HINSA features of G174.4-15A1 extracted by method 1 (left) and method 2 (right). Method 1 fails to fit the HINSA component because of the low S/N and the blending of two absorption components with similar velocities. In each panel, the gray line is the observed spectrum T_r, the blue line is the recovered T_H I, and the red line is T_ab. The T_ab shown here has been multiplied by a factor of five.