DISK ARRAY IMAGE MEMORY FOR LASER PRINTER

Abstract: A radiographic laser printer (14) has high speed memory (16) for storing digital images. The high speed memory (16) includes an array of magnetic or optical disk storage devices which are accessed in parallel from a digital data bus (12). The use of external FIFO memory is eliminated by transferring data from the data bus in interleaved format directly into buffer memories located in the disk storage devices (16).

Description: PTSK ARRAY IMAGE MEMORY FOR LASER PRINTER BACKGROUND OF THE INVENTION Technical Field This invention relates in general to digital data processing apparatus and in particular to a radiographic laser printer, including an array of parallel disk drives for the high speed storage of digital images. Bacfcqrouna Art Modern medical diagnostic imaging includes the production of digital images by various well-known . imaging modalities, such as ultrasound, magnetic resonance (MRI) , nuclear medicine, computed tomography (CT) , digital subtraction angiography (DSA) , and digital radiography. Such digital images are displayed on a video monitor where they are viewed by a diagnostician, such as a radiologist. Frequently, the diagnostician desires a hard copy of a monitor image which has greater diagnostic value then other images. In such case, it is necessary to transmit the image to a film printer, such as a radiographic laser printer. Often, the radiographic laser printer may be linked to several imaging modalities. In such a case, the laser printer must be capable of storing a number of digital images which are provided to the printer at high speed data rates. There is thus a need for a digital image transfer and storage system which is low in cost, simple in design and capable of handling high speed image transfer and storage rates. Prior art disk array storage devices have not been able to satisfy this need. Such devices are disadvantageous due to slow storage rates, non-interleaved storage, use of external buffer memories which increases cost and complexity, etc. (See: U.S. Patent 4,797,755, issued January 10, 1989, inventors Baldwin et al.; U.S. Patent 4,590,559, issued May 20, 1986, inventors Baldwin et al.; U.S. Patent 4,688,168 issued August 18, 1987, inventors Gudaitis et al.; U.S. Patent 4,653,112, issued March 24, 1987, inventor Ouimette.) SUMMARY OF THE INVEN-ZIΩH According to the present invention, there is provided a digital image transfer and storage system for laser printers which is cost effective, simple in design and capable of handling high speed digital image transfer and storage rates. According to an aspect of the present invention, a disk array image memory is provided for a laser printer which includes an array of two or more disk storage devices having internal FIFO buffer memory which is greater than a track on the disk. Digital image data transferred over a data bus is transferred in an interleaved format directly into buffer memories located in the disk storage devices by means of a multiplexer/demultiplexer. Thus, by eliminating external buffer memory controllers, cost and complexity are reduced, while effecting high digital image data transfer to and from the storage devices. The multiplexer/demultiplexer distributes the digital data among the disk storage devices in an interleaved format and causes the array of disk storage devices to appear as a single memory to the data bus. BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of the invention presented below, reference is made to the accompanying drawings in which like elements are numbered with like numbers. FIG. 1 is a block diagram of a laser printer incorporating an embodiment of the present invention; FIG. 2 is a block diagram of one embodiment of the present invention; and FIG. 3 is a block diagram of another embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Although the present invention will be described below with respect to a laser printer used in medical diagnostic imaging applications, it will be understood that the digital image transfer and storage apparatus of the present invention is applicable to other digital image utilization applications. More generally, the present invention is applicable to digital data transfer and storage applications other than digital image applications. Referring now to FIG. 1, a digital image source 10 (such as a well-known medical diagnostic imaging modality using ultrasound, MRI, CT, nuclear medicine, DSA, digital radiography or the like) transmits a digital image to a digital transfer bus such as a VME bus 12. The VME bus is an institute of electrical and electronic engineers (IEEE) industrial standard communications protocol, and is described in detail in the VME bus specification available from the Motorola Company. Bus 12 is linked to a radiographic laser printer 14 which includes a disk array 16, a master control 18, image processing circuitry 20, and laser printer engine 22. A digital image from image source 10 is transferred over bus 12 and stored in disk array 16. When a digital image is to be printed on film, it is transferred under the control of master control 18, from disk array 16 over bus 12 to image processing circuit 20. Circuit 20 processes the digital image for various parameters, such as window width/level and curve shape, and provides the processed digital image to laser printer engine 22. Laser printer 22 includes a source of laser light which is raster scanned over a sheet of radiographic film to expose the film. The exposed film is subsequently processed to produce radiographic film which may be viewed by the diagnostician. Referring to FIG. 2, there is shown a preferred embodiment of the disk array of FIG. 1. As shown, bus 12 provides a digital image in a sequence of data BYTES, such as BYTES labelled 0, 1, 2, 3, 4, 5, etc. A multiplexer/demultiplexer distributes the BYTES in interleaved format to an array of disk storage devices, such as disk storage devices 26 and 28. Disk storage devices 26 and 28 may comprise known magnetic and/or optical memories. For example, devices 26 and 28 may comprise multiple disk magnetic disk drives having internal FIFO buffers 30 and 32. As shown, BYTES 1, 3, and 5 are distributed by multiplexer/ demultiplexer circuit 24 to storage device 26 where they are stored in FIFO memory 30 before being written into disk memory 34. Simultaneously, BYTES 0, 2, 4, etc. are stored in FIFO buffer memory 32 of storage device 28 before being written into magnetic memory disks 36 thereof. Referring now to FIG. 3, there is shown another embodiment of the present invention in which the disk array includes four disk storage devices 38, 40, 42, and 44 which include respective FIFO buffer memories 46, 48, 50, and 52 having memory which is greater than a track on the disk and disk memories 54, 56, 58, and 60. Digital image data transferred on bus 12 is distributed by first multiplexer/demultiplexer circuit 62 to internal busses 64 and 66. Thus, for example, data BYTES 0, 2, 4, and 6 are transferred to bus 64 while simultaneously digital data BYTES 1, 3, 5, 7, etc. are transferred to bus 66. Additional multiplexer/demultiplexer circuits 68 and 70 distribute the digital image data BYTES further. Thus, multiplexer/demultiplexer circuit 68 distributes data BYTES 0 and 4 to internal bus 72 to be transferred to data storage device 38. Simultaneously, data BYTES 2 and 6 are distributed to internal bus 74 to be transferred to storage device 40. Similarly, multiplexer/demultiplexer circuit 70 distributes digital data BYTES 1 and 5 to storage device 42 over internal bus 76. Simultaneously, digital data BYTES 3 and 7 are distributed over internal bus 78 to disk storage device 44. BYTES 0, 2, 1, and 3 are transferred simultaneously into respective buffer memories 46, 48, 50, and 52 of disk storage devices 38, 40, 42, and 44. Subsequently, digital data BYTES 4, 6, 5 and 7 are transferred simultaneously into buffer memories 46, 48, 50, and 52. Then, buffer memories 46, 48, 50, and 52 are simultaneously read out to store the BYTES in disk memories 54, 56, 58, and 60 of the devices 38-44, respectively. In the embodiment of FIG. 3, storage devices 38, 40, 42, and 44 may be operated in a double buffer mode, wherein, for example, storage devices 38 and 40 are being operated to store a digital data image while storage devices 42 and 44 are being operated to read out a digital data image. In this way, digital images may be most efficiently stored when they are received from a digital image source and printed out as radiographic film images when the radiographic laser printer is free to print a digital image. Industrial ppl ca on The disclosed invention has application in the digital data processing industry and more specifically in the health industry where digital radiographic images are processed for display and reproduction by a laser or CRT printer.

