[讀書學習] 《AIOT與OpenCV實戰應用:Python、樹莓派、物聯網與機器視覺》
第三篇 OpenCV
. 3-13 特徵描述
. » cv2.ORB
. »» cv2.ORB_create( )
. »» cv2.ORB.detect( ) 回傳tuple,element內容為cv2.KeyPoint資料
[延伸] SIFT, SURF特徵演算法需「啟用營利」設定重灌OpenCV
[延伸] cv2.drawKeypoints( )
#Raspberry_pi #Python ORB特徵描述演算法
第三篇 OpenCV
. 3-13 特徵描述
. » cv2.ORB
. »» cv2.ORB_create( )
. »» cv2.ORB.detect( ) 回傳tuple,element內容為cv2.KeyPoint資料
[延伸] SIFT, SURF特徵演算法需「啟用營利」設定重灌OpenCV
[延伸] cv2.drawKeypoints( )
#Raspberry_pi #Python ORB特徵描述演算法
Basic reproduction number - Wikipedia
In epidemiology, the basic reproduction number of an infection can be thought of as the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection.
In epidemiology, the basic reproduction number of an infection can be thought of as the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection.
The definition describes the state where no other individuals are infected or immunized (naturally or through vaccination).
The basic reproduction number is not to be confused with the effective reproduction number R which is the number of cases generated in the current state of a population, which does not have to be the uninfected state. By definition R0 cannot be modified through vaccination campaigns.
R0 is not a biological constant for a pathogen as it is also affected by other factors such as environmental conditions and the behaviour of the infected population.
Furthermore R0 values are usually estimated from mathematical models, and the estimated values are dependent on the model used and values of other parameters.
Furthermore R0 values are usually estimated from mathematical models, and the estimated values are dependent on the model used and values of other parameters.
Thus values given in the literature make only sense in the given context and it is recommended not to use obsolete values or compare values based on different models.[13] R0 does not by itself give an estimate of how fast an infection spreads in the population.
我的理解是,R0 是某傳染病真正存在的一個理想數值,但是我們不知道這個真實數值,所以用已知數據估計出 R0,然後再以這個我們認知中(希望和真實R0會一樣)的 R0 去做其他應用,像是評估風險之類的
你把他想成說,我們要怎麼知道Chris Sale的stuff如何?那我們要用不同的方式去測量。譬如看ERA、FIP、WHIP、WAR blahbalhblah. 在不同情況下,譬如投手球場、打者球場,或是面對不同打線、有垃圾隊敲垃圾桶等情況,Sale的ERA等會改變,但是估計出來的R0應該是要能反應他的stuff,藉此知道他是否是一個好投手。
但這個推估不是說,一個病毒的恆定能力如何,而是一個傳染病在特定狀態下的stuff,所以他不是一個常數。例如Stephen Curry在現今的NBA不能hand check和打pace and space的環境下強到爆,但在90年代可能會被打斷腿。