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diff --git a/doc/illumread.html b/doc/illumread.html new file mode 100644 index 0000000..03b5648 --- /dev/null +++ b/doc/illumread.html @@ -0,0 +1,319 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> + <head> + <title>illumread</title> + <meta http-equiv="content-type" content="text/html; + charset=ISO-8859-1"> + <meta name="author" content="Graeme Gill"> + </head> + <body> + <h2><b>spectro/illumread</b></h2> + <h3>Summary</h3> + Use an instrument or instruments to measure an illuminant spectrum, + including estimate + its Ultra Violet content. A combination of direct illumination + readings + and readings from a piece of paper having some FWA content are used + for + this. (If the UV content is not needed, or a suitable instrument is + not + available, then <a href="spotread.html">spotread</a> should be used + instead.)<br> + <h3>Usage Summary</h3> + <small><span style="font-family: monospace;">illumread [-options] + illuminant.sp</span><br style="font-family: monospace;"> + <span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#v">-v</a><span + style="font-family: monospace;"> + + Verbose mode</span><span style="font-family: + monospace;"></span></small><small><span style="font-family: + monospace;"></span></small><br style="font-family: monospace;"> + <small><span style="font-family: monospace;"></span><span + style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#S">-S</a><span + style="font-family: monospace;"> + + + Plot + the readings in a graph window.</span><br style="font-family: + monospace;"> + <span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#c">-c comport</a><span + style="font-family: monospace;"> +Set + COM port, 1..4 + (default 1)</span><span style="font-family: monospace;"></span><span + style="font-family: monospace;"></span><span style="font-family: + monospace;"></span></small><small><span style="font-family: + monospace;"></span></small><font size="-1"><span + style="font-family: monospace;"></span></font><font size="-1"><span + style="font-family: monospace;"><br> + </span></font><font size="-1"><span style="font-family: + monospace;"> <a href="#N">-N</a> +Disable + initial calibration of instrument</span></font> if possible<br> + <font size="-1"><span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#H">-H</a><span + style="font-family: monospace;"> + + + Use high resolution spectrum mode (if + available)<br> + </span></font><font size="-1"><span style="font-family: + monospace;"> <a href="#W">-W n|h|x</a> +Override + serial port flow control: n = none, h = HW, x = Xon/Xoff</span></font><br> + <small><span style="font-family: monospace;"> </span><a + style="font-family: monospace;" href="#D">-D [level]</a><span + style="font-family: monospace;"> + + Print + debug diagnostics to stderr</span></small><br> + + <font size="-1"><span style="font-family: monospace;"><a + href="#file"><span style="font-style: italic;">illuminant.sp</span></a> +File + to save measurement to<br style="font-family: monospace;"> + </span></font><small><span style="font-family: monospace;"></span><span + style="font-family: monospace;"></span></small><br> + <h3>Usage Details and Discussion</h3> + <b>illumread</b> uses a suitable instrument to read an illuminant + spectrum, and uses an indirect method to estimate the Ultra Violet + content of the illuminant, so as to provide better accuracy with <a + href="FWA.html">FWA + compensation</a>. An instrument or combination of instruments + capable + of spectral measurement of both + emissive measurement and reflective measurement without a U.V. + filter + is required for this.<br> + <br> + <a name="v"></a>The <b>-v</b> flag causes extra information to be + printed out during + chartread operation.<br> + <br> + <a name="S"></a>The <b>-S</b> flag enables the plotting of the + spectral + reflectance/transmittance values. You must select the plot window + and + strike a key + in it to continue with another measurement.<br> + <br> + <a name="c"></a> The instrument is assumed to communicate through a + USB or serial communication port, and the initial port can be + selected + with the + <b>-c</b> + option, + if the instrument is not connected to the first port. If you invoke + <span style="font-weight: bold;">illumread</span> + so as to display the usage + information (i.e. "illumread -?" or "illumread --"), then the + discovered + USB and serial ports will be listed. On + UNIX/Linux, a list of all possible serial ports are shown, but not + all + of them may + actually be present on your system.<br> + <br> + <a name="N"></a><span style="font-weight: bold;">-N</span> Any + instrument that requires regular calibration will ask for + calibration on initial start-up. Sometimes this can be awkward if + the instrument is being mounted in some sort of measuring jig, or + annoying if several sets of readings are being taken in quick + succession. The -<span style="font-weight: bold;">N</span> + suppresses this initial calibration if a valid and not timed out + previous calibration is recorded in the instrument or on the host + computer. It is advisable to only use this option on the second and + subsequent measurements in a single session.<br> + <br> + <a name="H"></a> The -<span style="font-weight: bold;">H</span> + option + turns on high resolution spectral mode, if the instrument supports + it. + See <a href="instruments.html">Operation of particular instruments</a> + for more details.<br> + <br> + <a name="W"></a>The <b>-W</b> <span style="font-weight: bold;">n|h|x</span> + parameter overrides the default serial communications + flow control setting. The value <span style="font-weight: bold;">n</span> + turns all flow control off, <span style="font-weight: bold;">h</span> + sets hardware handshaking, and <span style="font-weight: bold;">x</span> + sets Xon/Xoff handshaking. This commend may be useful in workaround + serial communications issues with some systems and cables. <br> + <br> + <a name="D"></a>The <b>-D</b> flag causes communications + and other instrument diagnostics to be printed to stdout. A level + can + be set between 1 .. 