Coherence algorithm is widely used to describe geological discontinuity and subtle features of seismic data. Traditional coherence algorithms often use the linear correlation measurement to measure the relationship between two seismic traces. It does not work well because seismic data do not obey the normal distribution. To describe the coherence measurement of seismic data, we propose an improved coherence algorithm by combining the mutual information (MI) and third-generation coherence (C3) algorithm. The MI is a measurement of the general dependence and used to describe nonlinear relationships between two variables. Note that, the MI does not require that variables obey specific distribution (e.g., the normal distribution). Note that, we calculate precise MI values using the copula function. In addition, we introduce the information divergence to save calculation time by replacing the eigenvalue decomposition of the C3 algorithm. To demonstrate the effectiveness of the proposed algorithm, we apply it to field data. Field data experiments demonstrate the effectiveness of the proposed algorithm to describe geological discontinuity and heterogeneity, such as channels with different thicknesses.

Trellis-coded quantizers (TCQ) are designed for the binary erasure channel (BEC) for memoryless sources. When the bit erasure rate is large, the channel-optimized TCQ can provide up to 1.4 dB improvement over TCQ designed for a lossless channel.

The trellis-based scalar-vector quantizer (TB-SVQ) for memoryless sources combines the scalar-vector quantizer (SVQ) with trellis coded quantization (TCQ) to achieve both boundary gain and granular gain. The resulting quantizer outperforms all other reasonable complexity fixed-rate quantizers. Unfortunately, the resulting code is catastrophic-a single bit error within a block can propagate indefinitely into other blocks. This correspondence presents a new trellis source code that can achieve essentially the same, or in some cases better, performance as the TB-SVQ for error-free channels, but limits the propagation of channel errors.