What type of devices are used to measure color?
louis
am researching how color sensing is presently done. I have found the
following methods of measuring color:
a) Spectrophotometer devices, which use a diffraction grating to spread
the spectral energy, then using one or more sensors to measure the
energy of specific wavelengths. I understand that this can be used as a
colorimeter or densitometer. These seem to be the most descriptive and
precise of color sensors, and are used for scientific applications where
the presence or absence of a narrow spectrum of color is significant.
b) Devices which use individual light sensitive elements overlaid with
filters to sample the light. The responses of the light sensitive
elements are used to determine the nature of the light. These devices
can be used for colorimeters or densitometers, depending on the spectral
responsiveness of the filter/element combinations. These seem to be the
most common devices, used in scanners and video cameras. This seems to
be the preferred method of color detection for color reproduction,
taking advantage of the metameric nature of vision.
c) Devices which sequentially shine different colors of light onto a
sample, then use a single light sensitive element to determine the
intensity of the reflection from each pulse of light. I have only seen
one case of this type of device. It seems like a densitometer, but I am
not sure.
My questions are:
1) Does the above summarization of my findings indicate a accurate
(although admittedly limited) understanding of the nature of the
subject, or are there misconceptions apparent? (in other words: Hey, do
I to have it reasonably straight for a newbie, or am I totally out to
lunch?)
2) Are there other types of color sensors which I have overlooked? How
do they work? Where can I find more information?
3) Any recommended references? To date, I owe most of my understanding
to "Digital Color Management" by E.J. Giorianni and T. E. Madden, and to
various web sites.
Thank you.
Sincerely,
Louis Fuka