960/jtaf.v9i1.2715 ◽

2021 ◽

Vol 9 (1) ◽

pp. 103-110

Author(s):

Muhammad Irsal ◽

◽

Nurbaiti Nurbaiti ◽

Aulia Narendra Mukhtar ◽

Shinta Gunawati ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Effective Dose ◽

Iterative Reconstruction ◽

Signal To Noise Ratio ◽

Hounsfield Unit ◽

P Value ◽

Dose Length Product ◽

Reconstruction Image

Iterative reconstruction can optimize radiation dose and improve image quality on CT scan. This research method is quantitative analytic with the analysis of the results of the head CT examination parameters associated with image quality to changes in variations of 80 kV, 100 kV, 120 kV with the use of iterative reconstruction. Image quality measurements are the Hounsfield Unit (HU) value, standard deviation, and Signal to Noise Ratio (SNR) using Radiant Viewers. Effective dose measurement using the Dose Length Product (DLP). Then perform the Kruskal Wallis test to find out whether there is an effect of tube voltage and Iterative Reconstruction on the SNR value using IBM SPSS version 24. The results image quality of the HU value increase due to changes in the kV value, but the value does not change significantly when the iDose changes, for the standard The deviation has decreased due to changes in kV, but the value of the value does not experience a significant change at the time of change in iDose, while SNR increases due to changes in kV value and changes in iDose. The percentage ratio of the effective dose in the use of standard kV with 80 kV decreased radiation dose by 62%, while at 100 kV there was a decrease of 25%, and the use of 120 kV experienced an increase of 25%. The results of the Kruskal Wallis test p-value <0.001, therefore it can be concluded that there is a difference in the SNR image quality at each change in iDose and kV parameters.

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Time-division Color Holographic Projection in Large Size Using a Digital Micromirror Device

10.20944/preprints202106.0438.v1 ◽

2021 ◽

Author(s):

Takayuki Takahashi ◽

Tomoyoshi Shimobaba ◽

Takashi Kakue ◽

Tomoyoshi Ito

Keyword(s):

Image Quality ◽

High Speed ◽

Reconstructed Image ◽

Digital Micromirror Device ◽

Full Color ◽

Large Size ◽

Reconstruction Image ◽

Reduction Methods ◽

Time Division

Holographic projection is a simple projection because it enlarges or reduces reconstructed images without using a zoom lens. However, one major problem associated with this projection is the deterioration of image quality as the reconstructed image enlarges. In this paper, we propose a time-division holographic projection, in which the original image is divided into blocks and the holograms of each block are calculated. Using a digital micromirror device (DMD), the holograms were projected at high speed to obtain the entire reconstructed image. However, the holograms on the DMD need to be binarized, thereby causing uneven brightness between the divided blocks. We correct this by controlling the displaying time of each hologram. Additionally, combining both the proposed and noise reduction methods, the image quality of the reconstructed image was improved. Results from the simulation and optical reconstructions show we obtained a full-color reconstruction image with reduced noise and uneven brightness.

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Improving Reconstruction Image Quality of Digital Holography Using Median Filter and Intensity Subtraction

Laser & Optoelectronics Progress ◽

10.3788/lop48.120901 ◽

2011 ◽

Vol 48 (12) ◽

pp. 120901

Author(s):

王存帅 Wang Cunshuai ◽

张引科 Zhang Yinke ◽

郝劲波 Hao Jinbo ◽

吴艳 Wu Yan

Keyword(s):

Image Quality ◽

Digital Holography ◽

Median Filter ◽

Reconstruction Image

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Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064189 ◽

1971 ◽

Vol 29 ◽

pp. 26-27

Author(s):

K. Shibatomi ◽

T. Yamanoto ◽

H. Koike

Keyword(s):

Electron Microscope ◽

Image Quality ◽

Scanning Electron Microscope ◽

Chromatic Aberration ◽

Image Contrast ◽

Objective Lens ◽

Thick Specimen ◽

Transmission Electron ◽

Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

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