Patent Application
20130046803
This disclosure relates to image coding and coding in relation to an image pipeline.
Electromechanical systems include devices having electrical and mechanical elements, transducers such as actuators and sensors, optical components (e.g., mirrors), and electronics. Electromechanical systems can be manufactured at a variety of scales including, but not limited to, microscales and nanoscales. For example, microelectromechanical systems (MEMS) devices can include structures having sizes ranging from about one micron to hundreds of microns or more. Nanoelectromechanical systems (NEMS) devices can include structures having sizes smaller than one micron including, for example, sizes smaller than several hundred nanometers. Electromechanical elements may be created using deposition, etching, lithography, and/or other micromachining processes that etch away parts of substrates and/or deposited material layers, or that add layers to form electrical, mechanical, and electromechanical devices.
One type of electromechanical systems device is called an interferometric modulator (IMOD). As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and/or reflects light using the principles of optical interference. In some implementations, an interferometric modulator may include a pair of conductive plates, one or both of which may be transparent and/or reflective, wholly or in part, and capable of relative motion upon application of an appropriate electrical signal. In an implementation, one plate may include a stationary layer deposited on a substrate and the other plate may include a reflective membrane separated from the stationary layer by an air gap. The position of one plate in relation to another can change the optical interference of light incident on the interferometric modulator. Interferometric modulator devices have a wide range of applications, and are anticipated to be used in improving existing products and creating new products, especially those with display capabilities.
A display device can include a collection of IMODs. Joint Photographic Experts Group (JPEG) compression, a.k.a. JPEG encoding, is a widely used conventional compression scheme for encoding spatial domain image content to be displayed on the display device. JPEG compression generally quantizes high frequency spatial information without significant perceptual loss. Stages in a JPEG compression scheme can include quantizing 2-Dimensional (2D) Discrete Cosine Transform (DCT) coefficients based on their perceptual significance, such that higher frequency coefficients are quantized more aggressively than lower frequency coefficients. Quantization of DCT coefficients during JPEG compression can be based on a quantization table, which applies different weights to different frequency coefficients. Lower frequency components, considered more visually important, can be encoded with more bits, while higher frequency components, considered less visually important, can be encoded with fewer bits. Thus, by encoding the lower frequency components with more bits, the encoded lower frequency coefficients can have more precision.
The processes, devices, apparatus, modules, and systems of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.
Disclosed are implementations of dither-aware image coding processes, devices, apparatus, modules, and systems.
According to one innovative aspect of the subject matter described in this disclosure, image data is received, and a portion of the received image data is selected. A first transformation is performed to transform a first plurality of spatial domain values in the selected portion of the image data to a first plurality of transform domain coefficients. A second plurality of transform domain coefficients is accessed. The second transform domain coefficients are defined by a second transformation from a second plurality of spatial domain values in a designated dither matrix. A ratio of each of the first transform domain coefficients to a respective second transform domain coefficient is determined. The first transform domain coefficients are selectively coded in accordance with the determined ratios to define a plurality of coded first transform domain coefficients. A reverse transformation is performed to transform the coded first transform domain coefficients to a third plurality of spatial domain values defining a coded portion of the image data. By way of example, transformations such as discreet cosine transforms or discreet wavelet transforms can be used.
In some implementations, selectively coding the first transform domain coefficients includes comparing the determined ratios with a threshold, and discarding the first transform domain coefficients associated with the determined ratios if the determined ratios are less than the threshold. In some other implementations, selectively coding the first transform domain coefficients includes selectively quantizing the first transform domain coefficients. For example, the determined ratios can be compared with the threshold, and the first transform domain coefficients associated with the determined ratios can be quantized with a number of bits representing a function of the respective determined ratio if the determined ratio is less than the threshold.
