Wavelet-based contrast enhancement of dark images using dynamic stochastic resonance
16 Dec 2012-pp 73
TL;DR: The proposed dynamic stochastic resonance (DSR) technique has been proposed for contrast enhancement of dark and low contrast images in discrete wavelet transform (DWT) domain and is found to give noteworthy performance in terms of contrast enhancement, perceptual quality, as well as colorfulness.
Abstract: In this paper, a dynamic stochastic resonance (DSR)-based technique has been proposed for contrast enhancement of dark and low contrast images in discrete wavelet transform (DWT) domain. Traditionally, the performance of a stochastic resonance (SR)-based system is improved by addition of external noise. However, in the proposed DSR-based approach, the internal noise of an image has been utilized for the purpose of contrast enhancement. The degradation due to inadequate illumination is treated as noise, and is used to produce a noise-induced transition of the image from a low-contrast state to a high-contrast state. Stochastic resonance is induced in the approximation and detail coefficients in an iterative fashion, producing an increase in variance and mean of the coefficient distribution. Optimal output response is ensured by selection of optimal of bistable system parameters. An iterative algorithm is followed to achieve target value of performance metrics, such as relative contrast enhancement factor (F), perceptual quality measures (PQM), and color enhancement factor (CEF), at minimum iteration count. When compared with the existing SR-based and non SR-based enhancement techniques in spatial and frequency domains, the proposed technique is found to give noteworthy performance in terms of contrast enhancement, perceptual quality, as well as colorfulness.
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11 Nov 2013
TL;DR: A novel technique based on dynamic stochastic resonance in discrete cosine transform (DCT) domain has been proposed in this paper for the enhancement of dark as well as low-contrast images and gives remarkable performance in terms of contrast and color enhancement while ascertaining good perceptual quality.
Abstract: A novel technique based on dynamic stochastic resonance (DSR) in discrete cosine transform (DCT) domain has been proposed in this paper for the enhancement of dark as well as low-contrast images. In conventional DSR-based techniques, the performance of a system can be improved by addition of external noise. However, in the proposed DSR-based work, the intrinsic noise of an image has been utilized to create a noise-induced transition of a dark image to a state of good contrast. The proposed technique significantly enhances the image contrast and color information without losing any image or color data by optimization of bistable system parameters. The performance of the proposed methodology has been measured in terms of relative contrast enhancement factor, perceptual quality measure, and color enhancement factor. When compared with the existing enhancement techniques, such as adaptive histogram equalization, gamma correction, single-scale retinex, multi-scale retinex, modified high-pass filtering, multicontrast enhancement with dynamic range compression, color enhancement by scaling, edge-preserving multi-scale decomposition, automatic control of imaging tool, and various spatial/frequency-domain SR-based techniques, the proposed technique gives remarkable performance in terms of contrast and color enhancement while ascertaining good perceptual quality.
15 citations
Cites methods from "Wavelet-based contrast enhancement ..."
...Our other DSR-based investigations [10, 12] were based in spatial and wavelet domains, respectively, while the concept of DCT-based enhancement was introduced in [11]....
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TL;DR: The proposed noise-enhanced iterative processing on Fourier coefficients for enhancement of low-contrast images has been found to give noteworthy performance for both low- Contrast and dark images among the SR-based techniques and is found to be better than most of the non-SR- based techniques, in terms of contrast enhancement, perceptual quality and colorfulness.
Abstract: This paper presents a study of noise-enhanced iterative processing on Fourier coefficients for enhancement of low-contrast images. The processing equation is derived from the concept of dynamic stochastic resonance (SR), where the presence of optimum amount of noise produces an improved performance in the system. Similar to our earlier works on SR-based contrast enhancement, noise in the current context is the internal noise inherent in an image due to insufficient illumination. Here, however, the parameter selection is done so as to achieve large noise suppression. Iteration is terminated when target performance has been achieved. It is observed that the increase in the variance of the Fourier magnitude distribution leads to an increase in the contrast of the image. The increase in the variance is analytically proven to be equivalent to the process of coefficient rooting. Comparison has been made with various state-of-the-art SR and non-SR-based techniques in spatial/frequency domains. The proposed technique has been found to give noteworthy performance for both low-contrast and dark images among the SR-based techniques. The performance is also found to be better than most of the non-SR-based techniques, in terms of contrast enhancement, perceptual quality and colorfulness.
