JP4670577B2 - Printer - Google Patents

Description

  The present invention relates to a printer, and more particularly to a printer that prints using RAW data.

  Conventionally, a RAW data format in which pixel data of a color image sensor is digitally recorded as it is as a data recording format of an image input device such as a digital camera is known. Color image sensors usually have R (red), G (green), and B (blue) color filters for each pixel, so RAW data that has only one color component per pixel The image to be represented is incomplete information. Therefore, a demosaic process (also referred to as a color filter array interpolation process) that generates a color image having three color components for each pixel by predicting and interpolating at least the missing color component of each pixel with the color components of neighboring pixels. Until RAW data is applied to the RAW data, an image representing the object cannot be printed. There is an urgent need for technical development for printing images using RAW data files on printers with severe manufacturing and development cost constraints.

JP-A-2005-33468

  An object of the present invention is to make it possible to print an image from RAW data by a printer with severe restrictions on manufacturing and development costs.

(1) A printer for achieving the above object includes an input unit that inputs RAW data, an image generation unit that generates an image from the RAW data using demosaic processing, and a printing unit that prints the image. Prepare.
By adding a function for generating an image from RAW data to the printer using demosaic processing, the printer can print an image from the RAW data.

(2) The image generation means may generate the image in a general format from the RAW data. The printing unit may print the image in the general-purpose format.
Reduces manufacturing and development costs for printers that can print images in general format by generating images in general format defined by standards beyond the framework of printer manufacturers when generating images from RAW data However, an image can be printed from the RAW data.

(3) The printer further includes compression means for compressing the image for each block and storing the compressed image in a storage medium, and expansion means for expanding the image stored in the storage medium for each band to be printed. Good. The printing unit may generate print data for each print target band from the expanded image, and print the print target band for each print target band based on the print data.
Generally, print data has a density control value corresponding to the number of colors of ink or toner for the number of pixels corresponding to the printing resolution (the density control value includes binary values), and therefore the data size is considerably larger than that of an image. Therefore, it is possible to save storage resources such as a memory by generating print data for each band to be printed and executing printing for each band to be printed. However, in order to execute image processing such as rotation inside the printer, the entire image must exist statically in the storage space. For example, a digital camera generally records an image in a landscape format, but a printer often prints an image in a portrait orientation in order to suppress skew feeding of paper, so in a stand-alone printer, rotation processing by the printer is indispensable. is there. However, holding the print data in the internal memory while holding the entire image in the internal memory has a problem of greatly increasing the required capacity of the internal memory. For this reason, in a conventional printer, printing is executed while an image stored in a removable memory is read discretely for each band to be printed. However, if an image generated from RAW data is to be printed, the entire generated image needs to be held. If the image is held in the internal memory of the printer, a significant increase in manufacturing cost is inevitable. The problem is that the image generated from the RAW data is compressed block by block and stored in a storage medium, the compressed image is expanded for each print target band, and the print data is generated for each print target band from the expanded image. It is solved by doing. This is because the entire image can be held in the memory space by compressing the image block by block, and the data in the area that is not the band to be printed is held in the memory space in a compressed state. This is because print data can be generated while expanding an image for each band to be printed.

(4) The expansion unit may set the band to be printed so as to divide the image in the horizontal direction.
When printing horizontally long images (images with more horizontal pixels than vertical pixels) in the horizontal direction (when pixels aligned in the horizontal direction are printed sequentially according to the paper feed distance), or vertically long images When printing in the vertical direction, it is necessary to execute image expansion and print data generation for each band to be printed in which the image is divided in the horizontal direction. Printing a horizontally long image in the horizontal direction of the image corresponds to printing by rotating the image.

(5) The general-purpose format may be a JFIF format.
Since the JFIF format is a JPEG format image file format, it is highly versatile.

(6) The general-purpose format may be an Exif format.
Since the Exif format is a de facto standard file format for digital cameras, it is highly versatile.

(7) The compression unit may irreversibly compress the image with a quantization step width corresponding to a free capacity of the storage medium.
The lossy compression with quantization has an advantage that the data size of the image can be reduced as the quantization step width is increased, but there is a problem that the image quality deterioration becomes more significant as the quantization step width is increased. Therefore, the user-friendliness of the printer is improved by giving priority to the image quality when the free space of the storage medium is sufficient, and giving priority to printing even when the image quality deteriorates when the storage medium is insufficient.

(8) The printer may further include a user interface that notifies the user of the degree of image quality degradation due to the compression and receives a print stop request from the user.
By providing such a user interface in the printer, it is possible to prevent an image from being printed with an unintentional quality, thereby further improving the ease of handling of the printer.

(9) The storage medium may be an external storage medium.
By storing an image generated from RAW data in an external storage medium such as a removable memory, a hard disk, or an internal memory of an external system, it is possible to print an image from RAW data even when the free space of the internal memory is insufficient. The possibility increases.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other. The present invention can be specified not only as an apparatus invention but also as a program invention, a recording medium recording the program, and a method invention.

Hereinafter, embodiments in which the present invention is applied to a stand-alone printer will be described in the following order.
1. Printer configuration2. 2. Operation of printer 2-1. Raw data print setting-Free space securing process-Development correction setting process 2-2. Raw data processing 2-3. 2. Image printing process Other embodiments

1. Configuration of Printer FIG. 2 is a block diagram showing a schematic configuration of a printer 1 to which the present invention is applied. The printer 1 is a so-called stand-alone printer that can read RAW data and images in a general-purpose format from the removable memory 10 and can print based on these data. The printer 1 can directly input RAW data or an image in a general format from an external system such as a digital camera 30, a PC (Personal Computer) 32, or a camera-equipped mobile phone terminal 34, and can print based on the image. .