According to another innovative aspect of the subject matter described in this disclosure, apparatus includes a selecting module configured to select a portion of received image data. An image transformation module is configured to perform a first transformation from a first plurality of spatial domain values in the selected portion of the image data to a first plurality of transform domain coefficients. A ratio determining module is configured to determine a ratio of each of the first transform domain coefficients with a respective one of a second plurality of transform domain coefficients. The second transform domain coefficients are defined by a second transformation from a second plurality of spatial domain values in a designated dither matrix. A selective coding module is configured to selectively code the first transform domain coefficients in accordance with the determined ratios to define a plurality of coded first transform domain coefficients. A reverse transformation module is configured to perform a reverse transformation from the coded first transform domain coefficients to a third plurality of spatial domain values defining a coded portion of the image data.
In some implementations, the image data has a first tone-level, and the dither matrix is associated with an image pipeline of a display device having a second tone-level lower than the first tone-level.
In some implementations, the apparatus further includes a display and a processor configured to communicate with a display. The processor is configured to process image data. The apparatus further includes a memory device configured to communicate with the processor. In some implementations, the apparatus further includes a driver circuit configured to send at least one signal to the display, and a controller configured to send at least a portion of the image data to the driver circuit.
According to another innovative aspect of the subject matter described in this disclosure, apparatus includes means for receiving image data. The image data has a first tone-level. The apparatus further includes means for performing dither-aware coding on the image data for transferring the data to a display device having a second tone-level lower than the first tone-level. In some implementations, the means for performing dither-aware coding includes means for selecting a portion of the received image data. The apparatus also includes means for performing a first transformation from a first plurality of spatial domain values in the selected portion of the image data to a first plurality of transform domain coefficients. The apparatus further includes means for determining a ratio of each of the first transform domain coefficients with a respective one of a second plurality of transform domain coefficients. The second transform domain coefficients are defined by a second transformation from a second plurality of spatial domain values in a designated dither matrix. The apparatus further includes means for selectively coding the first transform domain coefficients in accordance with the determined ratios to define a plurality of coded first transform domain coefficients. The apparatus further includes means for performing a reverse transformation from the coded first transform domain coefficients to a third plurality of spatial domain values defining a coded portion of the image data.
According to another innovative aspect of the subject matter described in this disclosure, a non-transitory tangible computer-readable storage medium stores instructions executable by a computer to perform a process. The process includes: receiving image data; selecting a portion of the image data; performing a first transformation from a first plurality of spatial domain values in the selected portion of the image data to a first plurality of transform domain coefficients; accessing a second plurality of transform domain coefficients defined by a second transformation from a second plurality of spatial domain values in a designated dither matrix; determining a ratio of each of the first transform domain coefficients with a respective one of the second transform domain coefficients; selectively coding the first transform domain coefficients in accordance with the determined ratios to define a plurality of coded first transform domain coefficients; and performing a reverse transformation from the coded first transform domain coefficients to a third plurality of spatial domain values defining a coded portion of the image data.
Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.
The included drawings are for illustrative purposes and serve only to provide examples of possible structures and configurations of the disclosed processes, devices, apparatus, modules, and systems.
Like reference numbers and designations in the various drawings indicate like elements.
The following detailed description is directed to certain implementations for the purposes of describing the innovative aspects. However, the teachings herein can be applied in a multitude of different ways.
Some display devices are capable of displaying high tone-level digital image content in a spatial domain color space, such as standard Red, Green, and Blue (sRGB). For instance, image data in the sRGB color space can be encoded with 24 bits per pixel, corresponding to 8 bits per respective Red, Green, or Blue color channel. That is, at each pixel, there are 8 bits of information for each of the 3 channels. For instance, a sRGB color monitor, such as a liquid crystal display (LCD) monitor, can display 24 bits per pixel. Because there are 28=256 possible strings with 8 bits, a sRGB color monitor can provide up to 256 levels of intensity per channel. With such 3-color display devices, there can be 28×28×28=over 16 million different combined intensity variations, representing the total number of different colors that the display device can generate. However, to reduce computational complexity and processing demands, and to reduce hardware costs, some other modern displays are intentionally engineered to have lower tone-levels and have a fewer number of colors that can be shown. For example, some displays are configured to display 6 bits per pixel, corresponding to 2 bits per Red, Green, or Blue color channel, i.e., 22=4 levels of intensity per color channel. Much of the information in the content of a higher tone-level image, such as sRGB with 256 levels of intensity per color channel, may not be faithfully reproduced on such lower tone-level display devices.
