System and method for the lossless progressive streaming of images over a communication network

Abstract

Disclosed is a lossless image streaming system for the transmission of images over a communication network. The system eliminates the necessity to store a compressed version of the original image, by losslessly streaming ROI data using the original stored image. The imaging system of the present invention also avoids the computationally intensive task of compression of the full image. When a user wishes to interact with a remote image, the imaging server performs a fast preprocessing step in near real time after which it can respond to any ROI requests also in near real time. When a ROI request arrives at the server, a sophisticated progressive image encoding algorithm is performed, but not for the full image. Instead, the encoding algorithm is performed only for the ROI. Since the size of the ROI is bounded by the size and resolution of the viewing device at the client and not by the size of the image, only a small portion of the full progressive coding computation is performed for a local area of the original image.

What is claimed:  
     
         1 . A method for transmitting visual data over a communication network, comprising: 
 (a) performing a wavelet transform upon the visual data to produce wavelet coefficients, each wavelet coefficient having an associated spatial location, resolution and quality;    (b) grouping wavelet coefficients into data blocks, each data block described by a two-dimensional spatial coordinate pair, a resolution coordinate and an accuracy coordinate;    (c) selecting a region of interest of the visual data and a quality at which the visual data is to be rendered; and    (d) transmitting over the communication network only those data blocks corresponding to the selected region of interest and quality.    
     
     
         2 . The method claimed in  claim 1 , wherein the accuracy coordinates of the data blocks define the quality of visual data the coefficients represent, coefficients having a greater number of bits representing the visual data at a higher quality than coefficients having a fewer number of bits.  
     
     
         3 . The method claimed in  claim 1 , wherein the visual data comprises a digital image.  
     
     
         4 . The method claimed in  claim 1 , wherein the visual data comprises digital video.  
     
     
         5 . The method claimed in  claim 1 , wherein the visual data comprises a sequence of images.  
     
     
         6 . The method claimed in  claim 5 , wherein the visual data comprises computed tomography (CT) medical images.  
     
     
         7 . The method claimed in  claim 1 , wherein the step of selecting a quality at which the visual data is to be rendered includes selecting lossless quality.  
     
     
         8 . The method claimed in  claim 1 , wherein the coefficients of the accuracy blocks described by resolution coordinates defining a highest resolution are the result of local Discrete Cosine Transforms regarded as wavelet-like coefficients.  
     
     
         9 . The method claimed in  claim 1 , wherein: 
 the step of selecting a quality at which the visual data is to be rendered comprises a client computer coupled to the communication network generating at least one request for interaction with the visual data and at least one subsequent request for data blocks identifying a region of interest at a selected quality and a selected resolution within the visual data; and    the transmitting step comprises a server computer coupled to the communication network receiving the requests and progressively transmitting data blocks corresponding to the region of interest to the client computer via the communication network.    
     
     
         10 . The method claimed in  claim 9 , wherein the step of a client computer coupled to the communication network generating at least one request for interaction with the visual data and at least one subsequent request for data blocks identifying a region of interest comprises the client computer selecting a progressive mode from the group consisting of: resolution, quality and spatial.  
     
     
         11 . The method claimed in  claim 1 , wherein: 
 the step of selecting a quality at which the visual data is to be rendered comprises a client computer coupled to the communication network generating at least one request for interaction with the visual data and at least one subsequent request identifying a region of interest at a selected quality and a selected resolution within the visual data; and    the transmitting step comprises a server computer coupled to the communication network receiving the request identifying the region of interest and selecting and progressively transmitting data blocks corresponding to the region of interest to the client computer via the communication network    
     
     
         12 . The method claimed in  claim 11 , wherein the step of a server computer coupled to the communication network receiving the request identifying the region of interest and selecting and progressively transmitting data blocks corresponding to the region of interest to the client computer via the communication network is performed in response to the client computer selecting a progressive mode from the group consisting of: resolution, quality and spatial.  
     
     
         13 . The method claimed in  claim 1 , further comprising the client computer progressively performing the steps of: 
 decompressing compressed data blocks corresponding to the region of interest received from the server computer; and    rendering the region of interest.    
     
     
         14 . The method claimed in  claim 13 , wherein the rendering step comprises the client computer rendering the region of interest on a video display.  
     
     
         15 . The method claimed in  claim 13 , wherein the rendering step comprises the client computer rendering the decompressed region of interest on a printer.  
     
     
         16 . The method claimed in  claim 13 , further comprising the step of the client computer storing the data blocks in a cache associated with the client computer.  
     
     
         17 . The method claimed in  claim 16 , wherein: 
 the step of selecting a quality at which the visual data is to be rendered comprises a client computer coupled to the communication network generating at least one request for interaction with the visual data and at least one subsequent request for data blocks identifying a region of interest; and    the transmitting step comprises a server computer coupled to the communication network receiving the requests and progressively transmitting data blocks corresponding to the region of interest to the client computer via the communication network, and wherein the client computer only requests the data blocks associated with a portion of a region of interest that was not previously stored in the cache.    
     
