I need a word that describes two sensors that collect the same features, but in different ways. The raw data may be of different types, but the features would be the same. This word would imply that dodging one sensor does not help dodge the other sensor.

An example of two sensors that fit this criteria are visual cameras and infrared cameras. They both measure light with the purpose of seeing what is there, but an attempt to avoid one of them (ex: camouflage) will not help avoid detection by the other one.

I've considered both the words "orthogonal" and "complementary", but neither seems to fit. Orthognal implies that the sensors never detect the same thing and complementary seems to imply that one sensor always detects what the other doesn't.

Update: I should have mentioned that my target audience is mathematically minded people. When I use the words orthogonal or complementary, they will, in all probability, think of the mathematical definition.

  • @teylyn It was late and I'm a terrible speller. My humblest apologies.
    – cledoux
    Commented Jun 15, 2011 at 14:56
  • @karate, I really think the best answer is nothing more complicated than ... DUAL. In fact, dual with a hyphenation, such as simply "dual-wavelength" or "dual-process" or "dual-bandwidth" or whatever is relevant.
    – Fattie
    Commented Jun 15, 2011 at 15:48
  • @Joe Blow When using the @ in comments, please use the whole username. Otherwise the person the comment is directed towards doesn't receive notification of the comment.
    – cledoux
    Commented Jun 17, 2011 at 6:05
  • @karategeek6 Hi Karate! in fact on stackoverflow sites, it works so long as you match THREE letters ... notice Jeff Attwood's explanation ... meta.stackexchange.com/questions/1093/… It has worked like that for years on all the stackoverflow sites. Perhaps it has changed very recently? BTW with multi word names, say "joe blow", it stops working after any spaces anyway, so "@joe" is the only part worth typing.
    – Fattie
    Commented Jun 17, 2011 at 8:32
  • @kar ... in fact, regarding spaces, I just realised you can strip spaces. (But in any event, all you need is the first three characters.) Thus: to match Peter Smith you may use @pet ... or @petersmith From meta.stackoverflow.com/questions/43019/…
    – Fattie
    Commented Jun 17, 2011 at 8:36

4 Answers 4


Domain is often used in precisely the situation you describe. So you could call it a

dual-domain system

or you could also use "multi-domain system."

I also personally like milieu basically meaning the same, but even broader. I would say that a different milieu can be whole different paradigm—for instance, audio versus visual. A different domain tends to mean a hugely different metric within the same paradigm.

Redundant is also very close to what you are asking. Quite simply, redundant means a second independent system, which is after all exactly what you describe. I'm guessing a combination of redundant with something else is your best bet. "Two-channel" would also make a lot of sense to mathematicians.

Another approach here is hyphenating it, as in: "We defeated the stealth mechanism with the dual-mode vibration-radio detection device!" or for an ad brochure: "Redundant independent dual-mode multi-spectrum multi-system intruder detection!

My final candidates would be something like:

  • dual independent-domain detection (DIDD) system
  • dual-milieu detection (DMD) system
  • redundant sensors or doubly-redundant sensors
  • dual-mode sensors
  • dual-spectrum sensing or dual-spectrum detection
  • multi-detection sensors

As a final suggestion, you're probably making it hard for yourself by saying "sensors." If it's specifically a camera, heart-rate monitor, radar, or whatever, you'd do better to go with that specific term, since what you're trying to say is hard enough anyway.

  • The problem is, I need to be general. I'm in research and trying to describe a property that must hold for my technique to work. This technique does not rely on the sensors used, just the property described.
    – cledoux
    Commented Jun 15, 2011 at 6:27
  • I've tweaked the description a bit to better fit what I'm looking for. The change I made reflects the equivocalness of the sensors. I don't care what the raw data is, just that the features extracted are the same.
    – cledoux
    Commented Jun 15, 2011 at 6:28
  • BTW, the ad brochure line was quite clever :D
    – cledoux
    Commented Jun 15, 2011 at 6:29
  • @Joe Blow redundant complementary sensors... That just might work.
    – cledoux
    Commented Jun 15, 2011 at 15:56
  • @Joe Blow You raise some very interesting and valid points. The issue you raise with complementary was my original issue with it. I simply haven't found a word that fits better yet. I'll keep playing around with redundant though, something will fit eventually. I'm currently investigating the "two-channel" angle.
    – cledoux
    Commented Jun 15, 2011 at 17:52

It's a late suggestion, but you could use bimodal. Modality is used frequently in my former field of interface design to describe the mode of input or output (e.g., visual, vibrotactile, haptic). An interface that uses multiple modalities is referred to as "multimodal" and I think we applied similar terms to the sensor (non-human) inputs as well.

  • I don't see how it could apply to the two sensors separately, but perhaps if I refer to the system as whole...
    – cledoux
    Commented Jun 15, 2011 at 20:44
  • this is a great idea, Kit ....
    – Fattie
    Commented Jun 16, 2011 at 9:44
  • @karategeek6 You're right, it probably wouldn't work with two separate sensors, unless they were part of the same device (e.g., a bimodal motion detector might have both an infrared and a visible spectrum sensor).
    – Kit Z. Fox
    Commented Jun 16, 2011 at 12:20

If the sensors are correlated, the implication is that they will sens some things the same, some differently.

This is the closest one-word answer I can think of, but I don't think it is the best way to describe the relationship between the two kinds of sensors. Correlation might be used, but I think it needs to be embellished:

The sensors, though covering different wavelengths, will both result in detection of the object.

could be transformed to:

The detection success is correlated between the two sensors.

  • I'm not sure if it'll work or not, but it's a good idea none the less.
    – cledoux
    Commented Jun 15, 2011 at 17:54

Actually I would not disregard, according to WNWCD

complementary, adjective

  1. acting as a complement; completing
  2. making up what is lacking in one another



  • useful or attractive together

Applying either definition almost perfectly describes the relation between IR and visible spectrum camera:

Visual camera is complemented by IR camera.

The stricter sense of complement only applies in mathematics and in general usage is not implied (as neither is the specific grammatical sense of complement). In general sense complement is

a thing that contributes extra features to something else in such a way as to improve or emphasize its quality:

  • local ales provide the perfect complement to fine food.

I feel that the example would illustrate usual usage equally well with your case:

  • IR camera provides the perfect complement to visual camera.
  • Thanks for the feedback. If I can't find another word, I'll probably stick with complementary, but the problem is, I'm dealing with very mathematically minded people. It is almost guaranteed that they will think of the mathematical definition.
    – cledoux
    Commented Jun 15, 2011 at 15:04
  • @karategeek6, well there are two more choices, but I don't like them (ymmv): synergetic (was popular in scientific circles, but it is rather vague word: anything that works together as a system can be called synergetic as it will accomplish more then the sum of its parts), symbiotic (according to macmillan 2nd meaning applies to things as well, but I am sure you will be considered ignorant if you apply it to mechanisms and not organism).
    – Unreason
    Commented Jun 15, 2011 at 15:23
  • I went ahead and accepted your answer because I think complementary is the best single word I'm going to find. Now I go start brainstorming on a good phrase with the meaning I need. As things stand, I just use the word complementary and then explain what I mean by that.
    – cledoux
    Commented Jun 15, 2011 at 15:38
  • comments on down-vote, please?
    – Unreason
    Commented Jun 15, 2011 at 15:46

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