JP4706567B2 - Image processing method, image processing method program, recording medium storing image processing method program, and image processing apparatus - Google Patents

Description

  The present invention relates to an image processing method, a program for the image processing method, a recording medium on which the program for the image processing method is recorded, and an image processing apparatus, and can be applied to, for example, an electronic still camera. The present invention processes at least AC component coefficient data in accordance with a target format, encodes DC component coefficient data without referring to other minimum encoding processing units, and sets the start position of the minimum encoding processing unit. By setting the position information for identifying the intermediate format and generating the encoded data in the intermediate format, the image data can be encoded so that the minimum encoding processing unit can be decoded at random.

  2. Description of the Related Art Conventionally, a still image recording apparatus such as an electronic still camera compresses image data using a JPEG (Joint Photographic Coding Experts Group) technique and records it on a recording medium.

  Here, in JPEG, one still image is divided into 8 × 8 pixel blocks, and the 8 × 8 pixel block is set as a minimum coding unit (MCU). In JPEG, this minimum encoding processing unit is sequentially subjected to orthogonal transform processing in the order of raster scanning, and coefficient data obtained as a result is subjected to quantization processing and variable length encoding processing. At this time, in JPEG, a difference value is calculated between the DC component coefficient data and the corresponding data of the minimum encoding processing unit processed immediately before, and the difference value is subjected to variable length encoding processing. On the other hand, the AC component coefficient data is subjected to variable-length encoding processing without referring to the processing results of other minimum encoding processing units.

  Therefore, the image data encoded by JPEG has a drawback that it is difficult to randomly decode the minimum encoding processing unit at a desired location. For this reason, Japanese Patent Application Laid-Open No. 2002-229759 proposes a method of performing code conversion so that image data encoded by JPEG can be decoded at random.

  By the way, in recent years, imaging devices have become more sensitive and faster, so a plurality of still images are taken at a high speed and the plurality of still images are comprehensively processed to improve the image quality of the still images. It is considered possible. Specifically, this processing is processing such as noise reduction, camera shake correction, and dynamic range expansion.

  However, if a plurality of still images taken continuously are recorded and held in the memory without any data compression, the capacity of the memory increases. Therefore, it is conceivable to improve the image quality by compressing the data of the plurality of still images and holding them in a memory by the JPEG method.

  However, since it is difficult to randomly decode the minimum coding processing unit at the desired location in the image data encoded by JPEG, the minimum coding processing unit is sequentially decoded in the raster scan order one by one when image processing is performed. There is a problem that image processing cannot be efficiently performed.

That is, FIG. 21 is a flowchart showing a processing procedure when image processing is performed by compressing data of a plurality of still images using the JPEG technique. In this case, in the imaging apparatus, when an imaging result is acquired in response to a user operation, the process proceeds from step SP1 to step SP2, and the imaging result is encoded by the JPEG method. In subsequent step SP3, the data of the encoding process result is held in the buffer memory as intermediate buffer data. Further, for example, when the user instructs to record the imaging result, the process proceeds to step SP4, where the data held in the intermediate buffer is sequentially decoded from the head minimum encoding processing unit, and in the subsequent step SP5, the image data of the place to be image-processed is obtained. get.
JP 2002-229759 A

  The present invention has been made in consideration of the above points. An image processing method, an image processing method program, and an image processing method capable of encoding image data so that a minimum encoding processing unit can be decoded at random are provided. The present invention intends to propose a recording medium and an image processing apparatus on which a program is recorded.

  In order to solve the above-mentioned problem, the invention of claim 1 is applied to an image processing method for encoding image data to generate encoded data of a predetermined format, and the predetermined format is a minimum encoding processing unit. In addition, the image data is orthogonally transformed to generate DC component and AC component coefficient data, the AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units, The DC component coefficient data is a variable length encoding process with reference to the data corresponding to the minimum encoding processing unit processed immediately before, and the image processing method converts the image data into encoded data in an intermediate format. An intermediate format encoding step for encoding the image data, and an intermediate format for decoding the image data from the intermediate format encoded data. A decoding step, an image processing step of performing image processing on the image data decoded in the intermediate format decoding step, and encoding the image data processed in the image processing step into encoded data of the predetermined format An encoding process step of a predetermined format to be processed, and the encoding process step of the intermediate format performs orthogonal transform processing on the image data for each of the minimum encoding processing units, and the DC component and the AC component Coefficient data is generated, at least the AC component coefficient data is encoded in the predetermined format, and all or part of the DC component coefficient data is encoded without referring to other minimum encoding processing units. In the data sequence of encoded data that has been encoded and processed in the predetermined format, the minimum encoding processing unit Set the position information indicating the head position to generate the encoded data of the intermediate format.

  The invention of claim 8 is applied to a program of an image processing method for encoding image data to generate encoded data of a predetermined format, and the predetermined format is the image for each minimum encoding processing unit. Data is orthogonally transformed to generate DC component and AC component coefficient data, the AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units, and the DC component coefficient is generated. The data is a variable length encoding process with reference to the data corresponding to the minimum encoding processing unit processed immediately before, and the image processing method encodes the image data into encoded data of an intermediate format. Intermediate format encoding processing step, and intermediate format decoding for decoding the image data from the intermediate format encoded data A step of performing image processing on the image data decoded in the step of decoding the intermediate format, and a predetermined processing for encoding the image data processed in the image processing step into encoded data of the predetermined format A step of encoding the format, and the step of the intermediate format encoding process performs orthogonal transform processing on the image data for each of the minimum encoding processing units to generate the DC component and AC component coefficient data. Encoding at least the AC component coefficient data in the predetermined format, and encoding all or part of the DC component coefficient data without referring to other minimum encoding processing units. In the data string of encoded data encoded in the predetermined format, the leading position of the minimum encoding processing unit Set the position information indicating the generating the encoded data of the intermediate format.