  An external interface (IF) 20 as an input means includes a USB controller, a USB connector, and the like for communicating with an external system such as a digital camera 30, a PC 32, and a camera-equipped mobile phone terminal 34. The communication standard is not limited to USB, and may be any standard such as IEEE 1394, infrared, Ethernet (registered trademark). By providing the external IF 20 with a USB host function, the printer 1 can access a storage medium belonging to the external system when the external system supports the USB mass storage standard. In addition, even when there is a shared storage medium such as a hard disk in the LAN to which the printer 1 is connected, the printer 1 can output data to a storage medium under the control of an external system. That is, even if the storage medium is under the control of an external system, the printer 1 can temporarily store an image generated from the RAW data, and the printer 1 can also read the temporarily stored image therefrom. Further, the storage capacity of the printer 1 can be increased by providing the printer 1 with a hard disk device.

  A removable memory controller (RMC) 12 as input means is connected to a removable memory 10 as an external storage medium via a connector (not shown), and controls data transfer between the removable memory 10 and the RAM 14. The removable memory 10 may be a card-type flash memory (so-called memory card) or any other repetitively writable nonvolatile storage medium.

  The image processing unit 16 is an image processing LSI or DSP for executing image correction processing such as sharpness correction processing / tone correction processing, separation processing, halftoning, interlace processing, etc. at high speed in cooperation with the CPU 22. Composed. In addition, you may perform these processes by the program process by CPU22. Further, a JPEG compression / decompression function may be added to the image processing unit 16 to speed up the JPEG compression / decompression process.

The printing unit 18 as a printing unit includes a recording head for forming an image on a sheet by an ink jet method based on print data, a reciprocating mechanism of the recording head, a paper supply / discharge mechanism, and the like. As the printing method, any printing method such as an ink jet method, a laser method, a thermal method, or a dot impact method can be adopted.
The RAM 14 is a volatile memory that temporarily stores a control program and data to be processed by the control program, such as RAW data, images, and print data.
The CPU 22 as an image generation unit, a compression unit, a decompression unit, and a printing unit executes a control program stored in the flash memory 24 to generate an image from raw data using demosaic processing, JPEG compression / Image processing such as decompression processing is executed, and each part of the printer 1 is controlled to control execution of printing. The control program may be transferred from a computer-readable storage medium to the flash memory 24, or may be transferred from a remote server to the flash memory 24 via a network.

The operation unit 26 is provided with operation buttons for accepting user menu operations and print requests, a jog dial, and various other buttons. When a specific button is pressed in a specific mode, various requests corresponding to the mode are input to the printer 1.
The display unit 28 includes an FPD (Flat Panel Display) 27 (see FIG. 7) such as an LCD, a graphic controller, and the like. A frame memory area necessary for displaying characters and images on the FPD 27 may be secured in a dedicated memory of the display unit 28 or may be allocated to a partial area of the RAM 14. Characters and images displayed on the FPD 27 are updated by periodically reading data written in the frame memory area by the graphic controller.
The access indicator 19 includes a light such as an LED and a controller for notifying the user that data transfer is being performed between the RMC 12 and the RAM 14.

2. Operation of Printer FIG. 3 is a flowchart showing the operation of the printer 1. The process shown in FIG. 3 is activated when a user selects a RAW data file as a print target in the print target file selection mode. In the print target file selection mode, thumbnail images stored in the RAW data file and display images with a reduced VGA size are displayed on the FPD. The image to be displayed can be specified by analyzing the file header. A display image having a larger VGA size or the like than the 160 × 120 pixel thumbnail image is displayed on the FPD 27 with high definition, so that the user can predict the printing result more accurately. Therefore, if the manufacturer or model of the digital camera stored in the file header determines that a larger image than the thumbnail image is stored in the RAW data file, the larger image is displayed. When no image is stored in the RAW data file (in the present specification, the RAW data is described as not an image), the printer 1 can generate a reduced image of about VGA size with a simpler high-speed algorithm. Good. Specifically, for example, the demosaic processing is accelerated by generating an image having a resolution of 1/2 of the RAW data in each of the vertical direction and the horizontal direction, white balance correction processing, luminance correction processing, suspicious color suppression processing, etc. The generation of a reduced image can be speeded up by omitting.

  When a RAW data file is selected as a printing target, the printer 1 roughly executes two processes. They are RAW data print setting processing and print processing. In the RAW data print setting process, the printer 1 determines the free capacity of the removable memory 10. If there is not enough free capacity, the printer 1 requests the user to cope with it or accepts an image development correction setting change request. In the printing process, the printer 1 reads RAW data from the removable memory 10, generates an intermediate image in a general format from the RAW data, stores the generated intermediate image in the removable memory 10, and removes the intermediate image in the general format generated by itself. While reading from the memory 10, the intermediate image is printed.

  Note that the data format of the intermediate image handled in the process of printing the image from the RAW data by the printer 1 will be described using JPEG as an example in the present embodiment, but is not limited thereto, and other general-purpose formats such as JPEG2000, BMP, TIFF, and the like However, the data format may be optimized at the expense of versatility. The file format including attribute information other than the intermediate image is the same, and in this embodiment, Exif will be described as an example. However, a file format in which a part of the Exif standard is changed may be used. The JPEG file format may be a JFIF format, or may be a file format optimized at the expense of versatility.

