北京理工大學數(shù)碼相機性能評測實驗一視覺分辨率及空間頻率響應(SFR)測試

1、數(shù)碼相機性能評測實驗視覺分辨率及空間頻率響應（SFR測試實驗目的：1、理解數(shù)碼相機視覺分辨率的定義及其度量單位。2、了解數(shù)碼相機分辨率測試標準ISO12233以及GB/T 19953-2005數(shù)碼相機 分辨率的測量，熟悉測試標板構成，掌握其使用方法。3、掌握數(shù)碼相機視覺分辨率測試方法，能夠通過目視判別數(shù)碼相機的分辨率特 性。4、了解數(shù)碼相機空間頻率響應（SFR的測試原理，理解空間頻率響應（SFR 曲線的含義。5、掌握數(shù)碼相機空間頻率響應（SFR的測試方法，能夠通過 SFR曲線判別數(shù) 碼相機的分辨率特性。實驗要求：1、使用數(shù)碼相機拍攝ISO12233標準分辨率靶板,要求連續(xù)拍攝三幅圖。2、目視判

2、別數(shù)碼相機的視覺分辨率，需分別判別水平、垂直、和斜 45 度方向 的視覺分辨率 （ 注意：若拍攝的靶板有效區(qū)域高度僅占據(jù)相機幅面高度的一 部分，需將目視判別結果乘以修正系數(shù)以得到真實的測量結果。修正系數(shù) = 以像素為單位的相機幅面高度 /以像素為單位的靶板有效區(qū)域高度 ）。3、使用 Imatest 軟件測量數(shù)碼相機空間頻率響應（ SFR 曲線，需分別測量水 平及垂直方向的SFR并取MTF50 MTF20乍為測量結果，與視覺分辨率測 試結果進行比較。1、使用數(shù)碼相機拍攝ISO12233標準分辨率靶板,要求連續(xù)拍攝三幅圖 第一張圖I J r J1GTJ2 J 4:丿 -i卜! _?l 3 y QI

3、CL5rT2m=e二 0,=T2=苗 m 二勿t嚴勺-9岀f E9 L I n II II I三3 1 i 1 tA-|M I M M I 11 14 12 10 ft 水平條測中心垂直視覺分辨率1012豎直條測中心水平分辨率8/9對角線條測斜向上45視覺分辨率第三張圖的截圖:4 12 10 8水平條測中心垂直視覺分辨率101214豎直條測中心水平分辨率對角線條測斜向上45視覺分辨率相機型號iPhone5123平均值水平方向視覺分辨率1450128013301320垂直方向視覺分辨率1240122012601240斜向上45視覺分辨率900900900900實驗人員實驗日期2014.11.17

4、明確相機型號、相機基本設置。照相機制苣商Apple理相機型號iPhone 5光圖值f/2.4曝光時a1/30 秒工別謹度iso-sa嗯光補償0步豔焦距4 S米履犬進圈測光欖式碧目標?福丙光燈捕式無悶光】閃劃ns33強制3、使用Imatest軟件測量數(shù)碼相機空間頻率響應(SFR曲線，需分別測量水 平及垂直方向的SFR并取MTF50 MTF20乍為測量結果，與視覺分辨率測試結 果進行比較。過程由黑到白由白到黑次數(shù)1垂直 方向2垂直 方向3水平 方向4水平 方向5垂直 方向6垂直 方向7水平 方向8水平 方向分辨率(LW/PH)10881172158515421265130412441151均值(L

5、W/PH)1130156412851198第一次目視(LW/PH)1240145012401450實驗運行結果依次如下:IMG 2250.JPG0.2Nyquist fMTF: Horiz ontal w/NR00.81Io inwtEHj023-Nov-2014 17:31:27XLtIMVRFae e o pEEdge p rofile: Horiz ontalEdge -6.85 degsImatest 4.0.15 Image Se nsor3264 x 2448 p ixels (WxH)7.99 Mp xlsY-cha nnel (YA27)Gamma = 0.5010-90% r

6、ise = 2.35 p ixels =1042 per PHRGB rise = 2.38 2.35 2.28 p xlsRMS Edge rough ness = 0.0745 pxlsChart con trast = 10Gamma (from chart) = 0.755Lt, dk lvls = 217.2, 38.2 Lt/dk = 5.68ROI: 100x440 pixels27% above ctr-6-4-2024Pixels (Horizontal)10MTF50 = 0.222 Cy/Pxl=1088 LW/PH(RGB) = 0.22 0.222 0.23 Cy/P

7、 xl0.80.6MTF50 = 0.222 Cy/PxlMT.F20 = 0xl0.40.2Nyquist fMTF: Horizo ntal w/NR0.8Freque ncy, Cycles/pixelEvaluationwersitCf= 1088 LW/PHUn dersharpe ning 29.2%IMG 2250.JPGEdge profile: Horizorbta3264 x 2448 p ixels (WxH)7.99 Mp xlsEdge -6.83 degs_Y-cha nnel (YA21)Gamma = 0.5010-90% rise = 2.

