¡Hola, Mundo!

SURF (Speeded Up Robust Features)

It's like SIFT, but faster because it uses the Integral images to speed up image operations.  Any box region sum can be calculated in constant time using:Sum=D−B−C+A Gaussian vs. Box Filter Left: Gaussian FilterA Gaussian filter is smooth and continuous.It computes second-order derivatives of the image (like ∂²/∂x²) to detect blobs or corners.Precise but computationally expensive. Right: Box Fil..

SIFT (Scale-Invariant Feature Transform)

SIFT is a method to: - Detect keypoints (interesting, stable points in the image)- Describe them in a way that is invariant to scale and rotationScale Invariance - SIFT is robust to images taken at different zoom levels (scales).- It does this by detecting keypoints in multiple scales, not just a single image resolution.Detector: Difference of Gaussian (DoG)\begin{equation}D(x,y,\sigma)=L(x,y,k\..

Null Space In the linear equation Ax=b, when b is a zero vector (=Null vector or 0 vector), it is a set of all possible solutions x that satisfy the equation.  x = x 1 x 2 ..

Square Matrix  A matrix with the same number of rows and columns. An n-by-n matrix is known as a square matrix of order n. Any two square matrices of the same order can be added and multiplied.Square matrices are often used to represent simple linear transformations, such as shearing or rotation. Row Vector Transformation  v R T " data-ke-type="html">HTML ..

https://rfriend.tistory.com/181