Cross-Reference to Related Applications

[0001] This application claims priority from US Application No. 62/655042 filed 9 April 2018. For purposes of the United States, the application claims the benefit under 35 U.S.C. §1 19 of US Application No. 62/655042 filed 9 April 2018 and entitled PARTICLES FOR USE IN COLOR KEYING which is hereby incorporated herein by reference for all purposes.

Field

[0002] This invention relates to film, television, and photograph production.

Embodiments of the invention provide materials useful for color keying as well as methods and apparatus that are useful for creating composite images.

Background

[0003] Backdrops of particular colors of blue or green (“blue screens” or“green screens”) are commonly used in video, television, film, and photograph production. The subject of a scene (e.g. a person or an object) is placed in front of the blue or green screen as the subject is filmed or photographed by a camera. The blue or green screen reflects light of a specific color, which is picked up by the camera. Images of areas of the specific color of the screen can then be replaced with another image (e.g. an image of a desired scene or location). By replacing images of the specific color with different replacement images, a“layered” scene is created where the replacement image and the subject appear to be part of the same scene.

[0004] A common example of color keying is the weather segment of a television news broadcast, where a host is placed in front of a color key screen (usually a green screen). The green screen is replaced in real time with an image of one or more maps showing temperatures, a satellite image, or other weather information. The host appears to be in front of the map and is able to point to areas of the map, without the need for a physical map in the scene. That is, the host and the weather map are “layered” to appear to viewers as part of the same scene, even though the host is merely standing in front of a color key screen. [0005] Color keying is also used in video or film production. In a typical case actors perform in front of screens that are specific shades of green or blue. In post production areas of images that are colored the specific shade of green or blue are replaced with another image. This technique may be used for example to create a scene in which actors in a studio appear to be on a beach or in outer space or driving along a highway.

[0006] These methods are generally referred to as“color keying”. Specific variants of color keying include chroma keying and digital keying. The particular color of light reflected by the screen may be referred to as the“chroma key” or“digital key”.

[0007] Examples of commonly-used color keys include:

• RGB color value (0, 255, 0) (green)

• RGB color value (0, 0, 255) (blue). An example of a commonly-used digital key is RGB color value (0, 177, 64) (green). This color value is (81 , 0, 92, 0) in cmyk format, #00b140 as a hexadecimal color value, and corresponds to Pantone ^(TM) color 354C.

• RGB color value (68, 197, 83).

• Pantone ^(TM) 2728C (RGB color value (0, 71 , 187)) or

• Pantone 2735C (RGB color value (40, 0, 138))

• RGB color value (45, 36, 128).

Specific shades of green and blue are commonly used as color keys because these colors are less prominent in human skin tones and are less common in clothing. The terms“color keyed” and“color keying” should be interpreted to encompass both chroma keys and digital keys.

[0008] A problem with color keying is that the end effect is often not very realistic looking. Layered images of actors and replacement images can appear‘flat’ and unconvincing to viewers. The replacement images tend to be seen as being either entirely in front of or entirely behind the actors or other subjects of a scene.

[0009] There remains a need for new ways to create interesting effects in

photography, film and video production. Summary

[0010] This invention has a number of aspects. These aspects may be applied individually or in any combinations. These aspects include, without limitation:

• materials comprising color keyed particles that are useful, for example, for creating visual effects in film, video, and/or photographs;

• methods for performing color keying on specific areas of a scene; and

• methods for safely creating immersive scenes.

[0011] One aspect of the invention provides a method for color keying a scene. The method comprises providing a plurality of color keyed particles in one or more areas in the scene; filming the scene; and replacing, by a processor, images of the color keyed particles in the scene with one or more other images.

[0012] In some embodiments, replacing images of the color keyed particles with one or more images comprises receiving the filmed scene at the processor, inputting the color key of the particles to the processor, identifying pixels of the filmed scene with colors which match the color key and replacing the identified pixels with pixels representing the one or more images.

[0013] Another aspect of the invention provides a material useful for filmmaking comprising bulk particles having maximum dimensions of 2 cm or less. The particles are colored with one or more color key colors. Various embodiments are possible including:

• all of the particles are colored with the same color key color;

• the particles are colored with two or more color key colors (e.g. the particles may be a mixture of first particles colored with a first color key color and second particles colored with a second color key color;

• the particles may include some particles having a color key color and other particles having one or more other colors that are not color key colors.

[0014] In some embodiments, the material is colored in color key green or color key blue. In some embodiments, the color key is Pantone 354c or Pantone 2782c. In some embodiments, the color key is within ±5% of an RGB color value selected from the group consisting of: (0, 0, 255), (0, 255, 0), (0, 177, 64), (68, 197, 83), (45, 36, 128), (0, 71 , 187), and (40, 0, 138). [0015] In some embodiments, the particles, when softly packed, have densities in the range of 12 g/L to 45 g/L. In some embodiments, the particles, when dropped from a height of 4.9 m, take between 2 and 6 seconds to reach the ground.