2-1. Raw Data Print Setting In step S050, the printer 1 determines whether or not the removable memory 10 is in a writable state. For example, it is determined whether the write prohibition determination member is at the write prohibition position and the removable memory 10 is write protected. When a plurality of removable memories 10 can be connected to the RMC 12 at the same time, the printer 1 may determine that writing is possible if one or more removable memories 10 are writable. In this case, the writable removable memory 10 is set as a target for storing the intermediate image. Alternatively, printing based on the RAW data is executed only when a dedicated removable memory for storing the intermediate image is connected to the RMC 12 separately from the user's removable memory 10 in which the RAW data file is stored. Also good.

  If the removable memory 10 is not writable, the printer 1 displays on the FPD 27 a message that prompts replacement of the removable memory 10. For example, as shown in FIG. 8A, a message “Please replace with a writable removable memory” is displayed on the FPD 27. Alternatively, a message that prompts the user to cancel the write prohibition of the removable memory 10 may be displayed on the FPD 27. For example, the message “The memory card is set to write-protect. Please release the write-protect” may be displayed on the FPD 27. Note that the printer 1 may request exchange or cancellation of write prohibition by voice. When a predetermined operation button of the operation unit 26 is pressed while the message is being displayed, the printer 1 returns to step S050 and resumes processing.

  In step S <b> 100, the CPU 12 determines the free capacity of the removable memory 10. Specifically, for example, the data size of the intermediate image is predicted for each compression quality from the number of pixels of the RAW data to be printed, and when the free space is insufficient even at the minimum quality, it is determined as “absolute shortage” and step S104 is performed. Subsequent free space securing processing proceeds, and if the free space is sufficient even at the highest quality, it is determined as “sufficient”, the development correction setting processing after step S120 or the printing processing after step S130 proceeds, and the highest quality is achieved. If there is not enough free space, but the minimum quality is sufficient, the free space is determined to be “slightly insufficient”, and the process of step S102 described below proceeds.

  In step S102, the user is informed that the free capacity of the removable memory 10 is not sufficient, and that printing can be performed by reducing the compression quality or deleting unnecessary data. Specifically, for example, the printer 1 displays a message as shown in FIG. 8B on the FPD 27 to request selection of any one of print cancellation, data deletion, and compression rate increase. When the print cancellation is selected, the process ends for the RAW data to be printed. When printing is cancelled, the printer 1 displays a message to the effect that “printing is not possible. Printing will be stopped” on the FPD 27 and cancels the printing process. When data deletion is selected, the free space securing process after step S106 proceeds. When the compression rate increase is selected, the highest compression quality is displayed on the FPD 27 in numbers, high / medium / low, etc. within the constraints of the free capacity of the removable memory 10 and the number of RAW data pixels, and the compression quality is approved. Then, the quantization table changing process in step S116 proceeds. The approval and rejection of the compression quality is input, for example, when a predetermined button of the operation unit 26 is pressed in a state where the message of FIG. 8C is displayed. If the rejection of the compression quality is selected, a transition is made to the screen shown in FIG. In order to determine the highest compression quality within the constraints of the free capacity of the removable memory 10 and the number of pixels of the RAW data, the CPU 12 refers to, for example, a table in which the free capacity, the number of pixels, and the compression quality are associated with each other, A predetermined calculation is executed.

  In step S116, a quantization table corresponding to the compression quality approved by the user is set. The quantization table is a table in which the quantization step width is defined stepwise according to the DCT coefficient. As the quantization step width increases, the image quality degradation after stretching becomes more prominent, and as the quantization step width decreases, the image quality degradation after decompression is suppressed. If it is determined in step S100 that the free space is “sufficient”, the highest quality quantization table, which is the default setting, is used for compression.

Free Space Securing Process In step S104, the printer 1 requests the user to select data deletion or print cancellation for increasing the free space in the removable memory 10. Specifically, for example, the printer 1 displays the menu shown in FIG. 7 on the FPD 27 and accepts selection of data deletion or print cancellation. When a predetermined button of the operation unit 26 is pressed, either data deletion or print cancellation is selected. When the print cancellation is selected, the process for the RAW data to be printed is terminated.

  When data deletion is selected, the printer 1 displays a file deletion menu 33 on the FPD 27 (step S106). In the file deletion menu 33, images to be deleted are sequentially displayed one by one in accordance with, for example, button operation or rotation of the jog dial. The file deletion menu 33 also displays the required free space and the data size of the image being displayed. The user can select a file to be deleted by operating a button or jog dial to display a target image.

  When a deletion request is generated (step S108), the CPU 22 causes the RMC 12 to delete the deletion target file from the removable memory 10 (step S110). Specifically, for example, when the user presses a predetermined button in the file deletion menu 33, the deletion request is generated for the file selected at that time. When a file is deleted from the removable memory 10, the processes after step S100 are repeated.

  When deletion rejection occurs (step S112), the CPU 22 ends the printing process. Specifically, for example, the rejection of the deletion occurs when the user presses a predetermined button while the above-described message is displayed.

Development correction setting process When a development correction setting change request is generated in step S120, the following development correction setting process is executed. The development correction setting change request is generated when a predetermined button is pressed.
In step S122, the printer 1 sets a development correction operation value in accordance with a user operation. Specifically, for example, when the dialog screen shown in FIG. 8D is displayed on the FPD 27 and, for example, an EV operation value (development correction operation value) of “+1” is selected, an EV operation value of “+1” is set. At the same time, a control value in which the brightness is increased by 1 in terms of EV (Exposure Value), that is, a brightness control value in which the brightness is doubled in terms of brightness is set. It should be noted that control values other than the luminance correction processing, for example, operation values for sharpness correction processing and white balance correction processing may be settable. The sharpness operation value that can be set in this manner is corrected as will be described in detail later, and is attached to the intermediate image as “image correction control information for obtaining a preferable print result”.

