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PubMed2006

Real-time holographic deconvolution techniques for one-way image transmission through an aberrating medium: characterization, modeling, and measurements.

We propose and demonstrate a new photorefractive real-time holographic deconvolution technique for adaptive one-way image transmission through aberrating media by means of four-wave mixing. In contrast with earlier methods, which typically required various codings of the exact phase or two-way image transmission for correcting phase distortion, our technique relies on one-way image transmission through the use of exact phase information. Our technique can simultaneously correct both amplitude and phase distortions. We include several forms of image degradation, various test cases, and experimental results. We characterize the performance as a function of the input beam ratios for four metrics: signal-to-noise ratio, normalized root-mean-square error, edge restoration, and peak-to-total energy ratio. In our characterization we use false-color graphic images to display the best beam-intensity ratio two-dimensional region(s) for each of these metrics. Test cases are simulated at the optimal values of the beam-intensity ratios. We demonstrate our results through both experiment and computer simulation.

Journal Article↗
PubMed2006

Multiframe blind deconvolution of heavily blurred astronomical images.

A multichannel blind deconvolution algorithm that incorporates the maximum-likelihood image restoration by several estimates of the differently blurred point-spread function (PSF) into the Ayers-Dainty iterative algorithm is proposed. The algorithm uses no restrictions on the image and the PSFs except for the assumption that they are positive. The algorithm employs no cost functions, input parameters, a priori probability distributions, or the analytically specified transfer functions. The iterative algorithm permits its application in the presence of different kinds of distortion. The work presents results of digital modeling and the results of processing real telescope data from several satellites. The proof of convergence of the algorithm to the positive estimates of object and the PSFs is given. The convergence of the Ayers-Dainty algorithm with a single processed frame is not obvious in the general case; therefore it is useful to have confidence in its convergence in a multiframe case. The dependence of convergence on the number of processed frames is discussed. Formulas for evaluating the quality of the algorithm performance on each iteration and the rule of stopping its work in accordance with this quality are proposed. A method of building the monotonically converging subsequence of the image estimates of all the images obtained in the iterative process is also proposed.

Journal Article↗
PubMed2002

High-resolution imaging of the human retina with a Fourier deconvolution technique.

A high-resolution retinal imaging camera is described that uses a Shack-Hartmann wave-front sensor and a Fourier deconvolution imaging technique. The operation of the camera is discussed in detail and high-resolution retinal images of the human cone mosaic are shown for a retinal patch approximately 10 arc min in diameter from two different retinal locations. The center-to-center cone spacing is shown to be approximately 2.5 microm for the retinal images recorded at 2 degrees temporal from the central fovea and approximately 4 microm for the retinal images recorded at 3 degrees temporal from the central fovea.

Diagnostic Imaging↗
PubMed2004

Fresnel diffraction by a circular aperture with off-axis illumination and its use in deconvolution of microscope images.

The Fresnel approximation for off-axis illumination of a circular aperture is reexamined. The point-spread function for an aberration-free system can be expressed in terms of redefined optical coordinates. An improved expression is given for contours of constant intensity in the focal plane. The variation in axial width of the focal spot with angle of offset is discussed. The predictions are compared with exact calculations of the Rayleigh-Sommerfeld diffraction integral. Limitations for application in deconvolution of microscope images formed with objectives of finite tube length are discussed.

Journal Article↗
PubMed1992

Blind deconvolution of quantum-limited incoherent imagery: maximum-likelihood approach.

Previous research presented by the author and others into maximum-likelihood image restoration for incoherent imagery is extended to consider problems of blind deconvolution in which the impulse response of the system is assumed to be unknown. Potential applications that motivate this study are wide-field and confocal fluorescence microscopy, although applications in astronomy and infrared imaging are foreseen as well. The methodology incorporates the iterative expectation-maximization algorithm. Although the precise impulse response is assumed to be unknown, some prior knowledge about characteristics of the impulse response is used. In preliminary simulation studies that are presented, the circular symmetry and the band-limited nature of the impulse response are used as such. These simulations demonstrate the potential utility and present limitations of these methods.

