Lapped transform-based codec for frame-memory reduction in super-quality LCD overdrive

Overdrive is commonly used to reduce the liquid-crystal response time and motion blur in liquid-crystal displays (LCDs). However, overdrive requires a large frame memory in order to store the previous frame for reference. In this paper, a lapped transform-based codec (LTC) is proposed to reduce the frame memory needed for LCD overdrive. In the latest literature, a directional prediction-based codec (DPC) employs eight directional predictions, which takes up a large percentage of the computational complexity of the codec and does not consider the de-correlation of the inter-blocks. Therefore, the LTC first uses the lapped transform to decompose the correlation of the inter-blocks in the YUV color space. A hadamard transform is then used for energy compaction. The reordered coefficients are pre-quantized and encoded using the proposed adaptive bit-plane coding (ABPC) method for a simple hardware implementation. The simulation results show that the proposed LTC significantly improves the DPC in both subjective and objective performance and outperforms the block truncation coding (BTC) and adaptive multi-level BTC (AM-BTC), which have been described in the literature.