[0016] In some embodiments, the particles are composed of paper, cardboard, cellulose, starch, and/or plastic. In some embodiments, the material may be dry, pourable, capable of floating on water, capable of falling slowly from a height, capable of flowing or blowing, biodegradable, fire retardant, non-static, non-abrasive, non toxic, and/or malleable.

[0017] Another aspect of the invention provides a material made up of small particles that are colored with a color key. Such a material may be used to create special visual effects as described herein. In some embodiments, the material is an artificial snow material. The material may, for example, be extruded from a mixture comprising starch 80-90% by volume, polyvinyl alcohol 10-15% by volume, talc 0- 2.5% by volume, hydrogenated soy flakes 0-2.5% by volume, and colorant.

Enumerated Example Embodiments

[0018] The following are some non-limiting enumerated example embodiments of the invention:

1 . A method for providing special effects in visual media, the method comprising:

color keying elements of a scene by providing a plurality of color keyed particles in one or more areas in the scene, individual ones of the color keyed particles having maximum dimensions of 2 cm or less and being uniformly colored with a color key color;

acquiring one or more color images of the scene; and

processing the one or more color images to replace portions of the one or more color images depicting the color key with alternative image content.

2. The method according to enumerated example embodiment 1 (or any other enumerated example embodiment) wherein providing the plurality of color keyed particles comprises dropping the plurality of color keyed particles into the scene from a height.

3. The method according to enumerated example embodiment 1 or 2 (or any other enumerated example embodiment) comprising creating air currents in the scene and allowing the air currents to move the color keyed particles while the scene is being imaged.

The method according to enumerated example embodiment 3 (or any other enumerated example embodiment) wherein the scene includes one or more actors and at least some of the air currents are created by motion of the one or more actors.

The method according to enumerated example embodiment 3 (or any other enumerated example embodiment) comprising blowing the particles through the scene.

The method according to any one of enumerated example embodiments 1 to 5 (or any other enumerated example embodiment) wherein the processing comprises:

indicating to a processor the color key color of the color keyed particles and receiving the one or more color images at the processor;

identifying parts of the one or more color images associated with the color key color; and

replacing the identified parts of the color images with corresponding prats of one or more alternative images.

The method according to any one of enumerated example embodiments 1 to 6 (or any other enumerated example embodiment) wherein the color keyed particles include first color keyed particles colored with a first color key color and second color keyed particles colored with a second color key color distinct from the first color key color.

The method according to enumerated example embodiment 7 (or any other enumerated example embodiment) wherein the first color keyed particles have a density different from a density of the second color keyed particles.

The method according to enumerated example embodiment 7 or 8 (or any other enumerated example embodiment) comprising replacing parts of the one or more color images having the first color key color with one or more first alternative images of the alternative image content and replacing parts of the one or more color images having the second color key color with one or more second alternative images of the alternative image content. The method according to any one of enumerated example embodiments 1 to 9 (or any other enumerated example embodiment) wherein the scene comprises a background and a subject located in front of the background and the method comprises providing some of the color keyed particles in a depth range that includes a depth of the subject.

The method according to enumerated example embodiment 10 (or any other enumerated example embodiment) wherein the method comprises providing the color keyed particles both in front of and behind the subject.

The method according to enumerated example embodiment 10 (or any other enumerated example embodiment) comprising providing a plurality of color keyed particles in areas corresponding to the background of the scene and areas located at the same depth as the subject.

The method according to any one of enumerated example embodiments 1 to 12 (or any other enumerated example embodiment) wherein the color key particles are colored green or blue.

The method according to any one of enumerated example embodiments 1 to 12 (or any other enumerated example embodiment) wherein the color key particles are colored Pantone 354c or Pantone 2728c.

The method according to any one of enumerated example embodiments 1 to 12 (or any other enumerated example embodiment) wherein the color key particles are colored within ±5% of an RGB color value selected from the group consisting of: (0, 0, 255), (0, 255, 0), (0, 177, 64), (68, 197, 83), (45, 36, 128), (0, 71 , 187), and (40, 0, 138).

The method according to any one of enumerated example embodiments 1 to

15 (or any other enumerated example embodiment) wherein the color key particles, when softly packed, have densities in the range of 12 g/L to 45 g/L. The method according to any one of enumerated example embodiments 1 to

16 (or any other enumerated example embodiment) wherein the color key particles, when dropped from a height of 4.9 meters above a ground level, take between 2 and 6 seconds to reach the ground level. The method according to any one of enumerated example embodiments 1 to

17 (or any other enumerated example embodiment) wherein individual ones of the color key particles have weights of less than 0.1 grams.

