MEMORY MODULE FOR COMPACT PRINTER SYSTEM

Abstract: A memory module useful in a digital imaging system such as a compact printer system. The memory module includes an image processor that compresses an image read from an image source, such as a camera module or a printer module. The compressed image is stored in a flash memory. Images stored in the flash memory may be decompressed and transferred to the printer module, or other modules. The memory module preferably incorporates two connection means. One or other of the connection means connect to modules of the compact printer system and the other connection means allows further memory modules to be stacked. The connection means includes a physical connection and a logical connection. The logical connection is a serial bus that communicates power and data. Buttons are provided to select images, store images from and transfer images to the printer module. Images may be accessed at full resolution or thumbnail resolution. Feedback is provided via a LCD.

Description: MEMORY MODULE FOR COMPACT PRINTER SYSTEM FIELD OF THE INVENTION The invention relates to a memory module useful in a digital imaging system It is useful for stoπng images captured by a digital image sensor or camera The memory module finds particular application m a compact pπnter system able to print full-color, business card size documents from a device about the size of a pen Reference may be had to co-pending applications claiming pπoπty from Australian Provisional Patent Application number PQ0560 dated 25 May 1999 The co-pending applications descπbe related modules and methods for implementing the compact pπnter system The co-pending applications are as follows BACKGROUND OF THE INVENTION Microelectronic manufactuπng techniques have led to the miniatuπzation of numerous devices Mobile phones, personal digital assistant devices, and digital cameras are very common examples of the miniatuπzation trend One device that has not seen the advantage of microelectronic manufactuπng techniques is the pπnter Commercially available pπnters are large compared to many of the devices they could support For instance, it is impractical to carry a color pπnter for the purpose of instantly pπnting photographs taken with known compact digital cameras A compact pπnthead has been descπbed in co-pending Patent Cooperation Treaty applications filed simultaneously to the present application and hereby incorporated by cross reference It is known in compact devices such as cameras to provide on-board memory for storage of captured images It is also known to have replaceable memory, for example, in the form of flash cards that can be removed from the camera for temporary storage The problem with the replaceable memory is that a given memory slot on a digital camera can only accommodate a single memory card, and the single memory card can only store a certain number of images If more lmages need to be stored or accessed, the memory card must be pulled out and a different memory card must be inserted The combined memory of multiple memory cards cannot be used simultaneously Also existing replaceable memory solutions only provide access in terms of a single image at a time It is desirable to combine replaceable memory storage facilities as well as provide more vaπed access to images, for example, a single image containing a set of thumbnails of multiple stored images SUMMARY OF THE INVENTION In one form, the invention resides in a memory module compπsing a body, memory means withm said body for stoπng images, an image processor within said body that transfers one or more images from said memory means or to said memory means from an image source, at least one connection means incorporated in said body for connecting said memory module to a bus providing power and data between said memory module and said image source In a further form, the invention resides in a memory module for a compact pπnter system compπsing, a body, memory means within said body for stoπng images, an image processor within said body connected to said memory means that transfers one or more images from an image source to said memory means and transfers one or more stored images from said memory means to a pπnter module, at least one connection means at an end of said body for connecting said memory module to a bus providing power and data between said memory module, said image source and said pπnter module In a still further form the invention resides m a method of stoπng images in a compact pπnting system compπsing the steps of reading an stored image from a first storage location to an image processor, applying compression or decompression to said stored image, and wnt g a resultant image to a second storage location Further features of the invention will be evident from the following descπption BRIEF DESCRIPTION OF THE DRAWINGS In order to assist with descπbing preferred embodiments of the invention, reference will be made to the following figures in which FIG 1 is a pπnter module, FIG 2 is a camera module, FIG 3 is a memory module, FIG 4 is a communication module, FIG 5 is a flash module, FIG 6 is a timer module, FIG 7 is a laser module, FIG 8 is an effects module, FIG 9 is a characters module, FIG 10 is an adaptor module, FIG 1 1 is a pen module, FIG 12 is a dispenser module, FIG 13 is a first compact pπnter configuration, FIG 14 is a second compact pπnter configuration, FIG 15 is a third compact pπnter configuration, FIG 16 is a fourth compact pπnter configuration, FIG 17 is a perspective view of the memory module, FIG 18 is an exploded view of the memory module, and FIG 19 is a block schematic diagram of