Low-Noise Dynamic Reconstruction for X-Ray Tomographic Perfusion Studies Using Low Sampling Rates

Figure 3

Frequency response of the polynomial spline filter 𝜂^𝑛_𝜆(𝑡^). (a) 𝜆=0 and orders 𝑛=3, 5 and 9 (black arrow indicates increasing order). (b) 𝑛=9 and 𝜆=0,0.01,0.05,20 and 1000 (black arrow indicates increasing value of 𝜆). Frequency 𝜈^ is normalized by the sampling frequency.

(a)

(b)