The method according to any one of enumerated example embodiments 1 to

18 (or any other enumerated example embodiment) wherein the color key particles are composed of a substance selected from the group consisting of: paper, cardboard, cellulose, starch, and plastic.

The method according to any one of enumerated example embodiments 1 to

20 (or any other enumerated example embodiment) wherein the method comprises floating the color key particles on water.

The method according to enumerated example embodiment 20 (or any other enumerated example embodiment) comprising stirring the water and allowing the particles floating on the water to move on the surface of the water.

The method according to any one of enumerated example embodiments 1 to

21 (or any other enumerated example embodiment) wherein the method comprises pouring the color key particles.

The method according to any one of enumerated example embodiments 1 to

22 (or any other enumerated example embodiment) wherein the color key particles have a form selected from the group consisting of: beads, pellets, grains, and flakes.

The method according to any one of enumerated example embodiments 1 to

23 (or any other enumerated example embodiment) wherein the color key particles comprise a biodegradable starch.

The method according to enumerated example embodiment 24 (or any other enumerated example embodiment) wherein the color key particles comprise fine fragments of a material extruded from a mixture comprising:

starch 80-90% by volume;

polyvinyl alcohol 10-15% by volume;

talc 0-2.5% by volume;

hydrogenated soy flakes 0-2.5% by volume; and

color key colorant. The method according to any one of enumerated example embodiments 1 to

25 (or any other enumerated example embodiment) wherein the alternative images comprise images of sleet, snow, hail, insects, sparks, fire, lava, ash, and/or dust.

The method according to any one of enumerated example embodiments 1 to

26 (or any other enumerated example embodiment) wherein the color images comprise video images.

The method according to any one of enumerated example embodiments 1 to

27 (or any other enumerated example embodiment) wherein the color images comprise digital images, the digital images comprising pixels associated with color values, the color values for pixels in the one or more digital images which image the color keyed particles in the scene being any of one or more color key color values.

The method according to enumerated example embodiment 29 (or any other enumerated example embodiment) comprising, in postprocessing step performed by a data processor, identifying pixels associated with the color key values and replacing the color values of the identified pixels with color values from corresponding pixels of the alternative image content

The method according to enumerated example embodiment 29 (or any other enumerated example embodiment) wherein the processing comprises generating one or more masks indicating positions of pixels associated with the color key color values.

The method according to enumerated example embodiment 29 or 30 (or any other enumerated example embodiment) wherein the processing comprises dilating the portions of the one or more digital images in which pixels are associated with the color key color values to include a buffer layer of adjacent pixels before replacing the portions of the one or more digital images with the alternative image content.

The method according to any one of enumerated example embodiments 28 to 31 (or any other enumerated example embodiment) wherein acquiring the digital images comprises obtaining film images and digitizing the film images. The method according to any one of enumerated example embodiments 1 to 32 (or any other enumerated example embodiment) wherein the scene includes a color key screen and the method comprises processing the digital images to replace parts of the images corresponding to the color key screen with one or more background images.

A material useful for filmmaking comprising bulk particles having maximum dimensions of 2 cm or less, the particles uniformly colored with a color key color.

A material according to enumerated example embodiment 34 (or any other enumerated example embodiment) wherein the color key color is green or blue.

A material according to enumerated example embodiment 34 (or any other enumerated example embodiment) wherein the color key color is Pantone 354c or Pantone 2728c.

A material according to enumerated example embodiment 34 (or any other enumerated example embodiment) wherein the color key color is within ±5% of an RGB color value selected from the group consisting of: (0, 0, 255), (0, 255, 0), (0, 177, 64), (68, 197, 83), (45, 36, 128), (0, 71 , 187), and (40, 0, 138). A material according to any one of enumerated example embodiments 31 to 34 (or any other enumerated example embodiment) wherein the particles, when softly packed, have densities in the range of 12 g/L to 45 g/L.

A material according to any one of enumerated example embodiments 34 to

38 (or any other enumerated example embodiment) wherein the particles, when dropped from a height of 4.9 m above a ground level, take between 2 and 6 seconds to reach the ground level.

A material according to any one of enumerated example embodiments 34 to

39 (or any other enumerated example embodiment) wherein individual particles of the material have weights of less than 0.1 grams.

