U.S. patent application number 13/362927 was filed with the patent office on 2013-08-01 for camera flash filter.
The applicant listed for this patent is Alan P. Lemke, John Mick, Shane D. Voss, Jason Yost. Invention is credited to Alan P. Lemke, John Mick, Shane D. Voss, Jason Yost.
Application Number | 20130195435 13/362927 |
Document ID | / |
Family ID | 48701463 |
Filed Date | 2013-08-01 |
United States Patent
Application |
20130195435 |
Kind Code |
A1 |
Yost; Jason ; et
al. |
August 1, 2013 |
CAMERA FLASH FILTER
Abstract
Embodiments disclosed herein relate to a camera flash filter. In
one embodiment, a processor determines an intensity of light to
filter through areas of the flash filter based on the lighting of a
scene. The processor may determine a color of light to filter
though the areas of the flash filter based on the determined
intensity of light to filter through the areas of the flash
filter.
Inventors: |
Yost; Jason; (Windsor,
CO) ; Mick; John; (Fort Collins, CO) ; Voss;
Shane D.; (Fort Collins, CO) ; Lemke; Alan P.;
(Fort Collins, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yost; Jason
Mick; John
Voss; Shane D.
Lemke; Alan P. |
Windsor
Fort Collins
Fort Collins
Fort Collins |
CO
CO
CO
CO |
US
US
US
US |
|
|
Family ID: |
48701463 |
Appl. No.: |
13/362927 |
Filed: |
January 31, 2012 |
Current U.S.
Class: |
396/164 |
Current CPC
Class: |
G03B 15/05 20130101;
G03B 2215/0589 20130101; H04N 5/2354 20130101; H04N 5/222 20130101;
H04N 5/23219 20130101 |
Class at
Publication: |
396/164 |
International
Class: |
G03B 15/03 20060101
G03B015/03 |
Claims
1. An apparatus, comprising: a camera; a flash; a spatially variant
flash filter to filter light emitted from the flash onto a scene;
and a processor to: determine an intensity setting for an area of
the flash filter based on the lighting of the scene; determine a
color setting for the area of the flash filter based on the
determined intensity of the area of the flash filter and the
lighting of the scene; and cause the area of the flash filter to
filter light according to the determined intensity setting and
color setting.
2. The apparatus of claim 1, wherein the flash filter comprises a
Liquid Crystal Display.
3. The apparatus of claim 1, wherein the processor further
determines an intensity setting and a color setting of a second
area of the flash filter, wherein at least one of: the color
setting of the second area is different than the color setting of
the first area; and the intensity setting of the second area is
different than the intensity setting of the first area.
4. The apparatus of claim 1, wherein determining the intensity
setting comprises determining the intensity setting based on an
image of the scene taken without filtering the flash.
5. The apparatus of claim 1, wherein determining the intensity
setting comprises determining the intensity setting based on a
depth map of the scene.
6. A method, comprising: determining an intensity of light to
filter through a first portion and a second portion of a filter of
a camera flash based on a target lighting of a scene; determining a
color to filter through the first portion based on the intensity of
light filtered through the first portion and the target lighting of
the scene; determining a color to filter through the second portion
based on the intensity of light filtered through the second portion
and the target lighting of the scene; filtering light through the
first portion based on the determined intensity and color for the
first portion; and filtering light through the second portion based
on the determined intensity and color for the second portion.
7. The method of claim 6, wherein the filter comprises a display
element.
8. The method of claim 7, wherein a determined difference in the
intensity between the first and second portion is based on a
difference in a target lighting of the background and foreground of
the scene.
9. The method of claim 7, wherein a difference in the color between
the first and second portion is determined based on a blue hue of
the flash on an a foreground area of the scene.
10. The method of claim 7, wherein determining the color setting
and intensity setting is based on a lighting characteristic of the
flash.
11. The method of claim 7, wherein determining the intensity
setting is based on a depth map of the scene.
12. The method of claim 7, wherein determining the intensity
setting is based on an image of the scene.
