Displacement Vector Measurement Research Articles

Combined use of confocal microscopy and DIC for 3D displacement vector measurement

In the present paper the author describes the potential offered by the combined use of the Confocal Microscopy (CM) and Digital Image Correlation (DIC) to resolve the whole displacement vector in full-field fashion and with nanometric accuracy. By means of two different configurations of the same portion of the area under investigation, the surface profile retrieved at microscopic level by the CM functioned as a carrier for the DIC algorithm, both for a polished surface and an engineering standard roughness. The in-plane displacement components obtained by DIC were then used to extract the out-of-plane component from the profile information. After describing all steps that are necessary for applying the procedure, preliminary results of an indentation tests carried out on a polished steel specimen are reported and discussed.

Plural spectral frequency divisions for ultrasonic tissue displacement vector measurement.

For a human tissue displacement vector or strain tensor measurement, the plural spectral frequency division method (PSFDM) is presented. In this report, the effectiveness of the processing is demonstrated by performing the measurements on an agar phantom interrogated by wideband ultrasonic (US) single beam scanning and compounding of steered plane wave transmissions.

Ultrasonic lateral modulation imaging, speckle reduction, and displacement vector measurements using simple single-beam scanning or plural crossed-beam scanning with new spectra frequency division processing methods

Ultrasonic lateral modulation imaging, speckle reduction, and displacement vector measurements using simple single-beam scanning or plural crossed-beam scanning with new spectra frequency division processing methods Chikayoshi Sumi, Yousuke IshiiDepartment of Information and Communication Sciences, Faculty of Science and Technology, Sophia University, Tokyo, JapanAbstract: The development of effective ultrasonic tissue displacement measurement methods increases the number of possible applications for various tissue displacement and strain measurements. These applications include measurements of spontaneous motions/deformations generated by heart motion; pulsations from phenomena such as blood flow (intracardiac, intravascular, and carotid); heart, blood vessel, and liver motion; and motion from artificial sources such as motions/deformations generated by applying static compression/stretching forces, vibration or acoustic radiation forces (breast and liver). For arbitrary orthogonal coordinate systems obtained using arbitrary transducer types (eg, linear, convex, sector, arc, or radial array types, or single aperture types with a mechanical scan), several lateral modulation (LM) methods (eg, scanning with plural crossed or steered beams over a region of interest) have been developed that can be used with new echo imaging methods for tissue displacement/deformation measurements. Specifically, by using such beamforming methods, in addition to highly accurate displacement vector and lateral displacement measurements, LM echo imaging with a high lateral carrier frequency and a high lateral resolution has been developed. Another new beamforming method, referred to as “a steering angle (ASTA) method,” ie, scanning with a defined steering angle, is also described. In addition to conventional non-steered-beam scanning (ie, a version of ASTA) and conventional steered-beam scanning with a variable steering angle (eg, sector, arc, radial scan), a simple, single-beam scanning method also permits the use of LM, which yields an accurate displacement vector measurement with fewer calculations than the original LM methods. This is accomplished by using a previously developed spectra frequency division method (SFDM). However, the lateral carrier frequency and the measurement accuracy acquired by using such a single-beam scanning method are lower than those achieved with the original LM scanning methods and should be increased (ie, by using a quasi-LM method). In this report, the effectiveness of the use of the new SFDMs is verified with experiments on agar phantoms, in which conventional non-steered, focused single-beam transmission/reception scanning is performed together with high-speed non-steered single plane-wave transmission and non-steered, focused single-beam reception scanning using a linear array-type transducer. For comparison, the original LMs, with their respective transmissions of crossed, steered focused beams and plane waves are also performed. Because the use of rectangular apodization functions (ie, no apodization) yields a larger bandwidth in a lateral direction than the effective use of parabolic functions with the original LM method, it is shown that disregarding the lateral low-frequency spectra yields useful quasi-LM echo imaging with a high lateral frequency, and further significantly increases the measurement accuracy of a displacement vector. In addition, when no apodization is used with the original version of LM, disregarding the low-frequency lateral spectra is effective. In addition, the interchangeability of cosine and sine modulations performed after completing beamforming can also be used for single-beam scanning as well as for the original LM scanning method. Specifically, the cosine and sine modulations, respectively, are used for LM and quasi-LM imaging and displacement vector measurements. It is concluded that the appropriate use of the new SFDMs with simple single-beam scanning or with simple plural crossed-beam scanning with no apodization can achieve almost the same accuracy as the original LM scanning method using plural crossed beams with the effective apodization. Another new application of SFDM is also described: an incoherent superposition of the frequency-divided spectra reduces speckles. The new methods will also be effective for other beamforming methods and with other types of transducers.Keywords: lateral modulation scanning, single-beam scanning, apodization, spectra frequency division method, low-frequency spectra, quasi-LM imaging, coherent superposition, incoherent superposition