Algorithms↗
PubMed2004

Rapid supersampling of multiframe sequences by use of blind deconvolution.

Under certain conditions, multiframe image sequences can be processed to produce images that achieve greater resolution through image registration and increased sampling. This technique, known as supersampling, takes advantage of the spatiotemporal data available in an undersampled imaging sequence. In this effort the image registration is replaced by application of a fast blind-deconvolution technique to remove the motion blur in the upsampled average of the image sequence. This method produces a supersampled image with significantly decreased computational requirements compared with common methods. The method and simulated test results are presented.

Algorithms↗
PubMed2005

Brillouin spectral deconvolution method for centimeter spatial resolution and high-accuracy strain measurement in Brillouin sensors.

Combining a dc and a short pulse (approximately 1 ns) as the probe beam in the pump-probe configuration of Brillouin-based distributed sensors allows us to represent the Brillouin spectrum as a top Lorentzian-like portion and a bottom Gaussian-like portion. Because of the interaction of these two parts, the Lorentzian-like portion carries spatial information that can be extracted within centimeter spatial resolution. Using this information, we develop a spectrum deconvolution method, which considers the location correlation of the strain distribution, to find the number of Brillouin peaks and their frequencies in the top Lorentzian-like portion and hence achieve accurate strain information. An optimum level of dc to pulse power for the best signal and position detection capability is discussed.

Journal Article↗
PubMed2005

Self-deconvolution for shift-and-add imaging.

A shift-and-add (SAA) method is used to restore atmospherically degraded images. The operation of the SAA method is simple, but the deconvolution method of SAA images remains to be developed, especially for extended objects. We propose to deconvolve a SAA image of an extended object by use of a self-deconvolving data reconstruction algorithm (SeDDaRA). Computer simulations show the effectiveness of the SeDDaRA to SAA images. It is also shown that use of the SAA method after each data frame is self-deconvolved leads to a better reconstruction.

Journal Article↗
PubMed2005

Maximum entropy deconvolution of infrared spectra: use of a novel entropy expression without sign restriction.

Absorbance and difference infrared spectra are often acquired aiming to characterize protein structure and structural changes of proteins upon ligand binding, as well as for many other chemical and biochemical studies. Their analysis requires as a first step the identification of the component bands (number, position, and area) and as a second step their assignment. The first step of the analysis is challenged by the habitually strong band overlap in infrared spectra. Therefore, it is useful to make use of a mathematical method able to narrow the component bands to the extent to eliminate, or at least reduce, the band overlap. Additionally, to be of general applicability this method should permit negative values for the solution. We present a maximum entropy deconvolution approach for the band-narrowing of absorbance and difference spectra showing the required characteristics, which uses the generalized negative Burg-entropy (Itakura-Saito discrepancy) generalized for difference spectra. We present results on synthetic noisy absorbance and difference spectra, as well as on experimental infrared spectra from the membrane protein bacteriorhodopsin.

Algorithms↗
PubMed2025

Sparse deconvolution of cell type medleys in spatial transcriptomics.

Mapping cell distributions across spatial locations with whole-genome coverage is essential for understanding cellular responses and signaling However, current deconvolution models aim to estimate the proportions of distinct cell types in each spatial transcriptomics spot by integrating reference single-cell data. These models often assume strong overlap between the reference and spatial datasets, neglecting biology-grounded constraints such as sparsity and cell-type variations, as well as technical sparsity. As a result, these methods rely on over-permissive algorithms that ignore given constraints leading to inaccurate predictions, particularly in heterogeneous or unmatched datasets. We introduce Weight-Induced Sparse Regression (WISpR), a machine learning algorithm that integrates spot-specific hyperparameters and sparsity-driven modeling. Unlike conventional approaches that neglect biology-grounded constraints, WISpR accurately predicts cell-type distributions while preserving biological coherence, i.e., spatially and functionally consistent cell-type localization, even in unmatched datasets. Benchmarking against five alternative methods across ten datasets, WISpR consistently outperformed competitors and predicted cellular landscapes in both normal and cancerous tissues. By leveraging sparse cell-type arrangements, WISpR provides biologically informed, high-resolution cellular maps. Its ability to decode tissue organization in both healthy and diseased states highlights WISpR's practical utility for spatial transcriptomics, particularly in challenging settings involving noise, sparsity, or reference mismatches.

