Human head motion has been experimentally measured for high-resolution computed tomography (CT) design using a Canon digital camera. Our goal is to identify the minimal movements of the human head under ideal conditions without rigid fixation. In our experiments, all the 19 healthy volunteers were lying down with strict self-control. All of them were asked to be calm without pressures. Our results showed that the mean absolute value of the measured translation excursion was about 0.35 mm, which was much less than the measurements on real patients. Furthermore, the head motions in different directions were correlated. These results are useful for the design of the new instant CT system for in vivo high-resolution imaging (about 40 µm).

Image degradation due to scattered radiation is a serious problem in many short-wavelength (x-ray and EUV) imaging systems. Most currently available image analysis codes require the scattering behavior [data on the bidirectional scattering distribution function (BSDF)] as input in order to calculate the image quality from such systems. Predicting image degradation due to scattering effects is typically quite computation-intensive. If using a conventional optical design and analysis code, each geometrically traced ray spawns hundreds of scattered rays randomly distributed and weighted according to the input BSDF. These scattered rays must then be traced through the system to the focal plane using nonsequential ray-tracing techniques. For multielement imaging systems even the scattered rays spawn more scattered rays at each additional surface encountered in the system. In this paper we describe a generalization of Peterson's analytical treatment of in-field stray light in multielement imaging systems. In particular, we remove the smooth-surface limitation that ignores the scattered-scattered radiation, which can be quite large for EUV wavelengths even for state-of-the-art optical surfaces. Predictions of image degradation for a two-mirror EUV telescope with the generalized Peterson model are then numerically validated with the much more computation-intensive ZEMAX® and ASAP® codes.

We propose a fully digital programmable gain amplifier scheme that overcomes the clipped noise analog-to-digital converter (ADC) for complementary metal-oxide semiconductor (CMOS) image sensors. Adopting the new digital programmable gain amplifier (DPGA) scheme, it obtains low noise and low power usage, has a small size, and high robust gain characteristic. To reduce the clipping noise, one new current controling the reference voltage of a 9-bit flash ADC is brought about in this work. Using the fully digital amplification scheme with reduced clipping noise ADC solves almost all the problems of the conventional analog programmable gain amplifier (APGA) scheme, which has large noise, large power, and big chip size due to APGA, and two analog autozero loop (both clamping circuit loop and offset correction loop) circuits. Based on a 0.18-µm CMOS image sensor process, one product of video graphic array (VGA) format CMOS image sensor is fabricated. The silicon test shows a 68-dB dynamic range with the power consumption of 80 mW at 24 MHz and the total noise of about 2 mV (at 30 fps and 27 deg).

A method of fabricating a colloidal photonic crystal self-assembled onto an optical fiber's cladding is proposed. The coating of a single-mode fiber was removed, the cladding was exposed, and colloidal photonic crystal was overcladding through isothermal heating evaporation-induced self-assembly. The photonic crystal cylindrical annulus is characterized by optical and scanning electron microscopy. The optical characterization was analyzed and carried out followed by detailed discussion. The measurement results show a 1545.5-nm bandgap by optical transmission spectroscopy. The results also demonstrate a practical means of enveloping macro- or microcurved surfaces with three-dimensional photonic crystals.

In computer graphics applications, the standard diffusion model (SDA) is used to represent translucent materials. However, the SDA is not suitable for the representation of the translucent materials with weakly scattering properties. We represent the translucent materials with the weakly scattering properties by using the P3 approximation, since the P3 approximation can more accurately represent such translucent materials than the SDA. We also present an efficient and stable image-based bidirectional subsurface scattering reflectance distribution function measurement system that can measure the reflectance property of homogeneous translucent materials. From the high-dynamic-range image of a translucent material acquired from the proposed image-based measurement systems, the reduced scattering and the absorption coefficients of the material are estimated to represent its translucent property in computer graphics applications. We demonstrate the strength of the P3 approximation for representing the translucent materials using various examples with realistic illumination based on an environmental map.

Optical coherence tomography is a fundamentally new type of optical sensing technology that can perform high-resolution, cross sectional sensing of the internal structure of materials and biological samples. This work briefly describes its capability of exploring and analyzing the internal structures and textures of various jades. With a depth resolution of 4 µm in jade and penetration range of 5 mm in jade, swept-source OCT could be used as a new powerful instrument to generate 3-D volume data of jade, which is important for applications in jade industry and artwork, particularly for jade detection and classification, counterfeit recognition, and guided artistic carving.