an image processor for the memory module DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is descπbed in terms of the application to a compact pπnter system It will be understood that the invention is not limited to this particular application but rather can be employed with any digital imaging system Nonetheless, the compact pπnter system provides a convenient environment m which to descπbe the details of the memory module invention Referring to FIGs 1 to 12, there are shown vaπous modules that together form a compact pπnter system Individual modules can be attached and detached from the compact pπnter configuration to allow a user-definable solution to business-card sized pπnting Images can also be transferred from one compact pπnter to another without the use of a secondary computer system Modules have a minimal user-interface to allow straightforward interaction A compact pπnter system configuration consists of a number of compact pπnter modules connected together Each compact pπnter module has a function that contπbutes to the overall functionality of the particular compact pπnter configuration Each compact pπnter module is typically shaped like part of a pen, physically connecting with other compact pπnter modules to form the complete pen-shaped device The length of the compact pπnter device depends on the number and type of compact pπnter modules connected The functionality of a compact pπnter configuration depends on the compact pπnter modules in the given configuration The compact pπnter modules connect both physically and logically The physical connection allows modules to be connected in any order, and the logical connection is taken care of by the compact pπnter Seπal Bus - a bus that provides power, allows the modules to self configure and provides for the transfer of data In terms of physical connection, most compact pπnter modules consist of a central body, a male connector at one end, and a female connector at the other Since most modules have both a male and female connector, the modules can typically be connected in any order Certain modules only have a male or a female connector, but this is determined by the function of the module Adaptor modules allow these single-connector modules to be connected at either end of a given compact pπnter configuration A four wire physical connection between all the compact pπnter modules provides the logical connection between them in the form of the compact pπnter Seπal Bus The compact pπnter Seπal Bus provides power to each module, and provides the means by which data is transfeπed between modules Importantly, the compact pπnter Seπal Bus and accompanying protocol provides the means by which the compact pπnter system auto-configures, reducing the user-interface burden on the end-user Compact pπnter modules can be grouped into three types • image processing modules including a Pπnter Module (FIG 1), a Camera Module (FIG 2) and a Memory Module (FIG 3) Image processing modules are pπmaπly what sets the compact pπnter system apart from other pen-like devices Image processing modules capture, pπnt, store or manipulate photographic images, • housekeeping modules including an Adapter Module (FIG 10), an Effects Module (FIG 8), a Communications Module (FIG 4), and a Timer Module (FIG 6) Housekeeping modules provide services to other modules or extended functionality to other modules, and • isolated modules including a Pen Module (FIG 1 1) and a Laser Module (FIG 7) Isolated modules are those that attach to the compact pπnter system but are completely independent of any other module They do not necessaπly require power, and may even provide their own power Isolated Modules are defined because the functionality they provide is typically incorporated into other pen-like devices Although housekeeping modules and isolated modules are useful components in a compact pπnter system, they are extras in a system dedicated to image processing and photographic manipulation Life size (1 1) illustrations of the compact pπnter modules are shown in FIGs 1 to 12, and example configurations produced by connecting vaπous modules together are shown in FIGs 13 to 16 FIG 1 shows a pπnter module that incorporates a compact pπnthead descπbed in co-pending United States Patent Applications listed in the Background section of this application, incorporated herewith by reference, and referred to herewith as a Memjet pπnthead The Memjet pπnthead is a drop-on-demand 1600 dpi Inkjet pπnter that produces bi- level dots in up to 4 colors to produce a pπnted page of a particular width Since the pπnthead pπnts dots at 1600 dpi, each dot is approximately 22 5μm in diameter, and spaced 15 875μm apart Because the pπnting is bi-level, the input image should be dithered or error-diffused for best results Typically a Memjet pπnthead for a particular application is page-width This enables the pπnthead to be stationary and allows the paper to move past the pπnthead A Memjet pπnthead is composed of a number of identical 1/2 inch Memjet segments The pπnter module 10 compπses a body 11 housing the Memjet pπnthead Power is supplied by a three volt battery housed m battery compartment 12 The pπnthead is activated to commence pπnting when a business card (or similar sized pπntable media) is inserted into slot 13 Male connector 14 and female connector 15 facilitate connection of other modules to the pπnter module 10 FIG 2 shows a camera module 20 The camera module provides a point-and-shoot camera component to the compact pπnter system as a means of capruπng images The camera module compπses a body 21 having a female connector 22 A lens 23 directs an image to