In step S124, the CPU 22 executes image processing corresponding to the development correction operation value on the reduced image displayed on the FPD 27 in the print target file selection mode. Specifically, correction processing (luminance correction processing, sharpness correction processing, white balance correction processing, etc.) in which the control value set in step S122 is applied to a VGA size reduced image stored in the file to be printed. Is executed.
In step S126, the printer 1 updates the reduced image displayed on the FPD 27 to the reduced image after retouching in the print target file selection mode. Specifically, the reduced image in the frame memory area is rewritten to a reduced image after retouching, and the display of the FPD 27 is updated. Since the reduced image after retouching is displayed on the FPD 27, the user can repeatedly set the development correction operation value until a satisfactory result is obtained while checking the retouching result on the screen. Note that, as described above, the printer 1 may execute display update reflecting the operation values of the sharpness correction process and the white balance correction process.

2-2. Print Processing When a print request is generated in step S130, the following print processing is executed. The print request is generated when a predetermined button is pressed.
In step S132, the CPU 22 starts blinking of the access indicator 19. The flashing of the access indicator 19 continues until the end of printing. The printer 1 reads RAW data and intermediate images from the removable memory 10 during printing, and writes intermediate images into the removable memory 10. Therefore, when the removable memory 10 is removed from the RMC 12 during printing, the printer 1 stores the removable memory 10 in the removable memory 10. There is a possibility that an intermediate image that cannot be deleted remains or the FAT of the removable memory is destroyed, so that data cannot be read normally. By blinking the access indicator 19 during printing, it is possible to prevent such a problem from occurring due to the user inadvertently removing the removable memory 10.

  In step S <b> 134, the printer 1 starts a process of guiding the printing progress status to the user by displaying a progress bar on the FPD 27. The display of the print progress status continues until the end of printing. Specifically, the progress bar tells the user in real time how many percent of the RAW development processing has progressed. For example, when the processing is completed about 20%, a progress bar indicating the progress of 20% with respect to the scale of 100% is displayed. Usually, in a printer, the processing speed of the CPU is slow due to manufacturing cost restrictions, and therefore, several minutes are consumed until an image is generated from RAW data. Such a progress bar display is very effective because the user's feeling of irritation is eliminated and the user can know that the process is progressing reliably.

In step S136, an intermediate image is generated from the RAW data, and the intermediate image is stored in the removable memory 10.
In step S138, the intermediate image is read from the removable memory 10, print data is generated from the intermediate image, and printing based on the print data is executed.
In step S140, the progress bar is displayed as 100%, and the display of the print progress status is completed.
In step S142, the CPU 22 ends the flashing of the access indicator 19.

RAW Data Processing FIG. 4 is a flowchart showing in detail the flow of RAW data processing in step S136 described above.
In step S200, the CPU 22 analyzes the attribute information of the file to be printed, and specifies the manufacturer of the digital camera, the model of the digital camera, shooting information (shooting date, aperture, shutter speed, etc.), print control information, development control information, and the like. To do. The print control information includes print size designation, print number designation, image correction control information for obtaining a preferable print result, and the like. DPOF (Digital Print Order Format) is well known as a standard for transmitting a print size designation and a print number designation from a digital camera to a printer. PIM (Print Image Matching) and Exif Ver2.2 are well known as standards for transmitting image correction control information for obtaining preferable print results from a digital camera to a printer. Development control information includes sharpness manipulation values, optical black values, gain information for each chromatic color component, brightness correction information, area image sensor color filter array information, and device color to restore sharpness reduction due to the low-pass filter Information for color space conversion from space to sRGB color space, gamma correction information, and the like are included. Since the development control information is unique to each digital camera, the file header information is analyzed for each camera, and the analysis result is applied to subsequent processing. In addition, DNG is proposed as a general-purpose standard for development control information. The essential difference between the image correction control information and the development control information for obtaining a preferable print result is that the former is defined as information applied only to the image, whereas the latter is basically It is defined as information applied to processing for generating an image from RAW data.

  The processing from step S202 to step S220 described in detail below is executed in units of blocks. That is, in the first step S202, the raw data of the processing target block is read from the removable memory 10 to the CPU 22 and the processing result is stored in the RAM 14, and in each subsequent step, the processing target block data is read from the RAM 14 to the CPU 14 and processed. The result is stored in the RAM 14. In the JPEG standard 422 system, the Cb and Cr components are subsampled in the horizontal direction, and the DCT calculation processing is performed for each 8 pixel × 8 pixel block for each of Y, Cb, and Cr components. An image is encoded every block of 8 pixels in the direction × 16 pixels in the horizontal direction. Accordingly, the vertical width of the block is set to 8 pixels or an integral multiple thereof, and the horizontal width is set to 16 pixels or an integral multiple thereof. It is efficient to execute the processing by setting the vertical width to 8 pixels, and the use efficiency of the memory is also good.

  FIG. 1 is a diagram schematically showing how data of a block to be processed is held in the RAM 14 until print data is generated from RAW data. The data size that occupies the memory space statically is indicated by a solid line, and the data size of the processing target block is indicated by hatching. The broken line indicates the size of the memory space that is cumulatively required to process the entire RAW data. Note that general RAW data is recorded with a gradation of 12 bits per pixel, but in the process of processing, in order to increase the access efficiency for each pixel, it is handled with one word (16 bits) per pixel. Is reasonable. In the present embodiment, description will be made assuming that the RAW data has a 16-bit representation.