Humans↗
PubMed1996

Contrasts in the gonadotropin-releasing hormone dose-response relationships for luteinizing hormone, follicle-stimulating hormone and alpha-subunit release in young versus older men: appraisal with high-specificity immunoradiometric assay and deconvolution analysis.

The secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) is regulated by gonadotropin-releasing hormone (GnRH). As men age, mean serum concentrations of immunoreactive gonadotropic hormones tend to increase, while serum testosterone concentrations tend to decline. To evaluate age-related changes in gonadotroph cell function, we have assessed the dose-dependent secretory responses of immunoreactive LH, FSH and alpha-subunit to saline versus five doses of GnRH in older and young men. Ten older men, mean age 66 years (range 61-78), and nine young men, mean age 26 years (range 22-30), received iv bolus injections of GnRH (range 10-100 micrograms) in randomized order every 2 h, except that the 100-microgram dose was always given last. Blood samples for immunoradiometric assays of serum LH, FSH and alpha-subunit concentrations were obtained every 10 min for a total of 12 h, which included a 2-h preinjection baseline. Deconvolution analysis was performed to estimate gonadotropin and alpha-subunit secretory burst mass, amplitude and duration, as well as endogenous LH, FSH and alpha-subunit half-lives. The mean (+/- SEM) baseline 2-h serum FSH (IU/I) concentration was higher in older than younger men (5.9 +/- 0.8 vs 3.8 +/- 0.5, p < 0.05). The mean 2-h serum LH concentrations after GnRH were significantly higher than corresponding values in young men at GnRH doses of 25, 50 and 75 micrograms, and in the case of FSH at GnRH doses of 10 and 25 micrograms. Non-linear curve-fitting of these dose-response relationships revealed that the calculated maximal mean 2-h serum LH concentration response (IU/l) was higher in older than young men following GnRH stimulation: 15.4 (13.5-16.2) vs 10.8 (8.7-12.1) (95% confidence interval). The maximal mean 2-h serum FSH concentration response (IU/l) was also significantly higher in older men: 11.9 (10.2-13.1) versus 8.6 (7.2-9.6). Maximal alpha-subunit responses (microgram/l) were similarly increased in the older cohort: 1.16 (0.99-1.25) vs 0.83 (0.71-0.91). The incremental LH (p < 0.05) and FSH (p < 0.01) secretory burst mass from 10 to 25 micrograms GnRH was significantly greater in older than younger men. The LH and FSH half-lives and second component alpha-subunit half-lives were similar in older and young men. In addition, secretory burst durations were invariant of age. In contrast, by non-linear curve-fitting, the calculated mass of LH secreted was higher in older men at 13.5 (11.8-15) vs 10.6 (9.2-11.7) IU/l of distribution volume (p < 0.05) for the maximal absolute mass and 11.3 (9.5-12.7) vs 7.4 (6.0-8.4) IU/l (p < 0.05) for the maximal incremental mass of LH secreted after GnRH. The estimated maximal mass of FSH secreted after GnRH also was higher in older men: 4.6 (3.4-5.5) vs 3.2 (2.9-3.4) IU/l (p < 0.01). Finally, calculated maximal GnRH-stimulated alpha-subunit secretory burst mass was statistically greater in older individuals: 2.3 (1.8-2.5) vs 1.6 (1.4-1.8) micrograms/l. In contrast, half-maximally effective GnRH doses were not different in the two age groups. We conclude that older men show significantly increased maximal and incremental gonadotropin release due to amplified secretory burst mass in response to escalating doses of GnRH with no evident differences in LH, FSH, or alpha-subunit half-lives or secretory burst durations. Increased gonadotroph responsiveness may be due to diminished gonadal hormone negative feedback or primary alterations in the hypothalamo-pituitary unit with aging.

Adult↗
PubMed1988

[Evaluation of postoperative hepatobiliary function by deconvolution analysis of hepatobiliary image data by 99mTc-N-pyridoxyl-5-methyltryptophan].