With lower tone-level display devices such as those displaying 2 bits/4 intensity levels per color channel, any higher tone-level image delivered to the display device will automatically be reduced to 2 bits per channel. In light of this fact, image data to be displayed can be coded before being delivered to the display device, using the techniques disclosed herein, so the image data to be delivered does not include superfluous information.
An image pipeline generally refers to components that can be connected between an image source (such as a camera, a scanner, a network interface, or a storage medium) and an image rendering device (such as a display of a portable electronic device, a computer monitor, or a television). The components of the image pipeline can be configured as stages for performing desired intermediate digital image processing on image data received in the pipeline. Image pipeline stages can include, by way of example, image sensor correction, noise reduction, image scaling, gamma correction, image enhancement, color space conversion, chroma subsampling, framerate conversion, image compression/video compression, and computer data storage/data transmission.
One of the processing stages of image pipelines disclosed herein is dithering. In some implementations of a dithering stage, a set of intensity values generally referred to as dither is added to individual blocks of image data. The same set of values, often a form of noise used to randomize quantization error, is applied to each block to prevent large-scale patterns such as banding in images. Dither can be used in processing of both digital still image and video data, and it is often used in computer graphics to create the illusion of color depth in images with a limited color palette. In a dithered image, colors not available in the palette are approximated by a diffusion of colored pixels from within the available palette. The human eye perceives the diffusion as a mixture of the colors in the palette.
When a lower tone-level display device reduces higher tone-resolution image data, e.g., 8 bits per channel to 2 bits per channel, simply truncating the bits can result in undesirable artifacts such as contouring and/or banding. Dithering can compensate for these artifacts. Dithering is performed by adding noise to image data before quantizing the image data from a larger number of bits (e.g., 8 bits) to a smaller number of bits (e.g., 2 bits). A dither matrix can be implemented with a known set of coefficients configured to add noise to certain frequency coefficients, as further described herein. Because the dither matrix is known, it can be determined what dithering will do to an image before the image is received in the pipeline.
Disclosed are implementations of processes and related apparatus, devices, modules, and systems that provide for intelligent coding, a.k.a. dither-aware coding, of image content. In some implementations, the disclosed techniques include coding, e.g., discarding or quantizing, selected information in the image content. Using the disclosed coding techniques, certain information in the image content can be identified as not likely to be transmitted accurately by an image pipeline of a display with a lower tone-depth than the image content. Such information can be selectively coded.
In some implementations, the disclosed coding techniques can be performed in addition to and apart from an image or video data compression process, such as a JPEG compression process. For instance, the disclosed techniques can be performed as a pre-JPEG compression stage or a post-JPEG compression stage. When performed as a pre-compression stage, in some implementations, coded image data can be passed on to a JPEG encoder for further compression. In some implementations, where these stages are reversed, i.e., the disclosed coding techniques are performed after JPEG compression, compressed image data from the JPEG encoder is provided as input image data to the disclosed dither-aware coding operations described below.
In some implementations, operations of the disclosed dither-aware coding techniques generally include the following:
1) receive input image data having spatial domain values, for instance, in the sRGB color space;
2) tile input image data into portions, such as 8×8 blocks;
3) for each block, perform a transformation from the spatial domain values to transform domain coefficients; e.g., compute 2D DCT coefficients for each color component, e.g., Red, Green, and Blue;
4) use a dither matrix having known spatial domain values, for instance, in the sRGB color space, where the dither matrix is associated with a designated image pipeline;
5) perform a transformation on the spatial domain values of the dither matrix to transform domain coefficients such as 2D DCT coefficients;
6) compute the ratio of input image energy to dither energy at each corresponding transform domain coefficient of the input image data block and the dither matrix;
7) selectively code the transform domain coefficients of the input image data block in accordance with the determined ratios, for example, by performing one or more of the following operations:
8) perform a reverse transformation from the coded transform domain coefficients of the input image data block to spatial domain values to define a coded block of image data; for example, recover the sRGB color space image from the coded transform domain coefficients by performing an inverse 2D DCT operation.