  The invention of claim 9 is applied to a recording medium on which a program of an image processing method for encoding image data to generate encoded data of a predetermined format is recorded, and the predetermined format is a minimum encoding processing unit. Every time, the image data is orthogonally transformed to generate DC component and AC component coefficient data, and the AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units, The DC component coefficient data is a variable length encoding process with reference to the corresponding data of the minimum encoding processing unit processed immediately before, and the image processing method encodes the image data in an intermediate format. An intermediate format encoding process for encoding data, and an intermediate for decoding the image data from the intermediate format encoded data A format decoding step, an image processing step for image processing the image data decoded in the intermediate format decoding step, and encoding the image data processed in the image processing step into the encoded data of the predetermined format. A coding process step of a predetermined format for performing the coding process, and the step of the coding process of the intermediate format performs the orthogonal transform process on the image data for each of the minimum coding processing units, and Generating coefficient data of the component, encoding the coefficient data of at least the AC component in the predetermined format, and referring to all or a part of the coefficient data of the DC component without referring to another minimum encoding processing unit In the data sequence of encoded data that has been encoded and processed in the predetermined format, the minimum code Set the position information indicating the head position of the processing unit to generate encoded data of the intermediate format.

  The invention of claim 10 is applied to an image processing apparatus that encodes image data to generate encoded data of a predetermined format, and the predetermined format includes the image data for each minimum encoding processing unit. Orthogonal transformation processing is performed to generate DC component and AC component coefficient data, the AC component coefficient data is subjected to variable-length encoding processing without referring to other minimum encoding processing units, and the DC component coefficient data is , A format for performing variable-length encoding processing with reference to data corresponding to a minimum encoding processing unit processed immediately before, and the image processing apparatus performs intermediate processing for encoding the image data into encoded data of an intermediate format A format encoding processing unit, an intermediate format decoding unit for decoding the image data from the encoded data of the intermediate format, and the intermediate format An image processing unit that performs image processing on the image data decoded by the mat decoding unit, and an encoding processing unit of a predetermined format that encodes the image data processed by the image processing unit into encoded data of the predetermined format. And the intermediate format encoding processing unit generates the DC component and AC component coefficient data by orthogonally transforming the image data for each minimum encoding processing unit, and at least the AC component coefficients A code obtained by encoding data in the predetermined format, encoding all or part of the DC component coefficient data without referring to other minimum encoding processing units, and encoding the predetermined format In the data sequence of encoded data, position information indicating the start position of the minimum encoding processing unit is set, and encoded data of the intermediate format is generated That.

  According to the configuration of claim 1, claim 8, claim 9, or claim 10, in the predetermined format, the coefficient data of the DC component is variable with reference to the data corresponding to the minimum encoding processing unit processed immediately before. Since the long encoding process is performed, it is difficult to randomly decode the minimum encoding process unit with the encoded data of the predetermined format. However, since the data amount is reduced as compared with the image data, the capacity of the memory can be reduced as compared with the case where the image data is directly stored in the memory. On the other hand, in the intermediate format, at least AC component coefficient data is encoded in a predetermined format, and all or a part of the DC component coefficient data is encoded without referring to other minimum encoding processing units. Therefore, the desired minimum encoding processing unit can be decoded with the DC component encoded data and the AC component encoded data of the desired minimum encoding processing unit. In addition, since the position information indicating the start position of the minimum encoding processing unit is provided in the data sequence of the encoded data encoded in the predetermined format, the minimum encoding processing that changes variously by the variable length encoding processing. By specifying the head position of the unit, it is possible to select DC component encoded data and AC component encoded data of a desired minimum encoding processing unit. Therefore, according to the configuration of the first, eighth, ninth, or tenth aspect, the image data is temporarily converted into an intermediate format and image processing is performed. Can be processed.

  According to the present invention, image data can be encoded so that the minimum encoding processing unit can be decoded at random.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

(1) Configuration of Embodiment FIG. 2 is a block diagram showing an electronic still camera which is an image processing apparatus according to Embodiment 1 of the present invention. In this electronic still camera 1, the lens 2 condenses the incident light L <b> 1 with the magnification and the stop designated by the central processing unit 7, and forms an optical image on the imaging surface of the subsequent imaging device 3.

  The imaging element 3 is, for example, a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, and outputs an imaging result of an optical image formed on the imaging surface. More specifically, the image sensor 3 normally outputs a moving image imaging result, and outputs a still image imaging result under the control of the central processing unit 7 when the user operates the shutter button. Further, when outputting the still image capturing result, a plurality of still images are continuously output at a frame rate higher than that of, for example, 120 [frames / second].

  An analog / digital conversion unit (A / D) 4 performs analog / digital conversion processing on the output signal of the image sensor 3 and outputs image data D1.

  The camera signal processing unit 5 outputs the image data D1 output from the analog-digital conversion unit 4 to the bus BUS after performing gamma correction processing or the like.

  The display unit 6 displays image data output to the bus BUS, and the electronic still camera 1 is configured so that the display unit 6 can confirm the imaging results of moving images and still images.