an image sensor and specialized image processing chip within the camera 24 A conventional view finder 25 is provided as well as a lens cap 26 An image is captured when the Take button 27 is pushed Captured images are transferred to the Pπnter Module 10 for subsequent pπnting, manipulation, or storage The Camera Module also contains a self-timer mode similar to that found on regular cameras FIG 3 shows a Memory Module 30 compπsing a body 31, optional LCD 32, IN button 33, OUT button 34 and SELECT button 35 The Memory Module 30 is a standard module used for stoπng photographic images captured by the Camera 20 The memory module stores 48 images, each of which can be accessed either at full resolution or at thumbnail resolution Full resolution provides read and wπte access to individual images, and thumbnail resolution provides read access to 16 images at once in thumbnail form The Memory Module 30 attaches to other modules via a female connector 36 or male connector 37 The male and female connectors allow the module to be connected at either end of a configuration Power may be provided from the Pπnter Module 10 via the Seπal Bus or from another source, such as a separate power module A Communications Module 40 is shown in FIG 4 The communications module 40 consists of a connector 41 and a cable 42 that terminates in an appropπate connector for a computer port, such as a USB port, RS232 seπal port or parallel port The Communications Module 40 allows the compact pπnter system to be connected to a computer When so connected, images can be transfeπed between the computer and the vaπous modules of the compact pπnter system The communications module allows captured images to be downloaded to the computer, and new images for pπnting to be uploaded into the pπnter module 10 and the memory module 30 A Flash Module 50 is shown in FIG 5 The Flash Module 50 is used to generate a flash with flash cell 51 when taking photographs with the Camera Module 20 The Flash Module attaches to other modules via female connector 52 and male connector 53 It contains its own power source The Flash Module is automatically selected by the Camera Module when required A simple switch allows the Flash Module to be explicitly turned off to maximize battery life FIG 6 shows a Timer Module 60 that is used to automate the taking of multiple photos with the Camera Module 20, each photo separated by a specific time interval The captured photos are stored in Memory Module 30 Any flash requirements are handled by the Camera Module 20, and can therefore be ignored by the Timer Module The Timer Module 60 consists of a body 61 housing a LCD 62, START/STOP button 63 and UNITS button 64 A SELECT button 65 allows the user to select time units and the number of units are set by UNITS button 64 The Timer Module 60 includes a male connector 66 and female connector 67 The Timer Module takes its power from the Pπnter Module 10 via the Seπal Bus or from another source, such as a separate power module A Laser Module 70 is shown in FIG 7 The Laser Module 70 consists of a body 71 containing a conventional laser pointer operated by button 72 As the Laser Module is a terminal module it only has one connector, which in the example is a male connector 73 The Laser Module is an isolated module, in that it does not perform any image capture, storage, or processing It exists as a functional addition to the compact pπnter system It is provided because laser pointer services are typically incorporated into other pen-like devices The Laser Module contains its own power supply and does not appear as a device on the Seπal Bus The Effects Module shown in FIG 8 is an image processing module It allows a user to select a number of effects and applies them to the current image stored in the Pπnter Module 10 The effects include borders, clip-art, captions, warps, color changes, and painting styles The Effects Module compπses a body 81 housing custom electronics and a LCD 82 A CHOOSE button 83 allows a user to choose between a number of different types of effects A SELECT button 84 allows the user to select one effect from the number of effects of the chosen type Pressing the APPLY button 85 applies the effect to image stored in the Pπnter Module 10 The Effects Module obtains power from the Seπal Bus Male connector 86 and female connector 87 allow the Effects Module to be connected to other compact pπnter system modules FIG 9 shows a Character Module 90 that is a special type of Effects Module (descπbed above) that only contains character clip-art effects of a given topic or genre Examples include The Simpsons ® , Star Wars ® , Batman ® , and Dilbert ® as well as company specific modules for McDonalds ® etc As such it is an image processing module It consists of a body 91 housing custom electronics and a LCD 92 SELECT button 93 allows the user to choose the effect that is to be applied with APPLY button 94 The Character Module obtains power from the Seπal Bus through male connector 95 and female connector 96 The Adaptor Module 100, shown in FIG 10, is a female/female connector that allows connection between two modules that terminate in male connectors A male/male connector (not shown) allows connection between two modules that terminate in female connectors The Adaptor Module is a housekeeping module, in that it facilitates the use of other modules, and does not perform any specific processing of its own All "through" modules have a male connector at one end, and a female connector at the other end The modules can therefore be chained together, with each module connected at either end of the chain However some modules, such as the Laser Module 