Over the last couple of weeks extra measurments were performed to better understand the working and limitations of the Phase Detection Auto Focus Pixels.\u00a0 The extra measurements focused on :<\/p>\n
– the influence of the exposure time on the PDAF pixel signals and the possibility to extract useful focusing information from it,<\/p>\n
– angular light dependency of the PDAF pixels.<\/p>\n
The new measurements are included in an update version of the report.\u00a0 The full report is still available through info (at) harvestimaging (dot) com.<\/p>\n
Below you find the table of contents of the updated version of the report.<\/p>\n
15-01-2016.<\/p>\n
Table of Contents<\/span><\/strong><\/p>\n <\/p>\n List of Figures<\/span><\/p>\n Introduction<\/span><\/p>\n Working principle of PDAF pixels<\/span><\/p>\n Theoretical implementation of PDAF pixels<\/span><\/p>\n Practical implementation of PDAF pixels<\/span><\/p>\n From the theory to the reality<\/span><\/p>\n Measurement 1 : influence of F-number<\/span><\/p>\n Measurement 2 : influence of the object distance<\/span><\/p>\n Measurement 3 : influence of the object angle<\/span><\/p>\n Measurement 4 : influence of the PDAF location on the sensor<\/span><\/p>\n Measurement 5 : influence of the object colour<\/span><\/p>\n Measurement 6 : Influence of exposure time<\/span><\/p>\n Conclusions<\/span><\/p>\n Appendix : angular dependency of the PDAF pixel sensitivity<\/span><\/p>\n Acknowledgement<\/span><\/p>\n References<\/span><\/p>\n \u00a0<\/span><\/p>\n List of Figures<\/span><\/strong><\/p>\n \u00a0<\/span><\/strong><\/p>\n Figure 1. Imaging with a positive lens<\/span><\/p>\n Figure 2. Requirement to have an image in-focus at the surface of the image sensor<\/span><\/p>\n Figure 3. illustration of rear focus, in-focus and front focus<\/span><\/p>\n Figure 4. Illustration of two different rear focus situations<\/span><\/p>\n Figure 5. Illustration of two different front focus situations<\/span><\/p>\n Figure 6. Optical ray formation from the object till the photodiode of an image sensor<\/span><\/p>\n Figure 7. Optical ray formation from the object till the partly optically-shielded photodiodes\/pixels of an image sensor<\/span><\/p>\n Figure 8. Aptina\u2019s MT9J007C1HS architecture with 9 rows containing auto-focus pixels based on phase detection<\/span><\/p>\n Figure 9. Microphotograph of one of the AF rows<\/span><\/p>\n Figure 10. Magnified view of an AF row<\/span><\/p>\n Figure 11. Microphotograph of an AF row<\/span><\/p>\n Figure 12. Sensor architecture indicating the various AF lines as well as the different zones used to read the sensor<\/span><\/p>\n Figure 13. Image taken from a random scenery with the AF option switched ON<\/span><\/p>\n Figure 14. Analysis of the signals of AF-line 5 in zone 5<\/span><\/p>\n Figure 15. Image taken from the same scenery as in Figure 13 with the AF option switched OFF and manually focused on the \u201cmacro\u201d position<\/span><\/p>\n Figure 16. Analysis of the signal of AF-line 5 in zone 5 in the case the AF system is forced to \u201cmacro\u201d position<\/span><\/p>\n Figure 17. Image taken from the same scenery as in Figure 13 with the AF option switched OFF, and manually focused on the \u201cinfinity\u201d position<\/span><\/p>\n Figure 18. Analysis of the signals of AF-line 5 in zone 5 in the case the AF system is forced to \u201cinfinity\u201d position<\/span><\/p>\n Figure 19. Odd and even PDAF signal for an object place 50 cm in front of the camera and the lens switched to auto-focus \u201cON\u201d<\/span><\/p>\n Figure 20. Odd and even PDAF signal for an object placed 50 cm in front of the camera and the lens focusing on \u201cinfinity\u201d<\/span><\/p>\n Figure 21. Odd and even PDAF signal for an object place 50 cm in front of the camera and the lens focusing on \u201cmacro\u201d<\/span><\/p>\n Figure 22. Depth-of-field as a function of the object distance for 3 F-numbers, the dotted lines indicate the corresponding hyper-focal distances<\/span><\/p>\n Figure 23 PDAF pixel shift as a function of F-number for an object 50 cm in front of the camera and