  The encoding unit 8 encodes still image data output from the camera signal processing unit 5 to the bus BUS into encoded data of an intermediate format under the control of the central processing unit 7, and stores the image data in the memory via the bus BUS. Stored in section 9.

  The decoding unit 10 decodes the intermediate format encoded data held in the memory unit 9 and the JPEG format encoded data held in the external memory 12 and outputs the image data to the bus BUS.

  The signal processing unit 11 inputs image data decoded from the intermediate format from the decoding unit 10 via the bus BUS according to an instruction from the central processing unit 7, processes the image data, and outputs the processed image data to the bus BUS. Here, in this embodiment, the processing in the signal processing unit 11 is an image quality improvement process for improving the image quality of a still image using a plurality of still images acquired continuously. For example, a noise reduction process is applied. The Therefore, the signal processing unit 11 suppresses noise by averaging pixel values between corresponding pixels of the plurality of still images. This image quality improvement processing can also be applied with camera shake correction, processing for expanding the dynamic range, etc. In the case of camera shake correction, the signal processing unit 11 performs motion correction on these plural still images and then corresponding pixels. In the meantime, the pixel values are averaged to correct camera shake. In the process of expanding the dynamic range, the electronic still camera 1 captures a plurality of still images at different shutter speeds, and the signal processing unit 11 weights and adds the corresponding pixel values of the plurality of still images. Increase the dynamic range.

  The memory unit 9 temporarily stores and holds encoded data in an intermediate format output to the bus BUS.

  The external memory 12 is, for example, a memory card, records and holds encoded data in JPEG format output to the bus BUS, and outputs the stored encoded data to the bus BUS.

  The central processing unit 7 is a control means for controlling the operation of the electronic still camera 1. The central processing unit 7 secures a work area in a random access memory (RAM) 13 and executes a program recorded in a read only memory (ROM) 14. Thus, the operation of the entire electronic still camera 1 is controlled. The program may be provided by being installed in advance in the electronic still camera 1, or may be provided by being recorded on a recording medium such as an optical disk, a magnetic disk, a memory card, and the like. You may make it provide with the download via networks, such as the internet.

  FIG. 3 is a block diagram showing still image processing under the control of the central processing unit 7 in the electronic still camera 1. When the user operates the shutter button to instruct still image shooting, the central processing unit 7 controls the operation of the solid-state imaging device 3 and the like to acquire a plurality of still image data D1 and The image data D1 is processed by the camera signal processing unit 5. The image data D1 processed by the camera signal processing unit 5 is encoded by the encoding unit 8 into encoded data DT having an intermediate format, and the encoded data DT having the intermediate format is stored in the memory unit 9. In FIG. 3, the encoded data DT in the intermediate format is shown as a code set that can be randomly accessed.

  When the user instructs to store the imaging result, the central processing unit 7 converts the encoded data DT in the intermediate format held in the memory unit 9 into encoded data DJ in the JPEG format and records it in the external memory 12. At this time, when the user selects the image quality improvement operation mode, the central processing unit 7 decodes the intermediate format encoded data DT held in the memory unit 9 by the decoding unit 10, and the image quality of the decoded image data D1. Is improved by the signal processing unit 11. Also, the image data D1 with improved image quality is converted into encoded data DJ in JPEG format, and encoded data for recording in the external memory 12 is generated. The central processing unit 7 records the encoded data DJ in the JPEG format in the external memory 12.

  As shown in FIG. 1 in comparison with FIG. 3, the central processing unit 7 once converts the image data D1 whose image quality has been improved by the signal processing unit 11 into encoded data DT of an intermediate format, and then converts it into the memory unit 9 Then, the intermediate format encoded data DT is converted into JPEG format encoded data DJ and recorded in the external memory 12.

  Here, the intermediate format is a format that can be easily encoded into encoded data in the JPEG format and that can arbitrarily decode image data at a desired location. In the intermediate format, JPEG format processing is applied to encoded data that does not prevent the minimum encoding processing unit from being randomly decoded among the encoded data in JPEG format. On the other hand, among the encoded data in JPEG format, the encoded data that is a hindrance to randomly decode the minimum coding processing unit is not hindered to randomly decode the minimum coding processing unit. To process.

  More specifically, in this intermediate format, the minimum encoding processing unit of the JPEG format is set as the minimum encoding processing unit, and the minimum encoding processing unit is sequentially encoded in the order of raster scanning as in the JPEG format. To do. Further, as in the case of the JPEG format, this intermediate format performs orthogonal transform processing on each minimum coding processing unit, and performs quantization processing and variable length coding processing on the coefficient data as a result of the orthogonal transformation processing to generate coded data DDC, AC is generated.

  Accordingly, in this intermediate format, the AC component coefficient data of the coefficient data obtained by orthogonal transform processing is quantized without referring to the processing results of other encoding processing units as shown in FIG. Encoded data AC (AC1 to AC16) is generated by the encoding process and the variable length encoding process, and the AC component encoded data AC (AC1 to AC16) prevents any minimum encoding processing unit from being randomly decoded. It will not be.

  On the other hand, as indicated by the arrows in FIG. 4A, the DC component coefficient data is calculated as a difference value from the DC component coefficient data of the immediately preceding minimum encoding processing unit. Quantization processing and variable length encoding processing are performed to generate encoded data DDC (DDC1 to DDC16). Therefore, since the encoded data DDC (DDC1 to DDC16) of the direct current component is encoded with reference to the immediately preceding minimum encoding processing unit, the minimum encoding processing unit is randomly prevented from being decoded. FIG. 4 shows one still image in units of 4 × 4 minimum encoding processes.

