This investigation was designed to devise an accurate topographic method for description and comparison of infants and children with craniofacial anomalies. Variations from the norm also could be studied. Biostereometrics was the method of choice. As the infants could not be brought to one central office, a portable stereo camera unit was built. Two 23/4" x 23/4" cameras were mounted on one base and synchronized to expose simultaneously with the flash unit pointed towards the ceiling. A pair of stereo photographs was obtained. The stereo photographs were used to create a face contour diagram and measured in X, Y, Z coordinates and provided quantitative data in three dimensions which can be used for comparative studies.

In order to study empirically the relative efficiencies of different types of orthodontic appliances in repositioning teeth in vivo, we have designed and constructed a pair of fixed-focus, normal case, fully-calibrated stereometric cameras. One is used to obtain stereo photography of single teeth, at a scale of approximately 2:1, and the other is designed for stereo imaging of the entire dentition, study casts, facial structures, and other related objects at a scale of approximately 1:8. Twin lenses simultaneously expose adjacent frames on a single roll of 70 mm film. Physical flatness of the film is ensured by the use of a spring-loaded metal pressure plate. The film is forced against a 3/16" optical glass plate upon which is etched an array of 16 fiducial marks which divide the film format into 9 rectangular regions. Using this approach, it has been possible to produce photographs which are undistorted for qualitative viewing and from which quantitative data can be acquired by direct digitization of conventional photographic enlargements. We are in the process of designing additional members of this family of cameras. All calibration and data acquisition and analysis techniques previously developed will be directly applicable to these new cameras.

A system that uses stereophotogrammetry to semi-automatically generate three-dimensional facial soft tissue surfaces is presented. The basis of the system is the stereometric technique of Direct Linear Transformation (DLT) which is utilized to eliminate the elaborate instrumentation of present day systems. Automatic digitizing using a scanning image analyzer will require no hand digitizing, and a lightweight headframe will provide orientation information for use in evaluating facial changes. The system is computer based to provide graphic images of the resulting data to ease understanding and to provide the beginnings of a large data base concerning human facial form.

Many branches of dental practice would benefit from the availability of a relatively accurate, precise, and efficient method for monitoring the movements of the human mandible during function. Mechanical analog systems have been utilized in the past but these are difficult to quantify, have limited accuracy due to frictional resistance of the components, and contain information only on the borders of the envelopes of possible movement of the landmarks measured (rather than on the functional paths of the landmarks which lie within their envelopes). Those electronic solutions which have been attempted thus far have been prohibitively expensive and time consuming for clinical use, have had lag times between data acquisition and display, or have involved such restrictions of freedom of motion as to render ambiguous the meaning of the data obtained. We report work aimed at developing a relatively non-restrictive semi-real time acoustical system for monitoring the functional movement of the mandible relative to the rest of the head. A set of three sparking devices is mounted to the mandibular component of a light, relatively non-constraining extra-oral harness and another set of three sparkers is attached to the harness' cranial or skull component. The sparkers are fired sequentially by a multiplexer and the sound associated with each firing is recorded by an array of three or more microphones. Computations based on the known speed of sound are used to evaluate the distances between the sparkers and the microphones. These data can then be transformed by computer to provide numeric or graphic information on the movement of selected mandibular landmarks with respect to the skull. Total elapsed time between the firing of the sparkers and the display of graphic information need not exceed 30-60 seconds using even a relatively modest modern computer.

The conventional method for measuring small objects in three dimensions utilising close range stereo photogrammatic techniques is complex and time consuming. A recent development called the Reflex Metrograph allows unskilled operator to collect three dimensional co-ordinates both simply and rapidly. A clinical application to compare in vivo and in vitro measurements showed a similar level of precision. The results compare favourably with a conventional approach.

The use of photogrammetry to determine dimensional and volume data of animals from a remote distance is investigated. The animal tranquilization process requires a precise knowledge of the weight of the animal for adjusting the appropriate dosage of medication. Practical experimentation using graphical and analogical processing methods proves that close-range photogrammetry is the best tool for the determination of the correlation between dimensional and volume data and weight of the animal. A practical example of the correlation determination which involved a study of several horses is presented.