Dynamic hepatobiliary image data were analyzed by the mathematical deconvolution to derive the transfer function (TF) which represents the impulse response function of the liver following direct bolus injection of a tracer into the liver. Biliary flow was evaluated by TF in patients with previous hepatobiliary surgery to detect abnormal flow causing problems such as cholangitis. Serial image data were collected for 60 min after intravenous injection of 37-75 MBq (1-2 mCi) of 99mTc-N-pyridoxyl-5-methyltryptophan (99mTc-PMT). TF was obtained by the matrix algorithm, using regional hepatogram as output and time-activity curve over the heart as input function. Minimum, mean and maximum transit time (Max. TT) were determined from TF. The functional image for each of the transit times was constructed by displaying the distribution of the values for matrix elements with a color scale. In this study, a critical Max. TT of 60 min was used to detect abnormal biliary flow. Of 30 cases, 9 positive cases were discriminated from 21 negative cases on the basis of the finding of presence or absence of areas with Max. TT of more than 60 min anywhere in the liver. Bowel activity overlapping the liver was excluded in the judgment. The validity of this method was evaluated in comparison with the clinical courses after surgery with (8 cases) or without (22 cases) problems. The results were sensitivity of 88%, specificity of 91%, accuracy of 90% and positive predictive value of 78%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Abnormal hepatobiliary clearance of 99mTc-N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid in the altered state of thyroid--by an analysis of deconvolution method.

Hepatobiliary clearance of 99mTc-EHIDA was investigated in cases with altered thyroid function by deconvolution method. The results indicated that mean hepatic transit time of all control subjects revealed less than 10 minutes. On the other hand, mean hepatic transit time of cases with altered thyroid function revealed prolonged more than 13 minutes. Cases especially showing an elevated serum concentration of TSH compared with normal range (4.6 microU/ml) had a tendency of a high incidence of markedly prolonged mean hepatic transit time. These results suggest that thyroid hormone may influence on the hepatic metabolism of hepatobiliary radiopharmaceuticals. This phenomenon also could partly explain the cause of liver dysfunction seen in subjects with altered states.

Adult↗
PubMed1999

Deconvolution of the fluorescence spectra into its component Gaussians: a method to analyze the binding of coumarin to bovine serum albumin.

7-N,N-Diethylamino-4-methylcoumarin, (cou-1), a readily available laser dye binding to bovine serum albumin (BSA), at room temperature has been studied by steady state fluorescence spectroscopy. Existing methods of analysis of the binding to obtain the binding parameters are based on the change in fluorescence intensity at a particular wavelength. These methods are not convenient when there is a gradual shift in the emission maxima for increasing protein concentration. In this paper we present a method to obtain the binding constants of cou-1 to BSA using a Windows '95 based package to deconvolute the asymmetrical spectrum (fluorescence intensity versus wave number curve) into two Gaussians, each corresponding to the binding of the fluorophore to a particular site. This method is convenient to analyze the binding constant data and obtain the binding parameters of each binding site, and can also provide information about the microenvironment of each site, relating micropolarity and microviscosity.

Coumarins↗
PubMed2000

Prediction of a glucose appearance function from foods using deconvolution.

