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Edge enhancement

Edge enhancement is a fundamental technique in digital image processing that selectively identifies and amplifies the boundaries and contours of objects within an image, thereby increasing edge contrast to improve perceived sharpness, known as acutance, and overall visual detail without altering the image's core content.^[1] This process leverages the human visual system's reliance on edges for interpreting scenes, making enhanced images more comprehensible for analysis and perception.^[1] The development of edge enhancement traces back to the 1960s, coinciding with early advancements in computer vision and image analysis. By the 1980s, more sophisticated methods emerged. Traditional techniques such as unsharp masking—originating from analog photography and adapted for digital use—subtract a blurred version of the image from the original to highlight high-frequency edge details. More advanced methods include wavelet transforms for multi-resolution edge preservation amid noise reduction, and contemporary deep learning approaches, such as generative adversarial networks (GANs), transformer-based models, and diffusion models for automated enhancement in complex datasets.^[2] Edge enhancement finds broad applications across fields, including medical imaging, remote sensing, computer vision, and video processing. Despite its benefits, excessive application can introduce artifacts like haloing around edges or amplify noise, necessitating careful parameter tuning in practical implementations.^[3]

Fundamentals

Definition and Purpose

Edge enhancement is a fundamental technique in image processing that emphasizes the boundaries between regions of different intensities in an image or video, thereby increasing the perceived detail and sharpness without significantly altering the core content of the image. This process selectively amplifies the contrast at these edges, making subtle transitions more pronounced and improving overall visual clarity.^[1] The primary purpose of edge enhancement is to mitigate the blurring effects that occur during image acquisition, transmission, or display, which can degrade perceived sharpness due to factors like optical limitations or compression artifacts. By boosting the high-frequency components associated with edges, it enhances visual acuity for human observers, facilitating better interpretation of details in applications ranging from medical imaging to consumer photography. This targeted amplification helps restore or exaggerate edge information, aligning the image more closely with human visual perception preferences for crisp boundaries.^[1]^[4] Historically, edge enhancement originated in analog photography through techniques like unsharp masking, developed in the 1930s for high-contrast reproductions and widely adopted in the 1950s for photographic printing to preserve fine details. In television, sharpening circuits employing aperture correction emerged in the 1950s and 1960s to compensate for resolution losses in broadcast signals, using methods such as one-line delays to equalize vertical and horizontal edges. These analog approaches evolved into digital algorithms following the 1980s, with seminal works formalizing enhancement as a deblurring process through high-pass filtering.^[5]^[6] For instance, in a simple blurred edge profile—such as a gradual intensity ramp from black to white representing a boundary—edge enhancement steepens the transition, resulting in a sharper step that conveys greater definition, as commonly illustrated in image processing demonstrations. Edge detection often serves as a precursor, identifying these boundaries before enhancement refines their appearance.^[1]

Underlying Principles

The human visual system (HVS) demonstrates pronounced sensitivity to luminance transitions at edges, a phenomenon exemplified by the Mach bands illusion, where perceived bright and dark bands emerge adjacent to abrupt intensity changes despite their absence in the actual stimulus.^[7] This perceptual enhancement stems from lateral inhibition among retinal ganglion cells with center-surround receptive fields, which suppress uniform regions while amplifying contrasts at boundaries to facilitate object segmentation and depth perception.^[8] Edge enhancement algorithms exploit this HVS characteristic by artificially intensifying local contrast variations, thereby aligning processed images more closely with the system's innate tendency to exaggerate edge discontinuities for improved visual acuity.^[9] Mathematically, edges manifest as high-frequency components within an image's Fourier spectrum, arising from the rapid spatial variations in pixel intensity that require substantial high-frequency energy to represent sharp transitions.^[10] Enhancement techniques selectively amplify these components through operations like convolution with high-pass filters in the spatial domain, which equivalently multiply the spectrum by a boosting function in the frequency domain to restore or exaggerate lost detail without altering low-frequency content such as overall brightness.^[11] A foundational measure of edge strength involves computing the image gradient magnitude, approximated via the Sobel operator as

G(x,y) = \sqrt{G_x^2(x,y) + G_y^2(x,y)},

where G_x and G_y denote the partial derivatives along the horizontal and vertical axes, respectively, derived from convolving the image with 3×3 isotropic kernels that approximate directional gradients.^[12] In signal processing terms, spatial-domain edge enhancement equates to numerical differentiation of the image intensity function, which inherently accentuates discontinuities by emphasizing rate-of-change while preserving gradual variations.^[13] However, differentiation acts as a high-pass operation that proportionally amplifies high-frequency noise alongside true edges, often requiring pre- or post-processing smoothing to mitigate artifacts and maintain signal integrity.^[14] This noise sensitivity underscores the trade-off in enhancement design, where boosting edge signals must be calibrated to avoid over-amplification that could degrade perceptual quality.^[15]