A rotating microscope has been developed which can rotate around a single, living embryo. The purpose of this instrument is to allow the investigator to take mosaic images covering the whole surface of the embryo at regular time intervals. Such data is essential to an analysis of the cell motions and interactions involved in the first steps of the morphogenesis of the brain. Because the degrees of freedom and the image processing problems are so similar to photography of the earth from satellites, I have called this "LANDSAT" photography of embryos.

Photogrammetry in conventional practice requires the use of fixed focus cameras of high precision and calibrated internal geometry. The largest historical application of photogrammetry is aerial topographic mapping which utilizes near vertical photography at infinity focus in a well ordered scheme of flight path terrain coverage with very little vertical ground relief relative to the planned flight altitude. Serious efforts have been made to apply photogrammetry for non topographic purposes (terrestrial photogrammetry) by utilization of conventional or scaled down cameras and stereo compilation instruments with various hardware and applications schemes, Success has been limited, at best, and the solutions have not been economical enough to warrant broad application. With the advent of digital computors, the evolution of numerical photogrammetry in general and the analytic stereo compiler in particular the technical tools are available for a truly comprehensive universal system. With miniaturization and new mathematical techniques small commercial non-precision cameras can be utilized and the photogrammetric process can be greatly simplified and extended to broader application.

A simple and low-cost 3-dimensional stereometric measurement system has been developed which measures the shape of object by means of trigonometry. This system is composed of an X-Y optical scanner, cylindrical lenses and line sensors. A laser beam is incident on an object and is scanned over the area of interest by the optical scanner. Cartesian coordinates of a laser spot hit by the laser beam in a three dimensional space are determined simply and at high speed through the combined use of cylindrical lenses and line sensors. The cylindrical lens makes a line focus and, therefore, the coordinates of a light spot is projected onto a line orthogonal to the axis of the cylindrical lens. The position of the line focus in a line sensor can easily be measured by detecting the photo-cell which indicates the maximum output. Preliminary experiments suggest that the shape of the human torso surface can be measured with fairly good accuracy.

A technique has been developed to produce plane equidistant contouring surfaces on tooth-imprints. This technique consists of spatially filtering a negative obtained by photographing the imprint under a Moire illumination. Unfortunately this technique turned out to be very sensitive for a non-uniform surface reflectivity. To obtain an object-brightness depending only upon the contouring mechanism, the imprint has been coated with a fluorescent dye. A HeCd-laser (λ=422 nm) served as a lightsource for the projection of the Moire-interference pattern on the imprint. The radiation of the fluorescent coating (λ=530 nm) is used to form an image on the negative. In this way the surface with specular reflection properties is transformed into a Labertian surface. The spatial filtering technique allows multiple exposures of the final negative enabling an increased depth of field. Contour mappings with a resolution in depth of less than 10 μm have been obtained.

Three types of moire topographic methods using digital techniques are proposed. Deformed gratings obtained by projecting a reference grating onto an object under test are subjected to digital analysis. The electronic analysis procedures of deformed gratings described here enable us to distinguish between depression and elevation of the object, so that automatic measurement of 3-D shapes and automatic moire fringe interpolation are performed. Based on the digital moire methods, we have developed a practical measurement system, with a linear photodiode array on a micro-stage as a scanning image sensor. Examples of fringe analysis in medical applications are presented.

The biostereometric study of body changes can lead to valuable information regarding the metabolism and the physiological development of pregnancy as well as the well-being of the fetus. In this contribution a technique for the calculation of abdomen volume variations from measurements on moire photographs is outlined and experimental results are presented.

Optical metrology of three-dimensional objects is a subject of major interest for science and technology. Several methods have been proposed and research is pursuing on the study of various principles. The method to be described employes a coded illumination of the three-dimensional space by fringes projection and the information of the object is decoded with a moire technique. The principle of the method ranges a large spectrum of applications. The emphasis for practical applications is given on the field of biomedical studies. The analysis of dismorphosises in static (anatomy) and dynamical (functional) situations is presented, in particular for the study of feet-system and locomotor movement, face aesthetic morphology and trunk studies. Capabilities and advantages of the method are described and demonstrated including video recording.