70, are terminating modules, and therefore have either a male or female connector only Such single- connector modules can only be connected at one end of the chain If two such modules are to be connected at the one time, an Adaptor Module 100 is required FIG 11 shows a Pen Module 110 which is a pen in a module form It is an isolated module in that it attaches to the compact pπnter system but is completely independent of any other module It does not consume or require any power The Pen Module is defined because it is a convenient extension of a pen shaped, pen sized device It may also come with a cap 111 The cap may be used to keep terminating connectors clean in the case where the chain ends with a connector rather than a terminating module To assist with accurately feeding a business card sized pπnt media into slot 13 of the pπnter module 10, a dispenser module 120 is provided as shown in FIG12 The dispenser module 120 compπses a body 121 that holds a store of business card sized pπnt media A Pπnter Module 10 locates into socket 122 on the dispenser module 120 When coπectly aligned, a card dispensed from the dispenser module by slider 123 enters slot 13 and is pπnted In the sense that a minimum configuration compact pπnter system must be able to pπnt out photos, a minimum compact pπnter configuration contains at least a Pπnter Module 10 The Pπnter Module holds a single photographic image that can be pπnted out via its Memjet pπnter It also contains the 3V battery required to power the compact pπnter system In this minimum configuration, the user is only able to pπnt out photos Each time a user inserts a business card 130 into the slot in the Pπnter Module, the image in the Pπnter Module is pπnted onto the card The same image is pπnted each time a business card is inserted into the pπnter In this minimum configuration there is no way for a user to change the image that is pπnted The dispenser module 120 can be used to feed cards 130 into the Pnnter Module with a minimum of fuss, as shown in FIG 13 By connecting a Camera Module 20 to the minimum configuration compact pπnter system the user now has an instant pπnting digital camera in a pen, as shown in FIG 14 The Camera Module 20 provides the mechanism for captuπng images and the Pπnter Module 10 provides the mechanism for pπnting them out The battery in the Pπnter Module provides power for both the camera and the pπnter When the user presses the "Take" button 27 on the Camera Module 20, the image is captured by the camera 24 and transfeπed to the Pπnter Module 10 Each time a business card is inserted into the pπnter the captured image is pπnted out If the user presses "Take" on the Camera Module again, the old image in the Pπnter Module is replaced by the new image If the Camera Module is subsequently detached from the compact pπnter system, the captured image remains in the Pπnter Module, and can be pπnted out as many times as desired The Camera Module is simply there to capture images to be placed m the Pπnter Module FIG 15 shows a further configuration in which a Memory Module 30 is connected to the configuration of FIG 14 In the embodiment of FIG 15, the user has the ability to transfer images between the Pπnter Module 10 and a storage area contained in the Memory Module 30 The user selects the image number on the Memory Module, and then either sends that image to the Pπnter Module (replacing whatever image was already stored there), or bπngs the cuπent image from the Pπnter Module to the specified image number in the Memory Module The Memory Module also provides a way of sending sets of thumbnail images to the Pπnter Module Multiple Memory Modules can be included in a given system, extending the number of images that can be stored A given Memory Module can be disconnected from one compact pπnter system and connected to another for subsequent image pnnting With the Camera Module 20 attached to a Memory Module/Pπnter Module compact pπnter system, as shown in FIG 15, the user can "Take" an image with the Camera Module, then transfer it to the specified image number in the Memory Module The captured images can then be pπnted out in any order By connecting a Communications Module 40 to the minimum configuration compact pπnter system, the user ga s the ability to transfer images between a PC and the compact pπnter system FIG 16 shows the configuration of FIG 15 with the addition of a Communications Module 40 The Communications Module makes the Pπnter Module 10 and any Memory Modules 30 visible to an external computer system This allows the download or uploading of images The communications module also allows computer control of any connected compact pπnter modules, such as the Camera Module 20 Each module is visible on the Seπal Bus Each module is self identifying and self-configuπng using standard USB protocols Apart from the standard protocol functions (including identification), there are a number of functions to which each module is also capable of responding These are outlined in Table 1 Each module also has a number of module-specific functions These commends allow the modules to be controlled by an external device, such as a personal computer, and by other modules Table 1 Basic Module Functions The 8-bit mode returned by GetlmageAccessMethods is interpreted as follows The 8-bit mode used for image read and wπte access via Getlmage, Storelmage and Transferlmage is interpreted as follows In some situations, certain modules may be configured without the pπnter module For example, it may be convenient to configure a camera module 20 and a memory module 30 for captuπng and stoπng images for later pπnting by the