13. A machine-readable non-transitory storage medium comprising
instructions executable by a processor to: determine color settings
and intensity settings of areas of a camera flash filter to account
for lighting and color differences at different depths of a scene;
and cause the camera flash filter to filter according to the
determined color settings and intensity settings.
14. The apparatus of claim 13, wherein instructions to determine
color settings comprise instructions to cancel a blue hue of the
flash.
15. The apparatus of claim 13, wherein instructions to determine
intensity settings comprise instructions to determine the intensity
settings based on a lighting difference between a foreground and
background of the scene.
Description
BACKGROUND
[0001] A camera may include a flash for providing light to a scene
to be photographed. For example, a scene may be dark, and a flash
may illuminate a dark scene so that it appears more visible in the
photograph. In some cases, a flash may include a filter in front of
it for adjusting how the lighting from the flash illuminates the
scene. For example, a neutral density filter may be used to modify
the intensity of light wavelengths of the flash.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] The drawings describe example embodiments. The following
detailed description references the drawings, wherein:
[0003] FIG. 1 is a block diagram illustrating one example of a
camera with a spatially variant flash filter.
[0004] FIG. 2 is a flow chart illustrating one example of varying
the light intensity and color settings of different areas of a
flash filter.
[0005] FIG. 3A is a diagram illustrating one example of a camera
with a spatially variant flash filter photographing a scene.
[0006] FIG. 3B is a diagram illustrating one example of a table of
light intensity and color settings of different areas of a flash
filter.
DETAILED DESCRIPTION
[0007] A camera flash may include a filter for filtering the light
emitted from the flash. In one embodiment, a flash filter provides
spatial color and intensity differentiation for the flash lighting.
The filter may have different color and intensity settings for
different areas of the filter which may providing for lighting
intensity and color differences at different portions of the scene
to be photographed. For example, the filter may be adjusted to
account for lighting and color differences in the foreground and
background of the scene.
[0008] The filter may be placed in front of the flash such that
areas of the filter may alter the light from the flash differently.
The intensity of the light allowed through an area of the filter
may control the portion of the scene lit by the area of the filter.
For example, a first area of the filter may allow more light
through and the more intense light may light farther back in the
scene, and a second area of the filter may allow for less light
through and the less intense light may provide light to a portion
of the scene closer to the camera. The amount of light at different
intensities may change how much light from the flash illuminates a
particular depth of the scene. For example, if a smaller portion of
the filter blocks more light, the light from the filter may provide
more light to areas of the scene farther from the flash than if a
larger portion of the filter blocks more light. The color allowed
through the different portions may allow for different colors of
light to illuminate the different depths of the scene. For example,
the portion of the filter allowing for greater light intensity to
illuminate the scene at a greater depth may have a color filter for
the target color at that depth of the scene. The spatially variant
flash filter may allow a flash to better control the amount and
color of illumination at different areas of the scene.
[0009] FIG. 1 is a block diagram illustrating one example of a
camera with a spatially variant flash filter. The camera 100 may be
any suitable camera, such as a still or video camera, for capturing
an image of a scene. The camera 100 may be a digital camera. The
camera 100 may be a separate camera or a camera associated with
another electronic device, such as a camera on a mobile computing
device.
[0010] The camera 100 may have a flash 103. The flash 103 may
provide light to a scene to be captured by the camera 100. For
example, the flash 103 may provide light for a photograph to be
taken, such as where the natural light of the scene causes parts of
an image to appear dark or discolored. The flash 103 may be any
suitable flash for providing light to a scene, such as a Light
Emitting Diode (LED) or Xenon flash.