  In step S202, the CPU 22 executes an optical black compensation process based on the optical black value. The optical black value represents a value obtained by AD-converting the amount of charge accumulated in the light receiving element that is not incident on the light provided in the image sensor of the image input device. That is, the optical black value indicates the zero level of the luminance of the pixel. When there is an optical black area in the RAW data, the average value of this area is used as the optical black value. When the optical black value is calculated in advance by the image input device and stored in the file header, it is used. The optical black compensation process is an important process for establishing the linearity of subsequent processes. In the optical black compensation process, the value indicated by the optical black value acquired from the file header is regarded as black, and the value indicated by the optical black value is subtracted from all the pixel values of the RAW data. In general, in the case of 12-bit RAW data, since the optical black value is about 32/4095 to 64/4095, the number of bits is not changed by the optical black compensation process. The data to be processed in step S202 is stored in the removable memory 10 as shown in S1 of FIG. 1, and the processing result in step S202 is stored in the RAM 14 with the same data size as before processing.

  In step S204, the CPU 22 executes white balance correction processing based on gain information for each chromatic color component. Although the spectral radiant energy distribution of an object is naturally different if the illumination environment is different, humans perceive the same object color as the same color even if the illumination environment is different. This tendency is called color constancy. On the other hand, the image sensor accumulates electric charges corresponding to each chromatic color component (described as RGB in this embodiment) in a balance according to the spectral radiant energy distribution of the object. For this reason, for example, the color balance of each RGB component is corrected so that an object that is perceived as an achromatic color (for example, white) in the daytime in a sunny day is represented by achromatic pixels (pixels having the same RGB value). Color balance correction is necessary. This color balance correction is white balance correction. In the color balance correction, an operation is basically performed to multiply each RGB component by a constant using gain information designated for each RGB component. As a result, the number of bits representing the pixel value increases or decreases, but since the original raw data of 12 bits per pixel is processed at 16 bits per pixel, the RAM 14 temporarily before and after the processing of step S204. The size of block data to be held does not change. As constants (normally about 0.5 to 4) to be applied to each RGB component, values as gain information calculated as optimum coefficients by the digital camera may be used as they are, or the CPU 22 determines in advance from RAW data. What is calculated by a given algorithm may be used.

  In step S206, the CPU 22 executes luminance correction processing based on the luminance correction information. For example, when the physical exposure of the digital camera is inappropriate, the brightness adjustment is performed after the image is captured by the digital camera in order to recover it. This is performed when luminance correction information is stored in the file header. The luminance may be adjusted by multiplying the luminance component by a constant, but the luminance may be corrected by multiplying each of the chromatic color components by a constant. Specifically, when +1 EV exposure compensation is performed on the RAW data, a process of multiplying a factor of 2 is performed, and when -1 EV exposure compensation is performed, a factor of 1/2 is multiplied. A multiplication process is performed. As a result, the number of bits representing the pixel value increases or decreases. However, since the original raw data of 12 bits per pixel is processed at 16 bits per pixel, the RAM 14 temporarily before and after the processing of step S206. The size of block data to be held does not change.

  In step S208, the CPU 22 executes demosaic processing according to the arrangement of the color filters of the area image sensor. The demosaic process is basically a process of compensating for a lack of chromatic color components between neighboring pixels having only one chromatic color component (for example, any one of R, G, and B) per pixel. As a result, each pixel having only one of RGB components has three RGB components, so the size of the block data to be temporarily stored in the RAM 14 is as shown in S2 of FIG. 3 times as much as before.

  In step S210, the CPU 22 executes a color reproduction process. Since the value of each color component of the RAW data depends on the spectral sensitivity characteristic of the image sensor of the image input device, it does not correspond to the tristimulus values defined by general-purpose standards such as sRGB. The color reproduction process is a process for representing the color light represented by the RAW data that is the input value with a stimulus value defined by a general-purpose standard such as sRGB, and for each of the three chromatic color components, linear mapping or non-color mapping is performed. This is a process of generating a stimulus value (a color value measured to be the same as the color of an imaged object by using a colorimeter) that represents a correct color according to a general-purpose standard using a linear mapping. Specifically, the stimulus value of each pixel is converted using a 3 × 3 matrix operation for the three RGB components or a three-dimensional LUT (Look Up Table). The matrix or 3D LUT used for this conversion is acquired as development control information from the file header, or the matrix or 3D LUT defined in advance by the printer vendor according to the model is set according to the model information acquired from the file header. be able to. The size of the block data to be held in the RAM 14 does not change before and after the process of step S210.

In step S212, the CPU 22 executes color space conversion from the RGB color space to the YCbCr color space. This process is a simple linear conversion process of the color space for adapting the intermediate image to the JPEG format. As a result, the block data to be held in the RAM 14 is in the state shown in S3 of FIG. The size of the block data to be temporarily stored in the RAM 14 before and after the process of step S212 does not change.
In step S214, the CPU 22 executes 422-type subsampling. As a result, spatial thinning is performed in the horizontal direction only for the color difference components of Cb and Cr. That is, the Y component is not processed, and the average value of the adjacent two pixels is spatially sampled for the Cb component and the Cr component. As a result, the size of the block data to be dynamically stored in the RAM 14 is 2/3 (= 1/3 + (1/3) × (1/2) + ( 1/3) × (1/2)).

  In step S216, the CPU 22 executes a suspicious color suppression process. In an area image sensor having a Bayer array color filter, the number of R and B light receiving elements is half the number of G light receiving elements, and therefore aliasing tends to appear in the R and B components by demosaic processing. For this reason, the suspicious color generated is suppressed by a flattening process using a median filter or the like.