Techniques

Spatial Domain Methods

Spatial domain methods for edge enhancement involve direct manipulation of image pixels through local operations, primarily convolution with high-pass kernels that amplify intensity transitions to sharpen edges without altering the overall image structure.^[16] A core technique is convolution with the Laplacian kernel, which approximates the second-order spatial derivative \nabla^2 f = \frac{\partial^2 f}{\partial x^2} + \frac{\partial^2 f}{\partial y^2} to detect rapid intensity changes indicative of edges.^[17] A standard discrete implementation uses the 3×3 kernel

\begin{bmatrix} 0 & 1 & 0 \\ 1 & -4 & 1 \\ 0 & 1 & 0 \end{bmatrix},

where convolving the original image f with this kernel yields an edge map that, when scaled and added to f, produces an enhanced version with accentuated boundaries.^[16] Unsharp masking represents another foundational approach, generating a high-pass component by subtracting a low-pass filtered version of the image from the original, effectively isolating edge details for reinforcement.^[18] The process begins by applying a smoothing filter, such as a Gaussian, to obtain the blurred image g; the mask is then computed as m = f - g; and the enhanced image is formed as f_{\text{enhanced}} = f + k \cdot m, where k > 0 controls the enhancement intensity to balance sharpness against potential overshoot artifacts.^[18] For gradient-based enhancement, the Sobel operator approximates first-order derivatives using paired 3×3 kernels to compute horizontal and vertical gradients, with the gradient magnitude \sqrt{G_x^2 + G_y^2} serving as an edge strength map that can be scaled and blended with the original image.^[19] The kernels are

G_x = \begin{bmatrix} -1 & 0 & 1 \\ -2 & 0 & 2 \\ -1 & 0 & 1 \end{bmatrix}, \quad G_y = \begin{bmatrix} -1 & -2 & -1 \\ 0 & 0 & 0 \\ 1 & 2 & 1 \end{bmatrix},

originally developed for isotropic edge detection and suitable for real-time applications due to their simplicity.^[19] The Kirsch compass operators extend directional sensitivity with eight 3×3 kernels, each tuned to detect edges in compass directions (e.g., north, northwest) by weighting neighboring pixels to emphasize perpendicular transitions, allowing targeted enhancement of oriented features in images.^[20] For instance, the north kernel is

\begin{bmatrix} 5 & 5 & 5 \\ -3 & 0 & -3 \\ -3 & -3 & -3 \end{bmatrix},

with the maximum response across orientations providing a robust edge map for addition to the original.^[20] These methods typically follow a standard workflow: compute the edge or high-pass map via convolution, apply scaling to control amplification, and add the result to the original image to yield the enhanced output.^[16] Their primary advantages lie in low computational complexity, relying on small kernel convolutions that enable efficient implementation and real-time performance on embedded hardware.^[21] Such techniques offer a direct alternative to frequency domain approaches by avoiding global transforms while achieving localized edge boosting.^[16]

Frequency Domain Methods

Frequency domain methods for edge enhancement transform an image into the frequency spectrum via the discrete Fourier transform (DFT), multiply the spectrum by a high-pass filter to emphasize high-frequency components associated with edges, and apply the inverse DFT to reconstruct the enhanced image. This core approach leverages filters such as the ideal high-pass filter, which passes frequencies above a cutoff while blocking lower ones, or the Butterworth high-pass filter, which provides a smoother transition to avoid ringing artifacts.^[22]^[23] A fundamental aspect is the design of the filter transfer function, often expressed as H(u,v) = 1 - H_{LP}(u,v), where H_{LP}(u,v) denotes a low-pass filter that suppresses low-frequency content representing smooth areas, thereby isolating and boosting edge-related high frequencies for sharper boundaries.^[24] Among specific techniques, homomorphic filtering addresses challenges in images where edges are confounded by varying illumination; it applies a logarithm to convert multiplicative components into additive ones, filters in the frequency domain to enhance reflectance (edge details) while compressing illumination, and exponentiates back to the spatial domain. This method, rooted in nonlinear signal processing, effectively separates edge information from lighting variations.^[25] Wavelet-based multi-resolution enhancement decomposes the image into subbands using discrete wavelet transforms, enabling selective amplification of high-frequency coefficients at multiple scales to boost fine details and edges without over-sharpening coarser structures.^[26]^[27] These methods offer advantages in suppressing periodic noise by directly targeting specific frequency peaks and achieving efficiency on large images through the fast Fourier transform (FFT), which reduces computational complexity from O(N^4) to O(N^2 \log N) for an N \times N image.^[28] In contrast to spatial domain techniques like convolution, frequency domain processing provides global spectral control for uniform edge boosting across the image.