Consideration of generated beam angles increases the accuracy of ultrasonic displacement measurements

Consideration of generated beam angles increases the accuracy of ultrasonic displacement measurements Chikayoshi Sumi, Yuuki Takanashi, Kento IchimaruDepartment of Information and Communication Sciences, Faculty of Science and Technology, Sophia University, Tokyo, JapanAbstract: The development of practical ultrasonic (US) tissue displacement measurement methods increases the number of available and useful applications of displacement/strain measurements that can be made (eg, various blood flow measurements and measurements of tissue motion in organs such as the heart, liver, and so forth). Previously developed lateral modulation (LM) methods with a multidimensional autocorrelation method (MAM) or multidimensional Doppler method (MDM) and a steering angle method (ASTA) with lateral Doppler method produced accurate displacement vector and lateral displacement measurements, respectively. Such measurements cannot be obtained using only a conventional Doppler technique. Another new method has also been reported, using multiple crossed beams (MCBs) to obtain high-accuracy displacement vector measurements; that is, a displacement vector is synthesized using accurately measured axial displacements with previously developed multidimensional displacement measurement methods, including the one-dimensional autocorrelation method (1D AM) with a multidimensional moving average (MA), together with conventional rotation processing of global echo data or a coordinate system (ie, a global echo rotation referred to as r method) by the negative value of the steering angles used in beamforming. However, in real-world applications, directivities of transmission and reception apertures, scattering, reflection, and attenuation affect the direction and properties of US beams used for conventional axial displacement measurements employing beamforming methods such as a conventional nonsteered, steered, or secta beam, and they also affect ASTA and MCB methods. In this report, to improve accuracy in the measurements of an arbitrary directional displacement and a displacement vector using any beamforming methods, a spatial resolution in a beam angle (BA) is generated. For instance, for a two-dimensional (2D) Cartesian coordinate system, this is obtained by calculating the arctangent of the ratio of the axial and lateral instantaneous frequencies or the first moments of local spectra. On the basis of the 1D AM with a multidimensional MA, the local displacement in the beam direction is accurately measured by dividing the local instantaneous phase change by the instantaneous frequency calculated in the beam direction, and an arbitrary directional displacement can be measured (axial, lateral, radial, and so forth), which is done with or without a rotation of local echo data. These are respectively referred to as BA and BAr (BA + local rotation) methods or, specifically, as the 1D AMBA (1D AM + BA) and the 1D AMBAr (1D AM + BAr). Also, it is theoretically shown that the 1D AM with MCB but no echo rotation (ie, 1D AMBA with MCB) is equivalent to the most accurate MAM with LM, and that the 1D AMBA with ASTA can also provide a lateral Doppler measurement. Through agar phantom experiments, in addition to steered spherical focusing beams for both transmission and reception, measurement accuracies with all of the new methods are also evaluated for rapid scanning beamforming such as using one or plural, steered or nonsteered plane wave transmissions, and steered or nonsteered spherical focusing beam receptions. For comparisons with the 1D AMBA and the 1D AMBAr, the spectra frequency division method (SFDM) used in the MAM is also used instead of the 1D AM. All for the measurements of an axial displacement with axial compression and nonsteering, a lateral displacement with lateral compression and ASTA and a 2D displacement vector with lateral compression and MCBs, BA methods based on the 1D AM and SFDM approaches achieve more accurate measurements with significantly fewer calculations than the corresponding BAr or r methods (ie, real time). BA methods do not yield dead region data in a region of interest and they do not yield any measurement errors because of an approximate interpolation of echo data or of measured motion/deformation data. However, the measurement accuracies of one-directional displacements are significantly lower than those of displacement vectors, because of the practical three-dimensional deformation or motion (eg, about a half standard deviation of the lateral displacement measurement). In terms of required processing, the MAM or the MDM with LM is better than methods with MCB (ie, real time). The proper combination of the SFDM with LM or ASTA will yield more accurate measurements in a trade-off with increasing the number of calculations. Keywords: beam direction, beam angle (BA), axial displacement, lateral displacement, displacement vector, lateral modulation (LM), a steering angle (ASTA), multiple crossed beams (MCBs), multidimensional or one-dimensional autocorrelation method (MAM or 1DAM), multidirectional moving-average (MA), spectra frequency division method (SFDM)

