Computer controlled image sensor and its application

The rotation and data extraction of a linear array image sensor is controlled by a minicomputer, so that the desired information about the optical field at the face of the sensor can be extracted effectively. To obtain operations for the data, three kinds of averagings are adopted, that is, (1) simple averaging of intensity fluctuation at each sampling point, (2) second-order cross-correlation of fluctuations of intensities at two different sampling points, and (3) triple correlation of intensity fluctuations at three different sampling points. They are used (a) for the derivation of images averaged over any desired time interval, (b) for the measurement of the modulus of coherence function, and (c) for the measurement of a complex coherence function by an intensity triple correlator aiming at the imaging of incoherent objects with general shapes and measuring the statistical characteristics of the turbulence. Typically the characteristics of the system are: (1) observation area: over a disk of 8-mm diam; (2) spatial sampling interval: 50 microm; (3) temporal sampling interval: 500 microsec; (4) coherence function over the observation area is derived within 5 min and stored in a minicomputer, (5) by applying the Fourier transform to the observed coherence function the image or coherence function of the object is obtained in 2 min and is also displayed as the output of the minicomputer. The reconstructed images of incoherent objects show the usefulness of the device.