  Therefore, in this intermediate format, the DC component coefficient data is separately quantized without referring to the processing result of the immediately preceding minimum encoding processing unit, and encoded data DC (DC2 to DC16) (FIG. 4C). ) Is generated. In the JPEG format, there is no minimum encoding processing unit to be processed immediately before in the first minimum encoding processing unit. Therefore, in the first minimum encoding processing unit, the difference value between the DC component coefficient data and the value 0 is encoded, and eventually the encoding processing is performed without referring to the processing results of the other minimum encoding processing units. Will be. In this embodiment, therefore, only the DC component encoded data DDC in the JPEG format is generated and the encoded data DC is not generated in the minimum minimum encoding processing unit. Note that the DC component coefficient data may be subjected to variable-length coding processing, or quantization processing may be omitted.

  Further, in this intermediate format, since the encoded data DDC and AC encoded in the JPEG format are subjected to variable length encoding, each encoding processing unit is included in the encoded data DDC and AC data strings. Position information CM (CM1 to CM15) (FIG. 4 (D)) for specifying the head position is provided. In this embodiment, as shown in FIG. 5A, the information CM of the size of each minimum encoding processing unit is applied to this position information. As this position information, as shown in FIG. 5B, position information CM based on the start position of the head minimum encoding processing unit may be applied.

  Corresponding to this intermediate format, the encoding unit 8 is configured as shown in FIG. That is, the encoding unit 8 sequentially inputs the image data D1 of the minimum encoding processing unit to the discrete cosine conversion unit (DCT) 21 in the raster scanning order, and performs the discrete cosine conversion processing of the image data D1 for each minimum encoding processing unit. To do. Each coefficient data, which is the processing result, is quantized by the quantizing unit 22 and then variable length coding by the variable length coding unit 23. The encoding unit 8 is formed such that the discrete cosine transform unit 21, the quantization unit 22, and the variable length encoding unit 23 sequentially process the image data D1 in the JPEG format, and the variable length encoding unit 23 outputs the JPEG format. Encoded data DDC and AC are output.

  Therefore, when the electronic still camera 1 directly encodes the input image data D1 in the JPEG format and outputs the encoded data DJ, the output data of the variable length encoding unit 23 is output via a buffer memory (not shown). Set various control codes such as headers in the output.

  In this encoding unit 8, the position information setting unit 24 aggregates the data lengths of the encoded data DDC and AC output from the variable length encoding unit 23 for each minimum encoding processing unit, and Position information CM specifying the head position is detected and output.

  The DC coefficient processing unit 25 selectively inputs DC component coefficient data from the coefficient data output from the quantization unit 22, encodes the DC component coefficient data, and outputs encoded data DC.

  The central processing unit 7 holds the coded data DC of the DC coefficient data that has been coded without referring to other minimum coding processing units in the memory unit 9 in a table format (FIG. 1). Further, the position information CM specifying the head position of each minimum encoding processing unit is held in the memory unit 9 in a map format.

  When the central processing unit 7 instructs the recording of the still image stored in the memory unit 9 in the intermediate format to the external memory 12, the central processing unit 7 encodes the encoded data DT stored in the memory unit 9 in the JPEG format. The encoded data DDC and AC that have been processed are selected. Further, control data such as a header is added to the encoded data DDC and AC encoded by the JPEG format to generate encoded data DJ in the JPEG format, and the encoded data DJ is stored in the external memory 12.

  On the other hand, when the user instructs to improve the image quality, the encoded data DT in the intermediate format held in the memory unit 9 is transferred to the decoding unit 10 and the original image data D1 is decoded. Further, the decoded image data D1 is processed by the signal processing unit 11, and the encoding unit 8 performs encoding processing on the encoded data DT having an intermediate format. The intermediate format encoded data DT is converted into JPEG encoded data DJ and stored in the external memory 12.

  In this processing, the central processing unit 7 transfers the encoded data DT held in the memory unit 9 to the decoding unit 10 so that the signal processing unit 11 sequentially processes the minimum encoding processing units in the order of raster scanning. To process. Accordingly, when the central processing unit 7 stores, for example, three still images in the memory unit 9, the decoding unit 10 sequentially decodes the minimum encoding processing unit at the raster scan start position of these three still images. Subsequently, the minimum encoding processing unit of the subsequent raster scanning position is sequentially decoded. Accordingly, the image data D1 of each still image is sequentially decoded in the minimum encoding processing unit in the raster scanning order. However, in each minimum encoding processing unit, the minimum encoding processing unit processed immediately before is the other still image processing. It will be a thing. Therefore, in this electronic still camera 1, it is necessary to decode the minimum encoding processing unit at an arbitrary position.

  Therefore, as shown in FIG. 7, the central processing unit 7 stores the DC component encoded data DDC of the JPEG format encoded data DDC, AC in the map format and corresponding DC component encoded data DC. Then, the encoded data DC and AC are transferred to the decoding unit 10. At this time, the position information CM stored in the table format is used to detect the data position of the minimum encoding processing unit to be processed, and obtain the encoded data DDC, AC encoded in the JPEG format based on this data position. To do.