8、09 pixels=1172 per PHRGB rise = 2.1 2.09 2.03 p xlsRMS Edge rough ness = 0.0739 pxlsChart con trast = 10Gamma (from chart) = 0.75Lt, dk lvls = 217.1, 38.6 Lt/dk = 5.62-ROI: 100x238 pixels21% above ctrV|2014 17:33:19-6-4-2Imatest 4.0.15 Image Se nsorBrrr210Pixels (Horiz on tal)Selected EXIF data0.80.

9、6MTF50 = 0.254 Cy/Pxl0.4MTF50 = 0.254 Cy/Pxl=1241 LW/PH(RGB) = 0.252 0.252 0.263 Cy/P xlEvaluationverson = 1241 LW/PHUn dersharpe ning 24.7%-Purchas丄MTF20 = 0.423 Cy/Pxlat www；Fmaetsi0.GomFrequency, Cycles/ pixelROI: 100x440 p ixelsL R T B = 1680 1779 460 899Edge an gle = -6.85 degsEstm. ch

10、art con trast = 32.3Selected EXIF dataROI: 100x238 pixelsL R T B = 1664 1763 691 928Edge an gle = -6.83 degsEstm. chart con trast = 31.6IMG 2250.JPGJ III -Edge p rofile: Vertical23-Nov-2014 17:42:22yfaen mf pp eaaEmvbff aen i ye r pp eadEdge 6.14 degsImatest 4.0.15 Image Se nsor.Y-cha nnel (YB9)Gamm

11、a = 0.503264 x 2448 p ixels (WxH)7.99 Mp xlsLt, dk lvls = 210.7, 30.4 Lt/dk = 6.93ROI: 363x87 p ixels9.3% below ctr10-90% rise = 1.59 p ixels =1537 per PHRGB rise = 1.6 1.59 1.6 p xlsRMS Edge rough ness = 0.0741 pxlsChart con trast = 10Gamma (from chart) = 0.841-6-4-20 2Pixels (Vertical)10ROI: 363x8

12、7 pixelsL R T B = 1435 1797 1370 1450.200-0.2MTF50 = 0.324 Cy/Pxl=1585 LW/PH(RGB) = 0.325 0.323 0.325 Cy/P xlvaluation5ve ps2oC?= 1585 LW/pHUn dershar pening 17.1%MTF50 = 0.324 Cy/PxlPu rchase aMTF: Vertical w/NR0.2Edge an gle = 6.14 degsEstm. chart con trast = 48Selected EXIF da

13、taMTF20 = 0.479 Cy/PxlWTFmates=t0comNyquist f0.40.6Frequency, Cycles/pixelEdge p rofile: Vertical-40.8IMG 2250.JPG23-NOV-2014 17:45:12卜，I L . J mJ.?Imatest 4.0.15 Image SensorY-cha nnel (YBR11)Gamma = 0.50Edge 6.35 degsROI: 280x155 p ixels11% below -R of ctrLt, dk lvls = 212.1, 30.1 Lt/dk = 7.053264

14、 x 2448 p ixels (WxH)7.99 Mp xls10-90% rise = 1.66 pixels =1473 p er PHRGB rise = 1.66 1.66 1.66 p xlsRMS Edge rough ness = 0.0809 pxlsChart con trast = 10Gamma (from chart) = 0.848-20 2Pixels (Vertical)10ROI: 280x155 p ixelsL R T B = 1597 1876 1349 1503Undersharpening 18.0%MTF50 = 0.315 Cy/Pxlvalua

15、tionpersoCn= 1542 LW/pHMTF50 = 0.315 Cy/Pxl=1542 LW/PH(RGB) = 0.317 0.313 0.316 Cy/P xlEdge an gle = 6.35 degsEstm. chart con trast = 49.7Selected EXIF data0.2MTF20 = 0.476 Cy/Pxl wimOtetsboom0.40.6Freque ncy. Cycles/pixelNyquist fMTF: Vertical w/NR0.810 imat巒FIMG 2250.JPGNyquist fMTF: Horiz ontal w

