A Control Algorithm of LCD Dynamic Backlight Based on PSNR

2012 ◽  
Vol 241-244 ◽  
pp. 3014-3019 ◽  
Author(s):  
Xiao Bing Zhang ◽  
Xin Liu ◽  
Bo Liu ◽  
Jiang Hong Han ◽  
Hua Xia Wu
Keyword(s):  
Liquid Crystal ◽  
Image Quality ◽  
Power Consumption ◽  
Control Algorithm ◽  
Signal To Noise Ratio ◽  
Liquid Crystal Display ◽  
Gray Level ◽  
Quality Requirement ◽  
Signal To Noise

A new algorithm is proposed to adjust backlight luminance for local dimming of liquid crystal display (LCD) devices. PSNR (the peak signal-to-noise ratio) =30 is acted as the lowest standard to guarantee the quality of image in the algorithm. Based on the formula of PSNR=30, the square error value of the image distortion is gained. Then, luminance of backlight is gained dynamically by that the maximum gray level minus 1 into the formula proposed in the paper and decreases by one after each trial if the image quality requirement is not satisfied. In order to simplify the calculation, three important gray level values are selected to meet the requirements. The results show that the algorithm can greatly reduce the power consumption with guaranteeing the image quality and furthermore save much time in calculation and be better applied in hardware.

Image Quality Enhancing by Efficient Histogram Equalization

2014 ◽  
Vol 2 (2) ◽  
pp. 47-58
Author(s):  
Ismail Sh. Baqer
Keyword(s):  
Image Quality ◽  
Contrast Enhancement ◽  
Mean Squared Error ◽  
Signal To Noise Ratio ◽  
Histogram Equalization ◽  
Gray Level ◽  
Signal To Noise ◽  
Squared Error ◽  
Noise Ratio

A two Level Image Quality enhancement is proposed in this paper. In the first level, Dualistic Sub-Image Histogram Equalization DSIHE method decomposes the original image into two sub-images based on median of original images. The second level deals with spikes shaped noise that may appear in the image after processing. We presents three methods of image enhancement GHE, LHE and proposed DSIHE that improve the visual quality of images. A comparative calculations is being carried out on above mentioned techniques to examine objective and subjective image quality parameters e.g. Peak Signal-to-Noise Ratio PSNR values, entropy H and mean squared error MSE to measure the quality of gray scale enhanced images. For handling gray-level images, convenient Histogram Equalization methods e.g. GHE and LHE tend to change the mean brightness of an image to middle level of the gray-level range limiting their appropriateness for contrast enhancement in consumer electronics such as TV monitors. The DSIHE methods seem to overcome this disadvantage as they tend to preserve both, the brightness and contrast enhancement. Experimental results show that the proposed technique gives better results in terms of Discrete Entropy, Signal to Noise ratio and Mean Squared Error values than the Global and Local histogram-based equalization methods

The Influence of Alteration of kVp and mAs towards the Image Quality of Acrylic Using CBCT

2019 ◽  
Vol 829 ◽  
pp. 252-257
Author(s):  
Azhari ◽  
Yohanes Hutasoit ◽  
Freddy Haryanto
Keyword(s):  
Image Quality ◽  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Signal To Noise ◽  
Bite Block ◽  
Significant Difference ◽  
Noise Ratio ◽  
Post Hoc ◽  
Radiograph Image

CBCT is a modernized technology in producing radiograph image on dentistry. The image quality excellence is very important for clinicians to interpret the image, so the result of diagnosis produced becoming more accurate, appropriate, thus minimizing the working time. This research was aimed to assess the image quality using the blank acrylic phantom polymethylmethacrylate (PMMA) (C­5H8O2)n in the density of 1.185 g/cm3 for evaluating the homogeneity and uniformity of the image produced. Acrylic phantom was supported with a tripod and laid down on the chin rest of the CBCT device, then the phantom was fixed, and the edge of the phantom was touched by the bite block. Furthermore, the exposure of the X-ray was executed toward the acrylic phantom with various kVp and mAs, from 80 until 90, with the range of 5 kV and the variation of mA was 3, 5, and 7 mA respectively. The time exposure was kept constant for 25 seconds. The samples were taken from CBCT acrylic images, then as much as 5 ROIs (Region of Interest) was chosen to be analyzed. The ROIs determination was analyzed by using the ImageJ® software for recognizing the influence of kVp and mAs towards the image uniformity, noise and SNR. The lowest kVp and mAs had the result of uniformity value, homogeneity and signal to noise ratio of 11.22; 40.35; and 5.96 respectively. Meanwhile, the highest kVp and mAs had uniformity value, homogeneity and signal to noise ratio of 16.96; 26.20; and 5.95 respectively. There were significant differences between the image uniformity and homogeneity on the lowest kVp and mAs compared to the highest kVp and mAs, as analyzed with the ANOVA statistics analysis continued with the t-student post-hoc test with α = 0.05. However, there was no significant difference in SNR as analyzed with the ANOVA statistic analysis. The usage of the higher kVp and mAs caused the improvement of the image homogeneity and uniformity compared to the lower kVp and mAs.

