Fig. 2

Results of the experiment conducted using 20 semen samples. a Total numbers \(N_{\text{DFT}}\) and \(N_{\text{CASA}}\) versus the manual count \(N_{\text{manual}}\) that serves as the gold standard. b Average speeds \(v_{{{\text{ave}}\_{\text{DFT}}}}\) and \(v_{{\text{ave}}\_{\text{CASA}}}\) versus the serial number of the 20 semen samples. Green points: the manual counts \(N_{\text{manual}}\). Dark red points: \(N_{\text{DFT}}\) and \(v_{{{\text{ave}}\_{\text{DFT}}}}\) evaluated using the DFT method. Violet points: \(N_{\text{CASA}}\) and \(v_{{\text{ave}}\_{\text{CASA}}}\) measured using the CASA instrument