16、/NR0.81a imdtestd-60.8Edge p rofile: Horiz ontal-423-NOV-2014 17:23:46Imatest 4.0.15 Image SensorIIIp-Y-cha nnel (YA22)Gamma = 0.50Edge -6.61 degs3264 x 2448 p ixels (WxH)7.99 Mp xls10-90% rise = 2.10 pixels=1168 per PHRGB rise = 2.21 2.11 1.84 pxlsRMS Edge rough ness = 0.0845 pxlsChart con trast =

17、10Gamma (from chart) = 0.743Lt, dk lvls = 217.3, 39.3 Lt/dk = 5.53-ROI: 169x294 pixels22% above ctr-2024Pixels (Horizo ntal)MTF50 = 0.266 Cy/Pxl=1304 LW/PH(RGB) = 0.264 0.266 0.277 Cy/P xl10)t mdrts0.6EvaluatM!TFf0V e0-26ftC/1 = 1304 LW/PH,Un dersharpe ning 24.6%MTF50 = 0.266 Cy/Pxl0.4c ，、丄MTF20 = 0

18、.421 Cy/Pxl-Purchaseat wwwFOrtatesLGom0.2Nyquist fMTF: Horiz ontal w/NRFreque ncy. Cycles/pixel0.8IMG 2250.JPG23-Nov-2014 17:26:05ROI: 169x294 pixelsL R T B = 1533 1701 636 929Edge an gle = -6.61 degsEstm. chart con trast = 30.6Selected EXIF dataaenbrvel o 3 eodEEdge p rofile: Horiz ontalIm

19、atest 4.0.15 Image SensorIIIp-463264 x 2448 p ixels (WxH)7.99 Mp xlsY-channel (YA23)Gamma = 0.50Edge -6.6 degs10-90% rise = 2.21 pixels=1108 per PHRGB rise = 2.32 2.21 1.94 p xlsRMS Edge rough ness = 0.083 pxlsChart con trast = 10Gamma (from chart) = 0.752Lt, dk lvls = 217.2, 38.5 Lt/dk = 5.65-ROI:

20、126x418 pixels23% above ctr-2024Pixels (Horizo ntal)-610ROI: 126x418 pixelsL R T B = 1558 1683 537 9540.8MTF50 = 0.258 Cy/Pxl=1265 LW/PH(RGB) = 0.256 0.258 0.267 Cy/P xlEdge an gle = -6.6 degsEstm. chart con trast = 31.9Selected EXIF dataLtmvrfs0.60.4 EvaluatMonv 辭瀕=1265 圖Undersharpening 25.6%MTF50

21、= 0.258 Cy/Pxlr . MTF20 = 0.407 Cy/PxlPu rchaseat wwwFonOesbcom0.200Freque ncy. Cycles/pixelIMG 2250.JPGIhl I L - 一JEdge p rofile: Vertical23-Nov-2014 17:47:11Edge 5.91 degs7 3264 x 2448 p ixels (WxH)7.99 Mp xls_Y-cha nnel (YB15)Gamma = 0.50ROI: 216x117 pixels15% below ctr10-90% rise = 2.04

22、 p ixels =1202 p er PHRGB rise = 2.09 2.03 2.08 p xlsRMS Edge rough ness = 0.0779 pxlsChart con trast = 10Gamma (from chart) = 0.84Lt, dk lvls = 210.1, 30.4 Lt/dk = 6.91-6-4-20P ixels (Vertical)Imatest 4.0.15 Image Sensor t j g2Jr - :*H戶 J Q-I 亠JhhhIbv10ROI: 216x117 p ixelsL R T B = 1415 1630 1443 1

23、559XLtIMVRFS0.6ar / OKtlorp eaaE:;=7MTF50 = 0.254 Cy/Pxl=1244 LW/PH(RGB) = 0.252 0.252 0.268 Cy/P xlV EvaluatiOnF5Vers5OCT = 1244 LW/PHUn dersharpe ning 23.2%MTF50 = 0.254 Cy/P xlc .4 MTF20 = 0xlPu rchasat0.8 -Edge an gle = 5.91 degsEstm. chart con trast = 47.8Selected EXIF data0.4 r0.2 -Nyquist fMTF: Vertical w/NR000.20.6Freque ncy. Cycles/pixelEdge p rofile: Vertical-