资源描述：
《Brightness_and_Contrast.pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、CharlesPoyntonwww.inforamp.net/~poyntonpoynton@poynton.com“BRIGHTNESS”and“CONTRAST”controlsThisnoteintroducesthetwomainuseradjustmentsofavideomonitor,BRIGHTNESSandCONTRAST.Iexplaintheeffectthatthesecontrolshaveonpicturereproduction,andIexplainhowtose
2、tthem.Thisnoteappliestocomputermonitors,studiovideomonitors,andtelevisionreceivers.Unfortunately,thelabelsBRIGHTNESSandCONTRASTaremisleadingwithrespecttotheirfunctions:ThecontrolcalledBRIGHTNESSmainlyaffectsreproducedcontrast,andthecontrolcalledCONTR
3、ASTideallyaffectsonlybrightness!Themisleadinglabelshaveledtoagreatdealofconfusionabouthowtosetupamonitorforgoodreproduction.ThisiconindicatestheBRIGHTNESScontrol,moreproperlycalledBLACKLEVEL.Itaddsorsubtractsanoffset,orbias,intothered,green,andbluesi
4、gnals.Thiscontrolshouldbeadjustedsothatblackpicturecontentdisplaysastrueblackonyourmonitor.Misadjustmentofthiscontrolisthemostcommoncauseofpoorqualitypicturereproductiononcomputermonitors,videomonitors,andtelevisionsets.Laterinthisdocument,Iwillexpla
5、inhowtosetthiscontrolproperly.Thesettingissomewhatdependentuponambientlight.Moderndisplayequipmentissufficientlystablethatfrequentadjustmentisunnecessary.ThisiconindicatestheCONTRASTcontrol,sometimescalledPICTURE(orperhapsVIDEOGAIN).Itappliesascalefac
6、tor(gain)tothered,green,andbluesignals.Itaffectstheluminance(proportionaltointensity)thatisreproducedforafullwhiteinputsignal.OnceBRIGHTNESSissetcorrectly,CONTRASTshouldbesetforcomfortableviewingbrightness.Thisnotewasformerlycalled“BLACKLEVEL”and“PIC
7、TURE,”reflectingatimewhenIwasengagedinacampaigntogivethesecontrolsmean-ingfulandsensiblenames.I’msorrytoreportthatIhaveabandonedthatcampaign;however,Icontinuemyefforttoeducateusersandsystemdesigners.Copyright©2002-03-11Permissionisgrantedfornoncommerc
8、ialredistributionofthisdocumentinCharlesPoyntonitsentirety,includingthisnotice.Thelatestrevisionofthisdocumentisavailableatwww.inforamp.net/~poynton/notes/brightness_and_contrast/1of52“BRIGHTNESS”AND“CONTRAST”CONTROLScontrast(orpicture)Figure1CONTRAS