Beam steering and coordinate system rotation improves accuracy of ultrasonic measurements of tissue displacement vector and lateral displacement

Beam steering and coordinate system rotation improves accuracy of ultrasonic measurements of tissue displacement vector and lateral displacement Chikayoshi Sumi1,2, Kento Ichimaru2, Yusuke Shinozuka21Department of Information and Communication Science, 2Department of Electrical and Electronics Engineering, Faculty of Science and Technology, Sophia University, Kioi-cho, Chiyoda-ku, Tokyo, JapanAbstract: With the proper use of beam steering and apodization, a higher resolution lateral echo image is obtained than with conventional imaging. This is achieved by superimposing crossed, steered beams, which is referred to as “lateral modulation” (LM). This type of beamforming achieves almost the same accuracy in lateral displacement measurements as in axial displacement measurements, ie, displacement vector measurements. The steering angle (ASTA) can also be used instead of LM, which uses only beams with a steering angle. In this report, the accuracy of the displacement vectors and lateral displacement measurements for LM and ASTA were evaluated using simulations and agar phantom experiments. The parameters used were direction of a displacement vector, steering angles, and rotation angle for the coordinate system. Changes in the steering angle and rotation angle of the coordinate system permit control of frequencies in the respective directions of the coordinate axes. As shown, when performing a simple ASTA for displacement vector measurement, a spectra frequency division should be performed using a previously developed multidimensional autocorrelation or Doppler method instead of block-matching methods. In this version of ASTA, the combination of nonsteering and rotation of the coordinate system is also effective, because the lateral bandwidth does not decrease. In such a case, transmission of a laterally wide wave will also be effective, particularly for three-dimensional measurement/imaging using a two-dimensional array transducer. ASTA can also be used for accurate lateral displacement measurements. Although a proper beam steering and/or a proper coordinate rotation improves the measurement accuracy achieved with LM and ASTA, all measurement accuracies obtained with ASTA are lower than with LM.Keywords: lateral modulation, single steering angle, coordinate system rotation, spectra frequency division

Ultrasonic agar phantom experiment for comparison of the measurement accuracy of tissue elasticity obtained by displacement vector measurement using lateral modulation with multidimensional autocorrelation and Doppler methods and corresponding one-dimensional methods

Comparison of the measurement accuracy of elasticity was performed through agar phantom experiments, ie, two-dimensional (2D) strain tensor components and 2D shear modulus reconstruction obtained by previously developed multidimensional displacement vector measure- ment methods on the basis of autocorrelation and Doppler methods (2D AM and 2D DM) and the corresponding 1D methods. The multidimensional methods yield more accurate and stable results than the corresponding 1D methods. As is shown, however, such 1D methods can also be used when the echo signal-to-noise ratio is high, eg, obtainable by previously developed lateral modulation with parabolic apodizations.

Proper Analytic Point Spread Function for Lateral Modulation

For ultrasonic lateral modulation for the imaging and measurement of tissue motion, better envelope shapes of the point spread function (PSF) than of a parabolic function are searched for within analytic functions or windows on the basis of the knowledge of the ideal shape of PSF previously obtained, i.e., having a large full width at half maximum and short feet. Through simulation of displacement vector measurement, better shapes are determined. As a better shape, a new window is obtained from a Turkey window by changing Hanning windows by power functions with an order larger than the second order. The order of measurement accuracies obtained is as follows, the new window > rectangular window > power function with a higher order > parabolic function > Akaike window.

Determination of lateral modulation apodization functions using a regularized, weighted least squares estimation.

Recently, work in this group has focused on the lateral cosine modulation method (LCM) which can be used for next-generation ultrasound (US) echo imaging and tissue displacement vector/strain tensor measurements (blood, soft tissues, etc.). For instance, in US echo imaging, a high lateral spatial resolution as well as a high axial spatial resolution can be obtained, and in tissue displacement vector measurements, accurate measurements of lateral tissue displacements as well as of axial tissue displacements can be realized. For an optimal determination of an apodization function for the LCM method, the regularized, weighted minimum-norm least squares (WMNLSs) estimation method is presented in this study. For designed Gaussian-type point spread functions (PSFs) with lateral modulation as an example, the regularized WMNLS estimation in simulations yields better approximations of the designed PSFs having wider lateral bandwidths than a Fraunhofer approximation and a singular-value decomposition (SVD). The usefulness of the regularized WMNLS estimation for the determination of apodization functions is demonstrated.