pπnter module 10 The timer module 60 and the flash module 50 may be added to the camera module 20 and memory module 30 to produce a digital camera having many of the features of a conventional camera Additional memory modules can easily be added to provide virtually unlimited memory storage The above commands allow images to be transfeπed to and from the modules without going through the pπnter module For example, the Memory Module 30 can act under control of the Timer Module 60 to transfer a captured image from the Camera Module 20 to the Memory Module 30 using the Transferlmage command The Camera Module 20 will have a module specific 'capture' command for capturing an image In the general case, the Pπnter Module holds the "cuπent" image, and the other modules function with respect to this central repository of the current image The Pπnter Module is therefore the central location for image interchange in the compact pπnter system, and the Pπnter Module provides a service to other modules as specified by user interaction A given module may act as an image source It therefore has the ability to transfer an image to the Pπnter Module A different module may act as an image store It therefore has the ability to read the image from the Pπnter Module Some modules act as both image store and image source These modules can both read images from and wπte images to the Pπnter Module's cuπent image The standard image type has a single conceptual definition The image definition is deπved from the physical attπbutes of the pπnthead used in the Pπnter Module The pπnthead is 2 inches wide and pπnts at 1600dpi in cyan, magenta and yellow bi-level dots Consequently a pπnted image from the compact pπnter system is 3200 bi-level dots wide The compact pπnter system pπnts on business card sized pages (85mm x 55mm) Since the pπnthead is 2 inches wide, the business cards are pπnted such that 1 line of dots is 2 inches 2 inches is 508mm, leaving a 2mm edge on a standard business-card sized page The length of the image is deπved from the same card size with a 2mm edge Consequently the pπnted image length is 81mm, which equals 5100 1600dpi dots The pπnted area of a page is therefore 81mm x 51mm, or 5100 x 3200 dots To obtain an integral contone to bi-level ratio a contone resolution of 267 ppi (pixels per inch) is chosen This yields a contone CMY page size of 850 x 534, and a contone to bi-level ratio of 1 6 in each dimension This ratio of 1 6 provides no perceived loss of quality since the output image is bi-level The pπnthead pπnts dots in cyan, magenta, and yellow ink The final output to the pπnted page must therefore be in the gamut of the pπnthead and take the attπbutes of the inks into account It would at first seem reasonable to use the CMY color space to represent images However, the pπnter' s CMY color space does not have a linear response This is definitely true of pigmented inks, and partially true for dye-based inks The individual color profile of a particular device (input and output) can vary considerably Image capture devices (such as digital cameras) typically work in RGB (red green blue) color space, and each sensor will have its own color response characteπstics Consequently, to allow for accurate conversion, as well as to allow for future image sensors, inks, and pπnters, the CIE L*a*b* color model [CIE, 1986, CIE 15 2 Coloπmetry Technical Report (2 nd Edition), Commission Internationale De l'Eclairage] is used for the compact pπnter system L*a*b* is well defined, perceptually linear, and is a superset of other traditional color spaces (such as CMY, RGB, and HSV) The Pπnter Module must therefore be capable of converting L*a*b* images to the particular pecuhaπties of its CMY color space However, since the compact pπnter system allows for connectivity to PCs, it is quite reasonable to also allow highly accurate color matching between screen and pπnter to be performed on the PC However the pπnter driver or PC program must output L*a*b* Each pixel of a compact pπnter image is therefore represented by 24 bits 8 bits each of L*, a*, and b* The total image size is therefore 1,361 ,700 bytes (850 x 534 x 3) Each image processing module is able to access the image stored the Pπnter Module The access is either to read the image from the Pπnter Module, or to wπte a new image to the Pπnter Module The communications protocol for image access to the Pπnter Module provides a choice of internal image organization Images can be accessed either as 850 x 534 or as 534 x 850 They can also be accessed in interleaved or planar format When accessed as interleaved, each pixel in the image is read or wπtten as 24 bits 8 bits each of L*, a*, b* When accessed as planar, each of the color planes can be read or wπtten independently The entire image of L* pixels, a* pixels or b* pixels can be read or wπtten at a time The Memory Module 30 is a standard module used for stoπng photographic images The memory module stores 48 images, each of which can be accessed either at full resolution or at thumbnail resolution Full resolution provides read and wπte access to individual images, and thumbnail resolution provides read access to 16 images at once in thumbnail form FIG 17 shows a magnified perspective view of the Memory Module 30, as previously descπbed with reference to FIG 3 An optional LCD 32 provides visual feedback It contains a 2-dιgιt numeπcal display representing the image number An icon 38 below the number is visible when thumbnails are selected, and a seπes of block segments 39 are also present to provide feedback duπng image transfer As shown in FIG 17, LCD 32 is showing all segments active The