In implementations where the disclosed coding techniques are performed on pre-JPEG compressed image data, the coded image data output from operation 8) can be provided as an input to a JPEG encoder, which is configured to discard perceptually insignificant data.
Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. With the disclosed dither-aware coding techniques, it is possible to improve compression rates without reducing perceived image quality by discarding or quantizing information that cannot be faithfully reproduced on a display. In some examples, such improvements can be achieved by discarding or quantizing DCT coefficients of images that will be corrupted by a color image pipeline having designated characteristics. In some examples, two stages of processing, i.e., dither-aware coding before or after JPEG compression, as outlined above, can yield better compression rates than stand-alone JPEG compression for similar perceptual image quality.
In
In
In
In
In the example of
In one example of the image pipeline 100 of
y=ƒ
6(ax+d),
where ƒ6(·) is a function that quantizes data to 6 bpp by thresholding, and a is a linear operator applied at color gamut mapping stage 108 that transforms x to the color space and preserves the range of ax+d to be the same as x. The variable d is a spatial domain representation of the dither matrix, described in greater detail below. The ƒ6(·) function can be approximated as quantization noise n, which can be modeled as independent, uniformly distributed, additive white noise. Thus, in one example, the dithered image data y output from stage 112 can be approximated as:
y=ax+d+n,
where n is the noise component. In a transform domain such as the DCT space, the output dithered image can be modeled as:
Y=aX+D+N,
where upper-case letters denote DCT coefficients. In this example, N is white noise and contributes energy to all of the elements of Y, and D, the DCT version of the dither matrix, has significant energy only in particular designated coefficients.
The sequence of stages in image pipeline 100 of
The disclosed image coding techniques can be performed before or after JPEG encoding of image data. For example, spatial domain image data can be encoded using standard JPEG compression schemes, returned to a spatial domain such as sRGB, and then encoded using dither-aware image coding. By the same token, spatial domain image data can first be encoded using dither-aware image coding, and then encoded as a JPEG image.
In
In block 412, a transformation is performed on spatial domain values in the selected portion of the image data. That is, the spatial domain values are transformed to a first set of transform domain coefficients. For example, a 2D DCT operation can be performed on the spatial domain values, to yield a set of DCT coefficients corresponding to each selected block of image data. Such a DCT operation can be performed for each color component, e.g., red, green, and blue, in the selected block of image data. Other transformations can be performed in some other implementations, such as a discrete wavelet transform (DWT) operation to yield a set of DWT coefficients.
In
Also, in some implementations, when the spatial domain values of the dither matrix are in a different color space than the input image data, the dither matrix values can be converted to the same color space as the input image data, as explained above, so the corresponding transform domain representations are consistent.
In block 420, process 400 includes determining a ratio of the first transform domain coefficients, that is, the transform domain coefficients of the image data, with the coefficients representing the dither matrix in the same transform domain. In particular, block 420 includes determining a ratio of each first transform domain coefficient with a corresponding second transform domain coefficient. In this way, the ratio of input image energy to dither energy at each corresponding transform domain coefficient, representing a point in the transform domain space, can be computed.
In
In
In some examples of the soft thresholding techniques depicted in
In some other implementations, selectively coding the first transform domain coefficients in block 424 of
Referring back to
The disclosed processes, apparatus, devices, modules, and systems can be implemented in software, hardware, or some combination thereof. In on example, the disclosed processes are coded on a special-purpose digital signal processing (DSP) chip incorporating DCT transform capabilities. In another example, the disclosed processes are implemented on a customized application specific integrated circuit (ASIC). In some software implementations, the disclosed processes can form a service or other part of a content generation application on a data processing device such as a personal computer, tablet, smartphone, or other data processing device incorporating a particular display. For instance, a user could be provided with a selection in a toolbar of a graphical user interface (GUI) to save an image file in a designated display format. The disclosed processes could also be implemented as software components of content retrieval and/or delivery applications in relation to a display.