     
         18 . A system for transmitting visual data over a communication network, comprising: 
 (a) an image storage device for digitally storing visual data;    (b) a client computer coupled to the communication network; and    (c) a server computer, coupled to the communication network and the image storage device, wherein the server computer performs the steps of: 
 (i) performing a wavelet transform upon the visual data to produce wavelet coefficients, each wavelet coefficient having an associated spatial location, resolution and quality;  
 (ii) grouping wavelet coefficients into data blocks, each data block described by a two-dimensional spatial coordinate pair, a resolution coordinate and an accuracy coordinate;  
 (iii) selecting a region of interest of the visual data and a quality at which the visual data is to be rendered; and  
 (iv) transmitting over the communication network only those data blocks corresponding to the selected region of interest and quality.  
   
     
     
         19 . The system claimed in  claim 18 , wherein the accuracy coordinates of the data blocks define the quality of visual data the coefficients represent, coefficients having a greater number of bits representing the visual data at a higher quality than coefficients having a fewer number of bits.  
     
     
         20 . The system claimed in  claim 18 , wherein the step of selecting a quality at which the visual data is to be rendered includes selecting lossless quality.  
     
     
         21 . The system claimed in  claim 18 , wherein the coefficients of the accuracy blocks described by resolution coordinates defining a highest resolution are the result of local Discrete Cosine Transforms regarded as wavelet-like coefficients.  
     
     
         22 . The system claimed in  claim 18 , wherein: 
 the client computer generates at least one request for interaction with the visual data and at least one subsequent request for data blocks identifying a region of interest at a selected quality and a selected resolution within the visual data; and    the server computer receives the requests and progressively transmits data blocks corresponding to the region of interest to the client computer via the communication network.    
     
     
         23 . The system claimed in  claim 22 , wherein the client computer selects a progressive mode from the group consisting of: resolution, quality and spatial.  
     
     
         24 . The system claimed in  claim 18 , wherein: 
 the client computer generates at least one request for interaction with the visual data and at least one subsequent request identifying a region of interest at a selected quality and a selected resolution within the visual data; and    the server computer receives the request identifying the region of interest and selects and progressively transmits data blocks corresponding to the region of interest to the client computer via the communication network.    
     
     
         25 . The system claimed in  claim 24 , wherein the client computer selects a progressive mode from the group consisting of: resolution, quality and spatial.  
     
     
         26 . The system claimed in  claim 18 , further comprising the client computer progressively performing the steps of: 
 decompressing compressed data blocks corresponding to the region of interest received from the server computer; and    rendering the region of interest.    
     
     
         27 . The system claimed in  claim 26 , further comprising the step of the client computer storing the data blocks in a cache associated with the client computer.  
     
     
         28 . The system claimed in  claim 27 , wherein: 
 the client computer generates at least one request for interaction with the visual data and at least one subsequent request for data blocks identifying a region of interest; and    the server computer receives the requests and progressively transmits data blocks corresponding to the region of interest to the client computer via the communication network, and wherein the client computer only requests the data blocks associated with a portion of a region of interest that was not previously stored in the cache.    
     
     
         29 . A server computer for transmitting visual data over a communication network to a client computer, comprising: 
 (a) an image storage device for digitally storing visual data; and    (b) a processing system, coupled to the communication network and the image storage device, wherein the processing system effects the steps of: 
 (i) performing a wavelet transform upon the visual data to produce wavelet coefficients, each wavelet coefficient having an associated spatial location, resolution and quality;  
 (ii) grouping wavelet coefficients into data blocks, each data block described by a two-dimensional spatial coordinate pair, a resolution coordinate and an accuracy coordinate;  
 (iii) selecting a region of interest of the visual data and a quality at which the visual data is to be rendered; and  
 (iv) transmitting over the communication network only those data blocks corresponding to the selected region of interest and quality.  
   
     
     
         30 . The server computer claimed in  claim 29 , wherein the accuracy coordinates of the data blocks define the quality of visual data the coefficients represent, coefficients having a greater number of bits representing the visual data at a higher quality than coefficients having a fewer number of bits.  
     
     
         31 . The server computer claimed in  claim 29 , wherein the step of selecting a quality at which the visual data is to be rendered includes selecting lossless quality.  
     
     
         32 . The server computer claimed in  claim 29 , wherein the coefficients of the accuracy blocks described by resolution coordinates defining a highest resolution are the result of local Discrete Cosine Transforms regarded as wavelet-like coefficients.  
     
     
         33 . The server computer claimed in  claim 29 , wherein the server computer receives requests from the client computer for interaction with the visual data and at least one subsequent request for data blocks identifying a region of interest at a selected quality and a selected resolution within the visual data, and the server computer progressively transmits data blocks corresponding to the region of interest to the client computer via the communication network.  
     
     
         34 . The server computer claimed in  claim 29 , wherein the server computer receives requests from the client computer for interaction with the visual data and at least one subsequent request identifying a region of interest at a selected quality and a selected resolution within the visual data, and the server computer selects and progressively transmits data blocks corresponding to the region of interest to the client computer via the communication network.