A Demonstration of Optimal Apodization Determination for Proper Lateral Modulation

We have realized effective ultrasound (US) beamformings by the steering of plural beams and apodizations for B-mode imaging with a high lateral resolution and accurate measurement of tissue or blood displacement vector and/or strain tensor using the multidimensional cross-spectrum phase gradient method (MCSPGM), or multidimensional autocorrelation or Doppler methods (MAM and MDM) using multidimensional analytic signals. For instance, the coherent superposition of the steered beams performed in the lateral cosine modulation method (LCM) has a higher potential for realizing a more accurate measurement of a displacement vector than the synthesis of the displacement vector using the accurately measured axial displacements obtained by the multidimensional synthetic aperture method (MDSAM), multidirectional transmission method (MTM) or the use of plural US transducers. Originally, the apodization function to be used for realizing a designed point spread function (PSF) was obtained by the Fraunhofer approximation (FA). However, to obtain the best approximated, designed PSF in the least-squares sense, we proposed a linear optimization (LO) method. Furthermore, on the basis of the knowledge about the losts of US energy during the propagation, we have recently developed a nonlinear optimization (NLO) method, in which the feet of the main lobes in apodization function are properly truncated. Thus, NLO also allows the decrease in the number of channels or the confinement of the effective aperture. In this study, to gain insight into the ideal shape of the PSF, the accuracies of the two-dimensional (2D) displacement vector measurements were compared for typical PSFs with distinct lateral envelope shapes, particularly, in terms of full width at half maximum (FWHM) and the length of the feet, i.e., the Gaussian function, Hanning window and parabolic function. It was confirmed that a PSF having a wide FWHM and short feet was ideal. Such a PSF yielded an echo with a high signal-to-noise ratio (SNR), a large bandwidth and a large maximum spectrum of the center frequency. Moreover, for the three PSFs used, by calculating the PSFs using a typical transducer model and the apodization functions obtained by the respective LO and NLO methods and FA, we compare the approximation accuracies of the realized PSFs. NLO was effective for realizing such an ideal PSF. In addition, NLO allowed the significant decrease in the number of channels or the confinement of the effective aperture. Thus, in the comparisons of the three distinct PSFs, we obtain an appropriate apodization function. This study will assist the realization of the best lateral modulation.

Phantom experiments of axial strain measurements using multidimensional autocorrelation method, multidimensional Doppler method and direct strain measurement method

Various tissue displacement vector measurement methods have been proposed by us, i.e., the multidimensional cross-spectrum phase gradient method (MCSPGM), the multidimensional autocorrelation method (MAM) and the multidimensional Doppler method (MDM). In this paper, actual measurement results obtained by MAM and MDM are reported. Specifically, for a compressed agar-graphite phantom (infinitesimally compressed, ≈0.07%; largely compressed, ≈0.7%), the measurement results for axial strain using MAM and MDM are shown and compared with those using MCSPGM, the conventional one-dimensional (1D) AM and the direct strain measurement method based on 1D AM (DSMM). Although DSMM was also developed by us in 1993, the method and the actual measurement results have not been reported elsewhere. Because the multidimensional methods can provide more accurate axial displacement measurements in real time and enable displacement vector measurement, 1D AM and DSMM might now be ineffective for practical applications.

Shear modulus reconstruction by strain tensor measurement using lateral modulation

Two-dimensional (2D) shear modulus reconstructions are performed on an agar phantom using our previously developed ultrasound lateral Gaussian envelope cosine modulation method (LGECMM) together with multidimensional displacement vector measurement methods, i.e., the multidimensional cross-spectrum phase gradient method (MCSPGM), the multidimensional autocorrelation method (MAM) and the multidimensional Doppler method (MDM). The accuracies of the obtained 2D reconstructions are compared with each other in addition to those of 1D reconstructions obtained from the respective ratios of lateral and axial strains.