Quality of Computed Tomography Pulmonary Embolism and Aortic Phase Images Acquired with Power Injection via an Arm Port

2017 ◽  
Vol 22 (2) ◽  
pp. 88-92
Author(s):  
Ryan Verity ◽  
David Leswick ◽  
Brent Burbridge ◽  
Rhonda Bryce ◽  
Hyun Lim
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Thin Section ◽  
Signal To Noise Ratio ◽  
Contrast Injection ◽  
Signal To Noise ◽  
Streak Artifact ◽  
Noise Ratio

Abstract Background: The safety of power-injectable implanted arm ports is well established, but there is insufficient data to conclude that image quality of computed tomography resulting from contrast introduced via the port is of equal quality to images derived from contrast introduced via traditional peripheral access. The objective of this study was to determine whether the image quality of computed tomography pulmonary embolism and computed tomography aorta studies would differ when injecting contrast via an implanted arm port vs a peripheral intravenous site. We hypothesized that injecting via an implanted arm port would produce better-quality images, the result of more appropriate timing and less streak artifact. Methods: Scans from a provincial database search for patients who underwent a computed tomography pulmonary embolism or aorta study with contrast injection via the implanted arm port and thin section images available, were reviewed (pulmonary embolism studies n = 3, aorta studies n = 3). Only a limited number of patients were available for review because there are currently few patients with these ports in place and we limited evaluation to thin section images. Comparison was made with 6 control patients who did not have a port and had received a peripheral arm intravenous contrast injection for these study types. Objective measurements included signal-to-noise ratio and contrast-to-noise ratio of the pulmonary arteries (4 sites) and aorta (2 sites) as appropriate for scan type. Subjective analysis of image quality was performed by 2 radiologists. Results: Although sample size was limited, the implanted arm port group had similar or higher mean signal-to-noise ratio and contrast-to-noise ratio values at all sites. Subjective assessments showed the implanted arm port group to have similar or better opacification and diagnostic confidence; similar or less streak artifact was also observed at each of the sites. Conclusions: These exploratory results suggest that studies with implanted arm port injection can generate high-quality images on both objective and subjective assessment, similar to, or possibly better than, images generated from usual peripheral intravenous access for contrast injection.

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.

Determining the Quality of Compression in High Resolution Satellite Images Using Different Compression Methods

2015 ◽  
Vol 20 ◽  
pp. 202-217
Author(s):  
S. Sanjith ◽  
R. Ganesan
Keyword(s):  
High Resolution ◽  
Image Quality ◽  
Satellite Images ◽  
Signal To Noise Ratio ◽  
Joint Photographic Expert Group ◽  
Expert Group ◽  
Signal To Noise ◽  
High Resolution Satellite Images ◽  
Noise Ratio

Measuring the quality of image is very complex and hard process since the opinion of the humans are affected by physical and psychological parameters. So many techniques are invented and proposed for image quality analysis but none of the methods suits best for it. Assessment of image quality plays an important role in image processing. In this paper we present the experimental results by comparing the quality of different satellite images (ALOS, RapidEye, SPOT4, SPOT5, SPOT6, SPOTMap) after compression using four different compression methods namely Joint Photographic Expert Group (JPEG), Embedded Zero tree Wavelet (EZW), Set Partitioning in Hierarchical Tree (SPIHT), Joint Photographic Expert Group – 2000 (JPEG 2000). The Mean Square Error (MSE), Signal to Noise Ratio (SNR) and Peak Signal to Noise Ratio (PSNR) values are calculated to determine the quality of the high resolution satellite images after compression.

