Estimation and Correction of the Distortion in Forensic Image Due to Rotation of the Photo Camera
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Breaking Down the “Cosine Fourth Power Law”
Breaking Down The “Cosine Fourth Power Law” By Ronian Siew, inopticalsolutions.com Why are the corners of the field of view in the image captured by a camera lens usually darker than the center? For one thing, camera lenses by design often introduce “vignetting” into the image, which is the deliberate clipping of rays at the corners of the field of view in order to cut away excessive lens aberrations. But, it is also known that corner areas in an image can get dark even without vignetting, due in part to the so-called “cosine fourth power law.” 1 According to this “law,” when a lens projects the image of a uniform source onto a screen, in the absence of vignetting, the illumination flux density (i.e., the optical power per unit area) across the screen from the center to the edge varies according to the fourth power of the cosine of the angle between the optic axis and the oblique ray striking the screen. Actually, optical designers know this “law” does not apply generally to all lens conditions.2 – 10 Fundamental principles of optical radiative flux transfer in lens systems allow one to tune the illumination distribution across the image by varying lens design characteristics. In this article, we take a tour into the fascinating physics governing the illumination of images in lens systems. Relative Illumination In Lens Systems In lens design, one characterizes the illumination distribution across the screen where the image resides in terms of a quantity known as the lens’ relative illumination — the ratio of the irradiance (i.e., the power per unit area) at any off-axis position of the image to the irradiance at the center of the image. -
NIKKOR Photoguide
Photo Guide I AM YOUR VIEW Photo is a conceptual image. Enhance your expression with interchangeable lenses Control light and shadow using Speedlights Wide-angle zoom lens Normal zoom lens Telephoto zoom lens High-power-zoom lens Daylight sync Bounce flash DX DX DX DX format format format format AF-S DX NIKKOR 10-24mm f/3.5-4.5G ED AF-S DX NIKKOR 16-80mm f/2.8-4E ED VR AF-S DX NIKKOR 55-200mm f/4-5.6G ED VR II AF-S DX NIKKOR 18-300mm f/3.5-6.3G ED VR Speedlights SB-910/SB700/SB-500/SB-300 Speedlights SB-910/SB700/SB-500/SB-300 (15-36 mm equivalent*1) (24-120 mm equivalent*1) (82.5-300 mm equivalent*1) (27-450 mm equivalent*1) 109° 83° 28°50' 76° DX 61° DX 20° DX 8° DX 5°20' Fixed-focal-length lens Micro lens Fisheye lens Auto FP high-speed sync Advanced Wireless Lighting Fast lens DX Fast lens FX-format DX DX format compatible format format AF-S DX NIKKOR 35mm f/1.8G AF-S NIKKOR 50mm f/1.8G AF-S DX Micro NIKKOR 40mm f/2.8G AF DX Fisheye-Nikkor 10.5mm f/2.8G ED Speedlights SB-910/SB700/SB-500 Speedlights SB-910/SB700/SB-500 (52.5 mm equivalent*1) (When attached to DX-format D-SLR cameras: 75 mm equivalent in 35mm [135] format) (60 mm equivalent*1) (16 mm equivalent*2) DX 44° FX 47° DX 31°30' DX 38°50' DX 180° 2 *1: When converted to 35mm [135] format. -
Effects on Map Production of Distortions in Photogrammetric Systems J
EFFECTS ON MAP PRODUCTION OF DISTORTIONS IN PHOTOGRAMMETRIC SYSTEMS J. V. Sharp and H. H. Hayes, Bausch and Lomb Opt. Co. I. INTRODUCTION HIS report concerns the results of nearly two years of investigation of T the problem of correlation of known distortions in photogrammetric sys tems of mapping with observed effects in map production. To begin with, dis tortion is defined as the displacement of a point from its true position in any plane image formed in a photogrammetric system. By photogrammetric systems of mapping is meant every major type (1) of photogrammetric instruments. The type of distortions investigated are of a magnitude which is considered by many photogrammetrists to be negligible, but unfortunately in their combined effects this is not always true. To buyers of finished maps, you need not be alarmed by open discussion of these effects of distortion on photogrammetric systems for producing maps. The effect of these distortions does not limit the accuracy of the map you buy; but rather it restricts those who use photogrammetric systems to make maps to limits established by experience. Thus the users are limited to proper choice of flying heights for aerial photography and control of other related factors (2) in producing a map of the accuracy you specify. You, the buyers of maps are safe behind your contract specifications. The real difference that distortions cause is the final cost of the map to you, which is often established by competi tive bidding. II. PROBLEM In examining the problem of correlating photogrammetric instruments with their resultant effects on map production, it is natural to ask how large these distortions are, whose effects are being considered. -
Model-Free Lens Distortion Correction Based on Phase Analysis of Fringe-Patterns