12 citations
Patent•
06 Jan 2016TL;DR: In this article, a system and method for enhancing the detectability of objects in medical images is presented, which includes providing medical imaging data acquired using a medical imaging system, integrating dynamic noise with the imaging data to generate a modified set of images that achieves improved detection accuracy, and displaying the modified images.
Abstract: A system and method is provided for enhancing the detectability of objects in medical images. The method includes providing medical imaging data acquired using a medical imaging system, integrating dynamic noise with the imaging data to generate a modified set of images that achieves improved detection accuracy, and displaying the modified images.
11 citations
8 citations
01 Oct 2014
TL;DR: A noise-aided image enhancement algorithm focussed on addressing images that have a large dynamic range, i.e., images with both dark and bright regions, and the application of a new mathematical model, in a shifted double-well system exhibiting stochastic resonance, is investigated.
Abstract: This paper presents a noise-aided image enhancement algorithm focussed on addressing images that have a large dynamic range, i.e., images with both dark and bright regions. The application of a new mathematical model, in a shifted double-well system exhibiting stochastic resonance, is investigated for such images. The new mathematical model addresses the shortcomings of earlier SR-based enhancement model by deriving parameters purely from input values (instead of input statistics). This model is specific to spatial domain pixel representation and operates on a revised iterative equation. This iterative processing is here applied selectively to the under-illuminated regions of the image, characterized as the De Vries-Rose (DVR) region of a human psychovisual model. The idea of suitably modifying the existing universal image quality index is also proposed for its participation in iteration termination, and to gauge the property of dynamic range compression. While the iterative algorithm is terminated using the revised image quality index, entropy maximization, and contrast quality of DVR region with constraints on perceptual quality, the performance of the proposed algorithm is also characterized by observing color enhancement and subjective scores on visual quality.
7 citations
Cites background from "Wavelet-based contrast enhancement ..."
...Index Terms— Image enhancement, double-well model, stochastic resonance, dynamic range compression, HVS, image quality...
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References
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TL;DR: In this paper, it was shown that a dynamical system subject to both periodic forcing and random perturbation may show a resonance (peak in the power spectrum) which is absent when either the forcing or the perturbations is absent.
Abstract: It is shown that a dynamical system subject to both periodic forcing and random perturbation may show a resonance (peak in the power spectrum) which is absent when either the forcing or the perturbation is absent.
2,774 citations
2,671 citations
TL;DR: This paper extends a previously designed single-scale center/surround retinex to a multiscale version that achieves simultaneous dynamic range compression/color consistency/lightness rendition and defines a method of color restoration that corrects for this deficiency at the cost of a modest dilution in color consistency.
Abstract: Direct observation and recorded color images of the same scenes are often strikingly different because human visual perception computes the conscious representation with vivid color and detail in shadows, and with resistance to spectral shifts in the scene illuminant. A computation for color images that approaches fidelity to scene observation must combine dynamic range compression, color consistency-a computational analog for human vision color constancy-and color and lightness tonal rendition. In this paper, we extend a previously designed single-scale center/surround retinex to a multiscale version that achieves simultaneous dynamic range compression/color consistency/lightness rendition. This extension fails to produce good color rendition for a class of images that contain violations of the gray-world assumption implicit to the theoretical foundation of the retinex. Therefore, we define a method of color restoration that corrects for this deficiency at the cost of a modest dilution in color consistency. Extensive testing of the multiscale retinex with color restoration on several test scenes and over a hundred images did not reveal any pathological behaviour.
2,395 citations
"Wavelet-based contrast enhancement ..." refers methods in this paper
...Comparative analysis with non-SR-based techniques, like contrast-limited adaptive histogram equalization (CLAHE) [24], gamma correction (Gamma), single-scale retinex (Retinex) [9], multi-scale retinex (MSR) [8], and modi.ed highpass .ltering (MHPF) [21] has been performed....
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...Comparative analysis with non-SR-based techniques, like contrast-limited adaptive histogram equalization (CLAHE) [24], gamma correction (Gamma), single-scale retinex (Retinex) [9], multi-scale retinex (MSR) [8], and modified highpass filtering (MHPF) [21] has been performed....