The glycaemic response of an insulin-treated diabetic patient goes through many transitory phases, leading to a steady state glycaemic profile following a change in either insulin regimen or diet. Most models attempting to model the glucose and insulin relationship try to model the effect of oral or injected glucose rather than that from the digestion of food. However, it is clear that a better understanding of the glycaemic response would arise from consideration of intestinal absorption from the gut. It is assumed that this type of absorption can be modelled by a so-called glucose appearance function (systemic appearance of glucose via glucose absorption from the gut) predicting the glucose load from the food. Much research has been carried out in the areas of hepatic balance, insulin absorption and insulin independent/dependent utilization. However, little is known about intestinal absorption patterns or their corresponding glucose appearance profiles. The strategy under investigation herein is to use deconvolution or backward engineering. By starting with specific results i.e. blood glucose and insulin therapy, it is possible to work backwards to predict the glucose forcing functions responsible for the outcome. Assuming compartmental consistency, this will allow a clearer insight into the true gut absorption process. If successful, the same strategy can be applied to more recent glucose and insulin models to further our understanding of the food to blood glucose problem. This paper investigates the Lehmann-Deutsch modified model of glucose and insulin interaction, created from the model proposed by Berger-Rodbard. The model attempts to simulate the steady state glycaemic and plasma insulin responses, independent of the initial values from which the simulation is started. Glucose enters the model via both intestinal absorption and hepatic glucose production. We considered a 70 kg male insulin-dependent diabetic patient with corresponding hepatic and insulin sensitivity parameters of 0.6 and 0.3 respectively. Net hepatic glucose balance was modelled piecewise by linear and symmetric functions. A first-order Euler method with step size of 15 minutes was employed. For the simulation, only Actrapid and NPH injections were considered. The injection of insulin and the glucose flux to the gut were started simultaneously to avoid any delay associated with gastric emptying. The systemic appearance of glucose was compared from two view points, not only to assess the strategic principle, but also to assess the suitability of the modifications made by Lehmann and Deutsch. The first is a forward prediction using the compartmental structure. This analysis involves the rate of gastric emptying without time delay. The second is a backward prediction from experimentally observed blood glucose profiles. Investigations involved porridge, white rice and banana containing the same carbohydrate content (25 g). Results obtained from the first analysis were dependent on the rate of gastric emptying, especially its ascending and descending branches. Results from the second analysis were dependent on the dose and type of insulin administered. Both predicted profiles showed consistency with physiological reasoning, although it became apparent that such solutions could be unstable. Furthermore, both types of prediction were similar in structure and appearance, especially in simulations for porridge and banana. This emphasized the consistency and suitability of both analyses when investigating the compartmental accuracy and limitations within a model. The new strategic approach was deemed a success within the model, and the modifications made by Lehmann and Deutsch appropriate. We suggest that a gastric emptying curve with a possible gastric delay is the way forward in regulating the appearance of glucose via gut absorption. The Lehmann-Deutsch gastric curve is described by either a trapezoidal or triangular function dependent on the carbohydrate cont

Adult↗
PubMed2001

Quantification of histochemical staining by color deconvolution.

OBJECTIVE: To develop a flexible method of separation and quantification of immunohistochemical staining by means of color image analysis. STUDY DESIGN: An algorithm was developed to deconvolve the color information acquired with red-green-blue (RGB) cameras and to calculate the contribution of each of the applied stains based on stain-specific RGB absorption. The algorithm was tested using different combinations of diaminobenzidine, hematoxylin and eosin at different staining levels. RESULTS: Quantification of the different stains was not significantly influenced by the combination of multiple stains in a single sample. The color deconvolution algorithm resulted in comparable quantification independent of the stain combinations as long as the histochemical procedures did not influence the amount of stain in the sample due to bleaching because of stain solubility and saturation of staining was prevented. CONCLUSION: This image analysis algorithm provides a robust and flexible method for objective immunohistochemical analysis of samples stained with up to three different stains using a laboratory microscope, standard RGB camera setup and the public domain program NIH Image.

Algorithms↗
PubMed2002

Deconvolution of UV-VIS spectroelectrochemical thin-layer data for an EE electrochemical process.

A deconvolution method, based on Fixed Size Window Evolving Factor Analysis (FSWEFA) has been developed to analyse the spectroelectrochemical sequence of spectra obtained in OTTLE electrodes for EE electrochemical processes. The analysis of the data permits to reconstruct the concentration profiles, the spectra of the intermediates and an optical analogue of the i vs E curve.

Chromatography, Thin Layer↗
PubMed1976

The 99mTc-DTPA dynamic renal scan with deconvolution analysis.

Dynamic renal studies were performed with 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA). The results were analyzed by the method of mathematical deconvolution in order to obtain the impulse response function of the kidney. Regional analysis of the kidney was attempted by evaluating the independent responses of the renal parenchyma and renal pelvis to a bolus injection of 99mTc-DTPA.

Female↗