پایان نامه جدا سازی پروجکشن های پروتز و ایمپلنت های بافت در تصاویر ساینوگرام سی تی اسکن اسپایرال با استفاده از روش های کانتور فعال

فهرست:

1- فصل اول: مقدمه                                                                                                   1

1-1- مقدمه                                                                                      2

1-2-  Filtered Back Projection (FBP) و آرتیفکت­ها در سی تی                       4

1-2-1- سخت شدن پرتوها                                                                  6

1-2-2- کمبود فوتون                                                                        7

1-2-3- پراکندگی                                                                            7

1-2-4- اثر حجم نسبی                                                                      7

1-3- اهداف کلی این پایان نامه                                                                8

2- فصل دوم: مبانی نظری تحقیق                                                                             9

2-1- تاریخچه سی تی اسکن                                                                 10

2-2- اجزای اصلی تشکیل دهنده دستگاه سی تی اسکن                                  11

2-3- نسل­های مختلف دستگاه سی تی اسکن تا به امروز                                  14

2-3-1-  نسل اول                                                                          15

2-3-2-  نسل دوم                                                                          16

2-3-3-  نسل سوم                                                                         17

2-3-4-  نسل چهارم                                                                       17

2-3-5-  نسل پنجم، سی­تی اسکنهای EBCT                                           18

2-3-6-  نسل ششم، سی تی اسکن­های مارپیچ (اسپایرال یا هلیکال)                 19

2-3-7-  نسل هفتم، سی تی اسکنهای مالتی اسلایس                                 20

2-4- الگوریتم­های بازسازی تصویر                                                            21

2-4-1- ساینوگرام                                                                          23

2-4-2-  الگوریتم ART                                                                    27

2-4-3-  الگوریتم Back Projection Fourier Slice                                    28

2-4-4-  الگوریتم Filtered Back Projection Fourier Slice                         32

2-5- بازسازی تصویر در حالت پرتو بادبزنی شکل                                           34

2-5-1- بازسازی تصویر در حالت پرتو بادبزنی با زاویه­های مساوی                     35

2-5-2- بازسازی تصویر در حالت پرتو بادبزنی با فضاهای پوششی مساوی             38

2-6- بازسازی تصویر در سی­تی­های نسل اسپایرال                                          38

2-7- کانتورهای فعال                                                                          40

2-7-1- مدل­های اکتیو کانتور پارامتریک                                                 41

2-7-2- مدل­های کانتور فعال هندسی                                                   53

2-8- تبدیل هاف                                                                               62

3- فصل سوم: مروری بر تحقیقات انجام شده                                                        68

4- فصل چهارم: روش تحقیق                                                                                75

4-1- مقدمه                                                                                     76

4-2- روش تصویر برداری مارپیچ و مقایسه آن با اسکنر معمولی                          77

4-3- تشکیل ساینوگرام                                                                       78

4-4- الگوریتم مطرح شده                                                                    79

4-4-1- مدل کانتور فعال                                                                  80

4-4-2- الگوریتم بر پایه تبدیل هاف                                                      84

4-4-3- الگوریتم پس از پردازش                                                          86

4-5- نتیجه گیری                                                                              86

5- فصل پنجم: نتایج                                                                                             88

5-1- اعمال الگوریتم پیشنهادی بر داده­های واقعی و مقایسه به صورت شهودی         89

5-2- اعمال الگوریتم پیشنهادی بر مولاژ و مقایسه به صورت کمی                       90

5-2-1- میانگین و واریانس سطح خاکستری                                            92

5-2-2- میانگین مربع خطاها                                                              93

5-2-3- نسبت ماکزیمم سیگنال به نویز                                                  93

5-2-4- پارامتر Q                                                                          94

5-3- مقایسه الگوریتم مطرح شده با روش جداسازی با حد آستانه و تبدیل هاف     119

5-4- نتیجه گیری                                                                            122

مراجع

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