AU3998300A - Scaleable resolution motion image recording and storage system - Google Patents

Description

WO 00/46978 PCTIUSOO/03103 SCALEABLE RESOLUTION MOTION IMAGE RECORDING AND STORAGE SYSTEM Inventor: Kenbe D. Goertzen Related Application 5 The subject matter of this application is related to the subject matter of the following commonly owned applications: Serial Number 09/112,668, attorney docket number 3486, titled "Apparatus And Method For Entropy Coding", filed on July 9, 1998, also by Kenbe Goertzen; Serial Number , attorney docket number 4753, titled "A System And Method For Improving Compressed Image Appearance Using Stochastic Resonance And 10 Energy Replacement", filed concurrently, also by Kenbe Goertzen; Serial Number , attorney docket number 4755, titled "Optimized Signal Quantification", filed concurrently, also by Kenbe Goertzen; and, Serial Number _, attorney docket number 4756, titled "Quality Priority Image Storage and Communication", filed concurrently, also by Kenbe Goertzen; the contents of which are incorporated by reference as if fully disclosed herein. 15 Technical Field This invention pertains to the field of digital signal compression and quantification. More specifically, the present invention related to a system and method that provides scaleable resolution image recording and storage. Shortcomings of Prior Art 20 Electronic motion image recorders have traditionally been designed for one or at most only a few motion image formats. With the advent of various high definition video, medical, scientific, and industrial formats, there is a requirement for single systems which can support a broad range of motion image formats. As motion image frame rates, image sizes, and pixel resolutions increase, there is a tremendous increase in the amount of data that must be 25 maintained to represent the motion image stream in the sample domain. This places a large burden on the processing, storage, and communications costs to support these data sets at the desired resolution. Summary of Invention The present invention provides an efficient and cost effective system which can be 30 configured to effectively support all motion image formats. The system can be modularly expanded to increase throughput, and can trade off system throughput between the number of image streams, their frame rate, frame resolution, and pixel resolution. The system uses subband methods throughout to support variable image size and frame rate recording. This WO 00/46978 PCT/USOO/03103 allows a single image stream to be divided into multiple lower rate streams to allow more reasonable processing rates. The present invention also enables the application of a variable sized array of standardized image processing components. More specifically, optimized storage and efficient communication is achieved by 5 storing image streams in the information domain, rather than the sample domain. This typically provides a dramatic reduction in storage and communication requirements, while still providing a guaranteed recording quality. Unlike conventional video tape recorders, this system can also place recordings onto the same removable storage medium at any desired image resolution, frame rate, and quality. 10 Brief Description of the Drawings Detailed Description 15 The following description describes the method of the present invention as performed by the system of the present invention. The method described, however, could also be performed by an alternate image processing device. 20 The following provides a list of components that may be included in the system of the present invention. The function accomplished by each component is also provided. As will be appreciated by one skilled in the art, this list is neither exhaustive nor inclusive and other components that provide similar functionality, such as other band limiters, band splitters or color space conversion modules, may also be added. 25 Component Function

