Tag Archives: animation

How to Remove the Background from an Image (Part 1)

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In this post, I introduce a tutorial I created to show how to use Adobe Photoshop (CS5) to remove the background from an image.

Have you ever wondered how people superimpose graphs, isolated images, clip art, and other graphics onto another image so that they both have the same background?  You might wish to layer a series of images of plants or animals, for example, onto a map or a diagram so that they all share a common background.  To do this, you will have to delete the background of the original photographs (left-hand image below) so that when you layer the images onto a base photograph, they all have the same background (right-hand image below):

How is this done?  In the following tutorial, I show how easy it is to remove the background from this type of image in Photoshop.  This technique is a precursor to developing animations and montages of images in a video….so that the result looks professional.

Take a look (for best viewing, select the HD version and full-screen options (see menu bar at bottom of player window):

How to Make a Science Video Without Film Footage

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What if you would like to make a video about a topic but you don’t have a lot of footage?  Or perhaps you would like to describe a new technique, but have only still shots of your equipment and procedures.  Maybe you would like to describe a science concept, but have only audio of someone explaining their work?  Can you still make a video?  Of course.  In fact, there is an editing technique called “montage”, in which the videographer creates a narrative using a sequence of still images to tell a story.  This approach can be very effective, as this video illustrates:

You’ll note that in this video, “Congo River: Artery of the Forest”, the creators not only used montage, but also some other ideas I’ve discussed in previous posts.  Like many scientists, they had taken lots of pictures of various scenes and people, known a B-roll, which were the basis for this video.  As I described earlier, it’s important to shoot lots of still images and video footage in addition to your primary footage (e.g., interviews with key subjects), which can be used for opening and closing credit sequences, for transitions between video segments, and especially to break up long interviews (“talking heads”).

In addition to B-roll, the video also asks (and answers) a dramatic question:  “Will the scientists get their samples despite all the logistical challenges?” In a previous post, I explained the purpose of the dramatic question and why we should try to identify and incorporate the dramatic question into science videos.  The basic idea is to grab the viewer’s attention and keep them watching to see how things turn out.

Finally, it’s possible to mesh film clips with still images very effectively to create a more interesting video than one that is composed entirely of video clips.  In fact, by using a Ken Burns effect on still images, you can create the impression of movement, which blends well with film clips; the viewer often does not notice that the video contains a montage of still images. Here is one of my videos in which I used a combination of footage and still images (as well as animations) to explain sea-level rise and impacts on coastal wetlands (see minute 6:50 to 7:22 for one sequence):

In addition, you can also incorporate sound effects and voiceover to enhance a montage of still images. The “Congo River: Artery of the Forest” video does this very effectively (sounds of stamping along with passport images, for example).  In my video, I added sounds of water movement and frogs chirping to give life to still images.

So if you have an idea for a video, don’t be deterred by the lack of film clips. If you have still images of your research and a good dramatic question, you still can develop a compelling video.  In upcoming tutorials, I’ll show in greater detail how to incorporate the montage technique into your movie editing repertoire.

Bully Triangles and Terrified Circles

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There is an interesting video animation created by two psychologists, Fritz Heider and Mary-Ann Simmel, to illustrate the concept of “intentional causality”, whatever that is. In the video, there is a large rectangle, perhaps representing a house, a large aggressive triangle, a small triangle, and a terrified circle.  The triangles and circle appear to have intent and emotion, which the viewer senses based on the motions exhibited by these geometrical shapes.  Watch the animation and see what I mean:

The reason I find this interesting is the fact that the viewer is compelled to assign personalities to the geometric shapes and to also make up a mental “story” about what is happening in the video.  This seems ridiculous on the face of it.  Intellectually, we know that the animator is just moving these crudely drawn shapes around on the screen.  Yet, the movements of the objects contribute to the perception of intent and emotion.  Our minds are so receptive to this that we perceive these non-living objects as having personalities.  Psychologists interpret the viewer’s inclination to anthropomorphize the geometric “actors” as an inborn trait.  Infants apparently are capable of identifying bullies and victims and having expectations about pursuits they are shown.  In other words, humans are hard-wired from an early age to see causality, even when the interacting objects are simple geometric shapes.

What does this tell us about making effective videos?  Well, it tells us that people are willing to accept images, even crude representations, that appear to have “personalities” as being worthy of attention and empathy.  It also reveals our need to make up a story about whatever we are seeing and to become emotionally invested in the outcome.  Of course, I’m not telling you anything new.  We know how popular cartoons and animated features are.  Watching this very crude animation, however, drives home the point that using icons can be just as effective as using real people to deliver a message or tell a story.  I also recall reading somewhere (can’t put my hands on it right now) that the more iconic the image, the more the viewer is likely to accept the message.

Science Video Review: Up Your Nose

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Here’s a great video showing how a flu virus invades your body and replicates itself.

It’s informative but interesting; the narrators are funny even while talking about a serious subject; and there are excellent animations to illustrate what a virus might look like and how it gets a foothold in the tissues of your nose and throat.