auto focusing<\/span><\/p>\n Figure 24 PDAF pixel shift as a function of F-number for an object 50 cm in front of the camera and focusing at \u201cinfinity\u201d<\/span><\/p>\n Figure 25 PDAF pixel shift as a function of F-number for an object 50 cm in front of the camera and focusing at \u201cmacro\u201d<\/span><\/p>\n Figure 26 Front-focus situation<\/span><\/p>\n Figure 27. PDAF pixel shift as a function of object distance and auto-focus setting of the camera, with F2.8<\/span><\/p>\n Figure 28. PDAF pixel shift as a function of object distance and auto-focus setting of the camera, with F5.6<\/span><\/p>\n Figure 29. PDAF pixel shift as a function of object distance and auto-focus setting of the camera, with F11<\/span><\/p>\n Figure 30. PDAF pixel shift as a function of object distance, lens auto-focus setting on \u201cinfinity\u201d and with F2.8<\/span><\/p>\n Figure 31. PDAF pixel shift as a function of object distance, lens auto-focus setting on \u201cinfinity\u201d and with F5.6<\/span><\/p>\n Figure 32. PDAF pixel shift as a function of object distance, lens auto-focus setting on \u201cinfinity\u201d and with F11<\/span><\/p>\n Figure 33. PDAF pixel shift as a function of object distance, lens auto-focus setting on \u201cmacro\u201d and with F2.8<\/span><\/p>\n Figure 34. PDAF pixel shift as a function of object distance, lens auto-focus setting on \u201cmacro\u201d and with F5.6<\/span><\/p>\n Figure 35. PDAF pixel shift as a function of object distance, lens auto-focus setting on \u201cmacro\u201d and with F11<\/span><\/p>\n Figure 36. PDAF pixel shift as a function of object distance, lens focusing fixed at 60 cm and F2.8<\/span><\/p>\n Figure 37. PDAF pixel shift as a function of object distance, lens focusing fixed at 60 cm and F5.6<\/span><\/p>\n Figure 38. PDAF pixel shift as a function of object distance, lens focusing fixed at 60 cm and F11<\/span><\/p>\n Figure 39. PDAF pixel shift as a function of object angle and auto-focus setting of the camera, with F2.8<\/span><\/p>\n Figure 40. PDAF pixel shift as a function of object angle and auto-focus setting of the camera, with F11<\/span><\/p>\n Figure 41. PDAF pixel shift as a function of object angle, lens focusing on \u201cinfinity\u201d and with F2.8<\/span><\/p>\n Figure 42. PDAF pixel shift as a function of object angle, lens focusing on \u201cinfinity\u201d and with F11<\/span><\/p>\n Figure 43. PDAF pixel shift as a function of object angle, lens focusing on \u201cmacro\u201d and with F2.8<\/span><\/p>\n Figure 44. PDAF pixel shift as a function of object angle, lens focusing on \u201cmacro\u201d and with F11<\/span><\/p>\n Figure 45. PDAF pixel shift as a function of the PDAF location in readout zone 5 and auto-focus setting of the camera, with F2.8<\/span><\/p>\n Figure 46. PDAF pixel shift as a function of the PDAF location in readout zone 5 and auto-focus setting of the camera, with F11<\/span><\/p>\n Figure 47. PDAF pixel shift as a function of the PDAF location in readout zone 5 and lens focusing on \u201cinfinity\u201d and with F2.8<\/span><\/p>\n Figure 48. PDAF pixel shift as a function of the PDAF location in readout zone 5 and lens focusing on \u201cinfinity\u201d and with F11<\/span><\/p>\n Figure 49. PDAF pixel shift as a function of the PDAF location in readout zone 5 and lens focusing on \u201cmacro\u201d and with F2.8<\/span><\/p>\n Figure 50. PDAF pixel shift as a function of the PDAF location in readout zone 5 and lens focusing on \u201cmacro\u201d and with F11<\/span><\/p>\n Figure 51. Location of the various PDAF regions under test<\/span><\/p>\n Figure 52. PDAF pixel shift as a function of the PDAF location on AF-line 5 and on the diagonal with auto-focus setting of the camera and F2.8<\/span><\/p>\n Figure 53. PDAF pixel shift as a function of the PDAF location on AF-line 5 and on the diagonal with auto-focus setting of the camera and F11<\/span><\/p>\n Figure 54. PDAF pixel shift as a function of the PDAF location on AF-line 5 and on the diagonal with focus set to \u201cinfinity\u201d and F2.8<\/span><\/p>\n Figure 55. PDAF pixel shift as a function of the PDAF