A Moire system which rotates an object in front of a slit camera has been used to obtain continuous photographic maps around amputee socket and shoe last shapes. Previous analysis methods required the use of IBM 370 hardware and extensive software overhead. Using a systematic manual digitizing technique and user-interactive FORTRAN software, the shape reconstruction has been easily performed on a PDP-11 minicomputer system. Both the digitizing technique and the software are oriented towards the shape reproduction process. Numerically controlled machining parameters are used to identify a "skewed" grid of required points along the cutter path. Linear interpolation and anti-interference techniques resulted in reproduction of shoe lasts to within 0.05 inches (1.2 millimeters) from the sensing axis. Difficulties were experienced in obtaining information to resolve the ends of the shapes. Current efforts focus on circumferential shape sensing of live subjects and automatic digitization of sensed data.

Contour line patterns, as they are produced by moire topography are dependent on position, posture and body shape of the patient. For all medical applications data are needed, which are only dependent on shape and posture and which therefore are independent of positioning. The measurement of the kyphotic angle from topograms can be performed to meet these requirements and to yield results, which are independent of positioning. Different techniques for measuring this angle are discussed. Digitization and reconstruction of profiles from moire topograms are presented. In order to get reproducible results, landmarks are needed on the body surface. Landmarks may be found either by palpation or by analytical investigation of the back shape. Here, the inflectional points of the sagittal back profile are taken as intrinsic landmarks. Their relation to anatomical landmarks, which are found e.g. by palpation, is studied.

The use of surface topography for the assessment of scoliotic deformity in the clinic depends firstly on the quality of measures which reliably characterise deformity of the back, and secondly on the ease and speed with which these measures can be applied. A method of analysis of back shape measurements is presented which can be applied to any topographic measurement system. Measures presented are substantially independent of minor changes in the patient's posture in rotation and flexion from one clinic to the next, and yet sensitive enough to indicate significant improvement or degeneration of the disease. The presentation shows (1) horizontal cross-sections at ten levels up the back from sacrum to vertebra prominens, (2) angles of rotation of the surface over a small region about the spine, (3) three vertical profiles following the line of the spine, and (4) measures of maximum kyphosis and lordosis. Dependence on the operator has been reduced to a minimum. Extreme care in positioning the patient is unnecessary and those spinous processes which are easily palpable, the vertebra prominens and the two dimples over the posterior superior iliac spines are marked. Analysis proceeds entirely automatically once the basic shape data have been supplied. Applications of the technique to indirect moire topography and a television topographic measurement system are described.

Several techniques are presented for nonradiographic three-dimensional anthropometric assessment. Accuracy, validity, and reliability are discussed in light of existing techniques.

This study reports on 29 patients (58 breasts), selected in a stratified manner to include 7 cancers, 13 benign tumors and 38 apparently normal breasts, that were subjected to biostereometric analysis. This process consisted of analysis in a blind setting of contour mammograms made from stereophotographs of the breast which resulted in the correct identification of all 7 cancers, 11 of the 13 benign tumors and 30 of the remaining 38 normal breasts. There were 8 false positives identified. This study, in conjunction with a previous study, indicates that the biostereometric analyzed contour mammograms have the potential to be developed into a process for breast cancer screening. Suggested areas for further study include volume differences in individual breasts as well as the volume differences in individual breast slices and their relationship to breast pathology.

The measurement of three-dimensional body shape is of considerable interest in orthopaedic applications, for example the assessment of spinal deformities from the shape of the back surface. At present these measurements are mostly carried out using optical methods such as stereophotgrammetry or moire topography. The image data acquisition is generally performed by hand. However, due to the large number of measurement points necessary for a satisfactory representation of a surface, this procedure is very tedious and time consuming. In contrast to this, rastersterography using a line raster enables considerable time savings by automatic image scanning. The method of rasterstereography is briefly explained. Due to the simple structure of line rasterstereographs an automatic image evaluation is relatively easy. The evaluation procedure consisting of image scanning (using a CCD sensor camera), line detection, line pattern analysis and three-dimensional surface reconstruction is outlined. Examples of back surface measurements in the case of spinal deformities are presented.