[0011] The flash 103 may include a spatially variant filter 104
overlaying it. The spatially variant filter 104 may allow different
intensities and colors of light from the flash to be emitted
through different portions of the filter. The spatially variant
filter 104 may be a pixilated display element where a pixel or
group of pixels may filter light for a particular area of the
scene. In one example, the spatially variant filter 104 is a Liquid
Crystal Display (LCD) flash filter where a Liquid Crystal Display
is placed in front of the flash 103 to control how light is emitted
on the scene. For example, the Liquid Crystal Display may control
the intensity and color of light emitted on the scene based on
different areas of pixels of the Liquid Crystal Display filter. The
spatially variant filter 104 may include an array of pixels in
which the pixels do not emit light themselves, but may modulate
light passing through them. Each of the pixels may be, for example,
one or more liquid crystals.
[0012] In some implementations, the flash 103 and spatially variant
filter 104 are combined into the same element. For example, the
element providing the spatially variant characteristic may also
include a light source for the flash.
[0013] The filtering performed by the spatially variant filter 104
may be altered by the processor 101. The flash 103 and spatially
variant filter 104 may be attached to the camera or may communicate
with the processor 101 through a wired or wireless connection. The
processor 101 may execute instructions stored in the
machine-readable storage medium 102. The processor 101 may be any
suitable processor, such as a semiconductor-based microprocessor,
or any other device suitable for retrieval and execution of
instructions. In one implementation, the camera 100 includes logic
instead of or in addition to the processor 101. As an alternative
or in addition to fetching, decoding, and executing instructions,
the processor 101 may include one or more integrated circuits (lCs)
(e.g., an application specific integrated circuit (ASIC)) or other
electronic circuits that comprise a plurality of electronic
components for performing the functionality described below. In one
implementation, the camera 100 includes multiple processors. For
example, one processor may perform some functionality and another
processor may perform other functionality.
[0014] The machine-readable storage medium 102 may be any suitable
machine readable medium, such as an electronic, magnetic, optical,
or other physical storage device that stores executable
instructions or other data (e.g., a hard disk drive, random access
memory, flash memory, etc.). The machine-readable storage medium
102 may be, for example, a computer readable non-transitory medium.
The machine-readable storage medium 102 may include instructions
executable by the processor 101.
[0015] The machine-readable storage medium 102 may include
instructions executable by the processor 101 to adjust the
spatially variant filter 104. For example, the machine-readable
storage medium 102 may include instructions to determine intensity
settings and color settings of areas of the spatially variant
filter 104 to account for spatial differences in the lighting of a
scene. For example, portions of the spatially variant filter 104
may filter light such teat it reaches a first distance into the
scene and a second portion of the spatially variant filter 104 may
filter light such that it reaches a second distance into the scene.
The instructions may include instructions to determine how areas of
the spatially variant filter 104 should light different areas of
the scene. The instructions may include instructions for altering
how color is emitted from the areas of the spatially variant filter
104 based on the area of the scene to be lit by the area of the
spatially variant filter 104.
[0016] The machine-readable storage medium 102 may include
instructions to determine an intensity setting for an area of the
spatially variant filter 104 based on the lighting of the scene.
Areas of the spatially variant filter 104 may block more light
allowing a lower intensity of light through such that it reaches
the foreground of the scene. Another area of the spatially variant
filter 104 may block less light allowing a greater intensity of
light through such that it reaches the background of the scene. The
foreground of the scene may receive more lighting from the flash
where more areas of the filter allow a lower intensity of light
through, and the background may receive more lighting where more
areas of the filter allow a greater intensity of light through. The
amount of light intensity allowed through different areas of the
spatially variant filter 104 may depend on the existing lighting of
the scene and where additional lighting is desirable in the
scene.
[0017] The machine-readable storage medium 102 may include
instructions to determine a color setting for the area of the
spatially variant filter 104 based on the determined intensity of
the area of the spatially variant filter 104 and the lighting of
the scene. For example, the color allowed through a portion of the
spatially variant filter 104 may depend on the desired color for
the depth of the scene reached by the intensity of light allowed
through at that portion of the spatially variant filter 104.
[0018] The machine-readable storage medium 102 may include
instructions to cause the area of the spatially variant filter 104
to filter light according to the determined intensity setting and
color setting. For example, the spatially variant filter 104 may be
a display element, and the processor may send a signal to the
spatially variant filter 104 to display according to the determined
settings. The processor 101 may cause a first portion of the
spatially variant filter 104 to display according to an intensity
setting and color setting and may cause a second portion of the
spatially variant filter 104 to display according to a different
intensity setting and color setting.