  In step S218, the CPU 22 executes gradation reproduction processing. The brightness perceived by humans does not correspond to the brightness that is the photometric quantity of the image sensor. In general, the luminance is converted by a logarithmic function (eg, y = x ^ (1 / 2.2)) based on Weber-Fechner's hypothesis that the sensory amount is proportional to the logarithm of the stimulus amount. In order to avoid gradation loss due to saturation, it is possible to perform conversion in which gradation is gently suppressed in the highlight region. The conversion is executed using, for example, an LUT that is optimally defined for each model of the digital camera.

  In step S220, the CPU 22 executes JPEG compression processing. JPEG compression is a combination of DCT, quantization, and Huffman coding, and processing is executed for each block of 8 pixels in the horizontal direction and 8 pixels in the vertical direction. A predetermined quantization table determined in advance or the quantization table set in step S116 described above is applied to the quantization. The quantization step width is set so that the data stored in the removable memory 10 is, for example, about 1/6 to 1/4 before processing. As described above, the compression algorithm is not limited to JPEG, and any algorithm may be used as long as it is an algorithm for encoding for each block.

  The block data subjected to the JPEG compression process is cumulatively accumulated in another area of the RAM 14 (an area different from the area where the block data before JPEG compression is stored) by repeatedly executing the processes from step S202 to step S220. Stored in In the state where the processing from step S202 to step S220 has been repeatedly executed up to the final block (the state determined as Y in step S222), the JPEG generated from the RAW data as shown in S5 of FIG. The entire intermediate image of the format is retained.

  In step S224, the CPU 22 formats the file format of the intermediate image into the Exif format, executes the output process to the removable memory 10, and transfers the intermediate image file in the Exif format temporarily stored in the RAM 14 to the removable memory 10. Deleted when the output process ends. As a result, as shown in S6 of FIG. 1, the entire intermediate image file in the Exif format is held in the removable memory 10, and the print processing target data held in the RAM 14 temporarily disappears completely. Specifically, information necessary for expansion of an intermediate image, such as a quantization table, shooting information (shooting date, aperture, shutter speed, etc.), print control information, image correction control information for obtaining a preferable print result, etc. Is added as file header information to generate an intermediate image file in Exif format, the intermediate image file is stored in the removable memory 10, and the file size, file table / hidden attributes, and the like are stored in the FAT of the removable memory 10. The intermediate image file generated as a result of the development processing is stored in the removable memory 10 for the convenience of the printer 1 that generated the image file regardless of the user's intention, so the table / hidden attribute of the file is “hidden file”. It is desirable to set.

  If the RAM 14 has a sufficient capacity that does not require output processing to the removable memory 10, it is not necessary to delete the intermediate image file in Exif format from the RAM 14. Of course, in that case, output processing of the intermediate image file to the removable memory 10 is also unnecessary. It is also possible to perform processing in which the entire intermediate image file in the Exif format is not held in the RAM 14. For example, output processing to the removable memory 10 is executed for each block at the time of executing the above-described step S220, and after the output processing to the removable memory 10 is completed for all blocks, information necessary as an Exif file is stored in the removable memory 10. May be.

  By the way, in this embodiment, the sharpness correction process is not performed on the intermediate image stored in the removable memory 10. Since an image input device such as a digital camera is provided with a low-pass filter for preventing aliasing, sharpening is required to recover a reduction in sharpness due to the low-pass filter of the image input device. Therefore, in a conventional system that generates an image from RAW data, such sharpening is performed before image output. However, when resolution conversion processing is performed on an image that has undergone sharpness correction processing, the image quality tends to deteriorate. On the other hand, in the process of printing an image, resolution conversion and sharpness correction processing according to the printing resolution are always executed. This is because the larger the print size, the more blurred the image, and the smaller the print size, the sharper the image.

  Therefore, in the present embodiment, in order to enable sharpness correction processing to be executed at one time at the time of resolution conversion in accordance with the print resolution or after resolution conversion in accordance with the print resolution, the sharpness adjustment by the low-pass filter of the image input device is performed. Sharpening to recover the drop and other purposes (for example, to reduce the sharpness in portrait images and to increase the sharpness in landscape images, to optimize the visual impression, and sharpness depending on the print size The information for enabling the printer 1 to apply the control value of the sharpness correction processing combined with the sharpness correction processing executed for the purpose of optimizing the image to the image is the image correction control information for obtaining a preferable print result. To the subsequent processing. The image correction control information transmitted in this way corresponds to a correction parameter.

  Specifically, for example, it is assumed that the sharpness operation value is set to “+1” as image correction control information for obtaining a preferable print result in the RAW data file. In the case of a conventional printer (for example, a PIM-compatible printer), a sharpness of “+1” is obtained for any image generated by any digital camera as long as the sharpness operation value of the processing target image is set to “+1”. A uniform control value corresponding to the operation value is applied in the sharpness correction processing. On the other hand, in the printer 1 of the present embodiment, for example, even if the sharpness operation value is set to “+1” as image correction control information for obtaining a preferable print result for the RAW data file to be processed (note that There is no digital camera that attaches image correction control information for obtaining a preferable print result to a RAW data file.) For a sharpness operation value (for example, “0”) considering low-pass filter characteristics for each digital camera. ("+2" or "+3" for "+1", "+2", or "+1") is transmitted as the sharpness operation value of the intermediate image, so different control values for each digital camera are applied in the sharpness correction process described later Is done. The same applies to the development correction operation value set in step S122. Even if the sharpness operation value is set to “+1” as the development correction operation value, the sharpness operation value considering the low-pass filter characteristics for each digital camera (for example, “+1”, “+2”, “+1” with respect to “0”) "+2" or "+3") is transmitted as the sharpness operation value of the intermediate image. The low-pass filter characteristics for each digital camera can be specified by attribute information such as development control information and model information stored in the RAW data file. Therefore, the CPU 22 sets image correction control information for obtaining a preferable print result based on attribute information such as development control information and model information attached to the RAW data.

