Abstract: Aiming at the problem of quantum image enhancement， a pseudo-color enhancement method for quantum images based on rainbow coding is proposed. Firstly， the NEQR （Novel Enhanced Quantum Representation） model is used to represent grayscale images， then the quantum circuit of the RGB three-channel color conversion module is designed and optimized， and finally the QRMW （Quantum Representation of Multi Wavelength Images） model is used to represent pseudo-color images. In order to verify the effectiveness of the proposed method， 2×2 and 32×32 NEQR grayscale images are prepared on the IBM quantum computing framework Qiskit， and QRMW pseudo-color images of corresponding sizes are generated by measuring the collapse of the quantum circuit. The experimental results show that， compared with the classical and existing quantum image pseudo-color enhancement methods， this method only requires 958 quantum fundamental gates when processing images with a size of 2n×2n and a color depth of 2q. The time complexity is constant-level O（1）， and the space complexity is O（2n+2q+3）， which significantly reduces the quantum cost， and the information entropy and sharpness indicators of the processed image are good.

Key words: quantum image processing, quantum computing, quantum image pseudo-color enhancement, rainbow coding