location on AF-line 5 and on the diagonal with focus set to \u201cinfinity\u201d and F11<\/span><\/p>\n Figure 56. PDAF pixel shift as a function of the PDAF location on AF-line 5 and on the diagonal with focus set to \u201cmacro\u201d and F2.8<\/span><\/p>\n Figure 57. PDAF pixel shift as a function of the PDAF location on AF-line 5 and on the diagonal with focus set to \u201cmacro\u201d and F11<\/span><\/p>\n Figure 58. Pulses used to measure the PDAF pulse shifts in zones 2 to 5 on the AF-line 5, lens focus at \u201cinfinity\u201d and F2.8<\/span><\/p>\n Figure 59. Incoming rays for a PDAF pair at the edge of the sensor<\/span><\/p>\n Figure 60. Pulses used to measure the PDAF pulse shifts in zones 2 to 5 on the AF-line 5, lens focus at \u201cmacro\u201d and F11<\/span><\/p>\n Figure 61. Odd and even pulses in AF-line 5, in AF-line 5 + 1 line and in AF-line 5 + 2 lines, with green light input, F2.8 and focusing at \u201cinfinity\u201d<\/span><\/p>\n Figure 62. Odd and even pulses in AF-line 5, in AF-line 5 + 1 line and in AF-line 5 + 2 lines, with green light input, F2.8 and focusing at \u201cinfinity\u201d<\/span><\/p>\n Figure 63. Odd and even pulses in AF-line 5, in AF-line 5 + 1 line and in AF-line 5 + 2 lines, with green light input, F2.8 and focusing at \u201cinfinity\u201d<\/span><\/p>\n Figure 64. PDAF pixel shift as a function of object colour and auto-focus setting of the camera, with F2.8<\/span><\/p>\n Figure 65. PDAF pixel shift as a function of object colour and auto-focus setting of the camera, with F11<\/span><\/p>\n Figure 66. PDAF pixel shift as a function of object colour, lens focusing on \u201cinfinity\u201d and with F2.8<\/span><\/p>\n Figure 67. PDAF pixel shift as a function of object colour, lens focusing on \u201cinfinity\u201d and with F11<\/span><\/p>\n Figure 68. PDAF pixel shift as a function of object colour, lens focusing on \u201cmacro\u201d and with F2.8<\/span><\/p>\n Figure 69. PDAF pixel shift as a function of object colour, lens focusing on \u201cmacro\u201d and with F11<\/span><\/p>\n Figure 70. PDAF pixel shift as a function of exposure time, with F2.8, focusing on \u201cmacro\u201d and white light input<\/span><\/p>\n Figure 71. PDAF pixel shift as a function of exposure time, with F2.8, focusing on \u201cmacro\u201d and green light input<\/span><\/p>\n Figure 72. PDAF pixel shift as a function of exposure time, with F2.8, focusing on \u201cmacro\u201d and blue light input<\/span><\/p>\n Figure 73. PDAF pixel shift as a function of exposure time, with F2.8, focusing on \u201cmacro\u201d and red light input<\/span><\/p>\n Figure 74. Angular dependency of the PDAF pixels under the influence of white light<\/span><\/p>\n Figure 75. Angular dependency of the PDAF pixels (corrected data) in combination with the sum of the PDAF pixel signals<\/span><\/p>\n Figure 76. Angular dependency of the PDAF pixels (corrected data) in combination with the green pixels signals from neighbouring red-green and blue-green rows<\/span><\/p>\n \u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":" Over the last couple of weeks extra measurments were performed to better understand the working and limitations of the Phase Detection Auto Focus Pixels.\u00a0 The extra measurements focused on : – the influence of the exposure time on the PDAF pixel signals and the possibility to extract useful focusing information from it, – angular light […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1521","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1521","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1521"}],"version-history":[{"count":5,"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1521\/revisions"}],"predecessor-version":[{"id":1526,"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1521\/revisions\/1526"}],"wp:attachment":[{"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1521"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1521"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/harvestimaging.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1521"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}