A material according to any one of enumerated example embodiments 34 to

40 (or any other enumerated example embodiment) wherein the material is composed of a substance selected from the group consisting of: paper, cardboard, cellulose, starch, and plastic. A material according to any one of enumerated example embodiments 34 to

41 (or any other enumerated example embodiment wherein the material has one or more properties selected from the group consisting of: dry, pourable, capable of floating on water, capable of falling slowly from a height, capable of flowing or blowing, biodegradable, fire retardant, non-static, non-abrasive, non toxic, malleable.

A material according to any one of enumerated example embodiments 34 to

42 (or any other enumerated example embodiment) wherein the particles have a form selected from the group consisting of: beads, pellets, grains, and flakes. A material according to any one of enumerated example embodiments 34 to

43 (or any other enumerated example embodiment) wherein the particles comprise fine fragments of an extruded material comprising:

starch 80-90% by volume;

polyvinyl alcohol 10-15% by volume;

talc 0-2.5% by volume;

hydrogenated soy flakes 0-2.5% by volume; and

color key colorant.

An artificial snow colored with a color key and comprising fine fragments of a material extruded from a mixture comprising:

starch 80-90% by volume;

polyvinyl alcohol 10-15% by volume;

talc 0-2.5% by volume;

hydrogenated soy flakes 0-2.5% by volume; and

color key colorant.

The artificial snow of enumerated example embodiment 45 (or any other enumerated example embodiment) wherein the color key colorant is a green or blue colorant.

The artificial snow of enumerated example embodiment 45 (or any other enumerated example embodiment) wherein the color key colorant colors the artificial snow a color matching to Pantone 354c or Pantone 2728c.

The artificial snow of enumerated example embodiment 45 (or any other enumerated example embodiment) wherein the color key colorant colors the artificial snow a color that is within ±5% of an RGB color value selected from the group consisting of: (0, 0, 255), (0, 255, 0), (0, 177, 64), (68, 197, 83), (45, 36, 128), (0, 71 , 187), and (40, 0, 138).

49. The artificial snow according to any one of enumerated example embodiments 45 to 48 (or any other enumerated example embodiment) wherein the material has a water saturation 13% or less.

50. A method for producing color keyed particles, the method comprising:

mixing a base, a polyvinyl alcohol, a stabilizer and a softener to create a starch mixture;

extruding the starch mixture together with water and a color key colorant;

rendering the extruded starch mixture into small pieces; and smashing the pieces.

[0019] Further aspects of the invention and features of specific embodiments of the invention are described herein and/or illustrated in the accompanying drawings.

Brief Description of the Drawings

[0020] The accompanying drawings illustrate non-limiting example embodiments of the invention.

[0021] Figure 1 is a block diagram of a method for performing color keying on certain areas of a scene, according to one embodiment of the invention.

[0022] Figures 2, 3A, and 3B are representations of film scenes including color keyed particles, according to embodiments of the invention.

[0023] Figure 4 is a block diagram of a method for performing post-processing to replace color keyed particles in a film scene with a desired image.

[0024] Figure 5 is a schematic diagram of a production line for manufacturing color keyed particles.

[0025] Figures 6A and 6B show example color keyed particles.

Detailed Description

[0026] Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well-known elements have not been shown or described in detail to avoid unnecessary obscuring of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

[0027] One aspect of this invention provides a material useful for performing color keying on certain elements of a scene. The material is colored with a particular color key, for example, one of the specific color key values described above, such as chroma key or digital key green or blue colors mentioned above. A selected specific shade of red may also be used as a color key. The material is provided in the form of particles, such as flakes, beads, pellets, grains, or the like. References to one type of particle (e.g. flakes) herein should be interpreted as also applying to any of these other types of particles.

[0028] The particles may have a large surface area relative to their mass and/or volume. The particles may be one or more of dry, pourable, capable of floating on water, capable of falling slowly from a height, capable of flowing or blowing, and/or the like.

[0029] The material has applications in television production, film production, and still photography. Example embodiments described herein may refer to film scenes, but the material may also be used in a similar manner in still photography scenes.

[0030] Individual particles of the material in some embodiments have weights of less than 1/10 gram. Individual particles in some embodiments have a maximum dimension of 2 cm or less, 1 cm or less, ½ cm or less, ¼ cm or less, or 1 mm or less. In some embodiments, the material is provided in the form of a fine dust. In some embodiments, the particles are provided in a uniform size or size range. In other embodiments, a mixture of different sizes of the particles is provided in a particular scene.

[0031] The particles may have properties such that they do not damage cameras or other production equipment when blown through a scene or dropped from above a scene. For example, the particles may have one or more of the following properties:

• be soft or malleable;

• have sizes in the range of 1 mm - 2 cm;

• when softly packed, have densities in the range of 12 g/L to 45 g/L; • be non-abrasive;

• be non-toxic;

• be biodegradable;

• be anti-static (for example such that the flakes do not tend to cling to camera lenses or other equipment because of static electricity).