We present what we believe to be a new technique for the measurement of moderate wedge angles of optical wedge plates using a wedge shear plate (WSP). Using the technique, a wedge angle of up to 5 deg can be measured. The WSP, oriented at an angle to the incident collimated beam, produces shear fringes. The shear fringes are parallel-shifted by rotating a test wedge plate (TWP), in its plane, placed at the input beam of the WSP. The fringe shift is due to the variation of the optical path difference between the interfering beams reflected from the front and back surfaces of the WSP, brought about by the change in the angle of incidence on the WSP due to the rotation of the TWP. The maximum number of fringes shifted as the wedge direction of the TWP (initially aligned perpendicular to the wedge direction of the WSP) is rotated by 180 deg is used for the measurement of the wedge angle of the TWP. Results obtained for a 59.0-arcmin wedge plate with a measurement uncertainty of ±4.68 arcsec are presented. The technique is very simple, and the results are not affected by external vibrations.

With recent advancements in 3-D imaging and computational technologies, acquiring 3-D data is unprecedentedly simple. However, the use of 3-D data is still limited due to the size of 3-D data, especially 3-D video data. Therefore, the study of how to store and transmit the 3-D data in real time is vital. We address a technique that encodes a 3-D surface shape into a single 24-bit color image. In particular, this image is generated by advanced computer graphics tools with two primary color channels encoded as sine and cosine fringe images, and the third channel encoded as a stair image to unwrap the phase obtained from the two fringe images. An arbitrary 3-D shape can then be recovered from a single image. We test 3-D shapes with differing levels of complexity along with various image formats. Experiments demonstrate that, without significantly losing the shape quality, the compression ratio can go up to 1:36.86, compared with the native smallest possible 3-D data representation method.

Polymer/multiple walled carbon nanotube (MWNT) thin films on glass slide substrates have been fabricated by using the spin-coating method. The optical power limiting performance and nonlinear absorption in these films have been characterized experimentally. Transmission electron micrograph and scanning electron microscope (SEM) techniques have been used to investigate the interaction between polymer molecules and MWNTs. SEM images of polymer functionalized carbon nanotubes show that polymer molecules and MWNTs can interact via ∏-stacking to increase solubilization of MWNTs, which can be used to explain the optical power limiting effect. For quantitative comparison of different polymer MWNT thin film performance, the open Z-scan technique is employed to measure nonlinear absorption coefficient and optical power limiting effects of different polymer MWNT thin films.

In this study, we investigate the deposition of SiNx thin films by radio-frequency ion-beam sputtering deposition. By varying the amount of N2 and Ar flow and ion-beam voltage, we can obtain an optimal refractive index of 2.07, extinction coefficient (at the central wavelength of 500 nm) of 3.44×10−4, and deposition rate of 0.166 nm/s. The x-ray photoelectron spectra of SiNx films deposited with different beam voltages are also analyzed. The residual stress of the SiNx films varied from −1.38 to −2.17 GPa, depending on the beam voltage. The residual stress is reduced from −2.17 to −1.40 GPa when the film is divided into four layers with three interfaces.

We report a new method to measure the refractive index change in optical fiber core induced by femtosecond (fs)laser exposure. An in-line Fabry-Perot interferometer, serving as the measurement platform, is constructed on a commercial single-mode optical fiber by one-step femtosecond (fs) laser fabrication. A positive refractive index change is observed and measured accurately as the laser pulse energy surpasses the ablation threshold.

A high-resolution rangefinder equipped with a pulsed laser has been developed by introducing a high-resolution interpolation technique based on an undersampling method. Using this pulse method employed by the rangefinder, a new time-scale expansion has been realized that is similar to the heterodyne of the rangefinder that also employs the phase difference method. Therefore, high-resolution measurements are now possible. A bandpass-filtered temperature-compensated crystal oscillator signal with a reference frequency of 15 MHz is sampled at a timing determined by a received pulsed light with a repetition rate of 8.5 kHz. With this process, a time series of undersampled 2.5-kHz data are obtained as an intermediate step that can be further lowered to 85 Hz by final rearrangement of the undersampled data. With this technique, a reference frequency is transformed into a lower frequency. A distance is then calculated from the phase of this low frequency. The rangefinder developed shows good performances that include a range resolution of better than 1 mm, nonlinearity within ±1 mm, and a measurement range of up to 7000 m.

