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Optical Performance:: Characterization of a Pupillometric Camera RELATED TITLES Documents Science & Tech Tech Digital & Social Media 58 views 0 0 Abb Uploaded by Mabel Ruiz AP-Physical Low Light Manual Twilight Retrato Science Sample Photography for Render 1.4.5 Aberration document explaining the Seidel coefficients Full description Save Embed Share Print S-118.4250 PPOSTGRADUATE SEMINAR ON ILLUMINATION ENGINEERING ,, SSPRING 2008 LLIGHTING UUNIT,, DDEPARTMENT OF EELECTRONICS,, HHELSINKI UUNIVERSITY OF TTECHNOLOGY (TKK) OPTICAL PERFORMANCE:: CHARACTERIZATION OF A PUPILLOMETRIC CAMERA Petteri Teikari,, [email protected] Emmi Rautkylä,, emmi.rautkylä@tkk.fi RELATED TITLES Documents Science & Tech Tech Digital & Social Media 58 views 0 0 Abb Uploaded by Mabel Ruiz AP-Physical Low Light Manual Twilight Retrato Science Sample Photography for Render 1.4.5 Aberration document explaining the Seidel coefficients Full description Save Embed Share Print RELATED TITLES Documents Science & Tech Tech Digital & Social Media 58 views 0 0 Abb Uploaded by Mabel Ruiz AP-Physical Low Light Manual Twilight Retrato Science Sample Photography for Render 1.4.5 Aberration document explaining the Seidel coefficients Full description Save Embed Share Print TABLE OF CONTENTS A A BSTRACT .................................................................................................................................. TT ABLE OF CONTENTS ................................................................................................................2 11 IINTRODUCTION.................................................................................................................3 22 OOPTICS && IIMAGING ...........................................................................................................4 2.12.1 Structure of lenses and their optical characteristicss................................................................ 2.1.1 Focal lengthth........................................................................................................................... 2.1.2 Aperture................................................................................................................................. 2.1.3 Image formation ................................................................................................................... 2.1.4 Depth of field (DOF))....................................................................................................... 2.1.5 Modular transfer function (MTF) and contrast............................................................. 2.22.2 Noise......................................................................................................................................... 2.32.3 Dynamic range......................................................................................................................... 2.42.4 Optical aberratiotionsns .................................................................................................................. 2.4.1 Chromatic aberration.......................................................................................................... 2.4.2 Geometric aberrationss........................................................................................................ 2.4.3 Vignetting................................................................................................................................. 2.4.4 Diffraction........................................................................................................................... 2.52.5 Aberration correctionn.............................................................................................................. 33 A A PPLIED LENS DESIGN .................................................................................................... 3.13.1 Measurement science & Machine vision..................................................................................... 3.23.2 Photography............................................................................................................................. 44 CCHARACTERIZING OPTICAL PERFORMANCE IN PRACTICE.............................................. 4.14.1 Pupillometry & overview of the setup................................................................................... 4.24.2 Methods.................................................................................................................................... 4.34.3 Results of the measurementsts.................................................................................................. 4.3.1 Modulation transfer function and sharpness........................................................................ 4.3.2 Geometric aberrationss........................................................................................................ 4.3.3 Dynamic range.................................................................................................................... 4.3.4 Noise.................................................................................................................................... 4.44.4 Image restoration................................................................................................................... 4.4.1 Sharpness............................................................................................................................. 4.4.2 Geometric aberrationss........................................................................................................ 4.4.3 Dynamic range.................................................................................................................... 4.4.4 Noise.................................................................................................................................... 4.54.5 Conclusions.............................................................................................................................. 55 DDISCUSSION ..................................................................................................................... A A PPENDICES RELATED TITLES Documents Science & Tech Tech Digital & Social Media 58 views 0 0 Abb Uploaded by Mabel Ruiz AP-Physical Low Light Manual Twilight Retrato Science Sample Photography for Render 1.4.5 Aberration document explaining the Seidel coefficients Full description Save Embed Share Print OOPTICAL PERFORMANCE:: CCHARACTERIZATION OF A PUPILLOMETRIC CAMERA TTEIKARI && R R AUTKYLÄ 1 INTRODUCTION Cameras do not 'see' in the same way those human beings are able to. They are not equivalent to human optics because their lens design defines how the image is formed. Therefore, if cameras are to be used in research purposes, it is important to know how to minimize the effect of the lens system on the research data. The object of this work is to help to understand the process of characterizing a camera. Under special examination is a pupillometric camera, hence a camera used for providing data about the autonomous nervous system by recording pupil size and dynamics. The experimental part of the paper gives a practical example of characterizing such pupillometric camera very sensitive to aberrations and noise and discusses possible ways to improve the image quality. That, together with the discussion, forms the core of the paper and raises questions for experiments to come. The work is meant for people not very familiar with optics or pupillometry. It takes a simple approach to the optics and imaging in Chapter 2. Chapter 3, for one, gives more insight to metrology with a review of more specific lens design used in machine vision and measurement science applications. RELATED TITLES Documents Science & Tech Tech Digital & Social Media 58 views 0 0 Abb Uploaded by Mabel Ruiz AP-Physical Low Light Manual Twilight Retrato Science Sample Photography for Render 1.4.5 Aberration document explaining the Seidel coefficients Full description Save Embed Share Print OOPTICAL PERFORMANCE:: CCHARACTERIZATION OF A PUPILLOMETRIC CAMERA TTEIKARI && R R AUTKYLÄ 2 2 OPTICS & IMAGING In this chapter basic concepts of optic systems are reviewed in the detail needed for this work. 2.1 STRUCTURE OF LENSES AND THEIR OPTICAL CHARACTERISTICS Lens or lens system is the optical structure that defines how the image is formed. In practice there are always several lenses (basic types illustrated in Figure 1 [1] ) in ‘the lens’ that can be bought from a store and therefore in this work the word lens refers to the lens system. Lenses can be categorized roughly to wide-angle and telephoto lenses where wide-angles have larger angle of view (with smaller focal length) and telephoto lenses have smaller angle of view (with larger focal length). Lenses can either have a fixed focal length (prime lenses) or it can be changed for example from wide-angle to telephoto when Figure 1. Lenses classified by the curvature of the they are commonly referred as zoom lenses. two optical surfaces [1].. Lenses could be characterized also according to their lens design and the number of elements but that kind of characterization is beyond the scope of this work. Figure 2 demonstrates the typical structure of a lens for commercial digital cameras. The lens is mounted on the camera using specific bayonet mounts [2 ] which are poorly intercompatible in commercial cameras even though there exist adapters to fit different bayonets to a given camera. In machine vision cameras typically there are three bayonet types [3]: 1) CS-mount, 2) C- mount, and 3) M12x0.5
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