Notice also how the narrator uses everyday language to describe what is being shown, followed by the correct terminology: “knobby things on the virus surface” = “keys”.  When the term “key” is introduced, there appear images of door keys along the surface of the virus, which drives home the idea of how the virus locks into the cell surface of a human throat cell.  Then as the virus makes contact with the cell surface, there is the sound of a lock turning. This is a brilliant use of visual and audio effects to help viewers learn and remember the lock and key concept of viral invasion. Later, when the narrator describes how viruses copy themselves, there are sounds and flashing lights resembling a copying machine as the animation shows new virus particles being produced.

The double-teaming narration is also very effective, using a conversation between the NPR interviewer (Robert Krulwich) and the medical illustrator (David Bolinsky) to describe the entire process of viral invasion and immune system response.  I found this approach to be very appealing because the interviewer is asking questions that a viewer might ask while watching the video.  What are those pink things?  Why is the virus doing that? When the interviewer gets an answer, he interprets it in everyday terms.

Nicely done!

Sources of Public Domain Images

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The scientist videographer will often have occasion to use a still image or video footage that s/he has not shot. If you plan to publish your video (on the internet or elsewhere), you will need to get permission to use anyone else’s images.  The exception is when the images are in the public domain.  Where do you find such image collections?  Government websites are a good place to start.  Many government agencies (in the U.S., for example) are creating collections of images and video that are freely available to the public.  In some cases, the images were taken by government employees or were acquired with government funds, automatically placing them in the public domain. In other instances, the agency has compiled scanned images from historical books, maps, and other sources into collections on their websites that can be searched and then downloaded for free.

Below, I list a few of these websites; the list is not exhaustive, but is designed to give you an idea of where to look for images and footage you might need.

U.S. Department of Agriculture (USDA) has a nice gallery of images, including topics such as animals, plants, field research, lab research, illustrations, and education; you can download images at 72 or 300 dpi. The image at right is of Giant Salvinia (USDA, Peggy Greb).

The National Oceanic and Atmospheric Administration (NOAA) has an extensive collection of images taken in a variety of places around the world by scientists and other employees; high resolution images are available. The photo to the right is of pancake ice taken by Michael Van Woert (NOAA, NESDIS) in Antarctica (located in the Art in Nature Gallery (Patterns and Textures)).

 

Related NOAA sites contain more still images, animations, and video. An example is the NGDC Digital Marine Geology and Geophysics Images collection, which contains, for example, animations of dives to the ocean floor such as the Mariana Trench (click on photo at right to go directly to the animation).

The NOAA Fisheries Service (Northeast Fisheries Science Center) maintains an archive of historical photos related to fisheries in the northeastern U.S.  Hundreds of photos are available for download and free use with proper credit.  See photo of a basking shark at right (NEFSC, Paul Galtsof).  There are also photo galleries of marine mammals, seabirds, invertebrates, sharks, ships, and scenic views.

 

The National Marine Sanctuaries maintains a media library containing still images and many video clips of coastal areas, waves, reefs, deep sea views, fish, sharks, and invertebrates.  The media library is searchable.

 

 

 

The NASA Goddard Space Visualization Studio is the premier location for finding photos and especially animations of the earth and space processes.  Whether you’re looking for animations of arctic sea ice changes or volcanic eruptions, you’ll find them here. The NASA Earth Observatory contains an extensive set of photos, maps, and animations of the world that are downloadable and free to use.  NASA’s Visible Earth contains a massive catalog of images and animations, which are searchable.  See a high resolution image of the Sri Lankan coast during the 2004 Asian Tsunami (NASA, VE) below:

If you are looking for images of hazards, land, oceans, atmosphere, life, snow and ice, or human impacts, these NASA sites will likely contain the image or animation you need.

 

Another site I often visit for historical photos is the Library of Congress (LOC).  Their American Environmental Photographs 1891-1936 collection is a treasure-trove of material. Many of the images in this collection were taken by or of Henry Chandler Cowles (the “father” of American plant ecology); see his photo to the right with students on a botany field trip (note they are all female students!) (LOC, unknown photographer). Interestingly, I can trace my scientific lineage through my graduate adviser and several generations of professors back to Cowles.

The U.S. Geological Survey (USGS) has a digital photo collection containing many historical and modern images of earthquakes, national parks, and mines.  See photo at right of an earthquake at Hawkes Bay, New Zealand (1931) (USGS, unknown photographer).  There is also a large collection of historical images taken by pioneer photographers of early USGS expeditions (see stereo photo below of an expedition camp, part of the W.H. Jackson collection).

These are just a few of the many government sites where you can find media in the public domain. There are some sites that purport to catalog public domain images, but beware. Many of these are commercial sites and contain a mixture of images grabbed from government sites (public domain) and images that may be copyrighted.  Try to obtain such media from their original sources, which often offer them at different resolutions and contain all relevant information about the image.  If you do use media from secondary sites, be sure the image is really in the public domain and abide by any restrictions listed with the image you wish to use. For the media offered for download on government sites, the only restriction is that you cannot copyright any public domain image, and it’s always appropriate to credit the source and the photographer, if their name is given.