The described implementations may be implemented in any device that is configured to display an image, whether in motion (e.g., video) or stationary (e.g., still image), and whether textual, graphical or pictorial. More particularly, it is contemplated that the implementations may be implemented in or associated with a variety of electronic devices such as, but not limited to, mobile telephones, multimedia Internet enabled cellular telephones, mobile television receivers, wireless devices, smartphones, bluetooth devices, personal data assistants (PDAs), wireless electronic mail receivers, hand-held or portable computers, netbooks, notebooks, smartbooks, tablets, printers, copiers, scanners, facsimile devices, GPS receivers/navigators, cameras, MP3 players, camcorders, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, electronic reading devices (e.g., e-readers), computer monitors, auto displays (e.g., odometer display, etc.), cockpit controls and/or displays, camera view displays (e.g., display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, microwaves, refrigerators, stereo systems, cassette recorders or players, DVD players, CD players, VCRs, radios, portable memory chips, washers, dryers, washer/dryers, parking meters, packaging (e.g., electromechanical systems (EMS), MEMS and non-MEMS), aesthetic structures (e.g., display of images on a piece of jewelry) and a variety of electromechanical systems devices. The teachings herein also can be used in non-display applications such as, but not limited to, electronic switching devices, radio frequency filters, sensors, accelerometers, gyroscopes, motion-sensing devices, magnetometers, inertial components for consumer electronics, parts of consumer electronics products, varactors, liquid crystal devices, electrophoretic devices, drive schemes, manufacturing processes, electronic test equipment. Thus, the teachings are not intended to be limited to the implementations depicted solely in the figures, but instead have wide applicability as will be readily apparent to one having ordinary skill in the art.
An example of a suitable electromechanical systems (EMS) or MEMS device, to which the described implementations may apply, is a reflective display device. Reflective display devices can incorporate interferometric modulators (IMODs) to selectively absorb and/or reflect light incident thereon using principles of optical interference. IMODs can include an absorber, a reflector that is movable with respect to the absorber, and an optical resonant cavity defined between the absorber and the reflector. The reflector can be moved to two or more different positions, which can change the size of the optical resonant cavity and thereby affect the reflectance of the interferometric modulator. The reflectance spectrums of IMODs can create fairly broad spectral bands which can be shifted across the visible wavelengths to generate different colors. The position of the spectral band can be adjusted by changing the thickness of the optical resonant cavity, i.e., by changing the position of the reflector.
The IMOD display device can include a row/column array of IMODs. Each IMOD can include a pair of reflective layers, i.e., a movable reflective layer and a fixed partially reflective layer, positioned at a variable and controllable distance from each other to form an air gap (also referred to as an optical gap or cavity). The movable reflective layer may be moved between at least two positions. In a first position, i.e., a relaxed position, the movable reflective layer can be positioned at a relatively large distance from the fixed partially reflective layer. In a second position, i.e., an actuated position, the movable reflective layer can be positioned more closely to the partially reflective layer. Incident light that reflects from the two layers can interfere constructively or destructively depending on the position of the movable reflective layer, producing either an overall reflective or non-reflective state for each pixel. In some implementations, the IMOD may be in a reflective state when unactuated, reflecting light within the visible spectrum, and may be in a dark state when unactuated, reflecting light outside of the visible range (e.g., infrared light). In some other implementations, however, an IMOD may be in a dark state when unactuated, and in a reflective state when actuated. In some implementations, the introduction of an applied voltage can drive the pixels to change states. In some other implementations, an applied charge can drive the pixels to change states.
The depicted portion of the pixel array in
In
The optical stack 16 can include a single layer or several layers. The layer(s) can include one or more of an electrode layer, a partially reflective and partially transmissive layer and a transparent dielectric layer. In some implementations, the optical stack 16 is electrically conductive, partially transparent and partially reflective, and may be fabricated, for example, by depositing one or more of the above layers onto a transparent substrate 20. The electrode layer can be formed from a variety of materials, such as various metals, for example indium tin oxide (ITO). The partially reflective layer can be formed from a variety of materials that are partially reflective, such as various metals, e.g., chromium (Cr), semiconductors, and dielectrics. The partially reflective layer can be formed of one or more layers of materials, and each of the layers can be formed of a single material or a combination of materials. In some implementations, the optical stack 16 can include a single semi-transparent thickness of metal or semiconductor which serves as both an optical absorber and conductor, while different, more conductive layers or portions (e.g., of the optical stack 16 or of other structures of the IMOD) can serve to bus signals between IMOD pixels. The optical stack 16 also can include one or more insulating or dielectric layers covering one or more conductive layers or a conductive/absorptive layer.