As a result of conventional body surface measurements usually a list of coordinates of the surface points is obtained. However, in most cases the intrinsic shape properties of the body cannot be derived directly from coordinates. This is due to the fact that these data depend on the frame of reference. Therefore, position and orientation dependent information must be removed from original data in order to arrive at a coordinate independent (invariant) description of the body. Examples of invariant measures are distances, angles, volumes and curvatures. For the calculation of these properties a regular data structure based on a parametric surface representation is very advantageous. In the case of rasterstereography such a regular structure is naturally provided, whereas in the case of moire topography it has to be established in an extra procedure. In this paper the mathematics for parametric representation of body surfaces will be reported. Also, based on a parametric representation of the body surface the calculation of curvature from rasterstereographs and moire topograms and a practical implementation in an orthopaedic study will be given.

This is a design paper describing a 4 dimensional processing and display system for cardiovascular research. A 4 dimensional image in this paper refers to a time (or other) series of 3 dimensional images. The system consists of components to develop, test and run programs and to manipulate and store multidimensional digital images. A 4 dimensional display is used to study raw and processed data. The display uses binocular stereo to generate a 3 dimensional image and bulk memory to store multiple stereo pairs for the fourth dimension. Voice input and output will be used to communicate with the system. A binocular infrared eye tracker will be used as a multidimensional cursor to interact with the data. Software development areas are summarized. The current state of the project is presented at the end of the paper. An up to date summary of progress will be presented at the conference.

A specific software (EUCLID) for static and dynamic representation of human models is described. The data processing system is connected with ERGODATA and used in interactive mode by intrinsic or specific functions. More or less complex representations in 3-D view of models of the human body are developed. Biostereometric and conventional anthropometric raw data from the data bank are processed for different applications in ergonomy.

An octal tree subdivision recursively divides a bounded three-dimensional volume into octants about an internal division point. This scheme has been used to represent cellular or enumerated voxel models of solid objects. Given one or more sets of points sampled from the surface of a solid, an octal tree may be generated in which each leaf node contains m or less points. By specifying the tree traversal rule, the points are accessed in a sorted order. By defining m=3, a divide-and-conquer surface triangulation algorithm may be developed which does not require special sampling conditions (such as co-planarity) on subsets of the sample points. By assigning every polygon on a facetted surface to its containing octal element(octel) a pre-ordering is established on the faces. From any viewpoint, surface polygons can be visited in a priority ordered fashion by appropriate tree traversal. The pre-ordering established is shown to be useful in several graphics related contexts including: a viewpoint independent data structure leading to a hidden surface technique; a ray-tracing algorithm; a virtual frame buffer with reduced page faults; and, a simple geometric merging of sets of surface measurements containing no fiducial information.

A computer graphics array may contain all the information required for a three dimensional display but conventional VDU's (video display units) and printers can only provide a flat image. The problem is approached by converting the computer output into a form suitable for synthesis of a volume hologram. Suitable methods and apparatus are discussed and typical results presented, including CT (computer tomography) scan and radiological architecture applications.

The definition of human body models was elaborated with anthropometric data from ERGODATA. The first model reduces the human body into a series of points and lines. The second model is well adapted to represent volumes of each segmentary element. The third is an original model built from the conventional anatomical points. Each segment is defined in space by a tri-angular plane located with its 3-D coordinates. This new model can answer all the processing possibilities in the field of computer-aided design (C.A.D.) in ergonomy but also biomechanics and orthopaedics.

