{"id":417,"date":"2015-08-06T14:45:00","date_gmt":"2015-08-06T14:45:00","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/video-equipment\/uncategorized\/tv-cameras-and-analogue-colour-encodingimage-sensor-faceplate-configurations\/"},"modified":"2015-08-06T14:45:00","modified_gmt":"2015-08-06T14:45:00","slug":"tv-cameras-and-analogue-colour-encodingimage-sensor-faceplate-configurations","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/video-equipment\/tv-cameras-and-analogue-colour-encodingimage-sensor-faceplate-configurations\/","title":{"rendered":"TV CAMERAS AND ANALOGUE COLOUR ENCODING:IMAGE SENSOR FACEPLATE CONFIGURATIONS."},"content":{"rendered":"<div class=\"xhceu6a0dbb6d1bf07\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '61e5902552e2353963d8d2f1bd1f4a8f',\n\t\t'format' : 'iframe',\n\t\t'height' : 250,\n\t\t'width' : 300,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/61e5902552e2353963d8d2f1bd1f4a8f\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.xhceu6a0dbb6d1bf07 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.xhceu6a0dbb6d1bf07 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.xhceu6a0dbb6d1bf07 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.xhceu6a0dbb6d1bf07 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.xhceu6a0dbb6d1bf07 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h3 align=\"justify\">IMAGE SENSOR FACEPLATE CONFIGURATIONS<\/h3>\n<p align=\"justify\">Where it is required to get a full colour picture from a single image- sensor, there are several ways of arranging the colour \ufb01lter on its faceplate. One of several variants is shown in Fig. 6.7. Here the stripes run slantwise across the sensor face, yellow stripes (passing R and G) alternating with clear stripes in one direction, and cyan stripes (passing B and G) alternating with clear stripes in the other direction. At stripe crossover points only G light is permitted through to the faceplate. Consider the output signal during a random line <i>n<\/i>. It consists, as the line is scanned, of white (which is RGB), G, RGB etc. On the line <i>n <\/i>+ 1 below, the output sequence will be yellow, cyan, yellow, cyan, yellow etc., which is R + G, B + G, R + G, B + G etc. as shown in Fig. 6.7. The angle of the stripes is arranged such that the resultant from the yellow stripes comes 90\u00b0 <i>earlier <\/i>with each successive line scan, while the resultant from the cyan stripes comes 90\u00b0 <i>late<\/i><i>r <\/i>with each successive line scan. This gives rise to the offset between rows a\/b and c\/d in Fig. 6.7. Row a is the blue output for line <i>n<\/i>, and row b the red output for line <i>n<\/i>. When this signal is passed through a 1-line delay it will be available at the same time as the signals for line <i>n <\/i>+ 1, whose blue output is drawn in row c and whose red output is drawn in row d. Passing line <i>n <\/i>+ 1 through a simple 90\u00b0 <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-yDS8FnViPvI\/VcNyzPrUn0I\/AAAAAAAB0X0\/4fZIq2b_tMQ\/s1600-h\/TV%252520CAMERAS%252520AND%252520ANALOGUE%252520COLOUR%252520ENCODING-0093%25255B2%25255D.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"TV CAMERAS AND ANALOGUE COLOUR ENCODING-0093\" border=\"0\" alt=\"TV CAMERAS AND ANALOGUE COLOUR ENCODING-0093\" src=\"http:\/\/lh3.googleusercontent.com\/-2v1CoCysu5I\/VcNy014WVuI\/AAAAAAAB0X8\/lmbkKYMhdT4\/TV%252520CAMERAS%252520AND%252520ANALOGUE%252520COLOUR%252520ENCODING-0093_thumb.jpg?imgmax=800\" width=\"244\" height=\"222\" \/><\/a> <\/p>\n<p align=\"justify\">phase shift network renders waveforms e and f for blue and red respectively. It can be seen that whereas the B and R signals are in phase (i.e. time-coincident) in the delayed line <i>n <\/i>signal (rows a and b) they are in antiphase at the output of the 90\u00b0 phase shift network. Since the delay line has \u2018stored\u2019 row a\/b for exactly one scanning line, it and row e\/f are simultaneously available. Adding row a\/b to row e\/f will render 2 B (in-phase signals) while