[0032] The particles may have properties (e.g. size, weight, etc.) such that when dropped from a height of approximately 4.9 m, the time they take to fall to the ground may be more than 2 seconds (e.g. falling rate of less than 2.5 m/s), or more than 2.5 seconds (e.g. falling rate of less than 2 m/s), or more than 3 seconds (e.g. falling rate of less than 1.5 m/s), or more than 4.5 seconds (e.g. falling rate of ~1 m/s), or more than 5.5 seconds (e.g. falling rate of less than 1 m/s). This property is particularly advantageous when it is desired for the particles to drop though a scene or to be blown through a scene. Denser particles that fall faster may be used alone or together with less-dense particles that fall more slowly to simulate phenomena such as hail or rain or streams of sparks.

[0033] Properties of the particles (e.g. shape, size, weight, etc.) used in a particular scene to be filmed may be selected based on factors such as the subject matter of the scene to be filmed, the type of images that will be used to replace images of the particles, the type of visual effect desired, whether the particles will be arranged on the ground, on an object, or drifted through the air, room temperature, humidity, and the like.

[0034] Advantageously, the particles are pourable in bulk and can be poured, piled, and arranged to provide areas in a scene that are uniformly colored in a color key.

[0035] In some embodiments, the particles are provided in the form of artificial snow (i.e. the particles have a snow-like appearance apart from their color at least when viewed from a distance) which has been dyed in a particular color key. For example, the particles may be dyed chroma key green, chroma key blue, digital key green, digital key blue, or any of the specific color keys mentioned above.

[0036] The particles may be made of any of a wide range of substances including paper (e.g. paper pulp, chemically-treated fireproof paper, etc.), cellulose, starch, plastic, etc. Figure 6A shows example particles made of cellulose paper pulp in different sizes (three rows on the left) and plastic (row on the right). Figure 6B shows example particles made of starch in different sizes.

[0037] Advantageously, the particles may be biodegradable. The particles may be non-static, such that individual particles do not tend to stick to each other or to people or objects in a scene.

[0038] Advantageously the particles do not burn readily. For example, the particles may optionally be made of a substance that tends not to burn readily and/or may optionally incorporate a fire retardant. Particles that are flame retardant may be desirable when the particles are to be used inside a building such as a film studio.

[0039] Particles as described herein may optionally be packaged in packaging suitable for storage and shipping such as in bags, boxes etc. In some embodiments the particles are provided in bags incorporating an anti-static material which helps to prevent the particles from sticking to one another or to the bags by static electricity.

[0040] One non-limiting example way to make suitable particles is described in US Patent No. 8470192 which is hereby incorporated herein by reference for all purposes. Another non-limiting example way to make suitable particles is to shred, cut, or otherwise break up a suitable material. The material may comprise, for example, sheets of cardboard, paper, plastic, or the like or kraft pulp or cellulose pulp. The material is colored in a color key. The material may be colored in the color key before or after it is broken up to provide color keyed particles.

[0041] While the coloring of the particles is advantageously incorporated into the substance (e.g. paper, plastic, etc.) of the particles themselves, for example by way of a dye or other colorant distributed throughout the substance of the particles, it is additionally or alternatively possible to provide a colored surface coating on the particles. Such surface coating may be achieved, for example, by spraying, dipping, or soaking the particles with the coating.

[0042] One aspect of the invention provides a method for using the particles described herein in a color keying process, for example in the context of post processing a film, video, or photograph. The method comprises the steps of providing the particles in a scene to be filmed, filming the scene (including the particles), and, in a post-processing step, replacing images of the specific color of the particles with another image or images. [0043] For example, in a particular scene which is to be filmed, the particles may be provided in piles, pools, clusters, or the like in desired locations in the scene. The specific color of the particles may then be replaced in a post-processing step with any desired image. For example, the particles may be replaced with images of water, fire, dirt, snow, ice, volcanic ash, sand, lava, embers, any color or pattern, or the like.

[0044] This method may be used to provide new visual effects. The particles may be used outdoors, potentially removing the need to color key the background of a scene (for example, as generally performed using a blue or green screen in traditional color keying) with a desired image. By replacing only certain parts of a scene (i.e. the particles placed in desired locations in the scene) while leaving the background intact (i.e. without color keying the entire background into the scene), more realistic scenes may be obtained.

[0045] In other embodiments, the particles may be dropped from a height and/or blown through a scene as the scene is filmed. For example, the particles may be in the form of flakes of colored artificial snow which fall through a scene as the scene is filmed. The flakes may optionally be caused to swirl or otherwise move by blowing air through the scene as the flakes fall. Replacing images of the flakes in a post processing step may produce images which are not obtainable using current color keying technology. For example, images of the flakes may be replaced by images of fire, ash, dust, sparks, lava, liquids, insects or the like.

