EL: Local Image Descriptor Based on Extreme Responses to Partial Derivatives of 2D Gaussian Function

Figure 2

Extreme image responses. Maximal image responses are denoted by red dots and minimal by yellow dots. (a) The green cross marks the sample location at which image responses are computed. (b) Image response . The maximal and minimal image responses are equal in magnitude. (c) The blue curve represents . The maximal and minimal image responses are different in magnitude and can be of opposite signs, both negative, or both positive. The cyan curve represents . The image response is denoted by a red dot. (d) Color marking of the patches in column (a); cyan color indicates the sample locations where while blue represents the remaining locations.