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Saturday, July 26, 2014

I Thought This Was Cool

Posted by jlwile on July 13, 2011

I am working on an elementary science series right now, and I am up the point where I am looking for images to use in the first book of the series. While looking for images that were constructed using infrared light, I came across this one and thought it was really cool (click for credit):

The image is what an infrared camera sees when it looks at a snake wrapped around a person’s arm.

Remember, human eyes are not sensitive to infrared light. However, you can make cameras that see only infrared light. Generally, these cameras show you the amount of infrared light they are seeing by using a color scheme. In the picture above, for example, blue colors mean the camera is receiving a small amount of infrared light, red colors indicate a medium amount of infrared light, and yellow colors indicate a lot of infrared light.

The person’s arm “lights up” in yellow, because he or she is warm-blooded and is therefore warmer than the surroundings. Because of this, energy must flow from the person to the surroundings, and it does so mostly in the form of infrared light. As a result, the person’s arm emits a lot of infrared light. The snake, however, is not much warmer than its surroundings, because it is not warm-blooded. So it doesn’t lose much energy to the surroundings. As a result, it doesn’t emit much infrared light.

Using an infrared-sensitive camera to make such images is called thermography, and it can be used for various purposes, including seeing people in the dark.

Now it turns out you don’t need a thermographic camera to “see” infrared light. A cheap digital camera (like a cell phone’s camera) is sensitive to infrared light and can even take pictures of it. To see this for yourself, get a television remote control and look at the end. You should see a bulb or a glassy area. That area emits infrared light signals, which send instructions to the television.

Aim a cheap digital camera at a television remote control and look at the remote’s bulb or glassy area using the camera’s screen. While you are looking at the camera’s screen, touch buttons on the remote. You will see the end of the remote light up, because it is sending out infrared light, and the camera “sees” the infrared light. If you look at the end of the remote just with your eyes, you won’t see anything. However, a cheap digital camera will “see” the infrared light coming from the remote.

Now you won’t see this effect with an expensive digital camera, but not because the camera’s light-detection system isn’t sensitive to infrared light. It most certainly is. However, expensive digital cameras have filters on the lens that absorb the infrared light before it hits the light-detection system. That way, the camera doesn’t take pictures of infrared light.

If you’ve ever wondered why your phone’s digital camera doesn’t take pictures that are as sharp as your good digital camera, this is one of the reasons. Even if both your phone’s camera and your good digital camera have the same number of megapixels, the pictures from your phone camera seem a bit less sharp than the pictures from your good digital camera, because your phone’s camera is recording infrared light. That adds “noise” to the photo, making it less sharp. A good digital camera filters out that noise, which produces sharper images.

Comments

12 Responses to “I Thought This Was Cool”
  1. Amanda Read says:

    I didn’t know that you were working on an elementary science curriculum. Exciting!

    ~ Amanda

  2. josiah says:

    While this is interesting, I’m more convinced by the idea that phone cameras produce lower quality photos because it’s just plain impossible to hold them still.
    Most cameras have the trigger button on the top and are grasped all around. The motion of the finger as you take the shot is directly into the camera and then into your hands, so while there could be a slight sheer it doesn’t move much. By contrast the phone is grasped close to the bottom with the trigger button above the top finger on your hand. The push therefore doesn’t ram into the support, but creates a moment around it. The phone turns by an angle rather than move by a distance, and given the range at which most shots are taken this angular movement tends to be very bad for the quality of the shot.
    My response is to use the 3 second delay whenever possible, so that I can stabilize my hands before the shot is actually taken.

  3. jlwile says:

    I hope others find it exciting as well, Amanda! I am actually field-testing the first book starting this academic year. For contractual reasons, I can’t do anything like that in the U.S. for a while, so people in New Zealand, Australia, and Canada will be the first to use this new series.

  4. jlwile says:

    That’s an interesting thought, Josiah. I had never really considered that, but it does make sense.

  5. The Black Sheep says:

    As you know, I think you have pretty odd taste when it comes to things you think are “cool.” However, you got me with the camera talk. I have to agree with Josiah, cameras on phones are notoriously annoying. Another thing is most expensive digital cameras (as well as some of the cheaper one, though I seriously doubt any phone cameras) have a “image stabilizer” built in. This helps reduce blurriness from hand movement when taking a photo. It’s particularly helpful for people, like my mom, who tend to be a little shaky in general. Or for me when I’ve decided to drink Red Bull and coffee in the same day.

  6. Debra says:

    This is great… :)

  7. jlwile says:

    Well, Black Sheep, even if the image didn’t grab you, I am glad the camera talk did!

  8. jlwile says:

    I am glad that you enjoyed it, Debra!

  9. Vivielle says:

    That picture is very neat! So I wonder if one took a picture of the snake wrapped around the arm immediately after the snake wrapped on the arm and then again, say 30 minutes later, if the snake would have changed color from blue to more yellow from being in contact with the warm human. I also noticed that the little bit of the belly of the snake that is visible is pink while the rest is blue.

  10. jlwile says:

    Vivielle, the snake would definitely get warmer, so it would start emitting more infrared light. I expect that it would mostly be near the surfaces that are in contact with the arm, however.

  11. megs says:

    This is one of the coolest pictures ever! Whoever took the photo had a great idea. Thanks for sharing.

  12. jlwile says:

    My pleasure, Megs!

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