sensors Article Model-Free Lens Distortion Correction Based on Phase Analysis of Fringe-Patterns Jiawen Weng 1,†, Weishuai Zhou 2,†, Simin Ma 1, Pan Qi 3 and Jingang Zhong 2,4,* 1 Department of Applied Physics, South China Agricultural University, Guangzhou 510642, China; [email protected] (J.W.); [email protected] (S.M.) 2 Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; [email protected] 3 Department of Electronics Engineering, Guangdong Communication Polytechnic, Guangzhou 510650, China; [email protected] 4 Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Guangzhou 510650, China * Correspondence: [email protected] † The authors contributed equally to this work. Abstract: The existing lens correction methods deal with the distortion correction by one or more specific image distortion models. However, distortion determination may fail when an unsuitable model is used. So, methods based on the distortion model would have some drawbacks. A model- free lens distortion correction based on the phase analysis of fringe-patterns is proposed in this paper. Firstly, the mathematical relationship of the distortion displacement and the modulated phase of the sinusoidal fringe-pattern are established in theory. By the phase demodulation analysis of the fringe-pattern, the distortion displacement map can be determined point by point for the whole distorted image. So, the image correction is achieved according to the distortion displacement map by a model-free approach. Furthermore, the distortion center, which is important in obtaining an optimal result, is measured by the instantaneous frequency distribution according to the character of distortion automatically. Numerical simulation and experiments performed by a wide-angle lens are carried out to validate the method. -
1902. 5, Forensic Photography, Digital Cameras, and Digital Imaging Archive
ORLANDO POLICE DEPARTMENT POLICY AND PROCEDURE 1902. 5, FORENSIC PHOTOGRAPHY, DIGITAL CAMERAS, AND DIGITAL IMAGING ARCHIVE EFFECTIVE: 9/14/2017 RESCINDS: 1902. 4 DISTRIBUTION: ALL EMPLOYEES REVIEW RESPONSIBILITY: INVESTIGATIVE SERVICES BUREAU COMMANDER ACCREDITATION STANDARDS: 14.03, 14.06, 14.07, 35.03 CHIEF OF POLICE: ORLANDO ROLÓN CONTENTS: 1. DEFINITIONS 2. USE OF DIGITAL CAMERA 3. PROCEDURES FOR CAPTURED IMAGES 4. DIGITAL IMAGING ARCHIVE 5. CARE AND STORAGE 6. TRAINING 7. MAINTENANCE AND REPAIR POLICY: This directive is intended to provide information about the Forensic Imaging Lab and the duties and services of the Forensic Photographer. It also provides direction regarding the use of issued digital cameras, the handling of digital media, and digital archiving. With the ongoing development of technology and the availability of personally-owned recording devices, smart phones, tablets, etc., all employees shall acknowledge that this policy shall apply to the capture, handling and archiving of all digital evidence, even if such evidence is collected on an employee’s personal device. This may include, but is not limited to, incidents where certain evidence may be irretrievably altered or lost prior to the arrival of a supervisor, corporal or CSI. This may also include circumstances where fire department officials, public works personnel and/or any wrecker service have responded and the nature of their lawful duties directly creates a danger for certain evidence remaining intact. Further examples would include situations where rapidly-changing weather conditions jeopardize the position or structure of the evidence being documented. PROCEDURES: 1. DEFINITIONS 1.1 FORENSIC PHOTOGRAPHY Forensic Photography is the provision of general and forensic photographic services, including photography of evidence, for use in investigations. -
Depth of Field in Photography
Instructor: N. David King Page 1 DEPTH OF FIELD IN PHOTOGRAPHY Handout for Photography Students N. David King, Instructor WWWHAT IS DDDEPTH OF FFFIELD ??? Photographers generally have to deal with one of two main optical issues for any given photograph: Motion (relative to the film plane) and Depth of Field. This handout is about Depth of Field. But what is it? Depth of Field is a major compositional tool used by photographers to direct attention to specific areas of a print or, at the other extreme, to allow the viewer’s eye to travel in focus over the entire print’s surface, as it appears to do in reality. Here are two example images. Depth of Field Examples Shallow Depth of Field Deep Depth of Field using wide aperture using small aperture and close focal distance and greater focal distance Depth of Field in PhotogPhotography:raphy: Student Handout © N. DavDavidid King 2004, Rev 2010 Instructor: N. David King Page 2 SSSURPRISE !!! The first image (the garden flowers on the left) was shot IIITTT’’’S AAALL AN ILLUSION with a wide aperture and is focused on the flower closest to the viewer. The second image (on the right) was shot with a smaller aperture and is focused on a yellow flower near the rear of that group of flowers. Though it looks as if we are really increasing the area that is in focus from the first image to the second, that apparent increase is actually an optical illusion. In the second image there is still only one plane where the lens is critically focused. -
The Trade-Off Between Image Resolution and Field of View: the Influence of Lens Selection
