V VV VV Image Processing VVVVon.com VVVV Basic Photography in 180 Days Book XI - Image Processing Editor: Ramon F. aeroramon.com Contents 1 Day 1 1 1.1 Digital image processing ........................................ 1 1.1.1 History ............................................ 1 1.1.2 Tasks ............................................. 1 1.1.3 Applications .......................................... 2 1.1.4 See also ............................................ 2 1.1.5 References .......................................... 3 1.1.6 Further reading ........................................ 3 1.1.7 External links ......................................... 3 1.2 Image editing ............................................. 3 1.2.1 Basics of image editing .................................... 4 1.2.2 Automatic image enhancement ................................ 7 1.2.3 Digital data compression ................................... 7 1.2.4 Image editor features ..................................... 7 1.2.5 See also ............................................ 13 1.2.6 References .......................................... 13 1.3 Image processing ........................................... 20 1.3.1 See also ............................................ 20 1.3.2 References .......................................... 20 1.3.3 Further reading ........................................ 20 1.3.4 External links ......................................... 21 1.4 Image analysis ............................................. 21 1.4.1 Computer Image Analysis ................................... 21 1.4.2 Techniques .......................................... 21 1.4.3 Digital Image Analysis .................................... 22 1.4.4 Object-based Image Analysis ................................. 22 1.4.5 Land cover mapping ..................................... 22 1.4.6 References .......................................... 24 1.4.7 Notes ............................................. 24 1.4.8 External links ......................................... 24 2 Day 2 25 2.1 Photo manipulation .......................................... 25 i ii CONTENTS 2.1.1 History ............................................ 26 2.1.2 Political and ethical issues ................................... 28 2.1.3 Types of digital photo manipulation ............................. 32 2.1.4 Photoshopped ......................................... 32 2.1.5 See also ............................................ 34 2.1.6 References .......................................... 35 2.1.7 Further reading ........................................ 37 2.1.8 External links ......................................... 37 3 Day 3 38 3.1 Layers (digital image editing) ..................................... 38 3.1.1 Layer types .......................................... 38 3.1.2 Layer (basic) ......................................... 38 3.1.3 Layer mask .......................................... 38 3.1.4 Adjustment layer ....................................... 39 3.1.5 See also ............................................ 39 3.1.6 References .......................................... 39 4 Day 4 42 4.1 Image histogram ............................................ 42 4.1.1 Image manipulation and histograms .............................. 43 4.1.2 See also ............................................ 43 4.1.3 References .......................................... 43 4.1.4 External links ......................................... 43 4.2 Curve (tonality) ............................................ 43 4.2.1 See also ............................................ 43 4.2.2 References .......................................... 45 4.2.3 External links ......................................... 45 4.3 Sensitometry .............................................. 45 4.3.1 Details ............................................ 45 4.3.2 See also ............................................ 45 4.3.3 References .......................................... 46 4.3.4 External links ......................................... 46 4.4 Tone reproduction ........................................... 48 4.4.1 In photography ........................................ 48 4.4.2 In printing ........................................... 48 4.4.3 See also ............................................ 48 4.4.4 References .......................................... 49 5 Day 5 50 5.1 Gamma correction ........................................... 50 5.1.1 Explanation .......................................... 50 CONTENTS iii 5.1.2 Generalized gamma ...................................... 50 5.1.3 Film photography ....................................... 51 5.1.4 Windows, Mac, sRGB and TV/video standard gammas ................... 51 5.1.5 Power law for video display .................................. 51 5.1.6 Methods to perform display gamma correction in computing ................. 52 5.1.7 Simple monitor tests ..................................... 53 5.1.8 Terminology ......................................... 54 5.1.9 See also ............................................ 54 5.1.10 References .......................................... 55 5.1.11 External links ......................................... 55 5.2 Digital compositing .......................................... 59 5.2.1 Mathematics ......................................... 59 5.2.2 Software ........................................... 60 5.2.3 See also ............................................ 61 5.2.4 Further reading ........................................ 61 5.3 Computational photography ...................................... 61 5.3.1 Computational illumination .................................. 63 5.3.2 Computational optics ..................................... 63 5.3.3 Computational processing ................................... 63 5.3.4 Computational sensors .................................... 63 5.3.5 Early work in computer vision ................................ 63 5.3.6 See also ............................................ 63 5.3.7 References .......................................... 63 5.3.8 External links ......................................... 64 5.4 Inpainting ............................................... 64 5.4.1 Applications ......................................... 64 5.4.2 Methods ........................................... 65 5.4.3 See also ............................................ 66 5.4.4 References .......................................... 66 5.4.5 External links ......................................... 66 6 Day 6 67 6.1 Image processor ............................................ 67 6.1.1 Function ............................................ 68 6.1.2 Models ............................................ 68 6.1.3 References .......................................... 69 6.1.4 See also ............................................ 69 6.2 Noise reduction ............................................ 70 6.2.1 In audio ............................................ 70 6.2.2 In images ........................................... 71 6.2.3 See also ............................................ 73 6.2.4 References .......................................... 74 iv CONTENTS 6.2.5 External links ......................................... 75 6.3 Iterative reconstruction ........................................ 75 6.3.1 Basic concepts ........................................ 76 6.3.2 Advantages .......................................... 76 6.3.3 See also ............................................ 77 6.3.4 References .......................................... 77 7 Day 7 79 7.1 Distortion (optics) ........................................... 79 7.1.1 Radial distortion ....................................... 79 7.1.2 Software correction ...................................... 82 7.1.3 Related phenomena ...................................... 83 7.1.4 See also ............................................ 84 7.1.5 References .......................................... 84 7.1.6 External links ......................................... 84 7.2 Perspective control .......................................... 85 7.2.1 Perspective control at exposure ................................ 87 7.2.2 Perspective control in the darkroom ............................. 88 7.2.3 Perspective control during digital post-processing ...................... 88 7.2.4 Perspective control in virtual environments .......................... 88 7.2.5 See also ............................................ 89 7.2.6 References .......................................... 89 7.2.7 External links ......................................... 89 8 Day 8 90 8.1 Cropping (image) ........................................... 90 8.1.1 Cropping in photography, print & design ........................... 90 8.1.2 Cropping in cinematography & broadcasting ......................... 92 8.1.3 Additional methods ...................................... 93 8.1.4 Uncropping .......................................... 94 8.1.5 References .......................................... 94 8.2 Image warping ............................................. 94 8.2.1 Overview ........................................... 94 8.2.2 In the news .......................................... 95 8.2.3 See also ............................................ 95 8.2.4 References .......................................... 95 8.2.5 External links ......................................... 95 8.3 Vignetting ............................................... 95 8.3.1 Causes ............................................