| 摘要 |
Apparatus for measuring velocity is disclosed. The apparatus in its preferred embodiment comprises a first lens and a first array of photodiodes and a second lens and a second array of photodiodes. The photodiode arrays are functionally equivalent to low resolution vidcon camera tubes and momentarily store the image. As an object passes beneath the first lens, its image is stored on the photodiode array. The object then passes beneath the second array and the image is stored on the second array. After the image is stored on the second array a correlation is made between the two images by making an element by element comparison of the serial outputs of the two arrays. Instead of relying on the storage properties of the arrays to make the correlation, the arrays can be read into a small memory for comparison. Each array is exposed for only a short period of time. The invention includes apparatus for controlling the time interval between the exposures. If correlation is not achieved, the time interval between exposures is adjusted until correlation is achieved. When correlation is achieved, the velocity is obtained by dividing the distance between the arrays by the time interval between the exposures of the two arrays.
|