Applications

In Digital Imaging

In digital photography, edge enhancement plays a crucial role in post-processing workflows to counteract inherent blur from lens optics and capture imperfections. A widely used method is the Unsharp Mask filter in software like Adobe Photoshop, which selectively increases contrast around edges by duplicating the image layer, blurring the duplicate, and subtracting it from the original to highlight boundaries, thereby improving perceived sharpness without affecting uniform areas.^[29] Recommended settings typically involve an amount of 150-200% for high-resolution prints and a radius of 1-2 pixels to target fine details, though over-application can introduce halos.^[29] Additionally, many digital cameras apply edge enhancement automatically during in-camera JPEG conversion to sharpen raw sensor data, compensating for demosaicing artifacts and producing output with enhanced acutance, as seen in models from Canon and Nikon where sharpness parameters can be adjusted from low to high.^[30] This in-camera processing ensures immediate usability but requires careful calibration to avoid excessive artifacts in compressed files.^[31] In medical imaging, edge enhancement techniques are essential for delineating subtle anatomical features and pathologies in static images such as X-rays and MRIs. For X-ray analysis, fractional differential methods enhance edge contrast to improve visibility of bone fractures or soft tissue boundaries, outperforming traditional filters by preserving high-frequency details while reducing noise.^[32] In MRI, deep learning-based post-processing models apply edge-preserving enhancements to correct artifacts from motion or field inhomogeneities, enabling clearer visualization of brain lesions or vascular structures.^[33] A prominent application is in mammography, where adaptive neighborhood contrast enhancement algorithms boost the detection of microcalcifications—small calcium deposits indicative of early breast cancer—achieving up to 49% preference among radiologists over unenhanced images in preference studies, as they amplify local edge gradients without global over-sharpening.^[34] Such enhancements aid in distinguishing malignant from benign lesions, with wavelet-based variants showing particular efficacy for clustered microcalcifications under 1 mm.^[34] Since the 2010s, computational photography on smartphones has incorporated edge enhancement into algorithms for high dynamic range (HDR) merging and deblurring, leveraging multi-frame bursts to refine image quality under challenging conditions. In HDR pipelines, such as Google's HDR+ on Pixel devices, edge-aware alignment and fusion of bracketed exposures preserve sharp boundaries across tonal ranges, reducing ghosting in high-contrast scenes like landscapes with bright skies and shadowed foregrounds.^[35] For deblurring, computational methods analyze motion trajectories from raw sensor data and apply selective edge boosting to restore details lost to hand-shake, as implemented in iPhone and Android systems.^[36] These techniques rely on neural networks trained on diverse datasets to prioritize natural edge transitions, enabling real-time processing on mobile hardware. A notable case study in satellite imagery involves edge enhancement for terrain clarification, where multispectral data is processed to delineate geological features such as fault lines or vegetation boundaries. Techniques using vector operators extract and amplify edges across spectral bands, enhancing spatial structure for applications in environmental monitoring.^[37] Such methods, applied in tools like ENVI software, facilitate precise terrain modeling without altering spectral signatures, supporting tasks from disaster assessment to urban planning.^[37]