A multiple-laser flash shadowgraphy system has been innovatively designed and developed to study the terminal effects of projectiles. The system has been designed based on modulated laser diodes operated at low voltage and current. In order to study the ballistics effects of small arms, an exposure time of the order of a few hundreds ns and a delay time of the order of a few tens of µs are needed. An ultrashort pulse generator has been developed to provide the exposure and delay time pulses. The developed system has been integrated with a field lens assembly and camera assembly. To record the shadowgraphs, a target is placed near the center of the field lens and a bullet is fired from a fixed gun. The system is described, and experimental results and conclusions are reported.

We present the design and fabrication of a novel fiber optic multiparameter bend sensor. Unlike current intrinsic fiber optic multiparameter bend sensors that depend on multiple cores or multiple fibers, the new sensor is based on three circumferential active-cladding point modifications on a single optical fiber at specific axial locations along the length of the fiber. A commercial 30-W CO2 laser is used to cut three point modifications in the plastic cladding of the fiber. Each of the three defects is filled with fluorophores (quantum dots) with different peak emission wavelengths. A 405-nm laser (operating at 10-mW) is used to excite the quantum dots, while a spectrometer, coupled to the fiber, measures the emission signals of each of the three fluorophores simultaneously. Results show that bending direction and degree of curvature at a single localized modification region can be expressed as a function of the three fluorescence intensities.

Random residual circular birefringence induced by a twist of single-mode fiber is the main cause of magnetic field Faraday phase error in depolarized interferometric fiber optic gyroscopes (D-IFOGs). Magnetic field Faraday phase error in D-IFOG includes both radial and axial phase errors; however, axial phase error has not been thoroughly researched and is usually neglected. A magnetic phase error model of D-IFOG along a radial direction is established by using a Jones matrix; then, the mathematical description of radial direction phase drift in D-IFOG is deduced according to the model. Based on a quadrupolar winding distribution structure in a fiber loop, a magnetic phase error model of D-IFOG along the axial direction is established, and phase drift in D-IFOG is deduced by using a coil expansion method. Theoretical analysis shows that nonreciprocal phase error in D-IFOG induced by magnetic field correlates with several factors, such as optical coherent length, optical polarization degree, etc. Then, measures to restrain the magnetic field phase error in D-IFOG are investigated, such as the new Lyot depolarizer, electromagnetic shielding, etc. Further, we experimentally present the performance of D-IFOG with the magnetic intensity of 150 Gs along axial and radial directions, respectively, and verify the effect of a new Lyot depolarizer on restraining magnetic phase error in D-IFOG.

A novel two-dimensional high-bandwidth Shack-Hartmann wavefront sensor was designed and tested, addressing the high temporal bandwidth of aero-optical aberrations caused by compressible flows. The principle of operation and modifications from an earlier version of the wavefront sensor are presented and compared with a commercially available wavefront sensor with a 33×44 subaperture spatial resolution. A two-dimensional wavefront reconstruction algorithm is presented. The comparison was performed over a two-dimensional, acoustically forced heated jet. The high temporal resolution and spatial resolution of the sensor are demonstrated. The results show good agreement between the two sensors.

We demonstrate the minimization of background loss for arc-induced long-period fiber gratings in standard fiber by Taguchi's optimization method. We use Taguchi's method to determine the optimum values for parameters like electric-arc power, arc duration, and tensile strain applied over the fiber during the inscription process. With these optimal parameters, we minimize the background loss resulting from the geometrical deformations of the fiber. The experimental results show that background loss can be reduced from more than 1 dB to less than 0.3 dB at rejection bands with isolation >15 dB.

For a special solid coupled optical taper, a differential equation of its shape curve is deduced using the curvature-shape matching relationship, and the closed-form solution of the equation can be acquired by its concrete initial curvature and shape boundary condition. Since the physical formation process in different tapering conditions can be described conveniently by the solution, the variation relationships among the taper length, shape factor, large-end radius, small-end radius, and shape function are analyzed. The results show that the theoretical simulation is basically in accordance with the experimental data and the errors are also given. Thus, given the shape factor parameters of the special solid coupled optical taper, the solution can be properly used to predict the taper shape curve for any taper length, large-end radius, and small-end radius.