  FIG. 8 is a flowchart showing a processing procedure for a plurality of still images in the electronic still camera 1. In this case, when the electronic still camera 1 acquires an imaging result in response to a user operation, the electronic still camera 1 proceeds from step SP11 to step SP12, and encodes the imaging result into encoded data DT in an intermediate format. In the subsequent step SP13, the encoded data DT in the intermediate format is stored in the memory unit 9 as intermediate buffer data. For example, when the user gives an instruction to improve the image quality, the process proceeds to step SP14, where an arbitrary minimum encoding processing unit of the encoded data DT in the intermediate format is decoded by the decoding unit 10, and in the subsequent step SP15, the image of the portion to be image-processed You will get the data.

  As shown in FIG. 9 and FIG. 10 in comparison with FIG. 4 and FIG. 7, with respect to the minimum and minimum encoding processing units at the beginning and end, the DC component coefficient data is not encoded into the encoded data DC. The data amount of the intermediate format encoded data DT may be reduced. In this case, at the time of decoding, the encoded data DC of the minimum encoding processing unit immediately before the processing target is decoded to obtain a direct current value, and the encoded data DDC of the minimum encoding processing unit to be processed is based on this direct current value. Will be decoded.

(2) Operation of Embodiment In the above configuration, in this electronic still camera 1 (FIG. 2), when the user operates the shutter button, a plurality of still images are sequentially acquired by the image sensor 3 at a high frame rate. The still image pick-up result is converted into image data D1 by the analog-digital converter 4. The image data D1 is stored in the memory unit 9 after being subjected to predetermined signal processing by the camera signal processing unit 5. A plurality of still images stored in the memory unit 9 are processed by the signal processing unit 11 to improve the image quality, and then stored in the external memory 12 as encoded data DJ in JPEG format. In the electronic still camera 1, the processing in the signal processing unit 11 is a process for improving the image quality using a plurality of still images. Therefore, still images recorded in the external memory 12 are compared with the conventional one. The image quality can be improved.

  However, in the case of improving the image quality by processing a plurality of still images as described above, if the plurality of still images are stored in the memory unit 9 without any data compression, the capacity of the memory unit 9 is increased. Is required. Therefore, it is conceivable that these still images are encoded in the JPEG format and stored in the memory unit 9, but the encoded data in the JPEG format randomly decodes the minimum encoding processing unit at a desired location. This makes it difficult to efficiently process these multiple still images.

  Therefore, in the electronic still camera 1, the image data D1 of the plurality of still images is encoded into intermediate format encoded data DT capable of randomly decoding the minimum encoding processing unit at a desired location. The data is compressed (FIGS. 1 and 3) and stored in the memory unit 9. The encoded data DT is decoded by the decoding unit 10 and processed by the signal processing unit 11, and then stored in the external memory 12 as encoded data DJ in JPEG format.

  More specifically, in the electronic still camera 1, the image data D1 of the plurality of still images is subjected to orthogonal transform processing in the same JPEG format as the minimum encoding processing unit of the JPEG format, and the direct current component and the alternating current component. Coefficient data is generated. Among these coefficient data, the coefficient data of the AC component that does not interfere with decoding the minimum encoding processing unit at random by processing in the JPEG format is quantized and variable in the JPEG format together with the coefficient data of the DC component. The long encoding process is performed, and the DC component encoded data DDC and the AC component encoded data AC are generated.

  Also, the DC component coefficient data that prevents the minimum encoding processing unit from being randomly decoded by processing in the JPEG format is encoded without referring to other minimum encoding processing units to generate encoded data DC. In addition, in the data string of the DC component encoded data DDC and the AC component encoded data AC, position information CM indicating the head position of each minimum encoding processing unit is set.

  The intermediate format encoded data DT is encoded by the JPEG format encoded data DDC, AC, the DC component encoded data DC encoded without referring to other minimum encoding processing units, and the position information CM. It is formed so that it can be easily converted into encoded data DJ in a format and the minimum encoding processing unit can be decoded at random.

  That is, the encoded data DT in the intermediate format can be easily converted into the encoded data DJ in the JPEG format simply by setting the header information or the like in the data string of the encoded data DDC and AC in the JPEG format. Also, of the encoded data DDC and AC in the JPEG format, the DC component encoded data DDC is the corresponding DC component encoded data DC that has been encoded without referring to other minimum encoding processing units. By replacing, the minimum encoding processing unit can be decoded without referring to the immediately preceding minimum encoding processing unit. Also, the position of the corresponding minimum encoding processing unit can be specified by the position data, and the encoded data DDC, AC of the desired minimum encoding processing unit can be detected.

  Therefore, the electronic still camera 1 encodes the image data D1 into the encoded data DT in the intermediate format so that it can be easily converted into the encoded data DJ in the JPEG format and can be randomly decoded in the minimum encoding processing unit. It is possible to reduce the capacity of the memory unit 9 and efficiently process a plurality of still images.

  In particular, the electronic still camera 1 quantizes not only the AC component coefficient data, but also the DC component coefficient data, in the JPEG format, which does not interfere with decoding the minimum encoding processing unit at random by processing in the JPEG format. If the intermediate format encoded data DT is converted to JPEG format encoded data DT by performing processing and variable length encoding processing, header information and the like are added to the JPEG format encoded data DDC and AC data string. The format can be converted by simple processing that only requires setting.