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Input Bandsplit Input converters and optional analog bandsplit Deframer digital data stream in Color space optional RGB -> CbYCr 30 Bandlimit 1 D or 2D Bandlimit and arbitrary rate conversion of components Bandsplit Full band 2 pixel color to halfband chroma dual pixel "quad" CbYCr -> CbLCrH Full band 4 pixel color to visual space "quad" 2 WO 00/46978 PCT/USOO/03103 CbYCr -> CbLCrD Monochrome to bandsplit "quad" MM --L-H Monochrome to 2D bandsplit "quad" 5 MMMM -> LHVD Inverse Pulldown Sample only a portion of the input fields or frames Framebuffer Buffer and optional time multiplex frames Interlace Processing Interlaced image processing, to allow interlaced image to be processed as progressive 10 Router Routes N streams to N IP channels Using time multiplexed frames Using simple (Harr) temporal bandsplit of frames Temporal IP Temporal transform and optional time multiplex of frames Interlace Processing Interlaced image processing, to allow interlaced image to be 15 processed as progressive Spatial IP Spatial transform Quantification Component and temporal quantification as required Entropy coding Entropy coding, potentially for each temporatial and spatial component 20 DMA channels Provides channels for data movement RAM Queues Peak buffering Disk Queues Peak buffering Disk,Tape, Final output or Channel 25 The IO subsystems accept motion image input streams in one of numerous pixel formats. RGBA Red, Green, Blue, and Alpha YCbCrA Luminance, Blue color difference, Red Color difference, and Alpha YC Luminance and alternating color difference 30 M Monochrome MM Two sequential monochrome samples MMMM Four sequential monochrome samples 3 WO 00/46978 PCT/USOO/03103 The input analog converter can operate at up to a fixed rate of N conversions per second, where N is determined by the particular implementation. If a conversion rate higher than N is desired, the input system can use an analog bandsplit of the input signal into two or four streams at one half or one fourth rate to allow multiple channel conversion at or above N. 5 In one embodiment, the digital IO system converts these input pixel streams into quad component representational streams. In each case, it is assumes that the components have been decorrelated and can be processed separately. If the components have not been decorrelated, however, color space conversion may be used to decorrelate the color 10 components. This could also involve subband splitting certain color components in order to further decorrelate the components and spread the bandwidth evenly among the available channels. While splitting the pixel stream into quad component representations is described as one embodiment, the image processing resources can also process the pixel stream by splitting it into a number of different component representations. For example, the present system may 15 be used to process dual channel image streams. In these cases, the first and third components are assigned to the first channel, and the second and fourth are assigned to the second. CbYCrA Single color pixel, four component full band CbLCrH Dual color pixel, two subband luma component (L and H), half band chroma 20 Luma is bandsplit using either a Harr transform, an Odd near orthagonal 7 tap filter, or an Odd near orthagonal 9 tap filter. CbLCrD Quad color pixel, two halfband luma components (L and D), quarter band chroma. Luma is limited to a diagonal square providing 1/2 the original bandwidth, but full horizontal and vertical response. This is bandsplit using a 2D 25 filter of 3x3 or 9x9 taps into a low half and a diagonal half. The color is bandlimited to half band in both dimensions. LMMH Quad monochrome pixel, 1D four subband components LHVD Quad monochrome pixel, 2D four subband components 30 The frame buffers can store 1 to N frames of the input stream and distribute 1 to N frames among 1 to N signal processors. This allows time multiplexing image processing resources, or the support of temporal processing in the frame buffer or router. N is determined by the required quad throughput divided by the quad throughput of the individual 4 WO 00/46978 PCT/USOO/03103 signal processors. This also allows for support of temporal processing in the frame buffer or router. The router can accomplish simple spatial or temporal bandsplits. This accomplishes 5 additional decorrelation and allows subdivision of the signal stream among computing resources. It can also be used to support image resolutions or throughputs that exceed the physical buffers or individual throughput supported by the image processing modules. This system can also perform temporal transform processing. In the preferred 10 embodiment, a temporal processor is required for each quad stream which will require processing. The input to a temporal processor is a stream of image frames. The output is a stream of shuffled temporal transformed frames. For example, if one temporal transform is selected, an alternate stream of low and high temporal component frames is produced. If two temporal transforms are selected, a stream of low, midlow, midhigh, and high temporal 15 component frames is produced. Temporal transforms can be inserted as desired between the router and the spatial transform processor. From 1 to N spatial signal processors accept the quad streams of frames. They perform a spatial multiband transform, quantify the data to the specified recording signal quality and 20 entropy encode it. From 4 to 4N DMA channels deliver the encoded data to a RAM buffer which handles peak transfer loads. The data can then be transferred to queuing or output files on disks, tapes, or other peripherals that are capable of storing digital information. If the data rate is higher than the 25 specified peripheral can support, the information is queued to a faster storage device until the desired peripheral can accept the data. In the case of peak tolerant recording at a fixed rate, a phase delay is specified and a hierarchy of processes related to the hierarchy of buffer devices monitor the rate and potentially control the quality level. This allows the process to be as tolerant of peaks as possible. Each process in charge of buffering determines whether the data 30 budget is being exceeded over the time scale of interest to this process. If the local average rate exceeds a set point, the quality level of the images being received by the output or storage device is reduced until the local average rate no longer exceeds the set point. If the average is 5 WO 00/46978 PCT/USOO/03103 below the set point, and the quality level is below the target, the quality level of the images is increased. Example: Here is an example of this unique storage process. The target data rate is 12 MB/S and a 5 quality level may be 66 dB. This would allow peaks rates as high as 80 megabyte per second to occur for one frame time, peaks as high as 40 to occur for up to about a second, and peaks up to 20 megabyte per second for a few seconds. The steps up or down are all added together and to the target to obtain the next quality level. The quality level is re-computed for every frame. 10 Process Timescale Setpoint Peak Rate dB Steps