LCD is optional as visual feedback can be provided by a LCD in another module from information transmitted on the Seπal Bus FIG 18 is an exploded perspective view of the Memory Module 30 The LCD 32 is mounted on a flexible pπnted circuit board (PCB) 300 With reference to FIG 19, also formed on the PCB 300 is an image processor which is suitably an application specific integrated circuit (ASIC) 350 and a 64 MBit (8 MB) Flash memory 365 for image storage ASIC 350 and Flash memory 365 are depicted as a unit 330 in FIG 18 In reference to FIG 18, the SELECT button 35 is a double button and operates in the manner of a known rocker switch to increment or decrement the image number Selections made using the SELECT button 35 are communicated to the PCB 300 via contact 301 The flexible PCB 300 is mounted on a support 303 of chassis molding 302 In the preferred embodiment the PCB 300 is mounted such that the LCD 32 lies substantially parallel with a front face 304 of the support 303 The flexible PCB 300 passes over the support such that the ASIC and the Flash memory unit 330 lies substantially parallel with a back face 305 of the support 303 The flexible PCB 300 passes under the unit 330 and extends away from the base 306 of the chassis molding 302 The contact 301 conforms to a curved edge of the support 303 allowing the base of SELECT button 35 to e substantially parallel with a side face 310 of the support The male bayonet connector 37 compπses a cap molding 307, a latch stπp 308 and a plurality of contact stπps 309 The upper end of the cap molding is essentially dome-shaped and compπses two holes 311 positioned diametrically opposite each other The holes 311 are positioned and shaped to receive the folded ends 312 of latch stπp 308 The lower end of the cap molding 307 compπses an elongated section 313 that is shaped to cany contact stπps 309 The contact stπps extend from the upper end of the cap molding, where they form part of the male connector 37, to the bottom of the elongated section 313 The bottom of the elongated section fits into a recess 31 in the base 306 of the chassis molding such that the contact stπps 309 form part of the female bayonet connector 36 Raised portions 315 of the contact stπps 309 fit into an aperture 316 m the elongated section 313 of the cap molding Contacts on the flexible PCB 300 mate with the raised portions 315 to make contact with the Seπal Bus The IN button 33 and the OUT button 34 are incorporated in a molding 317 A contact in the base of the molding for each button connects with the PCB 300 when one or other of the buttons is pressed The internal components of the Memory Module 30 are contained within a metal extrusion 318 that compπses a plurality of apertures It is clear from FIG 18 the manner in which the buttons 33, 34 and 35, and the male connector 37 protrude from the extrusion through the associated apertures to perform their function A fascia molding 319 clips into the aperture 320 and provides a protective cover for the LCD 32 The Memory Module 30 connects to a compact pπnter configuration via the male connector 37 or the female connector 36 Either the male or the female bayonet connector joins the Memory Module to the Seπal Bus via contact stπps 309 Power is provided to the Memory Module from the Pπnter Module 10 via the Seπal Bus Alternatively, the Memory Module may be connected to a compact pπnter configuration via both the male and female bayonet connectors An example of this pπnciple is shown in FIG 16 where the Memory Module 30 is connected to the Pπnter Module 10 via its male connector and is connected to the Communications Module 40 via its female bayonet connectors The Memory Module may also be connected directly to the Camera Module to store images captured by an image sensor in the Camera Module The Memory Module may then be connected to the Pπnter Module at a later time to pπnt the captured images A separate power module will need to be connected to provide power Three buttons operate the Memory Module and feedback is given via a LCD The two pπncipal operations are to transfer an image to the Pπnter Module 10, or to read an image from the Pπnter Module or the Camera Module In both cases, the LCD displays the number of the image read or sent The SELECT button 35 changes the image number on the LCD display The numbers simply cycle between 1 and the storage capacity of the Memory Module, followed by a number of thumbnail sets (1 to n, 1 for each 16) In a Memory Module that stores 48 images the numbers cycle between 1 and 48, followed by 1 to 3 While the thumbnail number is being shown, the LCD thumbnail icon 38 is also displayed Pressing the OUT button 34 sends the current image number (or thumbnail set) to the Pπnter Module 10 Pressing the IN button 33 loads the image from the Pπnter Module or Camera Module into the named module If the cuπent setting is a thumbnail number the IN button does nothing A small animation takes place duπng the transfer process to let the user know that the image transfer is taking place The animation consists of a number of small black segments 39 being enabled on the left side of the LCD showing the proportionate amount of data successfully transfeπed The visual effect is that of a thermometer style status bar The transfer time and animation time is approximately 1 5 seconds, but the status bar is important for user feedback The Memory Module 30 is also visible on the Seπal Bus as an image storage device This enables the Memory Module to be controlled externally, either as a source or a destination for images The USB Module 40 makes any present Memory Modules visible to an external computer