(3) Effects of the embodiment According to the above configuration, at least the AC component coefficient data is processed according to the JPEG format, and the DC component coefficient data is encoded without referring to other minimum encoding processing units. By setting position information for specifying the start position of the minimum encoding processing unit and generating encoded data in an intermediate format, image data can be encoded so that the minimum encoding processing unit can be decoded at random it can. Accordingly, the present invention can be widely applied to a case where image data is processed by decoding encoded data in an intermediate format by a plurality of systems. In this case, the image speed can be remarkably increased.

  Further, by adding the DC component coefficient data to the AC component coefficient data and processing all the coefficient data in accordance with the JPEG format, the encoded data in the intermediate format can be easily converted into the encoded data in the JPEG format. .

  FIG. 11 is a schematic diagram showing an intermediate format applied to the electronic still camera according to the second embodiment of the present invention in comparison with FIG. The electronic still camera of the second embodiment is configured in the same manner as the electronic still camera of the first embodiment except that the configuration relating to the intermediate format is different.

  Here, in the intermediate format of this embodiment, among the coefficient data, only the AC component coefficient data that does not interfere with decoding the minimum encoding processing unit at random by processing in the JPEG format is processed and encoded in the JPEG format. Data AC is formed. The coefficient data of the DC component is all encoded without referring to other minimum encoding processing units.

  Therefore, as shown in FIG. 12 in comparison with FIG. 5, the position information CM is set so as to specify the head position of each minimum encoding processing unit in the data sequence of the AC component encoded data AC. In this case, size information may be assigned as shown in FIG. 12A, and position information based on the beginning of the data string is assigned as shown in FIG. May be.

  Correspondingly, as shown in FIG. 13 in comparison with FIG. 7 and in FIG. 14 in comparison with FIG. 1, the encoded data AC of the desired minimum encoding processing unit is obtained from the position information CM. Then, the coded data AC of the specified AC component and the coded data DC of the DC component are processed by the decoding unit, and the coded data DT in the intermediate format is decoded into the image data D1. The decoded image data D1 is processed to improve the image quality, and the intermediate format encoded data DT is generated.

  Further, as shown in FIG. 15, a difference value (DCn + 1−DCn) is calculated from the DC component encoded data DCn and DCn + 1 in the continuous minimum encoding processing unit, and the difference value is re-encoded to be in the JPEG format. Generates DC component encoded data DDCn. In addition, a header or the like is set in the data string of the generated DC component encoded data DDCn and the AC component encoded data AC to generate JPEG format encoded data DJ.

  As in this embodiment, even if only the coefficient data of the AC component is encoded in the JPEG format, the same effect as in the first embodiment can be obtained. If only the coefficient data of the AC component is encoded in the JPEG format, the amount of encoded data in the intermediate format can be reduced as compared with the configuration of the first embodiment, and the capacity of the memory unit is reduced. be able to.

  16 and 17 are schematic diagrams showing an intermediate format applied to the electronic still camera according to the third embodiment of the present invention in comparison with FIGS. 9 and 10. The electronic still camera of the third embodiment is configured in the same way as the electronic still camera of the first embodiment except that the configuration relating to the intermediate format is different.

  In this embodiment, as shown in FIG. 16, the encoded data DT in the intermediate format has a plurality of consecutive minimum encoding processing units set as decoding processing units. In addition, position information CM indicating the head position of the head minimum encoding processing unit is set. Also, with respect to the minimum encoding processing unit immediately before each decoding processing unit, the DC component coefficient data is encoded without referring to other minimum encoding processing targets, and encoded data DC is generated. Accordingly, FIG. 16 shows an example in which the decoding processing units are set to four minimum encoding processing units that are continuous in the horizontal direction. Also, the DC component and the AC component coefficient data are encoded in the JPEG format to generate encoded data DDC and AC.

  Also, as shown in FIG. 17 corresponding to FIG. 16, at the time of decoding into image data, the decoding processing unit including the minimum encoding processing unit to be processed is processed from the position information CM to the head minimum encoding processing unit. Is detected, and instead of the DC component encoded data DDC of the head encoding processing unit, the corresponding DC component encoded data DC that has been encoded without referring to another encoding processing unit is detected. Are set, and a plurality of minimum encoding processing units constituting the decoding processing unit are sequentially decoded.

  According to this embodiment, by encoding the DC component coefficient data without referring to other encoding processing units for each of a plurality of minimum encoding processing units, data of encoded data in an intermediate format is obtained. The amount can be further reduced, and the same effect as in Example 1 can be obtained.

  18 and 19 are schematic diagrams showing an intermediate format applied to the electronic still camera according to the fourth embodiment of the present invention in comparison with FIGS. 16 and 17. The electronic still camera of the fourth embodiment is configured in the same manner as the electronic still camera of the third embodiment except that the configuration relating to the intermediate format is different.

  Here, in the encoded data DT in the intermediate format, as in the third embodiment, a plurality of continuous minimum encoding processing units are set as decoding processing units, and the minimum of the beginning is set for each decoding processing unit. Position information CM indicating the head position of the encoding processing unit is set.

  Further, with respect to the minimum encoding processing unit at the head of each decoding processing unit, only the AC component coefficient data is encoded in the JPEG format to generate encoded data AC. In addition, with respect to the minimum encoding processing unit at the beginning and end of each decoding processing unit, the DC component coefficient data is not referred to other minimum encoding processing units except for the minimum minimum encoding processing unit. The encoded data DT is generated by performing the encoding process.

