At the transmitter a coder includes a motion vector generator providing vectors (MV) describing the movement of individual blocks of pixels. The video signal is 4:1 compressed in bandwidth by pre-filters and a sub-sampling unit to produce a signal (SSH) from which a high-definition image can be re-constructed in the coder and in the decoder. The sampling lattice is shifted in accordance with the motion vectors (MV) which are digitally transmitted along with the compressed bandwidth analogue signal, to enable the samples to be correctly located in the reconstructed image. Poorly correlated moving areas are handled by pure spatial filtering (pre-filter and sub-sampling unit) with reconstruction by spatial interpolation. The two reconstructed signals (RVH and RVL) at the coder are compared in a mode selector with the input video and a switch is set to transmit whichever of the compressed signals (SSH, SSL) gives the best match. A mode signal is also transmitted and, at the receiver decoder this operates a switch to select (RVH') or (RVL') correspondingly for feeding to the display. In a modified embodiment the sub-sampling unit does not employ a moving lattice but all samples for a four field sequence are taken from one field of each sequence.
A cinematographic camera is operated at three times normal frame rates and converted to digital video in a telecine operation. Motion estimation provides from the digital video motion vectors which are substantially free of temporal aliasing. These motion vectors are employed in film weave measurement and correction and in motion compensated noise reduction and scratch concealment to provide a high quality signal which can be displayed at the elevated frame rate or standards converted, using the high quality motion vectors, to any desired standard.
Disclosed is an intrafield interpolation circuit for interpolating pixel signals between pixel signals sampled based on Multiple Sub-nyquist Sampling Encoding (MUSE). There are provided in this interpolation circuit switches (S4a, S4b, S4c) for selecting pixel signals from delay elements (33h, 33i, 33j). Since these switches are controlled at a suitable timing, correct pixel signals obtained by an operation are interpolated between the sampled pixel signals. In addition, since pixel signals required only for an interpolation processing are handled, multipliers require half the operation speed of a conventional circuit, resulting in an enhanced reliability in operation.
In, for example, a motion compensated video standards converter blocks in a first field or frame of a video signal are each compared with a plurality of blocks in the following field or frame of the video signal for deriving motion vectors representing the motion of the content of respective blocks between the first field or frame and the following field or frame, a correlation surface is generated for respective blocks in the first field or frame, the correlation surface representing the difference between the content of the block in the first field or frame and the content of each block in the following field or frame with which it has been compared, the correlation surface is tested for a clear minimum, the size of the blocks is increased to generate new correlation surfaces, each new correlation surface is tested for a clear minimum, and motion vectors are derived in dependence on the clearest minimum so found.
In, for example, a motion compensated video standards converter wherein blocks in a first field or frame of a video signal are each compared with a plurality of blocks in the next succeeding field or frame of the video signal for deriving motion vectors representing the motion of the content of respective blocks between the first field or frame and the next field or frame, the blocks in a border region of each field or frame are assigned the same motion vectors as have been derived for the respective nearest block which is not in the border region.
In, for example, a motion compensated video standards converter wherein blocks in a first field or frame of a video signal are each compared with a plurality of blocks in the following field or frame of the video signal for deriving a plurality of motion vectors representing the motion of the content of respective blocks between the first field or frame and the following field or frame, a respective motion vector is derived, from the plurality of motion vectors for each pixel in each block of each input field or frame by luminance matching each pixel in an input field or frame with the pixels, in the previous and following input fields or frames, pointed to by said plurality of motion vectors, and the respective luminance matches are checked against a threshold value determined in dependence on the local frequency content of the picture corresponding to the video signal.