There has been a long-standing need for human figure simulations that are both accurate descriptions of the human body and at the same time adaptable to different user environments. This paper reviews developments by the author to meet this continuing need, especially the use of biostereometrics in high resolution human figure simulations. This research, including the use of biostereometrics spanned twenty years. The author's developments at Boeing were the "First Man" and "Second Man," representing pilots with surface lines having up to nineteen movable segments, and "Third Man and Woman," developed at Southern Illinois University at Carbondale, representing a hierarchial figure series. "Fourth Man and Woman," series 4.2, were designed at Southern Illinois Research Institute U.S. and its Siroco office in Washington State, consisting of polygonal descriptions derived from biostereometric data, appropriate for both line and raster displays. "Fourth Man and Woman," series 4.3, will be smoothed, clothed, and further incorporate hierarchial levels of detail.

A system for roentgen stereophotogrammetry has been used in Lund, Sweden, since August 1972 and by August 1982 ten thousand stereo films have been evaluated using this method. Patient investigations started March 1973 and of the more than 500 patients investigated 300 have been referred by orthopedic surgeons. The skeletal parts investigated had been permanently marked with tantalum balls 0.5 or 0.8 mm in diameter. The causes for the investigation have been bone growth disorders in the Lower extremity (134 patients), spinal fusions (35 patients), high tibial osteotomies for gonarthrosis (21 patients) and endoprosthetic replacement of the knee (68 patients) or hip (42 patients) joint. By the roentgen stereophotogrammetric analysis (RSA), information on for instance the development of angular deformities and staple loosening in the leg, the healing process of the intended fusion in the spine or at the knee, and on the migration and stability of prosthetic components have been obtained. RSA is of value both for prognostic and followup purposes, and is versatile enough in proper setting to be used as a routine clinical investigation.

Loosening is the number one complication of total joint replacements. A direct method of measuring small motions between the prosthetic implant and the surrounding bone would allow the surgeon to evaluate replacement surgery or activity restrictions. Single plane x-ray photogrammetry uses stainless steel markers in the bone and prosthetic implant and a control frame in order to accomplish this measurement. Testing of models representing a total hip replacement and total knee replacement has shown that displacements can be measured with a root mean square error of less than 0.2 mm.

A non-invasive biplanar radiographic technique for in-vivo determination of ligament lengths is presented. By taking biplanar X-rays of a human subject joint and locating the images of prominent bony reference points on the films, the three-dimensional locations of these points are determined. A unique scaling method is employed that compares the coordinates of the reference points with those previously obtained from a cadaver. Scaling equations that describe the subject joint in terms of the cadaver joint allow reference points to be clearly visible in only one X-ray view. The origin and insertion of ligament points from the cadaver are mapped onto the subject's joint and the ligament length is taken as the distance between the two. An application of this technique to the human knee joint is presented.

We have constructed and brought into use what we believe to be the first dedicated coplanar craniofacial stereometric x-ray system for clinical use. Paired Machlett Dynamax 50/58 x-ray tubes with 0.3 mm focal spots are employed. Displacement between emitters is 16 inches. The focus film distance for both emitters is 66.5 inches. The mid-sagittal plane to focus distance is 60 inches. One film of each stereo pair conforms with the standards of the Second Roentgenocephalometric Workshop and can be used to make all standard two-dimensional orthodontic and cephalometric measurements. When supplemented by data from the conjugate film, a three-dimensional coordinate map can be generated as a machine operation. Specialized complementary software has been developed to increase the reliability of landmark location both in two and in three dimensions.

For the past five years, we have been accumulating information on the performance of a stereoroentgenographic system developed for use in clinical medicine and first reported at the NATO Symposium on the Application of Human Biostereometrics. This system represents an adaptation of normal case coplanar stereometry and involves the use of a single emitter which is displaced in a controlled fashion between exposures. The system has been used primarily for the detection of applicance loosening and settling following the placement of total hip protheses and also for the detection of pseudorthosis following lumbo-sacral fusion. One major goal has been the development of a data acquisition and analysis system suitable for general hospital use which can be operated by technicians without specialized photogrammetric training. This report will focus on system design and on the delineation of technical problems encountered during routine clinical use of the system.