In Video and Broadcast Systems

In video and broadcast systems, edge enhancement has evolved significantly from analog to digital eras to address signal degradation during transmission and playback. In the 1980s, analog video formats like VHS relied on Y/C separation techniques to distinguish luminance (Y) from chrominance (C) signals in composite video, mitigating artifacts such as dot crawl and cross-color that blurred edges; however, imperfect separation often necessitated basic sharpening filters to restore perceived sharpness in consumer VCRs and early TVs.^[38] This transitioned to digital broadcast standards in the 1990s and 2000s, where edge enhancement became integral to compensating for compression losses and improving acutance in standards like MPEG-2 for initial digital TV. By the 2010s, with the adoption of H.264/AVC, post-processing edge enhancement emerged as a standard step to counteract ringing and blocking artifacts, evolving further in the 2020s to AI-driven methods integrated with codecs like AV1 for efficient streaming.^[39] Television and display technologies have long incorporated built-in edge enhancement circuits to optimize image quality across CRT, LCD, and OLED panels. In CRT systems, peaking filters—high-pass filters that amplify high-frequency components around edges—were commonly used to enhance sharpness without introducing excessive noise, often implemented via programmable architectures for consumer electronics. These filters detect luminance transitions and add overshoot/undershoot to edges, improving detail visibility in broadcast signals; for instance, adaptive coring in peaking circuits suppresses low-level noise from chroma residue in decoded composite signals, a technique applied in early digital TVs to maintain edge integrity during Y/C decoding.^[40] Modern LCD and OLED displays extend this with content-adaptive algorithms, such as those boosting high-frequency details in luminance signals post-decoding, ensuring sharper edges in high-definition broadcasts while adapting to varying input resolutions. Video compression introduces artifacts like blurring from quantization in codecs such as MPEG and H.264, where edge enhancement serves as post-processing to restore detail after decoding. Techniques like edge-preserving filters and detail enhancement algorithms analyze compressed frames to amplify gradients at boundaries, reducing mosquito noise and ringing while preserving texture; for example, sharpness enhancement systems apply peaking to luminance signals, scaling the boost based on local variance to counteract compression-induced softness. In streaming platforms like Netflix and YouTube, which predominantly use H.264 for compatibility, post-decoding enhancement mitigates bitrate-limited blurring, with perceptual models prioritizing edge contrast for subjective quality improvement without exceeding bandwidth constraints.^[41] Real-time edge enhancement is critical for 4K and 8K upscaling in modern broadcast and streaming, leveraging hardware accelerators like GPUs to process dynamic content at high frame rates. NVIDIA and AMD GPUs employ AI-optimized pipelines, such as parallel pixel upscaling with edge-aware neural networks, to sharpen low-resolution inputs in live streams, achieving sub-millisecond latency for immersive 4K broadcasts.^[42] In 2020s services, this manifests in GPU-accelerated enhancement for AV1-encoded content, where AI models detect and refine edges during upscaling, reducing artifacts in real-time scenarios like sports streaming while supporting 8K resolutions on compatible displays.^[43]

Effects and Artifacts

Visual Impacts

Edge enhancement significantly improves perceived image quality by amplifying the contrast at boundaries, thereby increasing apparent resolution and revealing finer details that might otherwise be obscured. This process reduces the softness often present in low-contrast areas, such as subtle gradients in skin tones or distant landscapes, making transitions crisper and more defined.^[30] A key perceptual metric for these improvements is the modulation transfer function (MTF), which measures how well an imaging system preserves contrast at different spatial frequencies; edge enhancement boosts MTF values at high frequencies, enhancing the visibility of small-scale structures without altering the actual pixel resolution. For instance, in endoscopic imaging systems, applying moderate edge enhancement can significantly increase the MTF50 (the frequency where MTF drops to 50%), leading to sharper perceived details preferred by medical professionals.^[30]^[44] Quantitatively, these changes are evident in the edge response function (ERF), which describes the intensity profile across an edge; post-enhancement, the ERF exhibits steeper transitions with greater overshoot amplitudes, indicating heightened edge acuity that contributes to a more dynamic visual experience.^[30] In practical examples, such as portrait photography, edge enhancement makes skin textures and hair strands appear more lifelike by accentuating natural micro-details, fostering a greater sense of depth and realism. However, excessive enhancement can result in haloing around edges, representing an extreme manifestation of these perceptual shifts that may detract from overall quality.^[30]

Common Artifacts and Limitations

One common artifact introduced by edge enhancement techniques, particularly unsharp masking, is overshoot and ringing, often referred to as the Gibbs phenomenon, which appears as spurious oscillations or halos adjacent to sharp edges. This occurs because the amplification of high-frequency components exaggerates transitions, leading to ripple effects around high-contrast boundaries. In textured areas, edge enhancement amplifies noise, resulting in granular distortions that reduce overall image fidelity, as the process boosts both signal edges and random noise fluctuations indiscriminately.^[45] Edge enhancement is highly sensitive to the input image's blur level; when applied to mildly blurred or already sharp images, it yields minimal perceptual benefits while introducing unnatural artifacts. On sufficiently sharp inputs, further enhancement proves ineffective, as it primarily adds noise without improving acutance.^[46] Additionally, processing high-resolution images incurs significant computational cost, scaling linearly with pixel count and demanding optimized algorithms or hardware for real-time applications.^[47] In video systems, edge enhancement can intensify mosquito noise, manifesting as flickering patterns around compressed edges due to block-based artifacts. Similarly, in smooth gradients, it may produce contouring, where subtle intensity transitions appear as banded steps, exaggerating quantization effects.^[48] Quantitatively, edge enhancement degrades the signal-to-noise ratio (SNR), reflecting the proportional noise boost from the gain parameter.^[46] These issues highlight the trade-off between perceptual sharpness gains and potential quality losses.