The Trade-off between Image Resolution and Field of View: the Influence of Lens Selection “I want a lens that can cover the whole parking lot and I want to be able to read a license plate.” Sound familiar? As a manufacturer of wide angle lenses, Theia Technologies is frequently asked if we have a product that allows the user to do both of these things simultaneously. And the answer is ‘it depends’. It depends on several variables - the resolution you start with from the camera, how far away the subject is from the lens, and the field of view of the lens. But keeping the first two variables constant, the impact of the lens field of view becomes clear. One of the important factors to consider when designing video surveillance installations is the trade-off between lens field of view and image resolution. Image Resolution versus Field of View One important, but often neglected consideration in video surveillance systems design is the trade-off between image resolution and field of view. With any given combination of camera and lens the native resolution from the camera is spread over the entire field of view of the lens, determining pixel density and image resolution. The wider the resolution is spread, the lower the pixel density, the lower the image resolution or image detail. The images below, taken with the same camera from the same distance away, illustrate this trade-off. The widest field of view allows you to cover the widest area but does not allow you to see high detail, while the narrowest field of view permits capture of high detail at the expense of wide area coverage. -
A Guide to Smartphone Astrophotography National Aeronautics and Space Administration
National Aeronautics and Space Administration A Guide to Smartphone Astrophotography National Aeronautics and Space Administration A Guide to Smartphone Astrophotography A Guide to Smartphone Astrophotography Dr. Sten Odenwald NASA Space Science Education Consortium Goddard Space Flight Center Greenbelt, Maryland Cover designs and editing by Abbey Interrante Cover illustrations Front: Aurora (Elizabeth Macdonald), moon (Spencer Collins), star trails (Donald Noor), Orion nebula (Christian Harris), solar eclipse (Christopher Jones), Milky Way (Shun-Chia Yang), satellite streaks (Stanislav Kaniansky),sunspot (Michael Seeboerger-Weichselbaum),sun dogs (Billy Heather). Back: Milky Way (Gabriel Clark) Two front cover designs are provided with this book. To conserve toner, begin document printing with the second cover. This product is supported by NASA under cooperative agreement number NNH15ZDA004C. [1] Table of Contents Introduction.................................................................................................................................................... 5 How to use this book ..................................................................................................................................... 9 1.0 Light Pollution ....................................................................................................................................... 12 2.0 Cameras ................................................................................................................................................ -
L E N S E S & a C C E S S O R I
H1-H4 LENSES & ACCESSORIES P. 4 P. 5 P. 6 P. 7 P. 8 Riley Joseph / Canada Ben Cherry / UK Tomasz Lazar / Poland Toshimitsu Takahashi / Japan Zack Arias / U.S.A. Supported by P. 9 P.10 Norifumi Inagaki / Japan Bobbie Lane / U.S.A. P.11 P.12 P.14 P.16 P.18 Christian Fletcher / Australia Bert Stephani / Belgium Tsutomu Endo / Japan Dave Kai Piper / UK Jára Sijka / Czech P.20 P.21 P.22 P.23 P.23 Afton Almaraz / U.S.A. Masaaki Aihara / Japan Chris Weston / UK Gathot Subroto / Indonesia Giulia Torra / Italy Visit these links to learn what the professionals are saying about X mount lenses and X accessories and XF LENS X-Accessories see some of the beautiful results! http://fujifilm-x.com/xf-lens/ http://fujifilm-x.com/accessories/ Specifications are subject to change without notice. For more information, please visit our website: http://www.fujifilm.com/products/digital_cameras/accessories/ c 2015 FUJIFILM Corporation P02-03/P31 The vision of the X Series, the choice for X Series owners A collection of creativity-oriented lenses, which complement the X-Trans CMOS sensor perfectly and eliminate the low-pass filter for ultimate sharpness. XF 50-140mmF2.8 R LM OIS WR P.18 XF55-200mmF3.5-4.8 R LM OIS P.22 XF18-135mmF3.5-5.6 R LM OIS WR P.21 XF16-55mmF2.8 R LM WR P.16 XF10-24mmF4 R OIS P.14 NEW XF90mmF2 R LM WR NEW XF23mmF1.4 R P.12 XF16mmF1.4 R WR P.7 XF18-55mmF2.8-4 R LM OIS P.5 P.20 XF 14mmF2.8 R P.4 XF35mmF1.4 R P.9 XC50-230mmF4.5-6.7 OIS II P.23 XF56mmF1.2 R APD P.10 XF 18mmF2 R XF56mmF1.2 R P.6 P.10 M Mount Adapter XF 27mmF2.8 P.25 P.8 XF60mmF2.4 R Macro P.11 MCEX-16 P.25 XC16-50mmF3.5-5.6 OIS II P.23 MCEX-11 P.25 X Accessories P.25 P04-05/P32 X-T10 : F16 1/125 sec. -
Notes on View Camera Geometry∗