Spatially variant regularization of lateral displacement measurement using variance

The purpose of this work is to confirm the effectiveness of our proposed spatially variant displacement component-dependent regularization for our previously developed ultrasonic two-dimensional (2D) displacement vector measurement methods, i.e., 2D cross-spectrum phase gradient method (CSPGM), 2D autocorrelation method (AM), and 2D Doppler method (DM). Generally, the measurement accuracy of lateral displacement spatially varies and the accuracy is lower than that of axial displacement that is accurate enough. This inaccurate measurement causes an instability in a 2D shear modulus reconstruction. Thus, the spatially variant lateral displacement regularization using the lateral displacement variance will be effective in obtaining an accurate lateral strain measurement and a stable shear modulus reconstruction than a conventional spatially uniform regularization. The effectiveness is verified through agar phantom experiments. The agar phantom [60 mm (height) × 100 mm (lateral width) × 40 mm (elevational width)] that has, at a depth of 10 mm, a circular cylindrical inclusion (dia. = 10 mm) of a higher shear modulus (2.95 and 1.43 × 10 6 N/m 2, i.e., relative shear modulus, 2.06) is compressed in the axial direction from the upper surface of the phantom using a commercial linear array type transducer that has a nominal frequency of 7.5-MHz. Because a contrast-to-noise ratio (CNR) expresses the detectability of the inhomogeneous region in the lateral strain image and further has almost the same sense as that of signal-to-noise ratio (SNR) for strain measurement, the obtained results show that the proposed spatially variant lateral displacement regularization yields a more accurate lateral strain measurement as well as a higher detectability in the lateral strain image (e.g., CNRs and SNRs for 2D CSPGM, 2.36 vs 2.27 and 1.74 vs 1.71, respectively). Furthermore, the spatially variant lateral displacement regularization yields a more stable and more accurate 2D shear modulus reconstruction than the uniform regularization (however, for the regularized relative shear modulus reconstructions, slightly accurate, e.g., for 2D CSPGM, 1.51 vs 1.50). These results indicate that the spatially variant displacement component-dependent regularization will enable the 2D shear modulus reconstruction to be used as practical diagnostic and monitoring tools for the effectiveness of various noninvasive therapy techniques of soft tissue diseases (e.g., breast, liver cancers). Application of the regularization to the elevational displacement will also increase the stability of a three-dimensional (3D) reconstruction.

Effective lateral modulations with applications to shear modulus reconstruction using displacement vector measurement

High accuracy in measuring target motions can be realized by combined use of our previously developed lateral Gaussian envelope cosine modulation method (LGECMM) and displacement vector measurement methods that enable simultaneous axial and lateral displacement measurements, such as the multidimensional autocorrelation method (MAM). In this paper, LGECMM is improved by using parabolic functions and Hanning windows instead of Gaussian functions in the apodization function, i.e., parabolic apodization and Hanning apodization. The new modulations enable decreases in effective aperture length (i.e., channels) and yield more accurate displacement vector measurements than LGECMM due to increased echo signal-to-noise ratio and lateral spatial resolution. That is, on the basis of a priori knowledge about ultrasound propagation using the focusing scheme and shape of the apodization function, we stopped using Fraunhofer approximation. As practical applications of the modulations, for an agar phantom that is deformed in a lateral direction, stable and accurate 2-D shear modulus reconstructions are performed using our previously developed direct inversion approach together with 2-D strain tensor measurements using MAM.

Comparison of Parabolic and Gaussian Lateral Cosine Modulations in Ultrasound Imaging, Displacement Vector Measurement, and Elasticity Measurement

Previously, we proposed to set ultrasound (US) beam-forming parameters in order to realize the required point spread function (PSF) on the basis of optimization theory. In this report, for high quality-lateral cosine modulation (LCM) US imaging and measurements of accurate displacement vector and elasticity (i.e., strain tensor, shear modulus), after briefly reviewing our trials that broke away from the use of the Fraunhofer approximation to determine the apodization function, images and measurements obtained for an agar phantom are shown. In this study, the previously reported lateral parabolic modulation (PAM) and lateral Gaussian envelope cosine modulation (LGECM) are carried out. Comparisons of the spatial resolutions of the US images obtained and the measurement accuracies of the displacement vectors and elasticity measurements obtained using our previously developed multidimensional autocorrelation and Doppler methods (i.e., MAM and MDM) are also made. The development of next-generation US imaging systems has already begun.