[0019] FIG. 2 is a flow chart illustrating one example of varying
the light intensity and color settings of different areas of a
flash filter. For example, a processor may determine color settings
and intensity settings of areas of a camera flash filter to account
for lighting and color differences at different depths of a scene
and cause the camera flash filter to filter according to the
determined color settings and intensity settings. The method may be
used to account for differences in different flashes. For example,
a first group of settings may be determined for a first flash for a
scene, but the settings may be updated if a new flash is attached
to the camera. A processor may determine intensity and color
settings for the pixels of a spatially variant flash filter and
cause the pixels to be updated according to the determined
settings. The intensity of light allowed to pass through areas of
the filter may be adjusted to provice different amounts of light to
different portions of a scene, and the color illuminated through an
area of the filer may be adjusted based on the portion of the scene
lighted by the particular area of the filter. Having different
portions of the filter with different filter settings may allow the
filter to provide different types of lighting and color to
different portions of the scene. The method may be implemented, for
example, by the processor 101 of FIG. 1.
[0020] Beginning at 201, a processor determines an intensity of
light to filter through a first portion and a second portion of a
filter of a camera flash based on a target lighting of a scene. The
flash filter may be any suitable filter, such as the spatially
variant filter 104. The flash filter may modulate light emitted
from another light source or may alter how light is emitted from
the flash filter. Filtering the same amount of light through the
entire filter may cause some areas of the scene to be overexposed
and some areas of the scene to be underexposed, such as where the
lighting is correct for one area but over exposes another area. The
camera flash filter may alter the intensity of fight illuminating a
scene based on a target amount of light in different areas of the
scene. For example, the foreground of the scene may have more
existing light than the background, and as a result the filter may
allow more light to be filtered through to the background.
[0021] As an example, a Liquid Crystal Display filter may allow for
the foreground and background of a scene to have different lighting
by adjusting the intensity of the Liquid Crystal Display pixels
such that the pixels have different intensity levels. Adjusting the
color setting of the individual pixels may make the color to appear
better in the scene.sub.--
[0022] The intensity of light to allow through the portions may be
determined in any suitable manner. In one implementation, a
processor analyzes a depth map of the scene to determine how to
vary the intensity of light allowed through different portions of
the filter. A depth map may make items in a scene appear
differently based on their distance from the camera. For example,
items may appear lighter or darker in the depth map image based on
their distance from the camera. The depth map may reveal how much
of the scene is at each of the different depths. The depth map may
be created by the camera or may be created by another processor and
sent to the camera. The size of the area of the filter to allow
light through at different intensities may be determined using the
depth map. In one implementation, it may be determined not to allow
light to filter through to reach beyond a particular depth in the
scene, for example, to avoid illuminating dust and other particles
with the higher intensity light that would be used to reach the
farther depths of the scene.
[0023] In one implementation, a processor analyzes an image of the
scene taken with a first flash setting to determine how to vary the
intensity of light allowed through different portions of the
filter. For example, the first flash setting may be a flash setting
without filtering to allow a large amount of light to illuminate
the scene. The processor may analyze the image to determine how to
make intensity adjustments to the flash filter. For example, the
processor may analyze the white balance of the image taken with the
first flash setting.
[0024] The processor may determine which areas of the filter to
filter a particular intensity of light in any suitable manner. For
example, the processor may determine a size of an area or
percentage of the filter for filtering light at a particular
intensity, and the processor may then determine where on the filter
to create the area of the determined size to filter at the
determined intensity.
