数字投影显示已成为现代数字显示领域的主流 ,阵列像素器件投影成像的的精确会聚 ,直接决定了显示的效果。阵列像素器件的自动对焦 ,是实现生产自动化的关键技术。以CCD(电荷耦合器件 )采集阵列像素器件的局部投影图像为基础 ,试验和分析了梯度算子、拉普拉斯算子、Sobel算子、Prewitt算子、方差函数和熵函数评价方法在阵列像素器件大屏幕投影显示系统中自动对焦的作用及性能。实验表明 ,方差算子具有良好的稳定性和对噪声的不敏感性 ,调节效果较好 ,可以作为这一特殊系统中的评价方法 Digital projection display has become the mainstream in the field of modern digital display. The accurate convergence of projection imaging of array pixel device directly determines the display effect. Autofocusing of array pixel devices is the key technology to automate production. Based on the local projection images of CCD (Charge Coupled Device) acquisition array, the gradient operator, Laplacian operator, Sobel operator, Prewitt operator, variance function and entropy function evaluation method are tested and analyzed in the array Pixel device large screen projection display system, the role and performance of auto-focus. Experiments show that the variance operator has good stability and insensitivity to noise, and the adjustment effect is good, which can be used as the evaluation method in this special system