[0046] Using the particles in this manner may thus be safer for people or objects in the scene, as they do not need to interact with potentially dangerous materials or substances (such as fire, ash, or the like). Using the particles in this manner may reduce the cost of filming a scene since the cost of obtaining and placing an ash-like substance or a liquid in the scene may be avoided.

[0047] Since the particles, when used in this manner, may interact with subjects in a scene (e.g. land on or move around people and objects in the scene), this method may produce more realistic images compared to visual effects currently used in the industry. This method may provide the illusion that the subjects in a scene are immersed in the images that replace the color key(s) corresponding to the particles. That is, an“immersive” scene may be created where subjects and particles can be at the same depth in a scene as opposed to a“layered” scene as is created in traditional color keying. Also, subjects may be able to interact with the particles. For example, movement of the subject may cause corresponding movements of the particles (and ultimately of the images that replace the particles). An actor may be immersed in a cloud of drifting or blowing particles in some cases.

[0048] Particles may land on actors or objects in the scene. Particles may move in response to motions of the actors or objects. Particles may be present at different depths in the scene, for example in front of, at the level of, and/or behind actors or objects. Particles may move in various directions while a scene is being filmed. For example the depth of the particles in the scene may change as a scene is filmed. The particles may, for example, be made to swirl around actors or objects in a scene by creating eddies in the air.

[0049] In other embodiments, the particles may be combined with traditional visual effects tools or props. For example, the particles may be provided together with flakes which simulate volcanic ash. Images of the color keyed particles may be replaced in a post-processing step with an image of embers or fire spaced throughout the volcanic ash flakes. Similar effects may be obtained by mixing the particles with dirt, snow, sand, or the like.

[0050] In addition, because the particles may be provided in locations which are small or dispersed compared to the subject of the scene, the risk of reflected light from the particles also reflecting off of the subject(s) and into the camera is reduced, compared to traditional color keying using a large blue or green screen.

[0051] Figure 1 shows an example method 10 for using a material as described herein for color keying specific areas or objects of a scene, according to one example embodiment of the invention. In this example embodiment, the material is provided in the form of flakes, and the scene is one for a film or video. In other embodiments, other types of particles may be used, and/or the scene may be one for still photography.

[0052] In steps 12A and/or 12B the flakes are provided in one or more locations in a scene to be filmed, as desired. Step 12A may be performed prior to the start of filming. Step 12A may involve placing the flakes in one or more locations in the scene. For example, the flakes may be provided in piles, pools, clusters, or the like; placed on or beneath one or more subjects (e.g. people or objects) in the scene etc. Step 12B may be performed before and/or after filming is commenced in step 14.

Step 12B may involve, for example, dropping the flakes from a height to fall through the scene, blowing flakes through the scene, tossing the flakes into the scene, advancing a pile of flakes into the scene, or the like.

[0053] An example of a simple scene 100 is shown in Figure 2. Scene 100 comprises a background 102, two subjects 104 (in this case, a person and a tree), and flakes 106. In the embodiment of Figure 2, flakes 106 are provided in three locations: in a pile 106A on the ground (i.e. on top of background 102) and in two locations 106B, 106C on one of the subjects 104 (i.e. the tree). When setting up a scene, flakes 106 may be vacuumed or scooped up if it is desired to remove flakes 106 from a particular location.

[0054] Figure 2 shows one frame of scene 100; subsequent frames of scene 100 may show subjects 104 in different positions, or may show more or fewer subjects 104. In some embodiments, flakes 106 may also move to different positions (e.g. flow, fall, blow, etc.) from frame to frame. In other embodiments, scene 100 may represent a still photograph, without subsequent frames.

[0055] In step 14 of method 10, scene 100 (including flakes 106) is filmed. Film lighting may be projected into scene 100, as is known in the art. Flakes 106 reflect only light of a certain color (a color key). In the embodiment shown in Figure 2, the flakes (and thus the reflected light) have an RGB color value of (0, 255, 0) (green). In other embodiments, the reflected light may have an RGB color value of (0, 0, 255) (blue), (0, 177, 64) (green), or any of the other color keys described above or another color key. This light is picked up by the camera filming scene 100.

[0056] In step 16 of method 10, images of flakes 106 in the filmed scene 100 are replaced with a desired image in a post-processing step. Because the color of flakes 106 is known, a processor may be instructed to replace all pixels of that color with pixels representing any static or moving image, as described in more detail below.

