scholarly journals Time-Division Color Holographic Projection in Large Size Using a Digital Micromirror Device

2021 ◽  
Vol 11 (14) ◽  
pp. 6277
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 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.

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

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.

scholarly journals Pre and Postprocessing for JPEG to Handle Large Monochrome Images

Algorithms ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 255 ◽  
Author(s):  
Walaa Khalaf ◽  
Abeer Al Gburi ◽  
Dhafer Zaghar
Keyword(s):  
Image Quality ◽  
Image Compression ◽  
Compression Ratio ◽  
Rapid Development ◽  
Reconstructed Image ◽  
Hyperbolic Function ◽  
Image Size ◽  
New Techniques ◽  
Large Size

Image compression is one of the most important fields of image processing. Because of the rapid development of image acquisition which will increase the image size, and in turn requires bigger storage space. JPEG has been considered as the most famous and applicable algorithm for image compression; however, it has shortfalls for some image types. Hence, new techniques are required to improve the quality of reconstructed images as well as to increase the compression ratio. The work in this paper introduces a scheme to enhance the JPEG algorithm. The proposed scheme is a new method which shrinks and stretches images using a smooth filter. In order to remove the blurring artifact which would be developed from shrinking and stretching the image, a hyperbolic function (tanh) is used to enhance the quality of the reconstructed image. Furthermore, the new approach achieves higher compression ratio for the same image quality, and/or better image quality for the same compression ratio than ordinary JPEG with respect to large size and more complex content images. However, it is an application for optimization to enhance the quality (PSNR and SSIM), of the reconstructed image and to reduce the size of the compressed image, especially for large size images.

Method for Improving Reconstructed Image Quality of Digital Hologram Based on SRAD and NSCT

2014 ◽  
Vol 41 (2) ◽  
pp. 0209024
Author(s):  
吴一全 Wu Yiquan ◽  
殷骏 Yin Jun ◽  
朱丽 Zhu Li ◽  
叶志龙 Ye Zhilong
Keyword(s):  
Image Quality ◽  
Reconstructed Image ◽  
Digital Hologram

Image Quality of Two-Primary Color Active-Matrix Liquid-Crystal Displays

1997 ◽  
Vol 39 (4) ◽  
pp. 618-641 ◽  
Author(s):  
David L. Post ◽  
William F. Reinhart
Keyword(s):  
Liquid Crystal ◽  
Image Quality ◽  
Liquid Crystal Display ◽  
Active Matrix ◽  
Primary Color ◽  
Aperture Ratio ◽  
Full Color ◽  
Series Of Experiments ◽  
Matrix Liquid

The demand for color head- and helmet-mounted displays (HMDs) is growing. Interest focuses on full-color systems, but a limited color repertoire is sufficient for some applications and can reduce cost and complexity significantly, especially when subtractive-color active-matrix liquid-crystal display (AMLCD) technology is used. We report a series of experiments that investigated important questions about the design and merits of two-primary color AMLCDs for HMD applications. Our main conclusion is that the image quality of a subtractive-color AMLCD with high (≥70%) aperture ratio is superior to a comparable, conventional color AMLCD. Evidence regarding requirements for resolution, aperture ratio, and gray scale is also provided.

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

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.

scholarly journals Evaluation of the effect of filters on reconstructed image quality from cone beam CT system

2021 ◽  
Vol 11 (1) ◽  
pp. 35-47
Author(s):  
Ngoc Ha Bui ◽  
Tien Hung Bui ◽  
Thuy Duong Tran ◽  
Kim Tuan Tran ◽  
Ngoc Toan Tran
Keyword(s):  
Image Quality ◽  
Cone Beam Ct ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Reconstructed Image ◽  
Cone Beam ◽  
Spatial Filters ◽  
Dimensional Reconstruction ◽  
Ct System

: 3D Filtered Back Projection (FBP) is a three-dimensional reconstruction algorithm usually used in Cone Beam Computed Tomography (CBCT) system. FBP is one of the most popular algorithms due to its reconstruction is fast while quality of the result is acceptable. It can also handle a more considerable amount of data with same computer performance with other algorithms. However, the quality of a reconstructed image by the FBP algorithm strongly depends on spatial filters and denoising filters applied to projections. In this paper an evaluation of the reconstructed image quality of the CBCT system by using different denoising filters and spatial filters to find out the best filters for the CBCT system is performed. The result shows that, there is a significantly decrease of the noise of projection with the combination of Median and Gaussian filters. The reconstructed image has high resolution with Cosine filter and becomes more sharpen with Hanning filter.

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