Notes on View Camera Geometry∗ Robert E. Wheeler May 8, 2003 c 1997-2001 by Robert E. Wheeler, all rights reserved. ∗ 1 Contents 1 Desargues’s Theorem 4 2 The Gaussian Lens Equation 6 3 Thick lenses 8 4 Pivot Points 9 5 Determining the lens tilt 10 5.1Usingdistancesandangles...................... 10 5.2Usingbackfocus........................... 12 5.3Wheeler’srules............................ 13 5.4LensMovement............................ 14 5.5BackTilts............................... 14 6Depthoffield for parallel planes 15 6.1NearDOFlimit............................ 15 6.2FarDOFlimit............................ 17 6.3DOF.................................. 17 6.4Circlesofconfusion.......................... 18 6.5DOFandformat........................... 19 6.6TheDOFequation.......................... 19 6.7Hyperfocaldistance......................... 20 6.8Approximations............................ 21 6.9Focusgivennearandfarlimits................... 21 6.9.1 Objectdistances....................... 21 6.9.2 Imagedistances........................ 22 7Depthoffield, depth of focus 23 8Fuzzyimages 24 9Effects of diffractiononDOF 26 9.1Theory................................. 26 9.2Data.................................. 27 9.3Resolution............................... 29 9.4Formatconsiderations........................ 31 9.5Minimumaperture.......................... 32 9.6Theoreticalcurves.......................... 33 10 Depth of field for a tilted lens 35 10.1NearandfarDOFequations.................... 35 10.2 Near and far DOF equations in terms of ρ ............ -
CATALOGUE the Lens Makes the Photograph
LENSCATALOGUE The Lens Makes the Photograph At the heart of photography meshing with the photographer’s Tools of inspiration a well established category in its own product development and R&D efforts Supported by this highly adaptable desire to capture the perfect shot. and imagination right. But at the time, “wide angle” are based on a policy of in-house system, Sigma’s unconventional Ever since Sigma’s founding, meant a prime lens, and nobody even development for the key technologies manufacturing approach focuses on we have always believed that a photo More options for At times we have ventured to introduce considered the need for variable that we consider most important. continuous improvement of advanced is only as good as the lens. It follows more photographers products for which there was no focal length. That Sigma saw things processing and fabrication technology, that choosing a new lens opens up precedent. Many of these world’s firsts, differently and had the technology to For our lenses, we not only design while creating greater freedom of design fresh possibilities for photographic Given a wide variety of optically we are proud to say, have revealed new create a new genre is a true reflection of the optics and mechanisms, but also through novel solutions to challenging expression. This philosophy has superior lenses, the photographer can dimensions for photographic exploration our inventive spirit regarding the tools the firmware, electronic circuits and optics issues. inspired Sigma’s quest for select the one that will best achieve and contributed to the very culture of of photography. -
Forensic Photography
Forensic Photography ABOUT THE PROGRAM The Forensic Photography PAY College Certificate program is The median hourly wage of designed to provide students with photographers was $14.00 in May the technical skills necessary to 2010. Forensic photography may photographically preserve crime have a higher salary depending scenes and items of evidence, on experience and training. from both technical and legal standpoints. The Forensic JOB OUTLOOK Photography program provides Employment of photographers is students with the necessary projected to grow by 13 percent skills needed in the principles from 2010 to 2020, about as fast of composition, focus, exposure, as the average for all occupations. color theory, and lighting. Salaried jobs in particular may The program enables students be more difficult to find as to work in front of the camera, companies and agencies may photography studios, and hire freelancers rather than computer based processing labs. hire their own photographers. The program addresses the need Competition for jobs will be for an alternative career track for strong because of substantial students that work in crime scene interest in forensic science. investigation, criminal justice, homeland security, fire safety, as well as other evidence gathering related occupations. There is a Bureau of Labor Statistics, U.S. Department demand for individuals that have the skills and talents as a photographer of Labor, Occupational Outlook Handbook, or a computer-based digital imaging specialist. 2012-13 Edition, Forensic Science Technicians, on the Internet at http://www.bls.gov/ooh/life-physical-and-social- WHAT DO FORENSIC PHOTOGRAPHERS DO? science/forensic-science-technicians.htm and http://www.bls.gov/ooh/media-and- Forensic photography, sometimes referred to as forensic imaging or crime communication/photographers.htm scene photography, is the art of producing an accurate reproduction of a crime scene or an accident scene using photography for the benefit of a court or to aid in an investigation.