In some implementations, the layer(s) of the optical stack 16 can be patterned into parallel strips, and may form row electrodes in a display device as described further below. As will be understood by one having skill in the art, the term “patterned” is used herein to refer to masking as well as etching processes. In some implementations, a highly conductive and reflective material, such as aluminum (Al), may be used for the movable reflective layer 14, and these strips may form column electrodes in a display device. The movable reflective layer 14 may be formed as a series of parallel strips of a deposited metal layer or layers (orthogonal to the row electrodes of the optical stack 16) to form columns deposited on top of posts 18 and an intervening sacrificial material deposited between the posts 18. When the sacrificial material is etched away, a defined gap 19, or optical cavity, can be formed between the movable reflective layer 14 and the optical stack 16. In some implementations, the spacing between posts 18 may be approximately 1-1000 um, while the gap 19 may be less than 10,000 Angstroms (Å).
In some implementations, each pixel of the IMOD, whether in the actuated or relaxed state, is essentially a capacitor formed by the fixed and moving reflective layers. When no voltage is applied, the movable reflective layer 14 remains in a mechanically relaxed state, as illustrated by the IMOD 12 on the left in
Here, the electronic device includes a controller 21, which may include one or more general purpose single- or multi-chip microprocessors such as an ARM®, Pentium®, 8051, MIPS®, Power PC®, or ALPHA®, or special purpose microprocessors such as a digital signal processor, microcontroller, or a programmable gate array. Controller 21 may be configured to execute one or more software modules. In addition to executing an operating system, the controller 21 may be configured to execute one or more software applications, including a web browser, a telephone application, an email program, or any other software application.
The controller 21 is configured to communicate with device 11. The controller 21 also can be configured to communicate with an array driver 22. The array driver 22 can include a row driver circuit 24 and a column driver circuit 26 that provide signals to, e.g., a display array or panel 30. Although
The display device 40 includes a housing 41, a display 30, an antenna 43, a speaker 45, an input device 48, and a microphone 46. The housing 41 can be formed from any of a variety of manufacturing processes, including injection molding, and vacuum forming. In addition, the housing 41 may be made from any of a variety of materials, including, but not limited to: plastic, metal, glass, rubber, and ceramic, or a combination thereof. The housing 41 can include removable portions (not shown) that may be interchanged with other removable portions of different color, or containing different logos, pictures, or symbols.
The display 30 may be any of a variety of displays, including a bi-stable or analog display, as described herein. The display 30 also can be configured to include a flat-panel display, such as plasma, EL, OLED, STN LCD, or TFT LCD, or a non-flat-panel display, such as a CRT or other tube device. In addition, the display 30 can include an interferometric modulator display, as described herein.
The components of the display device 40 are schematically illustrated in
The network interface 27 includes the antenna 43 and the transceiver 47 so that the display device 40 can communicate with one or more devices over a network. The network interface 27 also may have some processing capabilities to relieve, e.g., data processing requirements of the processor 21. The antenna 43 can transmit and receive signals. In some implementations, the antenna 43 transmits and receives RF signals according to the IEEE 16.11 standard, including IEEE 16.11(a), (b), or (g), or the IEEE 802.11 standard, including IEEE 802.11a, b, g or n. In some other implementations, the antenna 43 transmits and receives RF signals according to the BLUETOOTH standard. In the case of a cellular telephone, the antenna 43 is designed to receive code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile communications (GSM), GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA), Evolution Data Optimized (EV-DO), 1xEV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High Speed Packet Access (HSPA+), Long Term Evolution (LTE), AMPS, or other known signals that are used to communicate within a wireless network, such as a system utilizing 3G or 4G technology. The transceiver 47 can pre-process the signals received from the antenna 43 so that they may be received by and further manipulated by the processor 21. The transceiver 47 also can process signals received from the processor 21 so that they may be transmitted from the display device 40 via the antenna 43. Apparatus configured to perform dither-aware image coding techniques as described above can be incorporated in transceiver 47.
