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authorJörg Frings-Fürst <debian@jff-webhosting.net>2014-09-07 13:29:54 +0200
committerJörg Frings-Fürst <debian@jff-webhosting.net>2014-09-07 13:29:54 +0200
commita879b4e708b3e46c9697ba6581687eeb5b02a320 (patch)
treef85acc5cb1a7c0b03a050c879c20cab3deb9f40e /doc/illumread.html
parent556dffcdad42b938bc196819aa463247de709765 (diff)
parentc07d0c2d2f6f7b0eb6e92cc6204bf05037957e82 (diff)
state from 2014-09-07 13:30 MESZ
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@@ -10,15 +10,11 @@
<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>
+ 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;">
@@ -26,6 +22,7 @@
style="font-family: monospace;" href="#v">-v</a><span
style="font-family: monospace;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;
+
&nbsp; &nbsp; Verbose mode</span><span style="font-family:
monospace;"></span></small><small><span style="font-family:
monospace;"></span></small><br style="font-family: monospace;">
@@ -34,46 +31,46 @@
style="font-family: monospace;" href="#S">-S</a><span
style="font-family: monospace;">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
-&nbsp;
- &nbsp; &nbsp; Plot
- the readings in a graph window.</span><br style="font-family:
- monospace;">
+ &nbsp; &nbsp; &nbsp; Plot the readings in a graph window.</span><br
+ style="font-family: monospace;">
<span style="font-family: monospace;">&nbsp;</span><a
style="font-family: monospace;" href="#c">-c comport</a><span
style="font-family: monospace;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
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
+
+ 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;">&nbsp;<a href="#N">-N</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Disable
+
initial calibration of instrument</span></font> if possible<br>
<font size="-1"><span style="font-family: monospace;">&nbsp;</span><a
style="font-family: monospace;" href="#H">-H</a><span
style="font-family: monospace;">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
- Use high resolution spectrum mode (if
- available)<br>
+ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Use high resolution spectrum mode
+ (if available)<br>
+ <font size="-1">&nbsp;<a href="#Yr">-Y r</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+ Set refresh measurement mode</font><br>
</span></font><font size="-1"><span style="font-family:
monospace;">&nbsp;<a href="#W">-W n|h|x</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Override
+
serial port flow control: n = none, h = HW, x = Xon/Xoff</span></font><br>
<small><span style="font-family: monospace;">&nbsp;</span><a
style="font-family: monospace;" href="#D">-D [level]</a><span
style="font-family: monospace;">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
- Print
- debug diagnostics to stderr</span></small><br>
- &nbsp;
- <font size="-1"><span style="font-family: monospace;"><a
+ Print debug diagnostics to stderr</span></small><br>
+ &nbsp; <font size="-1"><span style="font-family: monospace;"><a
href="#file"><span style="font-style: italic;">illuminant.sp</span></a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
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>
@@ -81,40 +78,26 @@ File
<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>
+ 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>
+ 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>
+ 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
+ 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
@@ -129,40 +112,39 @@ File
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>
+ 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="Yr"></a> The -<span style="font-weight: bold;">Y r</span>
+ option turns on refresh mode measurement, if the instrument supports
+ it. This may improve the repeatability of measurements of
+ illuminants that have a repetitive flicker.<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>
+ 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
+ <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>
+ 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>
+ 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>
+ 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>
@@ -173,74 +155,55 @@ File
4) Select another instrument, Currently 1 'usb:/bus4/dev2/
(GretagMacbeth i1 Pro)'<br>
5) Compute illuminant spectrum, average result with 0 previous
- readings
- &amp; save it<br>
+ readings &amp; save it<br>
6) Compute illuminant spectrum from this reading &amp; 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>
+ 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>
+ 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>
+ 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&nbsp; DTP41 would be suitable instruments, as
- long
- as they are not fitted with UV filters.<br>
+ in reflective mode with UV included. For instance, a Spectrolino,
+ Eye-One Pro, DTP20, DTP22 or&nbsp; 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>
+ 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>
+ 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>
+ 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;"
@@ -250,22 +213,15 @@ File
</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>
+ 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 45&ordm;, so that it's aperture has a clear
- view of
- the illuminated paper, but avoiding shadowing the region that is
- in
- view. <br>
+ 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 45&ordm;, 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:
@@ -273,33 +229,29 @@ File
</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>
+ 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>
+ 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>
+ 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: