| 摘要 |
<p>PURPOSE:To obtain a CFAR coefficient being suitable for obtaining the detection probability of a target by deriving a hit and the detection probability to plural CFAR coefficients, and comparing them. CONSTITUTION:In a CFAR quantizing circuit 1, a digital video signal is inputted to shift registers 3a, 3b, and an average value of each video level of an N range cell before and behind a test cell is calculated by average value calculating circuits 4a, 4b. A larger one of its average values is selected by a large selecting circuit 5a and inputted to a divider 11. On the other hand, the video level of the test cell is inputted to a selecting circuit 10, compared with a CFAR lower limit value, the video level of the lower limit value or below is set to '0' and inputted to the divider 11, and a ratio (x) of both the inputs is outputted. By an accumulating circuit 12, (x) is compared with plural CFAR coefficients x0 - xn, and at the time of (x) > xi (i = 0 - n), it is counted as a hit to the coefficient xi and outputted to a CPU 8. The CPU 8 derives an optimum CFAR coefficient and outputs it to a comparator 13, compares it with an output of the divider 11, and when the latter is larger, it is outputted as a hit.</p> |
