Digitalimgaeprocessingisoneofthefastest-growingsubjectsininformationtechnologyinthepastdecades.Imagepre-processing,thebasisofdigitalimageidentificationandimageprocessing,playsanimportantroleinimageanalysis.Asoneofthemajortechniquesinimagepre-processing,themethodofkeepingthecolorsinvariantiswidelyusedinimageidentification,imagesegmentation，imageenhancementandimagecompressiontonormalizethepicturesinwhichcolorsmaychangeduetolightingconditions.Digitalimageprocessingisnowwidelyusedinaviationandastronautics,telecommunication,medicineandindustrialmanufacturing.Manymethodscanbeusedtokeepthecolorsinvariant. 　　Afteranalyzingandreviewingtheresultsofotherstudiesontheexistingalgorithmsforcolorinvariantsinimagepre-processingandcomparingthesealgorithms,thispaperchoosestodealwithhistogramequalizationanditerativemethodusingMatlab.Asamplingtestoftheabovetwoalgorithmsprovesthevalidityofthem.Alsoattmeptsaremadetoimprovethesetwoalgorithms. 　　Thetwoalgorithmsarecomparedintermsoftimeperformanceandefficacy.Finally,thesamplingtestleadstoavalidconclusion.Atthesametime,thispapersummarizethetwoalgorithmsbypointingouttheirprosandconsandproposesasolutiontoraisetheirprocessingspeed. 　　题主原文有些重复的地方，如下，我翻译时自己整合了一下。 　　并对详细的研究其中的迭代算法和直方图均衡化算法，利用MATLAB编程语言实现这两种算法，通过样本测试及分析其结果，以证明这些算法的有效性，并尝试对这些方法进行优化处理。 　　本论文详细地研究了上述算法，并用MATLAB实现了这些算法，通过样本测试及分析其结果，以证明这些算法的有效性。