It is now quite clear that under ideal conditions, discrete points can be located on x-ray films with standard deviations of less than 50 i. However, under routine clinical conditions, such considerations as individual variation in anatomy, movement of the subject between exposures, and variations in image quality combine to produce considerable reductions in the confidence which can be placed in quantitative assessments made from stereoroentgenographic films. This paper discusses some considerations involved in designing mathematical models in such a way as to optimize the use of imperfect data in answering specific clinical questions.

An X-ray stereometric technique has been developed for the determination of 3-dimensional coordinates of spherical metallic markers previously implanted in monkey skulls. The accuracy of the technique is better than 0.5mm. and uses readily available demountable X-ray equipment. The technique is used to study the effects and stability of experimental orthognathic surgery.

X-Ray photogrammetry has been applied to reconstruct the disposition of the radioactive sources in a patient to be treated by endocavitary radiation therapy.

An specific photogrammetric device is described. It is composed of one pair of cameras on a vertical base and two vertical mirrors. A sample of 50 young French males was studied by using this method for the purpose of establishing the relationship between overall and segmentary dimensions, surfaces and body volumes and evaluating the variability of these parameters. Conventional anthropometric method and photogrammetry are compared.

A four-camera SELSPOT system received at the Johnson Space Center is thought to be the first such system in the United States. The basic SELSPOT system has been interfaced by the Southwest Research Institute to custom-built hardware to provide a very flexible system. The four cameras provide a 360 degree field of view with a data redundancy which should permit a reduction in the number of missing data point errors. Some test data collected with the system and a brief description of the software used to present it are discussed.

In order to estimate the thoracic injury tolerance of a belted automobile occupant and to get a better knowledge about the mechanical behaviour of the belt/torso system, the dynamic deformation of the thorax is evaluated under the action of a safety belt load. Therefore, during the whole duration of a crash test (about 120 ms) the relative displacement of a set of points drawn on the thorax surface is measured by cinephotogrammetry. Five 16 mm cine-photo cameras (3 fix around the impact area and 2 on board the sled) filming at 500 frames per second permit to cover the whole trunk surface. Synchronization of film data is done by interpolating on a common time base. The three-dimensional coordinates of the measurement points enable the reconstruction of the thorax surface as a set of contiguous triangular plane facets which can be projected on various reference planes for display purposes. For clarity of drawings, an algorithm determines hidden lines not to be plotted. Cuts parallel to the projection plane are performed. By changing the orientation of this plane and the number and the pace of the cuts, either contour maps or transversal cuts are obtained providing a visualization of deformation which can then be related to compressive forces and resulting injuries.

The three-dimensional kinematic analysis of the wrist is a complex problem. A method utilizing high speed stereocinematography has been developed to accurately measure the motion of the bones in the wrist. Both relative and absolute motions can be obtained using this system. The system has been shown to accurately locate a point to ± 0.003 inch. The three-dimensional motion characteristics of the capitate in radial ulnar deviation were analyzed using this system, and the results are presented. A computer graphics program, developed by the authors, is used to display the motion characteristics of the carpal bones. In this program, the bone surface, defined using a special stereopointer and bicubic surface fitting algorithms, is displayed along with the kinematic data.

We have used transmission ultrasound imaging (TUS) with the SRI camera to visualize the index finger flexor tendons in live hands during flexion-extension movements. The digitised data on tendon trajectory is analysed to obrtain tendon curvature. Assuming the tendon to be frictionless, the relative transverse focuses on the tendon are computed. The distribution, indicate how tendon force may be transmitted to the bone to cause movement.

A biostereometric analysis of gestures was developed for the study of the influence of an aqueous environment on the biomechanical behaviour of man. Developed power and time of execution were collected for different test conditions, in air and water. By 3-D analysis, the phases of movement (flexion-extension of the upper limb) were reconstituted and the displacements of each segment were calculated. The influence of the aqueous environment on the execution of gesture and the effect of thrust and ballast in water are described.

