scholarly journals Effect of Overlapping Projections on Reconstruction Image Quality in Multipinhole SPECT

2006 ◽  
Author(s):  
Kathleen Vunckx ◽  
Johan Nuyts
Keyword(s):  
Image Quality ◽  
Reconstruction Image

SU-FF-I-20: Digital Tomosynthesis Mammography (DTM) : Dependence of Reconstruction Image Quality On Number and Angular Range of Projection Views

2006 ◽  
Vol 33 (6Part3) ◽  
pp. 2001-2001 ◽  
Author(s):  
H-P Chan ◽  
Y Zhang ◽  
MA Roubidoux ◽  
MA Helvie ◽  
MM Goodsitt ◽  
...  
Keyword(s):  
Image Quality ◽  
Digital Tomosynthesis ◽  
Angular Range ◽  
Reconstruction Image

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 Fractal Image Compression Based on High Entropy Values Technique

2018 ◽  
Vol 28 (2) ◽  
pp. 119
Author(s):  
Douaa Younis Abbaas
Keyword(s):  
Image Quality ◽  
Compression Ratio ◽  
Search Algorithm ◽  
Fractal Image Compression ◽  
High Entropy ◽  
Fractal Image ◽  
Reconstruction Image ◽  
Domain Block ◽  
Entropy Technique ◽  
Full Search

There are many attempts tried to improve the encoding stage of FIC because it consumed time. These attempts worked by reducing size of the search pool for pair range-domain matching but most of them led to get a bad quality, or a lower compression ratio of reconstructed image. This paper aims to present a method to improve performance of the full search algorithm by combining FIC (lossy compression) and another lossless technique (in this case entropy coding is used). The entropy technique will reduce size of the domain pool (i. e., number of domain blocks) based on the entropy value of each range block and domain block and then comparing the results of full search algorithm and proposed algorithm based on entropy technique to see each of which give best results (such as reduced the encoding time with acceptable values in both compression quali-ty parameters which are C. R (Compression Ratio) and PSNR (Image Quality). The experimental results of the proposed algorithm proven that using the proposed entropy technique reduces the encoding time while keeping compression rates and reconstruction image quality good as soon as possible.

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