2 results about "Ambiguity" patented technology

The invention discloses a visual dictionary close-loop detection method and device based on distance measure. The visual dictionary close-loop detection method based on distance measure comprises thefollowing steps: determining the shortest spatial distance between a first position corresponding to a current frame picture and a second position corresponding to a historical frame picture, whereinthe historical frame picture is a frame picture of which the similarity to the current frame picture reaches a first preset threshold; if the shortest spatial distance is less than a second preset threshold, putting the historical frame picture in a candidate frame picture set, wherein the second preset threshold is a pre-acquired preset multiple of the uncertainty of the current frame and an adjacent frame thereof; and carrying out close-loop detection on the candidate frame pictures and the current frame picture. The selection range of similar pictures in a visual dictionary is restricted bythe shortest spatial distance, so that appropriate similar pictures can be found for closed-loop detection. Therefore, visual ambiguity is reduced, the accuracy of closed-loop detection is improved,and the positioning accuracy of robots is increased.

The invention discloses a high speed parallel concatenated code coder decoder, which is widely applied to satellite communication systems, deep space communication systems and the like. The high speed parallel concatenated code coder decoder comprises a coder and a decoder, wherein the coder comprises a branch convertor, a first remote sensing (RS) coder, a second RS coder, a third RS coder, a fourth RS coder, a first frame inserting device, a second frame inserting device, a third frame inserting device, a fourth frame inserting device, a first interleaver group, a second interleaver group, a third interleaver group, a fourth interleaver group, a first convolutional code coder, a second convolutional code coder, a third convolutional code coder and a fourth convolutional code coder; and the decoder comprises a phase convertor, a first convolutional code decoder, a second convolutional code decoder, a third convolutional code decoder, a fourth convolutional code decoder, a first frame searching device, a second frame searching device, a third frame searching device, a fourth frame searching device, a first deinterleaver, a second deinterleaver, a third deinterleaver, a fourth deinterleaver, a first RS decoder, a second RS decoder, a third RS decoder and a fourth RS decoder. The coder directly performs concatenated code coding on high speed serial data through a high speed parallel technology, and transmits the coded data to modulation equipment in a parallel mode; and the decoder directly performs concatenated code decoding on parallel data with phase ambiguity output by a demodulator, and problems of sequence randomness of the parallel data, random malalignment of the parallel data and the like caused by the randomness of analog/digital (AD) sampling time can be solved.