~ false positives 虛警率

~ false negative 漏檢率

~ recall 檢出率/查全率

~ precision 正確率

~ intergral images 積分幀(算法),該算法能夠快速算出區塊的灰度和

An integral image helps you rapidly calculate summations over image subregions. Every pixel in an integral image is the summation of the pixels above and to the left of it.

To calculate the summation of a subregion of an image, you can use the corresponding region of its integral image. For example, in the input image below, the summation of the shaded region becomes a simple calculation using four reference values of the rectangular region in the corresponding integral image. The calculation becomes, 46 – 22 – 20 + 10 = 14. The calculation subtracts the regions above and to the left of the shaded region. The area of overlap is added back to compensate for the double subtraction.

In this way, you can calculate summations in rectangular regions rapidly, irrespective of the filter size.

視覺處理常用的一些概念和微小算法