[0025] FIG. 3A is a diagram illustrating one example of a camera
with a spatially variant flash filter photographing a scene. The
camera 309 may photograph a scene 305 with a flash having a flash
filter 300 overlaying it where the flash filter 300 includes areas
301, 302, and 303. The flash filter 300 areas 301, 302, and 303 may
correspond to, for example, a pixel or group of pixels of the flash
filter 300. Each of the areas 301, 302, and 303 allow light through
the filter at a different intensity level. The area 301 is larger
than the areas 302 and 303, indicating that more light passes
through the filter at the intensity level associated with the area
301.
[0026] . FIG. 3B is a diagram illustrating one example of a table
of light intensity and color settings showing different areas of
the flash filter 300. For example, area 301 is associated with high
intensity lighting, area 302 is associated with medium intensity
lighting, and area 303 is associated with low intensity lighting.
Greater intensity light may reach a greater depth into the scene
305. For example, the area 301 of the flash filter 300 may
illuminate area 306 of the scene 305, area 302 of the flash filter
300 may illuminate area 308 of the scene, and area 303 of the flash
filter 300 may illuminate area 307 of the scene. Because area 301
is larger with more light passing through at the greater intensity,
the area 306 of the scene 305 farther in the background may receive
more light from the flash than the areas 307 and 308 closer to the
foreground in the scene 305. In some cases, some depths of a scene
may not be lit by the flash, such as because the area is too far
from the camera or because it is undesirable to provide additional
light to a particular depth of a scene. For example, the area 306
may be too far from the camera 309 to receive light from the
flash.
[0027] Referring back to FIG. 2 and continuing to 202, the
processor determines a color to filter through the first portion
and second portion based on the intensity of light filtered through
the portions and the target lighting of the scene. In some cases,
the flash may be a white light flash, and the filter may alter the
color of different areas of light emitted from the flash. For
example, a first portion of the flash filter allowing for a light
intensity for reaching the background of the scene may alter the
color of the light passing through the first portion in a manner
tailored to the background. A second portion of the flash filter
allowing for a lesser light intensity for reaching the foreground
of the scene may alter the color of the light passing through the
second portion of the filter in a manner tailored to the
foreground.
[0028] In one implementation, the color may be altered to adjust
for colors caused by the flash. For example, a Light Emitting Diode
flash may cause a greater blue hue closer to the camera than
farther from the camera, and the filter may cancel out the blue hue
closer to the camera. Areas of the filter allow for greater
intensity of light to pass through for the background may cancel
the blue hue of the flash less. The processor may determine how to
adjust the light based on the lighting of a scene and may adjust
differently according to a particular camera or type of flash. In
one implementation, the color may be adjusted for artistic effect,
and the artistic effect color may be adjusted according to the
depth in the scene.
[0029] FIG. 3B shows a different color number associated with each
of the different areas of the flash filter. For example, the area
301 illuminating the background area 306 of the scene 305 filters
color differently than the area 303 illuminating the foreground
area 307 of the scene 305. As an example, it may be desirable to
color adjust for faces in a scene differently than the background
of a scene. In the scene 305, the faces in the areas 307 and 308
may be colored differently than the background in the area 306 by
providing different color adjustment in the areas 302 and 303 of
the filter providing light at an intensity that reaches the depth
of the scene where the faces are located.
[0030] Proceeding to 203, the processor causes the filter to filter
light through the first portion and second portion based on the
associated determined intensity and color. As one example, a
processor provides information to a transistor associated with a
pixel or area of the filter such that the transistor sends a signal
to the pixel or area to alter their light modulating properties.
The processor may provide different instructions to different
transistors such that the transistor provides different signals to
the area or pixels associated with them. The filter may be a Liquid
Crystal Display filter, and the signals may cause the liquid
crystals associated with the pixel to change the manner in which it
modulates color and intensity. In some cases, the processor may
send a signal to one transistor associated with multiple areas such
that the transistor provides the same or different signals to the
different areas associated with the transistor. The processor may
cause the filter to be updated with the determine settings such
that a first area of the filter allows a first intensity and color
of light to pass through and a second area of the filter allows a
second intensity and color of light to pass through. The scene may
be illuminated where different portions of the scene receive
different amounts and different colors of light from the flash.
* * * * *