Improving image encoding quality with a low-complexity DCT approximation using 14 additions

The quality of images is crucial in image and video compression, especially for resource-constrained systems that prioritize simplicity. To achieve fast and low-energy compression, such systems aim to strike a balance between image quality and computational complexity. While various Discrete Cosine Transform (DCT) approximations have been proposed, only two approximations with 14 additions are currently available. This paper presents a novel 8-point DCT approximation that improves image quality compared to the previous 14-addition transformations. Additionally, a pruned version is derived and shown to be efficient. The proposed approximation achieves an average quality gain of up to 1 dB while maintaining a similar computational structure to the previous transformations, resulting in comparable energy consumption. Therefore, this solution provides a compelling option for resource-constrained systems seeking efficient image compression while preserving high image quality.