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To RAM 4 Frames 40 MB/S 80 MB/S 3 dB To Disk 4 second 20 MB/S 40 MB/S 1 dB 15 To Tape/Channel 30 second 10 MB/S 12 MB/S 1/2 dB The playback process is a reversal of the recording process, with the exception that playing from a slower peripheral than required induces a preroll time while a faster peripheral is used to queue the required amount of data. A preroll time is the time needed to transfer data from a 20 slower peripheral to a faster storage device. For example, if the data was stored on a compact disc, the data could be prerolled to RAM in order to provide playback at the appropriate frame rate and quality level. Although the description above contains many detailed descriptions, these descriptions 25 should not be construed as limiting the scope of the invention but merely as providing illustrations of some of the presently preferred implementations of this invention. For example, although this method was described with reference to standard motion and still images, this method can be used to optimize quantification of any signal stream. Thus the scope of the invention should be determined by the appended claims and their legal 30 equivalents, rather than by examples given. 6

Claims (14)

1. An system for scaling resolution of an image input stream, the system comprising: a processor for pre-processing the image input stream; 5 coupled to the processor, an 10 system for receiving the image input stream; coupled to the IO system, an input analog converter; coupled to the input analog converter, a frame buffer for storing image frames; coupled to the input analog converter, a router for decorrelating the image input stream and dividing the stream among one or more processors; 10 coupled to the router, a temporal processor for performing temporal transforms of the image input stream; coupled to the temporal processor, a DMA channel for delivering the encoded data to a storage device; and coupled to the DMA channel, a local storage device for storing the processed 15 image input stream.

2. The system of claim 1, wherein the input analog converter further comprises an analog bandsplitter for splitting the image input stream into multiple streams.

3. The system of claim 1, wherein the 10 system further comprises a color space converter for decorrelating the color components. 20

4. The system of claim 1, wherein system comprises four DMA channels.

5. The system of claim 1, wherein the system comprises more than one temporal processor.

6. The system of claim 1, wherein the system further comprises, coupled to the router and the spatial transform processor, a temporal transform module. 25

7. A method for processing an image input stream, the method comprising the steps of: receiving a desired image input stream conversion rate; converting the image input stream into one or more representational streams; calculating a frame conversion rate; 30 responsive to the frame conversion rate being lower than the desired conversion rate, responsive to the image input stream components being correlated, converting the color space of the image input stream; and splitting the image input stream into one or more representational streams; 7 WO 00/46978 PCT/USOO/03103 routing the image streams to one or more signal processors; performing temporal transform processing on the representational streams; and storing the representation streams post-temporal processing.

8. The method of claim 7, wherein the step of splitting the image input stream into 5 two representational streams comprises splitting the image stream into four quad component representations.

9. The method of claim 7, wherein the step of splitting the image input stream into two representational streams comprises applying an analog bandsplit to the stream.

10. The method of claim 7, wherein the step of performing temporal transform 10 processing on the representational streams comprises using a separate temporal processor to process each representational stream.

11. The method of claim 7, wherein the step of performing temporal transform processing on the representational streams includes performing a spatial multiband transform of the stream. 15

12. The method of claim 11, wherein the step of performing temporal transform processing on the representational streams includes quantifying the data in the stream.

13. The method of claim 12, wherein the step of performing temporal transform processing on the representational streams includes entropy encoding the stream.

14. The method of claim 7, wherein the step of storing the streams comprises: 20 calculating the data budget of a first storage device used to store the data; responsive to the stream requiring a data budget higher than is supported by the first storage device, queuing the data to a second storage device until the first storage device is able to accept the stream. 8