Implementation Considerations

Algorithmic Parameters

Edge enhancement algorithms rely on several key tunable parameters to balance sharpness, noise suppression, and artifact minimization. In edge detection-based methods, such as those extending the Canny algorithm, upper and lower thresholds define the gradient magnitudes qualifying as edges, with the upper threshold identifying strong edges and the lower connecting weak ones while suppressing noise.^[49] These thresholds typically range from 0 to the maximum gradient value, and their selection directly impacts edge continuity and false positives.^[50] A core parameter in unsharp masking, a widely used sharpening technique, is the gain factor k (or \gamma), which amplifies the high-pass filtered component subtracted from the blurred version of the image. The process is formalized as

I_{\text{enhanced}} = I + k (I - I_{\text{blurred}})

where I is the original image and I_{\text{blurred}} results from a low-pass filter like Gaussian blurring.^[51] Values of k between 0.5 and 2.0 are common, as higher settings enhance edge contrast but amplify noise and introduce ringing artifacts around boundaries.^[46] The kernel size or radius further modulates enhancement scope by determining the filter's receptive field. In Gaussian-based unsharp masking or difference-of-Gaussians approaches, a larger radius (e.g., 2–5 pixels) targets broader edges while preserving fine details less effectively, whereas smaller radii (e.g., 1 pixel) emphasize high-frequency textures but risk over-sharpening.^[52] Kernel dimensions are often odd integers like 3×3 or 5×5 to center the operation symmetrically.^[53] Tuning these parameters involves trade-offs: elevating k or reducing thresholds boosts perceptual sharpness but heightens artifact visibility, such as overshoot halos.^[54] Adaptive strategies, which adjust parameters dynamically using image histograms, mitigate this by scaling enhancement to local contrast distributions, outperforming fixed global settings in varied lighting conditions like medical ultrasound.^[55] For instance, histogram-based adaptation normalizes edge gains regionally to avoid over-enhancement in uniform areas.^[56] Parameter optimization in automated systems frequently leverages quantitative metrics like Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM) to evaluate enhancement quality. PSNR quantifies pixel-level fidelity, favoring parameters that minimize mean squared error, while SSIM assesses perceptual structural preservation, guiding selections that maintain edge integrity without distortion.^[57] These metrics enable iterative tuning, such as particle swarm optimization for kernel and gain values, to achieve PSNR gains of 1–3 dB in benchmark tests.^[58] Since 2018, deep learning has advanced parameter handling through neural networks that implicitly learn optimal thresholds, gains, and kernels from data. Seminal works, like edge-enhanced feedback attention networks for super-resolution, use convolutional layers to adaptively modulate edge amplification, yielding SSIM improvements of approximately 0.01 to 0.02 over other CNN-based super-resolution methods on standard datasets like Set5.^[59] These AI-driven approaches, trained end-to-end, reduce manual tuning by incorporating edge priors directly into the loss function. As of 2025, recent advancements include lightweight 3D networks integrating Roberts edge enhancement for efficient processing and deep learning-based methods for edge-enhanced holography reconstruction, further improving detail preservation in specialized applications.^[60]^[61]

