In [Gottardi and Yang 93] Gottardi and Yang describe a 1D linear CCD image sensor and correlator. The outputs of the 1D imager are stored in two analog CCD memories, each storing one frame of the image. In the next stage the data from one frame is shifted by 5 pixels in the preshift block. In the correlator block the frames data are shifted spatially and correlated pixel-wise. Pixel correlation is performed by an absolute value of difference (AVD) circuit. The outputs of the AVD circuits (which are in the form of charge) in one row are added together. A winner-take-all circuit determines the position of the largest correlation among the eleven outputs of the correlator block. The block diagram of the chip and the architecture of the correlator are shown in Figure 3.20.
Figure 3.20: a) Block diagram of the chip. b) Architecture of the
correlator in Gottardi-Yang's CCD motion sensor.