system, allowing the download or upload of images to each one When multiple Memory Modules are present in a configuration, they are each controlled individually by the user The operation of one Memory Module does not interfere with another Since each module can be controlled by a computer or by another module, it is possible to attach a module that makes specific use of a Memory Module 30 One example of this kind of module is the Timer Module 60 which is descπbed in detail in a co-pending application titled Timer Module for Compact Pπnter System The Memory Module provides a black-box storage mechanism for images Any propπetary image storage format can be used, or changed over time since the stored image format is not externally available Since memory storage for multiple images is still somewhat expensive, image compression is used Thus, the Memory Module contains 2 chips as mentioned earlier The Memory Module contains 64 MBit (8 MB) Flash memory 365 for image storage and controlling image processor 350 with on-board image compression hardware The number of images that can be stored in the 64 MBit Flash memory is directly tied to the specific compression mechanism used The storage of images in the memory module will now be descπbed Uncompressed, an image requires 1 3 MB (850 x 534 x 3 bytes = 1,361,700 bytes) A 64 MBit DRAM would only be able to store 6 images We therefore use JPEG compression to compress the contone data Although JPEG is inherently lossy, for compression ratios of 10 1 or less the loss is usually negligible (Wallace , G K , "The JPEG Still Picture Compression Standard" , Communications of the ACM, 34 ( 4 ) , April 1991 , pp 30 -44) This yields a contone image size of 130KB, allowing the storage of between 50 and 60 images The JPEG compression algoπthm (ISO/ IEC 19018- 1 1994 , Information technology - Digi tal compression and coding of continuous- tone still images Requirements and guidelines , 1994) compresses a contone image at a specified quality level in a lossy manner It introduces imperceptible image degradation at compression ratios below 5 1 and negligible image degradation at compression ratios below 10 1 (Wallace , G K "The JPEG Still Picture Compression Standard" , Communi cations of the ACM 34 ( 4 ) , April 1991 , pp 30 -44) JPEG typically first transforms the image into a color space that separates luminance and chrominance into separate color channels This allows the chrominance channels to be sub-sampled without appreciable loss because of the human visual system's relatively greater sensitivity to luminance than chrominance After this first step, each color channel is compressed separately The image is divided into 8x8 pixel blocks Each block is then transformed into the frequency domain via a discrete cosine transform (DCT) This transformation has the effect of concentrating image energy in relatively lower- frequency coefficients, which allows higher-frequency coefficients to be more crudely quantized This quantization is the pπncipal source of compression in JPEG Further compression is achieved by ordeπng coefficients by frequency to maximize the likelihood of adjacent zero coefficients, and then runlength-encoding runs of zeroes Finally, the runlengths and non-zero frequency coefficients are entropy coded Decompression is the inverse process of compression Images in the compact pπnter system of the invention are in the L*a*b* color space as descπbed earlier, and are therefore already separated into luminance and chrominance channels It is quite reasonable for the luminance channel to use one set of Huffman tables, and the chrominance channels to share another set In addition, the chrominance channels can be sub-sampled Finally, it should be noted that the images have a fixed resolution of 850 x 534 Any JPEG implementation can therefore be tailored to this resolution and does not have to be general At the end of compression, a JPEG byte stream is complete and self-contained It contains all data required for decompression, including quantization and Huffman tables A low complexity ASIC 350 provides the processing power of the Memory Module The elements of the ASIC are shown in FIG 19 The ASIC includes a JPEG core 351, a Seπal Bus interface core 352, a microcontroller core 353, a small amount of program ROM 354 and a small amount of RAM 355 for program scratch Also included in the ASIC is a memory decoder 356, parallel interface 357 (that communicates with the LCD and vaπous buttons) and a memory interface 358 A Joint Test Action Group unit 359 may be included for self-test purposes In some circumstances a clock 360 and crystal oscillator 261 may be required Although an ASIC is shown in the embodiment, it is envisaged that alternatives known m the art, such as VLSI, may be used to configure the image processing chip Images from the Memory Module 30 must be made available in both planar and interleaved formats How this is accomplished will depend on the ability of the JPEG core 351 If the core is only capable of compressing/decompressing a single channel at once, limited buffeπng may be required The combination of the Memory Module 30 with the Pπnter Module 10 constitutes a minimum compact pπnter system that allows one or more images stored in the Memory Module to be pπnted This combination also allows an image stored in the Pπnter Module 10 to be stored in the Memory Module 30 The combination of the Memory Module 30 with a Camera Module 20 constitutes a digital imaging system This combination allows an image captured by the Camera Module to be stored in the Memory Module Throughout the specification the aim has been to descπbe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features Persons skilled in the relevant art may realize vaπations from the specific embodiments that will nonetheless fall within the scope of the invention

