Research On Realistic Graphics Rendering Algorithm Based On Pixel Plane Features

Under the framework of the Monte Carlo method to solve the rendering equation,the improvement of the ray tracing algorithm is still a very important part of the research content in photorealistic graphics.The distribution of samples in the pixel plane will have a greater impact on the rendering quality.Specifically,the Multiplexed metropolis light transport oriented by the brightness value,the acceptance rate of samples is low and the sampling is likely to be trapped in a local area;The Gradient-domain path tracing oriented by gradient value,the rendering quality of the generated image in different frequency regions is significantly different.Based on the above problems,this paper proposes two sampling strategies to adjust the sample distribution on the pixel plane.The first is the improved multiplexed Metropolis light transport based on fusion mutation strategy.On the one hand,this method introduces variance to evaluate the local brightness uniformity of the image,and adaptively modify the sampling step size,and finely sample in the uneven brightness area,and at the same time,enhance the ergodicity of the sample in the uniform brightness area;on the other hand,it also introduces a strategy that takes into account the number of sample and the image distribution to modify the sampling weight of the local area,and improve the algorithm’s rendering quality of the highlight area.Experimental results show that the improved algorithm can gather samples in uneven brightness areas for fine sampling,improve the asymmetry between the number of samples and the light distribution where the brightness changes sharply,and enhance the ergodicity of samples in uniform brightness areas.The second is the gradient-domain path tracing with gain control strategy.The method draws on the idea of non-uniform sampling in the first method,and introduces average gradient value to filter and mark the high and low frequency regions in the image,and assigns some samples of the low frequency region to the high frequency region.Experimental results show that,on the one hand,the introduction of the average gradient value can divide the image into regions quickly and efficiently;on the other hand,the improved algorithm makes the rendering of high-frequency regions sensitive to the human eye more delicate,speeds up the rendering convergence under the same sample size and improves the sampling efficiency.Through the research of this paper,it is found that whether in the rendering method based on the brightness value or the gradient value,adjusting the sample distribution on the pixel plane will affect the rendering efficiency and rendering quality.Under the established ray tracing method,Using samples allocation strategy on the pixel plane appropriately can make the rendering show better performance.