The fitting of sockets and artificial legs to amputees' stumps is a difficult and lengthy process that can take numerous trials. It has been proposed that most amputees can be fitted with a standard socket shape with minimal changes to the socket. To perform this task, a procedure is being developed at the Medical Engineering Resource Unit for computer aided socket design for amputees. An interactive PASCAL program, operating on a microcomputer, will prompt the operator (or prosthetist) by asking him to determine the condition of the stump. While the operator is inputing this information into the computer, together with a few critical anatomical measurements, a standard socket shape, viewed on the video monitor, will begin to change. Throughout the "shape fitting" procedure, the operator will have the ability to modify the socket shape on the screen with the use of a light pen. It will also be possible to view various cross-sections and different perspectives. The shape fitting procedure continues until a suitable socket shape is designed. Future efforts will focus on transferring the computer designed socket into a physical socket. The overall goal is to provide amputees with a better fit in less time and to objectify socket fitting so that new prosthetists may be easily taught.

A television/computer system is used to measure the apparent distortion of a line of light as it is scanned over an object. A projector and camera are fixed relative to one another in a swinging frame which rotates at a constant speed through a vertical arc. The displacement of the line in the television picture is a function of the distance of the object from an imaginary cylinder about the axis of rotation, while the position of the frame is also read by the television interface from a spot inserted into the video signal. The geometrical configuration of camera, projector and frame allows simple analysis of the data to yield an output consisting of scattered three-dimensional points. Calibration is achieved by measuring an object of known dimensions. The use of the system is illustrated by application to a project for the assessment of scoliotic deformity of the back. In this, the advantage of an instant digital data acquisition method is that analysis of the data can proceed immediately, without the intervening lengthy, expensive and error-prone digitising stage required by moire topography. The patient can receive his analysis within minutes, and the information can be used by the physician immediately at the clinic, rather than days later.

In this paper we introduce the method of Moir4 contourography to measure human body and animal's articular facies and teeth. The animal facies of articulation is rather complicated. We haven't seen an expression of a complete mathmatic formula yet. Hence, we adopt Moiri contourography to express three dimensions of animal's articular facies.1 We show here also the characteristic equation of Moire contourography of irradiation grating, and the relationship of the contour Moire frings and influence coefficients. So it is very useful to measure errors. Then we introduce some of our research on animal's articulation surface and teeth.

Study of transient force phenomena in the double stance period of normal gait suggests that high temporal resolution is required in concommittant movement analysis. The present study concludes that at least 300 pictures per second are necessary to resolve kinematic transients associated with heel strike.

Traditional locomotion analysis considers motion in a translating coordinate frame and the analysis is performed primarily in the sagittal plane. The results of several studies in the present work have shown that the aspect of symmetry is rarely present in pathological gait. Loss of function in one plane of movement gives rise to larger motions in other planes. This brings into focus the necessity for three dimensional measurement for adequately representing pathological gait. Description of quantities associated with gait in the appropriate moving frame of each segment would be closer to joint angulation of limb segments. Although this description has been attempted by a few researchers, the assumption of small angle theory and vectorial addition of rotation angles commonly employed for defining the rotation matrices is not applicable to pathological gait. The present work illustrates the use of biplane photography for displacement measurement in human movement. Transformations based on Eulerian angle rotations are derived based on biplane measurements. From the three dimensional ground reaction forces measured by a force plate, moments about the moving upper body coordinate axes are computed through a three dimensional mathematical model.

High-speed computerized motion analysis was used to assess the running parameters of a group of runners. Anthropometric measurements were taken on the group of runners in an effort to provide possible correlations between running style, speed, and anthropometry. The most consistent correlation was between speed and stride length. Femur length and stride length was only highly correlated for the runners at the fastest speeds. The faster runners also had a gait pattern characterized by significantly lower ground contact time than that of the slower runners. Of prime importance in running is behavior of the body during float phase, and mediated by anthropometry and the biomechanical characteristics of the stance phase.