anti-phase R signals cancel out: at the adder output pure B appears. Subtracting row a\/b from row e\/f renders 2 R (R \u2013 [\u2212R]) while B cancels out (B \u2013 B = 0): at the subtractor output pure R appears. A more detailed account of delay- line matrix systems appears in the next chapter. <\/p>\n<p align=\"justify\">Since green is present at all times (<i>no <\/i>colour \ufb01lter in Fig. 6.7 stops G) it would appear that its presence would upset the B and R phase- recovery system. It does not, because whereas the B and R chroma signals appear at a high frequency of 3.9 MHz (the product of the line \u2018scanning rate\u2019 and the stripe repetition frequency), the constant G signal has no such high frequency carrier, and is lost in a band- pass \ufb01lter centred on 3.9 MHz. <\/p>\n<p align=\"justify\">Fig. 6.8 shows the essentials of the phase system of colour recovery. The signal is \ufb01rst preampli\ufb01ed in a low-noise stage, then passed into two \ufb01lters. A low-pass \ufb01lter with response up to about 3 MHz <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-ibAlHv_unBg\/VcNy2UC3CMI\/AAAAAAAB0YE\/dGpqZXAEJlA\/s1600-h\/TV%252520CAMERAS%252520AND%252520ANALOGUE%252520COLOUR%252520ENCODING-0094%25255B2%25255D.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"TV CAMERAS AND ANALOGUE COLOUR ENCODING-0094\" border=\"0\" alt=\"TV CAMERAS AND ANALOGUE COLOUR ENCODING-0094\" src=\"http:\/\/lh3.googleusercontent.com\/-D60MGPd1SHs\/VcNy34ubrsI\/AAAAAAAB0YM\/E7Jcptis6ME\/TV%252520CAMERAS%252520AND%252520ANALOGUE%252520COLOUR%252520ENCODING-0094_thumb.jpg?imgmax=800\" width=\"244\" height=\"101\" \/><\/a> <\/p>\n<p align=\"justify\">separates off the mean signal to give a luminance output for process- ing in the Y channel. The B and R chrominance signals are picked off in the 3.9 MHz \ufb01lter and applied to the 1 H delay line and 90\u00b0 phase shifter for separation in the adder and subtractor. Their outputs are integrated in a low-pass \ufb01lter which eliminates the 3.9 MHz car- rier and renders smooth, pure B and R chrominance signals for application to the encoder section described earlier. The letters at circuit points in Fig. 6.8 relate to the waveform rows in Fig. 6.7. There is no true <i>subtractor <\/i>circuit arti\ufb01ce available; in fact the subtractor stage works on an invert-and-add principle, which achieves the same result. <\/p><div class=\"nculu6a0dbb6d1c0f4\" ><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-0778475562755157\"\n     crossorigin=\"anonymous\"><\/script>\n<!-- 300x600 television-and-video -->\n<ins class=\"adsbygoogle\"\n     style=\"display:inline-block;width:300px;height:600px\"\n     data-ad-client=\"ca-pub-0778475562755157\"\n     data-ad-slot=\"6549443290\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.nculu6a0dbb6d1c0f4 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.nculu6a0dbb6d1c0f4 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.nculu6a0dbb6d1c0f4 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.nculu6a0dbb6d1c0f4 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.nculu6a0dbb6d1c0f4 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"zlnme6a0dbb6d1c00e\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '0c1eb4c533eaedb7b996f49a5a4983a9',\n\t\t'format' : 'iframe',\n\t\t'height' : 300,\n\t\t'width' : 160,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/0c1eb4c533eaedb7b996f49a5a4983a9\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.zlnme6a0dbb6d1c00e {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.zlnme6a0dbb6d1c00e {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.zlnme6a0dbb6d1c00e {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.zlnme6a0dbb6d1c00e {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.zlnme6a0dbb6d1c00e {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\">The phase-detection colour recovery system works well, but the necessity for the scanning lines to coincide with the crossover of the stripe-\ufb01lter matrix on the