Claims: Wfaat is Claimed is: 1. A digital data apparatus comprising: a plurality of independently rotating digital data disk storage devices; wherein each of said disk storage devices includes an internal FIFO buffer memory which is greater than a track on the disk; an external digital data source for supplying a stream of digital data; a digital data bus connected to said external data source; and control means connected between said data bus and each of said storage devices for distributing the digital data stream transferred over said data bus among said storage devices in an interleaved format and for simultaneously transferring said interleaved digital data into said buffer memories of said disk storage devices. 2. The digital data apparatus of claim 1, wherein said rotating storage devices comprise magnetic disk storage devices, each of which includes an internal FIFO buffer memory, and wherein said control means includes a multiplexer/ demultiplexer circuit for directly distributing digital data received from said data bus in interleaved format to said FIFO buffer memories of said disk storage devices. 3. The digital data apparatus of claim 1, wherein said rotating storage devices comprise rotating optical disk storage devices having internal FIFO buffer memories. 4. The apparatus of claim 1 wherein said external digital data source is a source of digital images. 5. The apparatus of claim 4 wherein said digital image source is a medical diagnostic imaging apparatus. 6. A digital image apparatus comprising: a plurality of independently rotating digital data disk storage devices, wherein each of said disk storage devices includes an internal FIFO buffer memory which is greater than a track on the disk; an external source of digital images for supplying a digital image as a stream of digital data; a digital data bus connected to said external source of digital images; and control means connected between said data bus and each of said disk storage devices for distributing the digital data stream constituting a digital image transferred over said data bus among said disk storage devices in an interleaved format and for simultaneously transferring said interleaved digital data into said internal buffer memories of a disk storage devices. 7. The digital image apparatus of claim 6 wherein said rotating storage devices comprise magnetic disk storage devices, each of which includes an internal FIFO buffer memory, and wherein said control means includes a multiplexer/ demultiplexer circuit for directly distributing digital image data received from said data bus in interleaved format to said FIFO buffer memories of said disk storage devices. 8. The apparatus of claim 6 wherein said rotating disk storage devices comprise rotating optical disk storage devices having internal FIFO buffer memories. 9. The apparatus of claim 6 wherein said source of digital images is a medical diagnostic imaging apparatus. 10. The apparatus of claim 6 including a laser printer connected to said data bus; wherein said control means transfers a digital image stored in said storage devices to said laser printer which produces a visual copy of said stored image. 11. The apparatus of claim 9 including a radiographic laser printer connected to said data bus, wherein said control means transfers a medical diagnostic image stored in said storage devices to said radiographic laser printer which produces a radiographic film image of said stored image. 12. The apparatus of claim 11 including digital image processing means for processing a digital image transferred from said storage devices to said radiographic laser printer.

Inventors: DHURJATY SREERAM, DHURJATY, SREERAM
Applicants: EASTMAN KODAK CO, EASTMAN KODAK COMPANY
Application year: 1991
Main classification: G06F3
IPC codes: G06F3