Experiment Research of Image Transmission over Wired and Wireless Environment

2013 ◽  
Vol 739 ◽  
pp. 592-595
Author(s):  
Xiao Jun Zhong ◽  
Lu Yao
Keyword(s):  
Image Quality ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Image Transmission ◽  
Experiment Research ◽  
Signal To Noise ◽  
Relative Angle ◽  
Wireless Environment ◽  
Fast Ethernet

We experimentally achieved a VHF over Fast-Ethernet communication system for image transmission. The quality of image is studied with considering the antenna vertical relative angle of the transmitter and receiver and the distance between transmitter and receiver. The signal-to-noise ratio is also studied for analyzing the image quality in this paper.

Motion Estimation for Gray Level Videos Using Different Block Matching Algorithms

2021 ◽  
Vol 39 (1B) ◽  
pp. 53-66
Author(s):  
Tareq Z. Hammood ◽  
Matheel E. Abdulmunim
Keyword(s):  
Motion Estimation ◽  
Video Sequence ◽  
Signal To Noise Ratio ◽  
Block Matching ◽  
Gray Level ◽  
Signal To Noise ◽  
Search Point ◽  
Different Types ◽  
Full Search

Motion Estimation (ME) is a very important operation in video coding. In order to reduce complexity of computations involved in ME and to increase quality of this process, many Block Matching Motion Estimation (BMME) Algorithms are proposed. The aim of this paper is to compare between these algorithms and find the best one. Seven BMME algorithms are used in this paper. The performance of each algorithm is evaluated for different types of motion to determine the best one of these algorithms. The evaluation is based on search points, and Peak Signal to Noise Ratio (PSNR). The simulation shows that Hexagonal Search is faster than all other Block Matching (BM) algorithms used in this paper regardless the type of video because it requires less number of search points to evaluate motion vectors for the video sequence. It requires 11.2424 average search point (SP) for small motions and 13.9708 for fast motions. It also gives a good quality that is close enough to the quality given by Full Search

Moving image quality of liquid crystal display based on human factor

2020 ◽  
Vol 35 (10) ◽  
pp. 1051-1058
Author(s):  
Yu SONG ◽  
◽  
Zhen-ping XIA ◽  
Fu-yuan HU ◽  
Cheng CHENG ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Image Quality ◽  
Human Factor ◽  
Liquid Crystal Display ◽  
Moving Image

scholarly journals Enhancement of Image Quality in LCD by Doping γ-Fe2O3 Nanoparticles and Reducing Friction Torque Difference

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 911 ◽  
Author(s):  
Lin Gao ◽  
Yayu Dai ◽  
Tong Li ◽  
Zongyuan Tang ◽  
Xueqian Zhao ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Image Quality ◽  
Liquid Crystal Display ◽  
Friction Torque ◽  
Fe2o3 Nanoparticles ◽  
Dc Voltage ◽  
Absolute Value ◽  
Combined Action ◽  
Cell Capacitance

Improving image sticking in liquid crystal display (LCD) has attracted tremendous interest because of its potential to enhance the quality of the display image. Here, we proposed a method to evaluate the residual direct current (DC) voltage by varying liquid crystal (LC) cell capacitance under the combined action of alternating current (AC) and DC signals. This method was then used to study the improvement of image sticking by doping γ-Fe2O3 nanoparticles into LC materials and adjusting the friction torque difference of the upper and lower substrates. Detailed analysis and comparison of residual characteristics for LC materials with different doping concentrations revealed that the LC material, added with 0.02 wt% γ-Fe2O3 nanoparticles, can absorb the majority of free ions stably, thereby reducing the residual DC voltage and extending the time to reach the saturated state. The physical properties of the LC materials were enhanced by the addition of a small amount of nanoparticles and the response time of doping 0.02 wt% γ-Fe2O3 nanoparticles was about 10% faster than that of pure LC. Furthermore, the lower absolute value of the friction torque difference between the upper and lower substrates contributed to the reduction of the residual DC voltage induced by ion adsorption in the LC cell under the same conditions. To promote the image quality of different display frames in the switching process, we added small amounts of the nanoparticles to the LC materials and controlled friction technology accurately to ensure the same torque. Both approaches were proven to be highly feasible.

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