  Note that the control information transmission method considering the device characteristics of the image input apparatus such as a digital camera is not limited to the method of recording in the file header of the intermediate image, but via an API closed inside the printer 1. May be communicated.

Image Printing Process FIG. 5 is a flowchart showing in detail the flow of the image printing process in step S138 described above.
The process shown in FIG. 5 is substantially the same as the process executed when an image in the JPEG format or the like is selected as a print target. That is, the printer 1 according to the present embodiment executes image printing processing using exactly the same software resources and hardware resources regardless of whether the print target is RAW data or an image. As a result, the development period of the printer 1 is shortened and manufacturing and development costs are suppressed.

  In step S300, the CPU 22 analyzes the header of the intermediate image file that is the file to be printed, information necessary for decompressing the intermediate image, shooting information, print control information, image correction control information for obtaining a preferable print result, file The size and the like are specified, and control values necessary for printing the intermediate image are set based on the specified information. Specifically, for example, quantization table, sharpness compensation control value, color balance compensation control value, tone compensation processing control value, memory color compensation control value, number of copies, print paper size, print resolution, etc. Is set. DPOF data attached to the print target image may be used as the print control information, but it goes without saying that the user may set control values such as print size and print resolution via the operation unit 26. Nor.

  The processing from step S302 to step S306 described in detail below is executed for each band to be printed. Normal printing is sequentially performed from one side of the image toward the opposite side. For this reason, processing proceeds sequentially in band units in accordance with the printing direction. That is, in the first step S302, the compressed data of the print target band is read from the removable memory 10 to the CPU 22 and the processing result is stored in the RAM 14, and in each subsequent step, the print target band data is read from the RAM 14 to the CPU 22 and the processing result. Is stored in the RAM 14. The band to be printed is set according to the printing direction. Digital camera images are usually horizontally long at a ratio of 3 to 2, but it is reasonable to execute printing sequentially in the long side direction so that a larger area image can be printed by a narrow printer. is there. Therefore, in general, a horizontally long image is first rotated 90 degrees to be converted into a vertically long image, and the vertically long image is printed in the long side direction from one short side to the other short side.

For example, as shown in FIG. 6, when a horizontally long image is sequentially printed in the horizontal direction of the image (a direction in which print target bands are processed in order from A to G), that is, when an image rotated by 90 degrees is printed, The print target band is set so as to divide the image in the horizontal direction. In this case, as shown in FIG. 6, the generation direction of the intermediate image (one line is generated in the horizontal direction in the order of the broken line arrows, and each line is sequentially generated in the order of the numbers) and the printing direction of the intermediate image (A to G). Since the order in which the print target bands are processed in this order differs by 90 degrees, the generation of the intermediate image and the printing of the intermediate image cannot be sequentially processed in series. Therefore, in this case, the entire intermediate image needs to be held statically in the memory space. If the intermediate image is statically held in the memory space without being compressed, the RAM 14 must hold the entire intermediate image in a state where the data size is indicated by the entire broken line in S2 of FIG.
At the time of printing, the intermediate image that is the source information to be printed and the print data that is the output information must be held in the RAM 14 at the same time, so that the required capacity of the RAM 14 becomes considerably large. For this reason, in this embodiment, memory resources are saved by generating a compressed intermediate image, thereby enabling development printing of RAW data in an environment where the memory resources are limited. In addition, in the present embodiment, by holding the compressed intermediate image in the removable memory 10, it is possible to make the capacity of the RAM 14 to be mounted in the printer 1 substantially the same as that of a printer that does not support RAW data. .

  Such an effect is not advantageous only when the image is rotated and printed. For example, the effect of compressing the intermediate image is advantageous even when the entire image is analyzed to set the image correction control value. Also, for example, even if the output destination of the intermediate image is a device with a low data transfer speed such as a hard disk device, or the communication speed between the printer 1 and the external device of the output destination is low, the intermediate image is compressed. The effect of doing works favorably.

In step S <b> 302, the CPU 22 decompresses the block data in the print target band while sequentially reading from the removable memory 10, and stores the YCbCr image of the print target band obtained as a result in the RAM 14. As a result, the print target band data held in the RAM 14 is in the state shown in S7 of FIG.
In step S304, the CPU 22 corrects the image of the band to be printed in cooperation with the image processing unit 16. Specifically, resolution conversion, sharpness correction processing, color balance correction processing, gradation correction processing, memory color correction processing, and the like to which the control value set in step S300 is applied are executed. At this time, the data of the print target band held in the RAM 14 is in the state shown in S7 or S8 of FIG. 1 expressed in a color space corresponding to the processing content. The sharpness correction process is executed after the resolution conversion, and as described above, a control value in consideration of a reduction in sharpness due to a low-pass filter of an image input device such as a digital camera is applied. As described above, in the present embodiment, the sharpness correction processing is not executed before the resolution conversion, so that the print image quality is improved. Color balance correction processing, gradation correction processing, memory color correction processing, and the like may be executed after resolution conversion, or may be executed before resolution conversion.

