Autofocus For Mobile Phone Camera Based On Machine Vision

As the rapid development of mobile phone industry, the digital camera function of themobile telephone is in more and more people’s good graces. The requirement for theresolution and definition of the CCD camera gradually becomes higher and higher. Thebuilt-in digital camera of mobile phone could take photo and video. This important additionalfunction becomes ripe and perfect in the techniques and effect.At present the manufacturing process for the digital camera of the mobile phone is in thecontinuous development. Most production lines still adopt traditional human visual estimationto focus the lens for the cell phone. The contract method of work is as follows, the laborersmanual rotate the lens until the position meets the clearest point. Then they judge the camerawhether meets the requirement of definition and get rid of rejected camera productions. Thequalified products will be sent to the next station to glue and solidify. The weakness for thisstatus easily brings about the vision tired for human eyes. The efficiency is in low level. Sincethe workers are in different subjective judgment and skill level, the quality of the productionwill be instability. As the level of salary for the workers keeps rising, it brings higher andhigher pressure to the factory.This article devotes to the research on the autofocus for mobile phone camera based onmachine vision. We mainly aim at the focus of the low pixels cameras and definitionestimation. The following functions would be realized in this paper:(1) Depend on the characteristics of the focus system for the mobile phones camera, thepaper chooses the appropriate test chart.(2) The paper researches on the technology of circle center location based on the circleregion of interest for the test chart. It aims at finding the exact circle center location andsetting the stage for the following detect algorithm.(3) The paper researches on the local definition estimation of the region of interest andthe whole picture. We adopt the variance function to provide the quantitative analysis. Weutilize the adaptive mountain-climb searching strategy to search the extreme point.(4) The paper designs the auto-focus system of the camera with different modules anddifferent functions. It provides a nice human-computer interaction, and enhances the stabilityand the robustness.As a result of the above researches and design, we structure the auto-focus system for thecamera of the mobile phone which can be used as a well-done test and check environment forthe focus function.