傅楸善臺灣大學：資訊工程學研究所游啟昌Yu, Chi-ChengChi-ChengYu2007-11-262018-07-052007-11-262018-07-052004http://ntur.lib.ntu.edu.tw//handle/246246/53824In this thesis, we will present an automatic exposure method based on Nikon’s AMP (Automatic-Multiple-Pattern). Our method will add the fuzzy control into the AMP to get smooth transition effect. AMP needs to collect a lot of information for its database to offer optimal exposures for various conditions. In other words, the database is very huge and needs to cover all conditions, include weather conditions, contrast conditions, subject condition (subject is bright or dark) and so forth. We use fuzzy control to simulate the various conditions. It means we only construct three main frame reference tables, fuzzy control will simulate the ambiguous conditions (conditions not included in the reference table) to get a smooth transition effect. In this thesis, we also implement a subject growing function for dynamically guess where subject is. Our method classifies subject and background to get a better exposure. We also implement an easy evaluative function to estimate what is a well exposed picture in the same scene with different exposure parameters. The experiment results show that our evaluative function selects the best exposed picture similar to most people’s selection.Chapter 1......................................................................................................................1 1.1 Exposure.........................................................................................................1 1.2 Zone System....................................................................................................2 1.3 Aperture and Shutter.....................................................................................3 1.4 Automatic Exposure.......................................................................................4 1.4.1 Center-Weighted-Metering and Averaged-Metering and Center-Metering...........................................................................................4 1.4.3 Evaluative-Metering.........................................................................10 1.5 High Dynamic Range Image.......................................................................11 1.5.1 Special Sensor....................................................................................11 1.5.2 Synthesis with Multiple Exposed Pictures......................................12 1.6 Light Value and Exposure Value................................................................13 Chapter 2....................................................................................................................16 2.1 Introduction..................................................................................................16 2.2 Exposure Factors.........................................................................................16 2.3 Some Problems of AMP...............................................................................16 2.4 Improvement of AMP..................................................................................17 Chapter 3....................................................................................................................18 3.1 Scene Classification......................................................................................19 3.2 Cut Process...................................................................................................21 3.3 Fuzzy Control...............................................................................................24 3.3.1 Fuzzy Control for Foreground and Background...........................24 3.3.2 Fuzzy Control for Weather Condition............................................29 3.3.3 Fuzzy Control for Contrast Level....................................................30 3.4 Subject Growing...........................................................................................31 Chapter 4....................................................................................................................33 4.1 Introduction..................................................................................................33 4.2 Image Segmentation and Image Information Retrieval...........................33 4.3 Decision Making...........................................................................................36 Chapter 5....................................................................................................................38 5.1 Introduction..................................................................................................38 5.2 Results...........................................................................................................38 Chapter 6 Conclusion and Future Works................................................................52 6.1 Conclusion and Future works.....................................................................52 6.2 Problems of Our Automatic Exposure Method.........................................52 6.3 Future Works................................................................................................52 Reference ....................................................................................................................54 List of Figures Figure 1. 1: (a) Chessboard effect as seen by human vision or camera nearby. (b) Average luminance of (a) as seen by far-away auto-exposure sensor. ...........................................................................2 Figure 1. 2: Ansel Adam’s zone system and Grayscale Values. ................2 Figure 1. 3: (a) Original picture. (b) Over-exposed picture. ....................5 Figure 1. 4: (a) Original picture. (b) Under-exposed picture . .................5 Figure 1. 5: The CCD is divided into five segments. .................................6 Figure 1. 6: An example reference table. ....................................................7 Figure 1. 7: Three-dimensional reference table. ........................................8 Figure 1. 8: 3D Color matrix metering. .....................................................9 Figure 1. 9: Light sensitivity of human eye with various wavelengths. 10 Figure 1. 10: CCD is divided into fifteen segments. Segments 7, 8, and 9 are focal points. ..................................................................................10 Figure 1. 11: Weight-distribution when subject is in the left focal point...............................................................................................................11 Figure 1. 12: Sensor with different sensitivities and four pixels as a group. ..................................................................................................12 Figure 1. 13: A ~I is a series of picture with different exposures and the difference between A and B is one EV. J is the combination of A~I. ..............................................................................................................13 Figure 3. 1: CCD sensor is divided into 25 segments, blue group is center, and green group is background. .......................................................19 Figure 3. 2: The reference table of AMP. .................................................21 Figure 3. 3: CCD sensor is cut into five segments. ..................................21 Figure 3. 4: Example of Condition 1: (a) Only segment 2 is greater than W1. (b) Segments 2 and 3 are greater than W1. ..............................22 Figure 3. 5: Example of Condition 2: three segments are cut, but one segment’s LV is changed to W1. ........................................................22 Figure 3. 6: Example of Condition 3: (a) Only four segments are cut, but two segments’ LVs are changed to W1. (b) Five segments are cut, but two segments’ LVs are changed to W1. ......................................23 Figure 3. 7: Example of Condition 4: (a) Segment 2 is less than W4. (b) Segments 2 and 3 are less than W4. ..................................................23 Figure 3. 8: Example of Condition 5: (a) Two segments are cut, and one of them is set to W4. (b) Three segments are cut and one is set to W4. ..............................................................................................................24 Figure 3. 9: Reference table for bright subject. .......................................25 Figure 3. 10: Reference table for moderately bright subject. ................25 Figure 3. 11: Reference table for dark subject. .......................................26 Figure 3. 12: The relation between foreground and background. .........27 Figure 3. 13: Membership functions for different subject conditions (red: moderately bright subject, green: bright subject, blue: dark subject). ...............................................................................................28 Figure 3. 14: Membership functions of different weather conditions. ..29 Figure 3. 15: Membership functions for different contrast levels (red: flat contrast, green: some contrast, blue: medium contrast, cyan: strong contrast, magenta: very strong contrast). ............................30 Figure 3. 16: In initial state, segment 1 is the subject. ............................31 Figure 3. 17: Flow chart of our method presented in this thesis......31 Figure 4. 1: Subject is assumed to contain cyan region..........................33 Figure 4. 2: Table of zone numbers and their relative gray values and points..........................................................................................................34 Figure 4. 4: Red (340 degree), green (220 degree), blue (100 degree), cyan (160 degree), yellow (280 degree), and magenta (40 degree) showed on CrCb plane.................................................................................................35 Figure 4. 5: Color and its relative location in CrCb plane.....................36 Figure 5. 1: Result 1...................................................................................38 Figure 5. 2: Result 2...................................................................................39 Figure 5. 3: Result 3...................................................................................40 Figure 5. 4: Result 4...................................................................................41 Figure 5. 5: Result 5...................................................................................42 Figure 5. 6: Result 6...................................................................................43 Figure 5. 7: Result 7...................................................................................44 Figure 5. 8: Result 8...................................................................................45 Figure 5. 9: Result 9...................................................................................46 Figure 5. 10: Result 10...............................................................................47 Figure 5. 11: Result 11...............................................................................48 Figure 5. 12: Result 12...............................................................................49 Figure 5. 13: Result 13...............................................................................50 Figure 5. 14: Result 14...............................................................................51en-US自動曝光Automatic Exposurethesis