For example, in scene 100, the imaged flakes 106 in location 106A (the pile on the ground) may be replaced with an image of lava and the imaged flakes 106 in locations 106B and 106C (on the tree) may be replaced with images of fire. In some embodiments, in order to replace different imaged flakes with different images, different color keys may be used. For example, flakes in location 106A may have a green color key, and flakes in locations 106B and 106C may have a blue color key.

[0057] Post processing may process digital images or may use analog techniques to replace color key values. A wide range of postprocessing techniques that may be used to replace color key color values with alternative imagery are known and may be applied to practice the present invention.

[0058] Flakes 106 may be used on their own and/or in combination with a traditional blue or green screen. By using flakes 106 instead of a traditional green or blue screen, background 102 may be filmed naturally, instead of being color keyed into the image of scene 100 in a post-processing step. This may give the image of scene 100 a more realistic look. In addition, flakes 106 may replace dangerous materials or substances (such as lava or fire, in the embodiment shown in Figure 2) images of which are later color keyed into scene 100, thus making the filming safer for subjects 104.

[0059] Flakes 106 may be placed in any location or configuration in scene 100. For example, Figure 3A shows flakes 106 falling from above scene 100. Images of flakes 106 in Figure 3A may be replaced in step 16 of method 10 with images of ash, fire, snow, ice, insects, or the like, for example. Figure 3A differs from Figure 2 in that individual flakes 106 are filmed in Figure 3A, instead of clusters (e.g. piles) of flakes 106, as shown in Figure 2. As described above, flakes 106 may interact with subjects 104 as they fall through scene 100.

[0060] Figure 3B shows flakes 106 arranged in a long, thin strip. Images of flakes 106 in Figure 3B may be replaced in step 16 of method 10 with an image of a river, for example.

[0061] Figure 4 shows an example method 20 for performing the post-processing in step 16 of method 10; however, many different methods for performing step 16 are possible. Method 20 may be performed using any suitable processor, as is known in the art (for example on a desktop or laptop computer executing video or image editing software, or in a color grading station or a specialized digital post production suite).

In step 22, a filmed scene is received at the processor. For example, an image of scene 100 as shown in Figure 2 may be received by the processor (along with any subsequent frames of scene 100 not shown in Figure 2).

[0062] In step 24, a particular color key is input to the processor. That is, the known color key of flakes 106 in scene 100 is supplied to the processor. In step 26, the processor identifies all pixels in the image of scene 100 which have a color that matches the particular color key. In some embodiments, pixels with color values within a range of the particular color key (for example, ±1 %, ±2%, or ±5% of the RGB color value of the color key) may be identified as“matching” the particular color key.

[0063] In step 28, the processor deletes the identified pixels from the image of scene 100. In some embodiments, a“buffer” layer of pixels surrounding the identified pixels may optionally also be deleted, in order to account for errors in lighting or the like in scene 100. For example, for each pixel identified in step 26, each adjacent pixel (or a layer of 5 adjacent pixels, or 10 adjacent pixels, or the like) to the identified pixel may be deleted along with the identified pixel, to create a“hole” of deleted pixels which is slightly larger than the area of the color keyed flakes in the image of scene 100 as received by the processor in step 22.

[0064] In step 30, the processor replaces the deleted pixels with pixels which are appropriate to create any desired image, such as the images described above.

[0065] Steps 26 and 30 maybe combined. For example, steps 26 and 30 may be achieved by overwriting values of each identified pixel with corresponding values from the desired image. In some embodiments a mask image identifies locations of the identified pixels. The mask image may be used to identify parts of an image to be replaced with alternative image content and/or parts of the image not to be replaced with alternative image content.

[0066] Flakes as described herein may optionally be made by the process described in US 8470192 with the addition of a step where the flakes are colored in a selected color key, such as Pantone ^(TM) 2728c or Pantone ^(TM) 354c.

[0067] Figure 5 shows an example production line 200 for manufacturing flakes 106, according to one non-limiting example embodiment of the invention. Production line 200 has a source of a base such as starch 202, polyvinyl alcohol 204, a stabilizer such as talc 206 and a softener 207 such as soy flakes. These are mixed, for example, in an electric mixer 208, and fed into an extruder 210.

[0068] Water mixture 212 is added in extruder 210 to achieve suitable extrusion of the starch mixture. In an example embodiment, the starch mixture is extruded with a water saturation of up to 13%. In this example embodiment, the extrusion is performed at 170 °C and 600 psi through a 1 mm die.

[0069] The resulting extruded starch mixture has a crisp outer skin and an internal cellular structure that is highly porous and irregular. The extruded starch has a density of approximately 340 to 380 grams per cubic foot. The extruded starch has the form of a somewhat irregular cylindrical extrusion roughly ¾ inches in diameter.