We have experimentally investigated a full-duplex radio-over-fiber system transmitting 2.5-Gbit/s orthogonal frequency-division multiplexing (OFDM) signals with a 40-GHz optical millimeter wave as downlink. Meanwhile the central can be reused wavelength as the uplink connection for transmitting 2.5-Gbit/s on-off keying (OOK) signals. By experimentally comparing the transmission performance of OFDM downstream and OOK upstream signals, it can be seen that the power penalty for the downstream signals is about 1 dB at a bit error rate of 10−3 after transmission over a 50-km standard mode fiber. However, the power penalty for the upstream signals is less than 0.5 dB at a bit error rate of 10−9 after transmission over the same distance.

We present a new configuration for a polymer wavelength division multiplexing (WDM) filter based on multimode interference. We developed a hybrid integrated subassembly module for 1.31- and 1.55-µm bidirectional operation. Active devices including a laser diode with a monitoring photodiode and a receiving photodiode were integrated on a silicon optical bench (SiOB) platform using a flip-chip bonding technique. A polymer WDM filter chip made of polymethylmethacrylate was fabricated using a hot embossing technique. We then investigated the optical performance of the transmitter and receiver subassembly module using a SiOB platform. This hybrid integrated subassembly module exhibited bidirectional 2.5-Gbit/s signal modulation with a minimum sensitivity of −20.5 dBm at a bit error rate of 10−10 and an optical crosstalk of −35 dB.

We demonstrate a novel low-cost radio-over-fiber network architecture with one directly modulated laser and one intensity modulator. By employing an orthogonal frequency division mutiplexing modulation format and frequency quadruple scheme, the bandwidth requirement of the devices and the cost of the system is reduced. Experimental results show that the power penalty for the downlink data after transmission over 20-km single mode optical fiber (SMF)-28 is smaller than 1.3 dB, while for the up-link data, the power penalty after transmission over 20-km SMF-28 is smaller than 0.3 dB.

The design of double-coated optical fibers to minimize hydrostatic-pressure-induced microbending losses caused by creep deformation of polymeric coatings is investigated. The hydrostatic-pressure-induced stresses in optical fibers are derived from the viscoelastic behavior of commercial polymeric coatings. Microbending loss in these fibers is dominated by compressive radial stress at the interface between the glass fiber and the primary coating, which is a function of the material properties of the polymeric coatings and their thickness. To minimize these losses in double-coated optical fibers, one should diminish the Young's modulus, Poisson ratio, and relaxation time of the primary coating as well as the strain ratio of the secondary coating, but should raise the strain ratio of the primary coating and the radius, Young's modulus, Poisson ratio, and relaxation time of the secondary coating. The radius of the primary coating possesses an optimum value.

In this brief-article the effect of the number of taps on the quality (Q) for infinite- and finite-impulse-response microwave photonic filters (IIRMPFs and FIRMPFs) is analyzed. For FIRMPFs, an increas of Q with the number of taps from 2 to 10 is deduced by analyzing the free spectrum ranges with 3-dB bandwidths. For IIRMPFs, a pretty high Q can be realized when the product of the coefficient and the gain in the feedback loop equals 1. Our analytical results are verified by a typical IIRMPF structure based on a fiber Bragg grating (FBG), and the Q value can be increased up to 804 by using two FBGs with reflectivities of 50% and 99.5%, respectively.

A high-concentration Er3+/Yb3+ codoped core-cladding heterogeneous single-mode phosphate fiber amplifier with a similar numerical aperture to the Corning SMF-28 standard single-mode optical fiber is described. Measurements and calculations are given for the device's optical absorption, strong infrared fluorescence, absorption, and emission cross-sections of Er3+, Judd-Ofelt parameters, and spontaneous transition probabilities of Er3+ in the core glasses. The relative gain (the signal enhancement) of a 5.8-cm-long fiber amplifier was measured to be 32.3 dB, and after compensating for both the propagation loss and the absorption loss, a maximum internal gain of 2.6 dB/cm at 1.535 µm was obtained, which reveals an available core-cladding heterogeneous design strategy in developing high-gain amplifier devices.

We present a design of the conservative, reversible, and universal all-optical Fredkin logic gate based on a single bacteriorhodopsin (BR)-protein-coated silica microcavity. The switching of a near-IR laser beam at 1310 or 1550 nm by photoactivating a silica microsphere coated with BR monolayers with a low power control signal at 532 nm, in contact between two tapered single-mode fibers, is used as a template for a four-port tunable resonant coupler Fredkin gate. The proposed gate has also been used to design low-power all-optical AND, OR, NOT, XOR, and X-NOR gates and full-adder and demultiplexer/multiplexer circuits. The advantages of high Q-factor, tunability, compactness, low-power control signals, high fan-out, and flexibility of cascading switches in 2-D to 3-D architectures to form circuits, makes the designs promising for practical applications. The proposed design provides a new paradigm for hybrid nanobiophotonic integration for all-optical computing.