Regularization for ultrasonic measurements of tissue displacement vector and strain tensor

In this report, we present the regularization results of displacement vector measurement by the multidimensional cross-spectrum phase gradient method (MCSPGM), multidimensional autocorrelation method (MAM), and multidimensional Doppler method (MDM) without lateral modulation. In addition to the results of spatially variant regularization in displacement vector measurement using displacement variances, the results of displacement component-dependent regularization are presented. That is, according to the measurement accuracy of displacement components, the regularization is properly applied to the respective displacement components. For instance, only the regularization on the lateral displacement is effective. That is, for the lateral nonmodulation case, the accuracies and stabilities of lateral/elevational displacement measurements significantly increase. In conjunction, the convergence speed of phase matching also increases. The demonstrated measurements of the displacement vector distributions in experiments using inhomogeneous shear modulus agar phantoms confirm that displacement-componentdependent regularization enables better strain tensor measurement and shear modulus reconstruction from the viewpoints of accuracy and stability. The contrast-to-noise ratio (CNR) is useful to set regularization parameters properly for the displacement regularization, whereas the CNR is useless for shear modulus regularization in the sense that the accuracy of reconstruction value cannot be evaluated.

3P7a-3 Lateral modulation and displacement vector measurement using hyperbolic scan by virtual beam forming(Poster Session)

3P7a-3 Lateral modulation and displacement vector measurement using hyperbolic scan by virtual beam forming(Poster Session)

Spatially variant regularization for tissue strain measurement and shear modulus reconstruction.

Regarding the regularization of the displacement vector measurement and shear modulus reconstruction, we propose to properly set the regularization parameters, i.e., to use spatially variant regularization parameters at each point in the region of interest, because the measurement accuracies of the displacements and strains vary spatially. As the measurement accuracies of the strains can be evaluated using the correlation coefficient when using the cross-spectrum phase gradient method, preliminarily the regularization parameters were set proportional to the reciprocal of a power of the correlation coefficient. Such a regularization scheme realizes the spatially uniform stabilities of the strain measurement and shear modulus reconstruction. The effectiveness of this method was verified by showing the regularized results of the axial strain measurement and of one-dimensional (1-D) shear modulus reconstruction obtained in vivo from a human liver carcinoma (that was treated by interstitial microwave coagulation therapy) as well as by a 1-D shear modulus reconstruction obtained using an agar phantom.

Measurement of Displacement Vector of Grains in Polycrystalline ZrO2 during High-temperature Deformation

High-temperature tensile tests were repeatedly conducted for a TZP specimen at 1, 400°C in air at intervals of about 2% of the true plastic strain up to 17.4%. After each deformation, displacement vectors of the specified 760 grains were measured from their position vectors obtained by FE-SEM micrographs. In a short time period during plastic deformation, grains moved gradually turing to the tensile axis in a zigzag way. At an early stage of deformation, the length of displacement vector distributed in a wide range because of their initial configuration after sintering. Further plastic deformation, however, grains tended to have their own movements depending on the constraint of the surroundings. In a middle time period during plastic deformation, a group of grains moved to the same direction so that several domains were formed. However, the domains disappeared due to constraint by the surrounding matrix, and other domains were formed by re-combination of grains. In a long time period during plastic deformation, grains seemed to be moving along path lines of a non-compressive fluid subjected to uniaxial tensile loading.

P1-57 Improvement of accuracy and stability for measurement of tissue displacement vector and strain tensor by regularization

P1-57 Improvement of accuracy and stability for measurement of tissue displacement vector and strain tensor by regularization

Quantitative modal analysis using electronic speckle pattern interferometry

Existing modal analysis techniques based on pointwise methods such as accelerometers and laser vibrometers, suffer from the compromises required to infer whole field vibration behaviour from a predetermined number of discrete measurement data points. The measurement grid is normally chosen before the most sensitive areas of the test piece have been identified and this can lead to a requirement for further grid refinement, with the consequent spatial and temporal disadvantages. Whole-field modal analysis using electronic speckle pattern interferometry (ESPI) has been developed, and focuses on the manipulation of optical information to provide a grid of data points which is transferred to a modal analysis software package for comparison with traditional point wise modal data sets. The advantages of obtaining the initial whole-field vibration picture in real time and subsequently overlaying a chosen measurement data grid, are demonstrated. Modal analysis of a steel plate is presented, which demonstrates single displacement vector measurements. Data is transferred into modal analysis software allowing ESPI mode shape information to be directly compared with measurements using other pointwise techniques and finite element analysis (FEA), through a modal assurance criterion (MAC) calculation. Further results are presented for multiple displacement vector analysis of high-power ultrasonic components, demonstrating the ability to accurately measure the modal characteristics of complex dynamic components.