In step S306, the CPU 22 generates print data of the print target band from the image of the print target band, and the printing unit 18 executes printing based on the print data. At this time, the print data of the print target band held in the RAM 14 is in the state shown in S9 of FIG.
When the processing from step S302 to step S306 is completed up to the final print target band (when determined as Y in step S308), the CPU 22 causes the RMC 12 to delete the intermediate image held in the removable memory 10 (step S310). If the intermediate image is deleted after printing, it is possible to prevent the storage area of the removable memory 10 from being unnecessarily consumed by the intermediate image generated regardless of the user's intention. If the number of copies is two or more, the intermediate image may be held in the removable memory 10 until the printing of all the copies is completed, or generation and deletion of the intermediate image may be repeated each time one copy is printed. Good.

3. Other Embodiments In the above-described free space securing process, the example in which the file deletion menu 33 is displayed to secure the free space when the free space of the removable memory 10 is insufficient has been described. However, the user can add another removable memory. May be requested. Specifically, for example, as shown in FIG. 8 (E), the printer 1 displays a message “Removable memory is insufficient. Please add removable memory with free space of 1.2 MB or more”. You may display on FPD27 and may output the audio | voice of the content. “1.2 MB” in the message is the data size of the intermediate image predicted from the RAW data selected at that time. When this message is displayed, the user exchanges with another removable memory having a free space of 1.2 MB or more, and presses a predetermined operation button of the operation unit 26 while the message is displayed. Then, the printer 1 repeats the processes after step S100 to execute the free capacity securing process and confirm the free capacity of the removable memory. When the free space is sufficient, the removable memory after the replacement becomes the output destination of the intermediate image. If the replacement of the removable memory is rejected, the printer 1 executes error processing.

  When a plurality of external storage media can be connected to the printer 1 without being limited to the removable memory, the free space of each external storage medium is determined, and the intermediate image is stored in the external storage medium whose free space is equal to or larger than the data size of the intermediate image. May be stored. For example, as shown in FIG. 2, it is assumed that a digital camera 30, a personal computer 32, and a mobile phone 34 are connected to the printer 1 as external storage media. Further, it is assumed that a plurality of removable memories can be connected to the RMC 12 of the printer 1, and that the printer 1 has a hard disk (not shown) built therein. In this case, the printer 1 determines these free capacities in a predetermined order. The determination order can be arbitrarily set, but it is desirable to determine first from an external storage medium directly connected to the printer 1 such as a removable memory or a built-in hard disk. When an external storage medium having a free space equal to or larger than the data size of the intermediate image is found, the external storage medium becomes the output destination of the intermediate image. In this way, if the printer 1 finds an external storage medium having a free space equal to or larger than the data size of the intermediate image, printing can be continued without bothering the user, so that operability when printing RAW data is further improved. improves. When an external storage medium having a free space equal to or larger than the data size of the intermediate image is not finally found, the printer 1 may display the file deletion menu 33 or request replacement of the removable memory. The printing may be stopped.

  In the above embodiment, an example in which the intermediate image is output to the outside of the printer 1 has been described. However, as described above, the entire intermediate image may be held in the RAM 14 as a storage medium. Even in such a case, it is possible to reduce the capacity additionally required for the RAM 14 to print the image from the RAW data by compressing the intermediate image.

The schematic diagram which concerns on one Example of this invention. 1 is a block diagram illustrating a schematic configuration of a printer according to an embodiment of the present invention. 5 is a flowchart showing the operation of the printer according to the embodiment of the present invention. The flowchart which shows the flow of the process in FIG.4 S136. The flowchart which shows the flow of the process in step S138 of FIG. The schematic diagram which concerns on one Example of this invention. The screen transition figure concerning one Example of this invention. The schematic diagram of the message and menu which concern on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer, 10 Removable memory (storage medium, external storage medium), 12 Removable memory controller (input means), 14 RAM (storage medium), 16 Image processing unit, 18 Printing unit (printing means), 20 External IF (input means) ), 22 CPU (image generation means, compression means, expansion means, printing means), 26 operation unit (user interface), 28 display unit (user interface), 30 digital camera (storage medium, external storage medium), 32 personal computer (Storage medium, external storage medium), 34 Mobile phone terminal with camera (Storage medium, external storage medium)

Claims (7)

Input means for inputting RAW data;
Image generation means for generating an image in a general format from the RAW data using demosaic processing and storing the image in an external storage medium;
Printing means for acquiring and printing the image in the general-purpose format from the external storage medium;
With
The printing means acquires the image from the external storage medium, prints all the numbers, and then erases the image from the external storage medium;
Printer. Compression means for compressing the image for each block and storing it in a storage medium;
Expansion means for expanding the image stored in the storage medium for each band to be printed;
The printing means generates print data for each print target band from the expanded image, and prints for each print target band based on the print data.
The printer according to claim 1. The expansion means sets the band to be printed so as to divide the image in a horizontal direction;
The printer according to claim 2. The general-purpose format is a JFIF format or an Exif format.
The printer according to claim 1. The compression means irreversibly compresses the image with a quantization step width corresponding to a free capacity of the storage medium;
The printer according to any one of claims 2 to 4. A user interface for notifying the user of the degree of image quality degradation due to the compression and receiving a print stop request from the user;
The printer according to claim 5. A reception unit for receiving at least RAW data and user designation for the image in the general-purpose format;
The image generation means, when a user specifies the RAW data, acquires the specified RAW data and generates an image of the general format,
The printing unit acquires and prints the image in the general format specified by the user when the user specifies the image in the general format, and when the user specifies the RAW data, the print unit The printer according to claim 1, wherein the image in the general format generated by the image generation unit is acquired and printed.

Images