... the multistage electronic focus, the dynamic filter, the logarithm compression, the image enhancement, the line correlation, the frame correlation, and the linear ... . It may survey and calculate the distance, the area, the perimeter, the heart rate, and the pregnant week (five ways: BPD ... conversion: 2.5MHz/3.0MHz/3.5MHz/4.0MHzCalculation: distance, perimeter, area, heart rate, pregnancy week (BPD ...