A novel method of integrating a total internal reflection (TIR) mirror into an optical waveguide embedded in a printed circuit board (PCB) was demonstrated for application in chip-to-chip optical interconnects. Plastic optical fiber (POF) was placed into channels that were mechanically machined into FR-4 composite plates. The TIR mirror was created by a second mechanical machining. The mirror loss was measured to be approximately −1.6 dB per reflection. The use of POF resulted in attenuation losses in the waveguide over an order of magnitude lower than what is obtainable with typical planar waveguides that are integrated into PCBs. Monte Carlo ray tracing was used to determine the theoretical efficiency of the system as well as cross talk between channels due to optical device alignment tolerances.

Digital holography and electronic speckle pattern interferometry are promising tools for industrial applications for deformation and shape measurements. Because of the limited measuring range, compensation methods can be applied in practical measurements. They can be digital, because these measuring techniques operate with images recorded with digital camera. We develop a new measurement setup, combining two out-of-plane displacement measurements with different sensitivities and an adaptive compensation method. Using this compensation method much more precise displacement maps can be produced than would be possible from a single measurement. One major task is to perform automatic measurements even if the deformation is higher than the upper measuring range of the basic method.

Recently, a high-order instantaneous moments (HIM)-operator-based method was proposed for accurate phase estimation in digital holographic interferometry. The method relies on piece-wise polynomial approximation of phase and subsequent evaluation of the polynomial coefficients from the HIM operator using single-tone frequency estimation. The work presents a comparative analysis of the performance of different single-tone frequency estimation techniques, like Fourier transform followed by optimization, estimation of signal parameters by rotational invariance technique (ESPRIT), multiple signal classification (MUSIC), and iterative frequency estimation by interpolation on Fourier coefficients (IFEIF) in HIM-operator-based methods for phase estimation. Simulation and experimental results demonstrate the potential of the IFEIF technique with respect to computational efficiency and estimation accuracy.

Atmospheric radiance structures are induced by local temperature and density fluctuations. The design, development, and use of electro-optical surveillance systems require the knowledge of atmospheric radiance clutter at small spatial scales. A model is developed to study radiance fluctuations observed by an airborne IR sensor. This model uses intermediate results of the Air Force Research Laboratory background radiance code SAMM-2 and synthesizes an image of atmospheric background clutter according to the sensor characteristics. Inputs are a 3-D grid of temperature fluctuations and SAMM-2 transfer functions. We extend this code to calculate atmospheric limb viewing irradiance images for airborne and satellite sensors. We detail the irradiance extension of the clutter calculation code and present some results for satellite and airborne viewing conditions.

Iris recognition is used for information security with a high confidence level because it shows outstanding recognition accuracy by using human iris patterns with high degrees of freedom. However, iris recognition accuracy can be reduced by noisy iris images with optical and motion blurring. We propose a new iris recognition method based on the fuzzy difference-of-Gaussian (DOG) for noisy iris images. This study is novel in three ways compared to previous works: (1) The proposed method extracts iris feature values using the DOG method, which is robust to local variations of illumination and shows fine texture information, including various frequency components. (2) When determining iris binary codes, image noises that cause the quantization error of the feature values are reduced with the fuzzy membership function. (3) The optimal parameters of the DOG filter and the fuzzy membership function are determined in terms of iris recognition accuracy. Experimental results showed that the performance of the proposed method was better than that of previous methods for noisy iris images.

Chromatic aberration is a form of aberration in color optical devices that produces undesirable color fringes along borders within images. It is becoming a more critical problem these days as digital cameras are getting smaller, while the number of picture elements is increasing. We propose a novel method for detecting and eliminating chromatic aberration using image processing. We first analyze the color behavior on edges that do not show chromatic aberration and propose a range limitation for color difference signals. When pixels violate the preceding condition, they can be considered as color fringes caused by chromatic aberration. Corrected pixel values are generated to eliminate the chromatic aberrations. The proposed algorithm corrects both lateral and longitudinal aberration in an image, and experimental results are provided to demonstrate its efficacy.

