TL;DR: In this paper, the authors propose a method to measure the attitude of a group on a specified issue in the form of a frequency distribution, where opinions are allocated to different positions on the base line in accordance with the attitudes which they express.
Abstract: The object of this study is to devise a method whereby the distribution of attitude of a group on a specified issue may be represented in the form of a frequency distribution. The base line represents ideally the whole range of opinions from those at one end who are most strongly in favor of the issue to those at the other end of the scale who are as strongly against it. Somewhere between the two extremes on the base line will be a neutral zone representing indifferent attitudes on the issue in question. The ordinates of the frequency distribution will represent the relative popularity of each attitude. This measurement problem has the limitation which is common to all measurement, namely, that one can measure only such attributes as can be represented on a linear continuum, such attributes as volume, price, length, area, excellence, beauty, and so on. For the present problem we are limited to those aspects of attitudes for which one can compare individuals by the "more and less" type of judgment. For example, we say understandingly that one man is more in favor of prohibition than another, more strongly in favor of the League of Nations than another, more militaristic than some other, more religious than another. The measurement is effected by the endorsement or rejection of statements of opinion. The opinions are allocated to different positions on the base line in accordance with the attitudes which they express. The ordinates of the frequency distribution are determined by the frequency with which each of the scaled opinions is endorsed. The center of the whole problem lies in the definition of a unit of measurement for the base line. The scale is so constructed that two opinions separated by a unit distance on the base line seem to differ as much in the attitude variable involved as any other two opinions on the scale which are also separated by a unit distance. This is the main idea of the present scale construction. The true allocation of an individual to a position on an attitude scale is an abstraction, just as the true length of a chalk line, or the true temperature of a room, or the true spelling ability of a child, is an abstraction. We estimate the true length of a line, the true temperature of a room, or the true spelling ability of a child, by means of various indices, and it is a commonplace in measurement that all indices do not agree exactly. In allocating an individual to a point on the attitude continuum we may use various indices, such as the opinions that he endorses, his overt acts, and his past history, and it is to be expected that discrepancies will appear as the true attitude of the individual is estimated by different indices. The present study is concerned with the allocation of individuals along an attitude continuum based on the opinions that they accept or reject.
TL;DR: In this article, it is concluded that all length measurements are biased and that this bias must be corrected before meaningful geological interpretations can be made, and it is recommended that track-length measurements in minerals be restricted to horizontal confined fission tracks, because the length bias is then simple and easy to correct.
TL;DR: In this paper, a new procedure to determine all the geometrical parameters of a stereo-system is presented, based on surveying a rigid bar carrying two markers on its extremities moved inside the working volume and it does not require grids or complex calibration structures.
TL;DR: In this paper, a calibration factor derived from a relationship between a true dimension of a marker and a dimension of the marker in pixel units in the image is used to scale an object within an image.
Abstract: The invention relates to an image processing apparatus arranged to scale an object within an image, said image processing apparatus comprising a calibrator arranged to scale the object based on a calibration factor derived from a relationship between a true dimension of a marker and a dimension of the marker in pixel units in the image, wherein the calibrator is further arranged to generate a plurality of calibration factors obtained using a plurality of differently oriented markers identified within said image. The image I comprises a plurality of objects (3, 8, 9) which are oriented differently in space resulting in a different alignment of these objects with respect to the anatomical structures (2). The object (3) is linked to a measurement tool, which is arranged to measure a length of the object (3) in pixel units and to calculate a true length of the object (3) using a calibration factor determined from a marker (A), which has a similar alignment in space as the object (3). The image (1) further comprises objects (8, 9), linked to a measurement tool, which is arranged to calculate a true length of the objects (8, 9) based on respective lengths of these object in pixel units and a calibration factor determined using the marker (B). Preferably, the objects corresponding to a different marker are grouped to form a calibration group, whereby an update in the calibration factor results in an automatic update of true dimensions for all objects within the same calibration group. Preferably, each calibration group is identified differently for user's convenience. The invention further relates to an imaging system, a computer program and a method for enabling scaling of objects in the image.
TL;DR: For a reliable quantitative assessment of vascular lesions the three-dimensional orientations and connections have to be known accurately and can be extracted systematically from two DSA-projections using a digital image processing system.
Abstract: For a reliable quantitative assessment of vascular lesions the three-dimensional orientations and connections have to be known accurately. This information can be extracted systematically from two DSA-projections using a digital image processing system. Automatic identification and calculation of three-dimensional coordinates of the vessel centrelines are possible at angles of 15–45° between the two projections. The knowledge of the three-dimensional coordinates allows the determination of the true length and corrected densitometric values of foreshortened vessel sections.