Abstract Coherence-based adaptive imaging has been investigated for the improvement of image quality in medical ultrasound imaging. The coherence factor (CF) was developed for the improvement of lateral resolution and contrast. We enhanced the effect of the CF by converting it into the signal-to-noise (SNR) ratio factor, and the effect of the SNR factor was further enhanced by introducing a linear regression (LR) beamformer. Although lateral resolution and contrast were improved significantly by the SNR factor and LR beamformer, the contrast-to-noise ratio (CNR) was degraded. In the present study, a temporal averaging procedure was introduced in LR beamforming for the improvement of the CNR. The phantom experimental results showed that the CNR was improved by 40% without significant degradation in lateral resolution and contrast.