[0070] Colorant 214 is added to the starch material. Colorant 214 is a suitably- colored, non-toxic colorant, having a particular color key. Colorant 214 may, for example, be mixed with the water injected in extruder 210 during the extrusion process. The amount of colorant 214 added can be selected to achieve a desired intensity of color. For example, in the embodiment of Figure 3A, where individual flakes 106 are filmed, it may be desirable to use flakes 106 which have a higher intensity of color, in order to ensure that sufficient light is reflected off of flakes 106, so their images can be properly replaced in step 16 of method 10. In embodiments where flakes 106 are provided in pools, piles, clusters, or the like (e.g. as in Figures 2 and 3B), a lower intensity of color may be used.

[0071] The extruded starch mixture, as extruded through a 1 mm die, is

approximately ¾ inches in diameter. Other die sizes may be used. The mixture is cut into small pieces (e.g. approximately 2 inches long) in a cutter 216. Cutter 216 may be integrated with extruder 210. The cut mixture is conveyed to a storage hopper 218. The extruded starch product is allowed to cool to ambient temperature.

[0072] The extruded starch product is then processed to create flakes 106. This may be done by smashing the extruded products in a smasher 220 and then sorting the resulting flakes 106 by size in a sorter 222. Flakes 106 may then be suitably packaged by a packager 224.

[0073] As described above, the color keyed particles need not be provided in the form of flakes 106. Different forms of particles may be most suitable for different applications and effects. The color keyed particles may be in the form of beads, pellets, grains, or the like. It is desirable that the color keyed particles have large surface areas relative to their mass, regardless of the exact form or shape that they are provided in. For example, the particles may have a ratio of surface area

(measured in cm ² ) to mass (measured in g) of at least 2:1 , or at least 3:1 , or at least 5:1 . This property allows for better light reflectance and facilitates easier storage, transport, and arrangement of the color keyed particles.

[0074] Color keyed particles may be packaged in bags, for distribution and use.

Optionally, the color keyed particles may be supplied in a range of different densities so that, when dropped, the particles fall through air at different speeds. Optionally, the color keyed particles are available in a range of different sizes which may facilitate different visual effects. In some embodiments, a mixture of color keyed particles of different densities and/or different sizes is dropped during filming of a scene. In some embodiments, a mixture of color keyed particles colored with different color keys are used in one scene. Different images may be introduced for each of the plural color keys in post-processing.

[0075] As will be apparent to those skilled in the art in light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof.

Interpretation of Terms

[0076] Unless the context clearly requires otherwise, throughout the description and the claims:

• “film” means acquiring an image and can encompass any of taking a movie with a film movie camera, taking still images with a film camera, taking videos or other moving video images, and taking still digital images. Digital images may be acquired directly using a digital camera or indirectly by digitizing images on film or other medium.

• “comprise”,“comprising”, and the like are to be construed in an inclusive

sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”;

• “connected”,“coupled”, or any variant thereof, means any connection or

coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, or a combination thereof;

• “herein”,“above”,“below”, and words of similar import, when used to describe this specification, shall refer to this specification as a whole, and not to any particular portions of this specification;

• “or”, in reference to a list of two or more items, covers all of the following

interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list;

• the singular forms“a”,“an”, and“the” also include the meaning of any

appropriate plural forms. [0077] Words that indicate directions such as“vertical”,“transverse”,“horizontal”, “upward”,“downward”,“forward”,“backward”,“ inward”,“outward”,“vertical”, “transverse”,“left”,“right”,“front”,“back� ��,“top”,“bottom”,“below”,“above”,“under� �, and the like, used in this description and any accompanying claims (where present), depend on the specific orientation of the apparatus described and illustrated. The subject matter described herein may assume various alternative orientations.

Accordingly, these directional terms are not strictly defined and should not be interpreted narrowly.

[0078] For example, while processes or blocks are presented in a given order, alternative examples may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or

subcombinations. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or may be performed at different times.

[0079] Where a component (e.g. a camera, screen, post-processor, imaging device, processor, conveyor, device etc.) is referred to above, unless otherwise indicated, reference to that component (including a reference to a“means”) should be interpreted as including as equivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments of the invention.

[0080] Specific examples of systems, methods and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to systems other than the example systems described above. Many alterations, modifications, additions, omissions, and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled addressee, including variations obtained by: replacing features, elements and/or acts with equivalent features, elements and/or acts; mixing and matching of features, elements and/or acts from different embodiments; combining features, elements and/or acts from embodiments as described herein with features, elements and/or acts of other technology; and/or omitting combining features, elements and/or acts from described embodiments.

[0081] It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, omissions, and sub-combinations as may reasonably be inferred. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.