Spatial and temporal analysis of walking provides the orthopaedist with objective evidence of functional ability and improvement in a patient. Patients with orthopaedic problems experiencing extreme pain and, consequently, irregularities in joint motions on weightbearing are videorecorded before, during and after a course of rehabilitative treatment and/or surgical correction of their disability. A specially-programmed computer analyzes these tapes for the parameters of walking by locating reflective spots which indicate the centers of the lower limb joints. The following parameters of gait are then generated: dynamic hip, knee and foot angles at various intervals during walking; vertical, horizontal and lateral displacements of each joint at various time intervals; linear and angular velocities of each joint; and the relationships between the joints during various phases of the gait cycle. The systematic sampling and analysis of the videorecordings by computer enable such information to be converted into and presented as computer graphics, as well as organized into tables of gait variables. This format of presentation of the skeletal adjustments involved in normal human motion provides the clinician with a visual format of gait information which objectively illuminates the multifaceted and complex factors involved. This system provides the clinician a method by which to evaluate the success of the regimen in terms of patient comfort and function.

The efficiency of any motion analysis is largely dependent on the software generated for the specific purposes intended. Many of the problems in acquiring and analyzing data with computers of limited memory can be circumvented by clever algorithms. Several algorithms for two-camera video motion analysis are discussed in detail. These algorithms are intended for resolution of problems that include video ghosts, blockage of data points by extraneous movement of ancillary body parts, statistical techniques to improve accuracy, efficient searching routines, and calibration programs. All of these algorithms have been implemented as specific programs in a complete system intended for the analysis of the parameters of human motion.

Three dimensional analysis of the optic nerve head is important in the detection and treatment of eye diseases, particularly glaucoma. In glaucoma, the fluid pressure within the eye increases. Since there is a wide variability in people's sensitivity to elevated pressure, it is not possible to predict which eye will be damaged by a given pressure. The side effects of treatment preclude treating everyone with elevated pressure. However, those eyes susceptible to elevated pressure slowly begin to show erosion of the optic nerve head. The erosion process progresses very slowly and imperceptibly. By the time it can be detected visually, permanent visual loss has often occurred.

Glaucoma, a common cause of blindness, can be detected in the early stages by studying topographic changes or cupping in the optic disc. The direct observation of fundus using an ophthalmoscope or the evaluation of the disc in fundus photographs has been primarily subjective , differing considerably from observer to observer. We have, therefore, developed an objective quantification technique -- the photogrammetric radial section method, which can quantitate not only cupping or swelling of the optic nerve, but also the growth of tumor or the development of posterior staphyloma in the myopic eye.

Biosterometric techniques have demonstrated advantages over traditional craniometric methods in describing and analyzing irregular biological forms and form-changes. This paper demonstrates how data obtained with a simple stereoplotting craniostat can be used to precisely describe growth-related changes observed in a cross-sectional collection of olive baboon (Papio cynocephalus anubis) skulls. Data obtained from this extremely prognathic primate species are analyzed using principles of stereographic projections. Demonstrations are made showing how readily understandable representations of otherwise complex multidimensional shapes and shape changes associated with the skull can be made.

The glucose metabolism in certain areas of the brain becomes highly active and reflects the degree of the epileptic seizure when evoked. In order to visualize the localization of glucose, C¹⁴ labeled glucose is used to produce autoradiographs from brain slices in chicken. The areas having a high concentration of C¹⁴ labeled glucose appear darker in the developed film. This paper describes an image processing computer system which displays 3 dimensional perspective views from the brain slice autoradiographs. The series of autoradiographs were digitized by a video frame grabber. The shape of the brain was displayed 3 dimensionally by means of surface contours and the dark areas representing high glucose concentration was embedded in the outlines.

In this brief account, an effort will be made to describe examples of areas of neurobiological and clinical neuroscientific knowledge whose growth appears to have become more and more dependent on stereological information. The availability of such information is perceived to be related to methods and techniques of acquisition which embody many biostereometric principles. Although limitations of space prevent comprehensive treatment, the examples should serve to portray the status of knowledge as well as the opportunities for the foreseeable future.

By examining the concepts of natural vision, a non-computer image processor was developed. This device uses a cellular contrast pattern matching and searching technique to define elements of the image. Coupling the pattern matching and searching technique with a stereometric capability provides considerable information about the shape, size, orientation, depth and location of a subject. This type of information is very useful in machines and robots that must acquire objects in unpredictable orientations or in unknown environments.