9, that may give progressively more verbose + information, depending on the instrument. This can be useful in + tracking + down why an instrument can't connect.<br> + <br> + <a name="file"></a>The <span style="font-weight: bold; font-style: + italic;">illuminant.sp</span> is + the name of the file to save the resulting illuminant spectrum to. + The + format used is <a href="File_Formats.html#.sp">.sp</a>.<br> + <br> + <hr style="width: 100%; height: 2px;"><br> + Unlike the other measurement utilities, <span style="font-weight: + bold;">illumread</span> doesn't connect to the + instrument until it is about to make a measurement. This allows for + the + possibility of using a different instrument for each measurement.<br> + <br> + It will display a menu:<br> + <br> + Press 1 .. 6<br> + 1) Measure direct illuminant<br> + 2) Measure illuminant reflected from paper<br> + 3) Measure paper<br> + 4) Select another instrument, Currently 1 'usb:/bus4/dev2/ + (GretagMacbeth i1 Pro)'<br> + 5) Compute illuminant spectrum, average result with 0 previous + readings + & save it<br> + 6) Compute illuminant spectrum from this reading & save result<br> + 7) Exit<br> + <br> + There are three measurements to be made, after which the illuminant + can + be computed and saved. Before each measurement, the instrument may + need + calibrating.<br> + <br> + The first measurement needs a spectral instrument capable of reading + in + an ambient or emissive mode. For instance, a Spectrolino, Eye-One + Pro + or ColorMunki would be suitable instruments.<br> + <br> + The second measurement needs a spectral instrument capable of + reading + in an projector or emissive mode. For instance, a Spectrolino, + Eye-One + Pro or ColorMunki would be suitable instruments.<br> + <br> + The third measurement needs a spectral instrument capable of reading + in + reflective mode with UV included. For instance, a Spectrolino, + Eye-One + Pro, DTP20, DTP22 or DTP41 would be suitable instruments, as + long + as they are not fitted with UV filters.<br> + <br> + To be able to estimate the level of Ultra Violet (UV) light in the + illuminant, a reasonable sized piece of white paper needs to be + used. + The paper should have some noticeable level of FWA (Fluorescent + Whitener Additive, or Optical Brightening Agents) in it, so that it + responds to UV light. A piece of cheap copier paper is ideal, since + cheap paper is typically whitened with large amounts of FWA. If the + paper is thin (less than 160 gsm) then two or three sheets should be + used to prevent any background showing through. [If the intention is + to + use the illuminant spectrum for proofing to a particular paper, then + an + alternative might be to use a piece of the intended paper for this + purpose. It's unclear which may give a better result.]<br> + <br> + The first measurement <span style="font-weight: bold;">1)</span>, + is + to use either the ambient or emissive measurement mode to measure + the + illumination directly.<br> + <br> + <div style="margin-left: 40px;">If the instrument supports an + ambient + measurement capability, then it will be used. If the insrument + does not + have an ambient mode, then an emissive measurement mode can be + used, + although typically many illuminants are too bright to directly + point + the instrument at. A work-around is to reflect the illuminant from + a + spectrally flat white surface. A good candidate for this is a + piece of + white, fine textured polystyrene foam. [The suitability of a + reflector + can be checked using <span style="font-weight: bold;">spotread -S</span> + to check that the reflection characteristic is close to flat.]<br> + <br> + <img style="width: 228px; height: 300px;" alt="Measuring Ambient" + src="illumread_1.jpg"><img style="width: 141px; height: 282px;" + alt="Measuring Ambient" src="illumread_2.jpg"> <img + style="width: 226px; height: 282px;" alt="Measuring Ambient" + src="illumread_3.jpg"><br> + </div> + <br> + The second measurement <span style="font-weight: bold;">2)</span>, + is + to measure the illuminant after it has reflected from the paper.<br> + <br> + <div style="margin-left: 40px;">This is done by placing the paper + such + that it is uniformly illuminated with reasonable brightness, and + then + placing the instrument so that it receives the reflected light + from the + paper. This is typically achieved by placing the instrument close + to + the paper at about 45º, so that it's aperture has a clear + view of + the illuminated paper, but avoiding shadowing the region that is + in + view. <br> + <br> + <img style="width: 219px; height: 261px;" alt="Measuring via + Paper" src="illumread_5.jpg"><img style="width: 252px; height: + 259px;" alt="Measuring via Paper" src="illumread_4.jpg"><br> + </div> + <br> + The third measurement <span style="font-weight: bold;">3)</span>, + is + to measure the paper directly using the instrument reflective mode + measurement.<br> + <div style="margin-left: 40px;"><img style="width: 186px; height: + 162px;" alt="Measuring Paper" src="illumread_6.jpg"><br> + </div> + If a different instrument is needed, use <span style="font-weight: + bold;">4)</span> to select from the available + instruments attached to your computer.<br> + <br> + Once these three measurements have been made, then the illuminant + readings spectrum + can be computed and save using <span style="font-weight: bold;">6)</span>, + or a series of readings can be made with each reading being averages + with the previous readings before saving it by using <span + style="font-weight: bold;">5)</span>. Note that the averaged + readings + will be weighted by their absolute intensities, and that while the + direct and indirect illumination needs measuring for each reading, + the + same paper measurement can be used each time.<br> + <br> + If plotting is enabled, a plot of the + measured (black) and with estimated UV (red) is plotted. This is + followed by a plot showing measured paper reflectance (black) and + the + FWA calculated paper reflectance (red).<br> + <br> + <br> + Illumread can then be terminated using <span style="font-weight: + bold;">7)</span>.<br> + <br> + <br> + <br> + <br> + <br> + <br> + <br> + <br> + <br> + <br> + <br> + </body> +</html> |