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...4(a) Method F PQM CEF F PQM CEF F PQM CEF DWT-DSR 3.0 10.0 3.1 2.5 10.0 2.7 5.3 8.95 5.75 SVD-DSR 5.8 9.4 1.3 3.1 9.7 3.1 5.23 8.40 4.62 SSR 2.2 9.5 6.5 6.1 8.9 5.1 2.51 7.95 6.00 CLAHE 1.9 10.8 0.5 2.2 10.5 1.3 1.98 7.85 2.73 Photoshop 5.4 8.5 1.3 2.1 11.0 1.3 4.69 8.69 4.75 Gamma 9.5 8.5 11.5 1.2 10.9 1.5 5.92 6.92 5.01 Retinex 7.8 8.2 7.1 0.1 12.4 0.2 4.78 6.96 8.37 MSR 1.8 9.5 7.1 0.4 11.7 0.7 1.68 7.18 2.77 MHPF 8.4 8.2 16.8 0.6 11.7 0.8 5.02 9.01 7.21 MCE 1.0 12.2 0.2 1.1 8.8 1.0 1.18 8.77 0.96 MCE-DRC 0.7 11.9 0.2 0.9 11.1 1.0 0.97 9.01 7.21 CES 1.2 11.3 0.3 0.9 10.3 1.5 1.13 8.32 1.58 contrast enhancement of dark images using non-dynamic stochastic resonance....
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TL;DR: A practical implementation of the retinex is defined without particular concern for its validity as a model for human lightness and color perception, and the trade-off between rendition and dynamic range compression that is governed by the surround space constant is described.
Abstract: The last version of Land's (1986) retinex model for human vision's lightness and color constancy has been implemented and tested in image processing experiments. Previous research has established the mathematical foundations of Land's retinex but has not subjected his lightness theory to extensive image processing experiments. We have sought to define a practical implementation of the retinex without particular concern for its validity as a model for human lightness and color perception. We describe the trade-off between rendition and dynamic range compression that is governed by the surround space constant. Further, unlike previous results, we find that the placement of the logarithmic function is important and produces best results when placed after the surround formation. Also unlike previous results, we find the best rendition for a "canonical" gain/offset applied after the retinex operation. Various functional forms for the retinex surround are evaluated, and a Gaussian form is found to perform better than the inverse square suggested by Land. Images that violate the gray world assumptions (implicit to this retinex) are investigated to provide insight into cases where this retinex fails to produce a good rendition.
1,674 citations
"Wavelet-based contrast enhancement ..." refers background or methods in this paper
...Comparative analysis with non-SR-based techniques, like contrast-limited adaptive histogram equalization (CLAHE) [24], gamma correction (Gamma), single-scale retinex (Retinex) [9], multi-scale retinex (MSR) [8], and modified highpass filtering (MHPF) [21] has been performed....
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...Many techniques for contrast enhancement that operate in spatial domain exist in literature [10], [3], [9], [20]....
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10 Dec 2002
TL;DR: It is shown that Peak Signal-to-Noise Ratio (PSNR), which requires the reference images, is a poor indicator of subjective quality and tuning an NR measurement model towards PSNR is not an appropriate approach in designing NR quality metrics.
Abstract: Human observers can easily assess the quality of a distorted image without examining the original image as a reference. By contrast, designing objective No-Reference (NR) quality measurement algorithms is a very difficult task. Currently, NR quality assessment is feasible only when prior knowledge about the types of image distortion is available. This research aims to develop NR quality measurement algorithms for JPEG compressed images. First, we established a JPEG image database and subjective experiments were conducted on the database. We show that Peak Signal-to-Noise Ratio (PSNR), which requires the reference images, is a poor indicator of subjective quality. Therefore, tuning an NR measurement model towards PSNR is not an appropriate approach in designing NR quality metrics. Furthermore, we propose a computational and memory efficient NR quality assessment model for JPEG images. Subjective test results are used to train the model, which achieves good quality prediction performance.
913 citations
"Wavelet-based contrast enhancement ..." refers methods in this paper
...Here, perceptual quality is calculated from a model [19] taking into account the activity, blurriness and blockiness of an image....
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...For evaluation of perceptual quality, we have used a no-reference metric for judging the image quality which we shall refer to as perceptual quality metric (PQM ) [19, 11], where for good perceptual quality, PQM should be close to 10....
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