  As shown in FIG. 19 corresponding to the configuration of FIG. 18, at the time of decoding into image data, the decoding processing unit including the minimum encoding processing unit to be processed is determined from the position information CM as in the third embodiment. The head position of the head minimum encoding processing unit is detected. Also, the corresponding DC component encoded data DC encoded without referring to another encoding processing unit is set as the DC component encoded data of the first encoding processing unit, and this decoding processing unit is set. Are sequentially decoded.

  Further, as shown in FIG. 20 in comparison with FIG. 15, during the conversion processing to the encoded data DJ in the JPEG format, it is the minimum encoding processing unit at the head of the decoding processing unit and the immediately preceding encoded data DC. The difference value (DCn + 1−DCn) is calculated by the above and the difference value (DCn + 1−DCn) is re-encoded to generate the encoded data DDC of the direct current component in the head minimum encoding processing unit.

  According to this embodiment, the coefficient data of the direct current component is encoded without referring to other encoding processing units for each of the plurality of minimum encoding processing units. Even if the coefficient data of the direct current component is encoded in the first and last encoding processing units without referring to other minimum encoding processing units, the same effect as in the third embodiment can be obtained.

  In the above-described embodiment, the case has been described in which the encoded data in the intermediate format is decoded and image-processed, and then converted into the intermediate format and converted into the encoded data in the JPEG format. However, the present invention is not limited to this. Instead, after image processing, it may be converted directly into encoded data in JPEG format.

  Further, in the above-described embodiments, the case where the intermediate format encoded data is decoded and image processing is described for the purpose of improving the image quality. However, the present invention is not limited to this, for example, partially imaging results. The present invention can also be widely applied to the case of enlarging display.

  In the above-described embodiment, the case where the still image is set as the processing target and the encoded data in the JPEG format is generated has been described. However, the present invention is not limited thereto, and the moving image is set as the processing target and the MPEG format is set. The present invention can be widely applied to the case where image data is subjected to orthogonal transform processing and variable length coding processing in units of the minimum coding processing, such as when generating encoded data. In the MPEG format, the minimum encoding processing unit is a macro block.

  In the above-described embodiments, the case where the present invention is applied to an electronic still camera has been described. However, the present invention is not limited to this, and an image reproducing device, a PDA (Personal Digital Assistants), various game machines, mobile phones, personal computers, and the like. The present invention can be widely applied to processing in a computer. When applied to processing in this personal computer, the corresponding program may be installed and provided in advance, or may be provided by being recorded on a recording medium such as an optical disk, a magnetic disk, or a memory card. Alternatively, it may be provided by downloading via a network such as the Internet.

  The present invention can be applied to, for example, an electronic still camera.

It is a basic diagram with which it uses for description of the intermediate format applied to the electronic still camera of Example 1 of this invention. It is a block diagram which shows the electronic still camera of Example 1 of this invention. It is a block diagram with which it uses for description of the process of the still image in the electronic still camera of FIG. FIG. 3 is a schematic diagram for explaining an intermediate format in the electronic still camera of FIG. 2. FIG. 5 is a schematic diagram for explaining position information in the intermediate format of FIG. 4. It is a block diagram which shows the encoding part in the electronic still camera of FIG. FIG. 6 is a schematic diagram for explaining the decoding process of the intermediate format in FIG. 5. 3 is a flowchart showing a still image processing procedure in the electronic still camera of FIG. 2. FIG. 5 is a schematic diagram illustrating an intermediate format according to an example different from FIG. 4. FIG. 10 is a schematic diagram for explaining the decoding process of the intermediate format in FIG. 9; It is a basic diagram with which it uses for description of the intermediate format applied to the electronic still camera of Example 2 of this invention. FIG. 12 is a schematic diagram for explaining position information in the intermediate format of FIG. 11. FIG. 12 is a schematic diagram for explaining the decoding process of the intermediate format in FIG. 11. FIG. 12 is a schematic diagram for explaining a process of converting the encoded data in the intermediate format in FIG. 11 into encoded data in the JPEG format. It is a basic diagram with which it uses for description of the conversion process of FIG. It is a basic diagram with which it uses for description of the intermediate format applied to the electronic still camera of Example 3 of this invention. FIG. 17 is a schematic diagram for explaining a process at the time of decoding the intermediate format in FIG. 16. It is a basic diagram with which it uses for description of the intermediate format applied to the electronic still camera of Example 4 of this invention. It is a basic diagram with which it uses for description of the process at the time of decoding of the intermediate format of FIG. FIG. 19 is a schematic diagram for explaining a process of converting the encoded data in the intermediate format in FIG. 18 into encoded data in the JPEG format. It is a flowchart which shows the process sequence estimated when processing the encoding data of a JPEG format.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic still camera, 2 ... Imaging device, 7 ... Central processing unit, 8 ... Encoding part, 9 ... Memory part, 10 ... Decoding part, 11 ... Signal processing part

Claims (10)