In some implementations, the transceiver 47 can be replaced by a receiver. In addition, the network interface 27 can be replaced by an image source, which can store or generate image data to be sent to the processor 21. The processor 21 can control the overall operation of the display device 40. The processor 21 receives data, such as compressed image data from the network interface 27 or an image source, and processes the data into raw image data or into a format that is readily processed into raw image data. The processor 21 can send the processed data to the driver controller 29 or to the frame buffer 28 for storage. Raw data typically refers to the information that identifies the image characteristics at each location within an image. For example, such image characteristics can include color, saturation, and gray-scale level. Controller 21 is also configured to interact with device 11 to perform desired operations.
The processor 21 can include a microcontroller, CPU, or logic unit to control operation of the display device 40. The conditioning hardware 52 may include amplifiers and filters for transmitting signals to the speaker 45, and for receiving signals from the microphone 46. The conditioning hardware 52 may be discrete components within the display device 40, or may be incorporated within the processor 21 or other components. In one implementation, device 11 is incorporated as a component of conditioning hardware 52.
The driver controller 29 can take the raw image data generated by the processor 21 either directly from the processor 21 or from the frame buffer 28 and can re-format the raw image data appropriately for high speed transmission to the array driver 22. In some implementations, the driver controller 29 can re-format the raw image data into a data flow having a raster-like format, such that it has a time order suitable for scanning across the display array 30. Then the driver controller 29 sends the formatted information to the array driver 22. Although a driver controller 29, such as an LCD controller, is often associated with the system processor 21 as a stand-alone Integrated Circuit (IC), such controllers may be implemented in many ways. For example, controllers may be embedded in the processor 21 as hardware, embedded in the processor 21 as software, or fully integrated in hardware with the array driver 22.
The array driver 22 can receive the formatted information from the driver controller 29 and can re-format the video data into a parallel set of waveforms that are applied many times per second to the hundreds, and sometimes thousands (or more), of leads coming from the display's x-y matrix of pixels.
In some implementations, the driver controller 29, the array driver 22, and the display array 30 are appropriate for any of the types of displays described herein. For example, the driver controller 29 can be a conventional display controller or a bi-stable display controller (e.g., an IMOD controller). Additionally, the array driver 22 can be a conventional driver or a bi-stable display driver (e.g., an IMOD display driver). Moreover, the display array 30 can be a conventional display array or a bi-stable display array (e.g., a display including an array of IMODs). In some implementations, the driver controller 29 can be integrated with the array driver 22. Such an implementation is common in highly integrated systems such as cellular phones, watches and other small-area displays.
In some implementations, the input device 48 can be configured to allow, e.g., a user to control the operation of the display device 40. The input device 48 can include a keypad, such as a QWERTY keyboard or a telephone keypad, a button, a switch, a rocker, a touch-sensitive screen, or a pressure- or heat-sensitive membrane. The microphone 46 can be configured as an input device for the display device 40. In some implementations, voice commands through the microphone 46 can be used for controlling operations of the display device 40.
The power supply 50 can include a variety of energy storage devices as are well known in the art. For example, the power supply 50 can be a rechargeable battery, such as a nickel-cadmium battery or a lithium-ion battery. The power supply 50 also can be a renewable energy source, a capacitor, or a solar cell, including a plastic solar cell or solar-cell paint. The power supply 50 also can be configured to receive power from a wall outlet.
In some implementations, control programmability resides in the driver controller 29 which can be located in several places in the electronic display system. In some other implementations, control programmability resides in the array driver 22. The above-described optimization may be implemented in any number of hardware and/or software components and in various configurations.
The various illustrative logics, logical blocks, modules, circuits and algorithm steps described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and steps described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.
The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and systems described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular steps and methods may be performed by circuitry that is specific to a given function.
In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.
If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a non-transitory tangible computer-readable medium. The steps of a method or algorithm disclosed herein may be implemented in a processor-executable software module which may reside on such a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program from one place to another. A storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection can be properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.
Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of the IMOD as implemented.
Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.