We propose a robust and fast quarter-pixel motion estimation algorithm. This algorithm is an advanced version of the previously proposed model-based quarter-pixel motion estimation (MBQME). MBQME has many advantages in computational complexity, running speed, and hardware implementations. But it has the problem that it does not find the quarter-pixel positions that locate beyond the half-pixel positions. That is one of limitations of model-based motion estimation methods, and it leads to both peak-SNR degradation and bit-rate increase. To solve this problem, we propose a hierarchical mathematical model with minimum interpolations. Through this model, we can determine a motion vector at every quarter-pixel point, which is perfectly compatible with the quarter-pixel motion estimation method within international video coding standards such as MPEG-4 and H.264/AVC. The simulation results show that the proposed method yields almost the same or even better peak-SNR performance than that of full-search quarter-pixel motion estimation, with much lower computational complexity.

The systematic error introduced when using 1-D peak detection algorithms to decompose elliptically shaped correlation peaks is investigated. First, an analytical description of this error is derived, and it is shown that this error can lead to a systematic influence of more than one pixel. Additionally, a general linear 2-D Gaussian algorithm based on least squares estimation is presented to allow correlation peak detection of elliptically shaped peaks without any significant bias error. Finally, the performance of the presented algorithms for subpixel displacement estimation, as well as algorithms provided by commercial software packages, is tested with artificial image pairs of random dot patterns.

Film dirt is the most commonly encountered artifact in archive restoration applications. Since dirt usually appears as a temporally impulsive event, motion-compensated interframe processing is widely applied for its detection. However, motion-compensated prediction requires a high degree of complexity and can be unreliable when motion estimation fails. Consequently, many techniques using spatial or spatiotemporal filtering without motion were also been proposed as alternatives. A comprehensive survey and evaluation of existing methods is presented, in which both qualitative and quantitative performances are compared in terms of accuracy, robustness, and complexity. After analyzing these algorithms and identifying their limitations, we conclude with guidance in choosing from these algorithms and promising directions for future research.

H.264/AVC is the video coding standard with the highest coding efficiency, and its use has increased in various applications, such as digital multimedia broadcasting. We propose an effective method for recovering video data when the H.264/AVC-coded bit stream is corrupted. This method uses an affine transformation and cost criteria based on an overlapping boundary-matching algorithm and adaptively applies concealment methods. The proposed method also divides a corrupted macroblock into eight triangular regions and then conceals the macroblock by units of each partial region. The simulation results show that the proposed method yields a video quality that is objectively and subjectively superior to those produced using conventional approaches.

The best performance in compression efficiency is provided by MPEG-4 AVC/H.264 but at the cost of high computational complexity to select the best mode during the mode decision process. To reduce this complexity, we propose a fast mode decision algorithm that exploits the spatiotemporal correlation of the macroblock (MB) modes and the rate-distortion (RD) costs from the previous and current frames. The proposed method determines the candidate modes for the current MB based on the modes of the four spatially neighboring and temporally collocated MBs. It also incorporates the RD costs of the four reference MBs and the current MB. The experimental results show that the AVC/H.264 encoder using our proposed method achieves about 73% speedup (up to 86.5%) compared to the AVC/H.264 JM 11.0 encoder while preserving a 0.25% increment in total encoding bits with a loss of only 0.09 dB in peak SNR.

This work proposes an efficient bit-plane-based lossless depth-map coding method for an MPEG 3-D video coding scheme. This method uses the distinctive image characteristics between bit planes of the depth map. In the simulations, the performances of the proposed coding method are compared with those of the conventional lossless coding methods, i.e., JPEG-LS, JPEG-2000, and H.264/AVC, in terms of the intra- and also intercoding modes. In intracoding mode, the proposed method achieves the highest compression ratios as 14.28:1 on average. JPEG-LS, JPEG2000, H.264/AVC (CAVLC), and H.264/AVC (CABAC) obtain the compression ratios as 9.74:1, 7.68:1, 9.13:1, and 10.97:1, respectively. In intercoding mode, the proposed method also accomplishes the highest compression ratios as 28.91:1 on average. However, H.264/AVC (CAVLC) and H.264/AVC (CABAC) obtain the compression ratios as 19.82:1 and 23.45:1, respectively.

We explore certain symmetry properties of the Fourier spectrum of speckle from smooth objects and the effects of these symmetries on image speckle contrast. The cases examined include bright-field imaging, dark-field imaging, and single-sideband imaging.