In an image processing method for encoding image data to generate encoded data of a predetermined format,
The predetermined format is:
For each minimum encoding processing unit, the image data is orthogonally transformed to generate DC component and AC component coefficient data,
The AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units,
The DC component coefficient data is a format for variable length encoding processing with reference to the corresponding data of the minimum encoding processing unit processed immediately before,
The image processing method includes:
An intermediate format encoding process step for encoding the image data into intermediate format encoded data;
An intermediate format decoding step of decoding the image data from the intermediate format encoded data;
An image processing step for image processing the image data decoded in the intermediate format decoding step;
A predetermined format encoding process step for encoding the image data processed in the image processing step into encoded data of the predetermined format;
The intermediate format encoding process step includes:
For each of the minimum encoding processing units, the image data is orthogonally transformed to generate the DC component and AC component coefficient data,
Encoding at least the coefficient data of the AC component in the predetermined format;
All or part of the coefficient data of the DC component is encoded without referring to other minimum encoding processing units,
An image processing method characterized in that, in a data string of encoded data encoded by the predetermined format, position data indicating a head position of a minimum encoding processing unit is set to generate encoded data of the intermediate format . A memory storage step of storing in the memory the encoded data of the intermediate format generated in the encoding process of the intermediate format;
The intermediate format decoding step comprises:
The image processing method according to claim 1, wherein the image data is decoded from the encoded data in the intermediate format stored in the memory. The intermediate format encoding process step includes:
Encoding all of the coefficient data in the predetermined format,
The image processing method according to claim 1, wherein all of the DC component coefficient data is encoded without referring to another minimum encoding processing unit. The intermediate format encoding process step includes:
The image processing method according to claim 1, wherein only the coefficient data of the AC component is encoded in the predetermined format. The intermediate format encoding process step includes:
All the DC component and AC component coefficient data are encoded in the predetermined format,
The image processing method according to claim 1, wherein the DC component coefficient data is encoded for each of a plurality of minimum encoding processing units without referring to other minimum encoding processing units. The encoding process of the predetermined format is
Encoding the image data processed in the image processing step into encoded data of the intermediate format;
The image processing method according to claim 1, further comprising: a format conversion step of converting the encoded data of the intermediate format into the encoded data of the predetermined format. The image processing step includes
The image processing method according to claim 1, wherein the image processing is a process for improving an image quality of the image data. In an image processing method program for encoding image data to generate encoded data of a predetermined format,
The predetermined format is:
For each minimum encoding processing unit, the image data is orthogonally transformed to generate DC component and AC component coefficient data,
The AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units,
The DC component coefficient data is a format for variable length encoding processing with reference to the corresponding data of the minimum encoding processing unit processed immediately before,
The image processing method includes:
An intermediate format encoding process step for encoding the image data into intermediate format encoded data;
An intermediate format decoding step of decoding the image data from the intermediate format encoded data;
An image processing step for image processing the image data decoded in the intermediate format decoding step;
A predetermined format encoding process step for encoding the image data processed in the image processing step into encoded data of the predetermined format;
The intermediate format encoding process step includes:
For each of the minimum encoding processing units, the image data is orthogonally transformed to generate the DC component and AC component coefficient data,
Encoding at least the coefficient data of the AC component in the predetermined format;
All or part of the coefficient data of the DC component is encoded without referring to other minimum encoding processing units,
An image processing method characterized in that, in a data string of encoded data encoded by the predetermined format, position data indicating a head position of a minimum encoding processing unit is set to generate encoded data of the intermediate format Program. In a recording medium recording a program of an image processing method for encoding image data to generate encoded data of a predetermined format,
The predetermined format is:
For each minimum encoding processing unit, the image data is orthogonally transformed to generate DC component and AC component coefficient data,
The AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units,
The DC component coefficient data is a format for variable length encoding processing with reference to the corresponding data of the minimum encoding processing unit processed immediately before,
The image processing method includes:
An intermediate format encoding process step for encoding the image data into intermediate format encoded data;
An intermediate format decoding step of decoding the image data from the intermediate format encoded data;
An image processing step for image processing the image data decoded in the intermediate format decoding step;
A predetermined format encoding process step for encoding the image data processed in the image processing step into encoded data of the predetermined format;
The intermediate format encoding process step includes:
For each of the minimum encoding processing units, the image data is orthogonally transformed to generate the DC component and AC component coefficient data,
Encoding at least the coefficient data of the AC component in the predetermined format;
All or part of the coefficient data of the DC component is encoded without referring to other minimum encoding processing units,
An image processing method characterized in that, in a data string of encoded data encoded by the predetermined format, position data indicating a head position of a minimum encoding processing unit is set to generate encoded data of the intermediate format The recording medium which recorded the program. In an image processing apparatus that encodes image data to generate encoded data of a predetermined format,
The predetermined format is:
For each minimum encoding processing unit, the image data is orthogonally transformed to generate DC component and AC component coefficient data,
The AC component coefficient data is subjected to variable length encoding processing without referring to other minimum encoding processing units,
The DC component coefficient data is a format for variable length encoding processing with reference to the corresponding data of the minimum encoding processing unit processed immediately before,
The image processing apparatus includes:
An intermediate format encoding processor that encodes the image data into intermediate format encoded data;
An intermediate format decoding unit for decoding the image data from the encoded data of the intermediate format;
An image processing unit that performs image processing on the image data decoded by the decoding unit of the intermediate format;
A predetermined format encoding processing unit that encodes the image data processed by the image processing unit into encoded data of the predetermined format;
The intermediate format encoding processing unit includes:
For each of the minimum encoding processing units, the image data is orthogonally transformed to generate the DC component and AC component coefficient data,
Encoding at least the coefficient data of the AC component in the predetermined format;
All or part of the coefficient data of the DC component is encoded without referring to other minimum encoding processing units,
An image processing apparatus characterized in that, in a data string of encoded data encoded in the predetermined format, position information indicating a head position of a minimum encoding processing unit is set to generate encoded data in the intermediate format .

Images