faceplate means that the sensor must be designed and speci\ufb01ed for the scanning standards to be used. <\/p>\n<h4 align=\"justify\">Step-energy colour recovery<\/h4>\n<p align=\"justify\">The use of vertical RGB \ufb01lter stripes in conjunction with a segmented target was described earlier in this chapter. An alternative vertical striping system was pictured in Fig. 5.16 with the primary-colour steps which appear in the output signal from the target. This arrangement is also applicable to solid-state image sensors. The combination of horizontal scanning rate and stripe spacing (hence repetition frequency) gives to the colour signals a carrier frequency of about <\/p>\n<p align=\"justify\">4.1 MHz. There are two possible methods of recovering R and B baseband chroma signals from the step waveform. The \ufb01rst (Fig. 6.9(a)) requires opposite-polarity recti\ufb01ers working on the upper and lower envelope pro\ufb01les followed by add\/subtract matrices to recover R\u2212Y and B\u2212Y signals. The second (Fig. 6.9(b)) involves the use of 4.1 MHz (fundamental) and 8.2 MHz (2nd harmonic) bandpass \ufb01lters; the 8.2 MHz signal is amplitude-limited and its <i>phase<\/i><i> <\/i>compared with that of the fundamental (4.1 MHz) component. Further \ufb01ltering take place before application to add\/subtract <\/p>\n<p align=\"justify\"><a href=\"http:\/\/lh3.googleusercontent.com\/-W8W7j-Yva4I\/VcNy5btanqI\/AAAAAAAB0YU\/nB8-2_f_Gjs\/s1600-h\/TV%252520CAMERAS%252520AND%252520ANALOGUE%252520COLOUR%252520ENCODING-0095%25255B2%25255D.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"TV CAMERAS AND ANALOGUE COLOUR ENCODING-0095\" border=\"0\" alt=\"TV CAMERAS AND ANALOGUE COLOUR ENCODING-0095\" src=\"http:\/\/lh3.googleusercontent.com\/-r4mKT5NgoKc\/VcNy7GO-H5I\/AAAAAAAB0Yc\/TsIzGXS0FfY\/TV%252520CAMERAS%252520AND%252520ANALOGUE%252520COLOUR%252520ENCODING-0095_thumb.jpg?imgmax=800\" width=\"244\" height=\"212\" \/><\/a> <\/p>\n<p align=\"justify\">matrices, which render modulated R and B carrier signals, restored to baseband by a synchronous demodulator for each. <\/p>\n<h4 align=\"justify\">Frequency discrimination colour recovery<\/h4>\n<p align=\"justify\">Another faceplate-\ufb01lter stripe con\ufb01guration is shown in Fig. 6.10(a). In this case the \ufb01lter colours are red and blue, and their widths are typically 61 \u03bcm for red, 47 \u03bcm for blue. This gives rise to different carrier frequencies for R and B; to further reduce crosstalk between the two the angle from vertical is made +15\u00b0 for R and \u221220\u00b0 for B. The result, at 625-line scanning rate, is a carrier frequency of 3.9 MHz for R and 5.1 MHz for B. The colour-recovery circuits here are very simple as Fig. 6.10(b) shows, but the performance of this arrange- ment is not as good as more sophisticated systems.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>IMAGE SENSOR FACEPLATE CONFIGURATIONS Where it is required to get a full colour picture from a single image- sensor, there are several ways of arranging the colour \ufb01lter on its faceplate. One of several variants is shown in Fig. 6.7. Here the stripes run slantwise across the sensor face, yellow stripes (passing R and G) [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/video-equipment\/tv-cameras-and-analogue-colour-encodingimage-sensor-faceplate-configurations\/\" class=\"more-link\" >Continue reading&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"aioseo_notices":[],"views":607,"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/417"}],"collection":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/comments?post=417"}],"version-history":[{"count":0,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/posts\/417\/revisions"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/media?parent=417"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/categories?post=417"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/video-equipment\/wp-json\/wp\/v2\/tags?post=417"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}