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- Granlund, Gösta H.
(författare)
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A Nonlinear, Image-content Dependent Measure of Image Quality
- 1977
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, considerable research effort has been devoted to the development of useful descriptors for image quality. The attempts have been hampered by i n complete understanding of the operation of the human visual system. This has made it difficult to relate physical measures and perceptual traits.A new model for determination of image quality is proposed. Its main feature is that it tries to invoke image content into consideration. The model builds upon a theory of image linearization, which means that the information in an image can well enough be represented using linear segments or structures within local spatial regions and frequency ranges. This implies a l so a suggestion that information in an image has to do with one- dimensional correlations. This gives a possibility to separate image content from noise in images, and measure them both.Also a hypothesis is proposed that the visual system of humans does in fact perform such a linearization.
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| 2. |
- Rowa, Per, et al.
(författare)
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Automated Malaria Parasite Detection
- 1977
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A system for malaria parasite detection in thin blood-smears is presented. Sample slides prepared with standard methods are accepted. A low-cost TV-camera mounted on an ordinary microscope with a computer controlled stage is used as a picture sensor. Frames, digitized in windows of 64 x 64 pixels are fed into a special purpose picture processor at normal frame rate (25 frames/sec). In the picture processor measurements are made on the images at high speed. The classification problem is split into different levels each having different characteristics such as different sampling density. Four classes, three of which are different types of malaria parasites, are recognized. As a whole the classification is best labelled as a sequential pattern recognition procedure.In its preliminary version the system has been run at a speed comparable to that of a human operator, that is l 500 cells per minute. A test on 80 000 cells gave 25 false negatives out of 283 parasites (9%) and 41 false positives (0.05%).
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| 3. |
- Vegelius, Jan, et al.
(författare)
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Polari, a Fortran IV program for measures of attitudinal polarization
- 1976
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Ingår i: Educational and Psychological Measurement. - : SAGE Publications. - 0013-1644 .- 1552-3888. ; 36:3, s. 717-719
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Tidskriftsartikel (refereegranskat)abstract
- The two major purposes of this paper were: (1) to describe the theoretical background underlying the mathematical development of different measures of the degree of attitudinal polarization applicable to bipolar questions and (2) to outline a small FORTRAN IV program POLARI that provides a rapid means for calculation of four of these measures.
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| 4. |
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| 5. |
- Rowa, Per, et al.
(författare)
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Datoriserad mätning av vita blodkroppars rörelse
- 1978
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna skrift redovisar försök att kvantitativt mäta rörelsen hos levande vita blodkroppar .Mätningarna sker helt automatiskt och i reell tid.Bilden av preparatet överförs via en TV-kamera på mikroskopet till en dator. Datorn utnyttjar en speciell bildprocessor för bildoperationer och mätvärdesextraktion .Cellernas individuella rörelser både i form av globala tyngdpunktsförflyttningar och lokala formförändringar uppmäts. För hela populationen beräknas en mängd statistiska uppgifter och resultatkurvor uppritas under mätningen .Praktiska och principiella svårigheter vid analysen av TV-bilden beskrivs utförligt.
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