Claims: CLAIMS 1 A memory module compπsing a body, memory means within said body for stoπng images, an image processor within said body that transfers one or more images from said memory means or to said memory means from an image source, at least one connection means incorporated in said body for connecting said memory module to a bus providing power and data between said memory module and said image source 2 The memory module of claim 1 having two or more connection means incorporated in said body, at least one connection means connecting said memory module to at least said image source 3 The memory module of claim 1 having two or more connection means incorporated in said body including a first connection means connectable to said image source and a second connection means connectable to further said memory modules in a stackable manner 4 The memory module of claim 1 having two or more connection means incorporated m said body, said two or more connection means providing through connection to said image source and one or more further modules of a compact pπnter system 5 The memory module of claim 1 wherein said image processor includes compression means for compressing said one or more images before stoπng said image in said memory means 6 The memory module of claim 5 wherein compression means performs decompression of said image when transfemng said image from said memory means 7 The memory module of claim 5 wherein said compression means is a JPEG compression unit 8 The memory module of claim 1 wherein said image source is a camera module of a compact pπnter system 9 The memory module of claim 1 wherein said image source is a pπnter module of a compact pπnter system 10 The memory module of claim 1 wherein said images stored in said memory means can be accessed at full resolution or at thumbnail resolution 11 The memory module of claim 1 further compπsing a LCD within said body connected to said image processor and providing information about said stored images 12 The memory module of claim 11 wherein said LCD is capable of displaying a plurality of icons indicative of image reference number, image type and image transfer status 13 The memory module of claim 1 wherein said memory means is an 8 MB flash memory 14 The memory module of claim 1 wherein said at least one connection means compπses a male bayonet fitting providing physical connection between said memory module and said image source 15 The memory module of claim 1 wherein said at least one connection means compπses a female bayonet fitting providing physical connection between said memory module and said image source 16 The memory module of claim 1 further compπsing a SELECT button to increment or decrement an image reference number 17 The memory module of claim 1 further compπsing an IN button to load an image from said image source into said memory module 18 The memory module of claim 1 further compπsing an OUT button to send a cuπent image or thumbnail set of images on said bus 19 The memory module of claim 1 wherein said bus is a Seπal Bus 20 The memory module of claim 1 wherein said bus enables said memory module to be controlled externally allowing the download or upload of images from/to said memory module 1 The memory module of claim 1 wherein said image processor is an application specific integrated circuit A memory module for a compact pπnter system compπsing, a body, memory means within said body for stoπng images, an image processor within said body connected to said memory means that transfers one or more images from an image source to said memory means and transfers one or more stored images from said memory means to a pπnter module, at least one connection means at an end of said body for connecting said memory module to a bus providing power and data between said memory module, said image source and said pπnter module The memory module of claim 22 having two or more connection means incorporated in said body including a first connection means connectable to said pπnter module and a second connection means connectable to further said memory modules in a stackable manner A method of stoπng images in a compact pπnting system compπsing the steps of reading an stored image from a first storage location to an image processor, applying compression or decompression to said stored image, and wπting a resultant image to a second storage location The method of claim 24 wherein said compression or decompression is JPEG The method of claim 24 wherein said first storage location is a pπnter module of said compact pπnter system and said second storage location is an 8 MB flash memory in a memory module of said compact pπnter system The method of claim 24 wherein said first storage location is a camera module of said compact pπnter system and said second storage location is an 8 MB flash memory in a memory module of said compact pπnter system The method of claim 24 wherein said first storage location is an 8 MB flash memory m a memory module of said compact pπnter system and said second storage location is a pπnter module of said compact pπnter system

Inventors: SILVERBROOK KIA, WALMSLEY SIMON ROBERT, SILVERBROOK, KIA, WALMSLEY, SIMON, ROBERT
Applicants: SILVERBROOK KIA, SILVERBROOK RES PTY LTD, WALMSLEY SIMON ROBERT, SILVERBROOK RESEARCH PTY LTD, SILVERBROOK, KIA, WALMSLEY, SIMON, ROBERT
Application year: 2000
Main classification: B41J2
IPC codes: B41J2, B41J3, B41J13, B41J23, B41J29, H04N1, H04N5