Viewing and Display Factors

The efficacy of edge enhancement in digital imaging is significantly influenced by the type of display technology used, as different screens render edges differently due to their underlying structures. Cathode ray tube (CRT) displays produce inherently softer edges through electron beam scanning across a phosphor-coated surface, resulting in natural blending that reduces the need for aggressive edge enhancement to achieve perceived sharpness. In contrast, liquid crystal display (LCD) panels feature a fixed pixel grid structure, which can introduce visible pixelation or aliasing at edges, particularly when content is not at native resolution; this often necessitates stronger edge enhancement to compensate and enhance edge definition. Organic light-emitting diode (OLED) displays, with their self-emissive pixels enabling infinite contrast ratios and true blacks, provide natural sharpness at edges by amplifying local contrast without additional processing, minimizing the reliance on enhancement algorithms.^[62]^[63] Viewing conditions further modulate the perceived effectiveness of edge enhancement. Optimal viewing distance for high-definition television (HDTV) content is approximately three times the vertical screen height, allowing viewers to resolve fine details without distortion from excessive proximity or remoteness. Ambient light levels play a critical role, as higher illumination reduces perceived contrast and sharpness by increasing veiling glare on the screen, thereby diminishing the visibility of enhanced edges; controlled low-light environments (e.g., under 20 lux) preserve enhancement benefits more effectively than bright settings (e.g., 200 lux or higher).^[64]^[65] Standards such as ITU-R BT.500 provide guidelines for assessing sharpness under controlled viewing conditions to ensure consistent evaluation of edge enhancement. These recommendations specify laboratory setups with low ambient illumination, a design viewing distance where pixels subtend 1 arc-minute (approximately 3 times screen height for HDTV), and high-contrast displays to accurately gauge perceived sharpness without external biases. Since the mid-2010s, the advent of high dynamic range (HDR) displays has introduced challenges for edge enhancement, requiring dynamic adjustments to prevent clipping in high-luminance regions. HDR systems, with peak brightness exceeding 1,000 cd/m², can cause oversharpening artifacts or highlight clipping if static enhancement is applied; adaptive algorithms dynamically scale enhancement based on local tone mapping to maintain edge integrity while preserving dynamic range.^[66]

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Oct 6, 2022 · Edge enhancement or sharpening is a known technique to sharpen edges by adding an undershoot on the darker side of an edge and an overshoot on ...
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Difference of Gaussians Edge Enhancement Algorithm
A majority of the edge enhancement algorithms commonly employed in digital image processing often produce the unwanted side effect of increasing random noise in ...
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[PDF] Self-Example-Based Edge Enhancement Algorithm for Around View ...
This paper proposes a self-example-based edge enhancement algorithm to improve the definition of such edges. First, a low-resolution (LR) version of a blurred ...
[56]
An Adaptive Edge Enhancement Method Based on Histogram ...
This paper presents an adaptive edge enhancement method based on histogram matching for ultrasound images. Because of the speckle noises of ultrasound ...
[57]
Automatic x‐ray image contrast enhancement based on parameter ...
Sep 6, 2017 · We developed a method to perform automatic and user-independent contrast enhancement on 2D kilo voltage (kV) and megavoltage (MV) x-ray images.1 Introduction · 2. C Implementation · 3 Results
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[PDF] Quality Assessment Metrics for Edge Detection and Edge-aware ...
Jan 1, 2018 · The most popular image quality metrics such as Mean squared error (MSE), Peak signal-to- noise ratio (PSNR) and Structural similarity (SSIM) ...
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[PDF] Design of Unsharp Masking Filter Kernel and Gain using Particle ...
In the present work, the design of the UMF is focused on the optimization of the filter kernel parameters and the enhancement gain factor such as to maximize ...
[60]
Edge-Enhanced with Feedback Attention Network for Image Super ...
Abstract. Significant progress has been made in single image super-resolution (SISR) based on deep convolutional neural networks (CNNs).Missing: seminal | Show results with:seminal
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Edge-Enhanced with Feedback Attention Network for Image Super ...
The introduced feedback mechanism enables our network to adjust the input by effectively feeding back the high-level output information to the low-level input.2.4. Edge Detection And... · 3. Proposed Methods · 5. Experimental Results
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Comparison Chart for CRTs versus LCDs - DisplayMate Technologies
The CRT beam produces images with softer edges that are not as sharp as an LCD at its native resolution. Imperfect focus and color registration also reduce ...
[63]
Beyond Picture Quality: LG Display's OLED, Considering Human ...
Dec 3, 2024 · Its ability to achieve perfect blacks eliminates the need for excessively high brightness, ensuring sharp and vivid visuals in any environment.
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Recommended viewing distance for watching TV | Sony USA
Jan 17, 2025 · The best viewing distance depends on the TV's size ... The recommended distance for watching a 4K TV is 1.5 times the TV's vertical screen size.
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https://escholarship.org/content/qt4br2t66m/qt4br2t66m.pdf
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(PDF) Enhancement of Bright Video Features for HDR Displays
Aug 6, 2025 · The enhancement algorithm can significantly stretch the contrast of clipped regions while avoiding amplification of noise and contouring. We ...<|control11|><|separator|>