Source: http://www.google.com/patents/US7388992?dq=inassignee:Temic
Timestamp: 2018-01-20 09:56:24
Document Index: 497816409

Matched Legal Cases: ['art 41', 'art 42', 'art 43', 'art 16', 'art 41', 'art 42', 'art 42', 'art 42', 'art 43', 'Application No. 2005']

Patent US7388992 - Digital photographic device for controlling compression parameter of image ... - Google Patents
This device includes an image data creator that creates a first type of image data for test shooting and creating a second type of image data for real shooting; a compressor that compresses the image data in a predetermined compression format; and a processor; wherein the compressor has one or plural...http://www.google.com/patents/US7388992?utm_source=gb-gplus-sharePatent US7388992 - Digital photographic device for controlling compression parameter of image data and method of deciding compression parameter value of image data
Publication number US7388992 B2
Application number US 11/314,110
Also published as US20060192860, WO2005002206A1
Publication number 11314110, 314110, US 7388992 B2, US 7388992B2, US-B2-7388992, US7388992 B2, US7388992B2
Inventors Eiji Atsumi, Kazunobu Shin, Yusuke Toriumi
Digital photographic device for controlling compression parameter of image data and method of deciding compression parameter value of image data
US 7388992 B2
deciding the value of the compression parameter to be used for the second type of image data according to a predetermined standard, based on two and more files of first type image data that are compressed using values of the compression parameters which are different from each other.
The camera-equipped cellular phone 1 is provided with a photograph mode and a preview mode. The photograph mode is a mode to acquire the image data used as a photograph, namely, the so-called picture taking mode. In the photograph mode, the camera module 11 may create the image data at the maximum resolution that is photographable by the solid-state image pickup device 13. In addition, in order to save the capacity of a main storage unit 34 to be described later, sometimes shooting is carried out with the resolution decreased to half of the maximum resolution of the solid-state image pickup device 13 or ¼ thereof. The image data created in the photograph mode is saved in the data recording medium in order to use this image data afterward. Hereinafter, this image data is called the image data for saving. The preview mode is a mode to check the image to be photographed, using the display 2 for the purpose of deciding the structural outline of the actual photograph. In the preview mode, the image data with the resolution greatly decreased in comparison with the image data to be created in the photograph mode. This image data is used by a display unit 36 that is provided in the host module 12 and it is mainly used for displaying the preview, so that this image data is hereinafter called as the image data for display. Since the display unit 36 only has a small display screen, the resolution of the image data for display may also be small and typically, the resolution is about QQVGA (160 pixels×120 lines). In the preview mode, not by acquiring the output signal from the all pixels of the solid-state image pickup device 13 but by acquiring the output signal only from partial pixels, the image data for display with a small resolution is created. In order to create the image data for display, there are well-known methods such as the above-described CFA interpolation processing.
With reference to FIG. 3, the structure and the operation of the JPEG compressor 17 will be described below. The JPEG compressor 17 is provided with a buffer memory 40, a DCT part 41, a quantization part 42, and a Huffman coding part 43. This buffer memory 30 may store plural lines, for example 8 lines, of the image data 47 sequentially constructed by an image construction part 16 one line or several lines at a time. The DCT part 41 may apply a discrete cosine transformation to each data block 46 composed of 8×8 units of the image data 47 from the eight lines stored in the buffer memory, and may convert this data into the information of a frequency domain. The quantization part 42 may smooth the data block that has been converted into the frequency information. The quantity of data used for smoothing may be that of a quality factor 44 or a quantization table 45. The quantization table 45 is a quantization matrix of 8×8 and it is divided by the block converted into the frequency information. The quality factor 44 is a coefficient and by multiplying this with the quantization table 45, each element of the quantization table 45 is increased or decreased at the same rate. Depending on a degree of this smoothing in the quantization part 42, the compression rate is changed. Accordingly, by using the different quality factor 44 or the different quantization table 45, the compression rate can be changed. According to the camera-equipped cellular phone of the present invention, the host module 12 can, by controlling the quantization part 42 through the control interface 20, change the quality factor 44 and the quantization table 45. The Huffman coding part 43 may perform compression by converting the data block, which is a two-dimensional data row of 8×8, into a one-dimensional data row by zigzag scan and allocating a short code to a bit pattern with a high frequency of appearance. Thus, the JPEG-compressed image data 48 is sequentially created for each data block.
QW=Q1+(Q1−Q2)/(S1−S2)×(SW−S1) equation 1
Next, with reference to FIG. 4, a flow of the processing in order to decide the value of the compression parameter for use in the compression of the image data for saving will be described below. At first, in step 51, the estimation of the compression parameter value will be started. The preview mode to create and display the image data for display may be started before the estimation of the parameter value is started. The estimation of the parameter value is started, for example, by pressing the function button 4 halfway. In step 52, in order to create the image data for preview, the data collection due to the solid-state image pickup device 13, namely, the conversion into an optical electric signal due to the solid-state image pickup device 13, is carried out. In step 53, the image data for display is created from the output signal of the solid-state image pickup device 13. The image data for display composing one frame is sequentially created one line or several lines at a time. The steps of the sequence of operations from the conversion into the optical electric signal due to the solid-state image pickup device 13 until creation of the image data for display are carried out at predetermined time intervals, for example, each 1/10 second (step 54). Every time the step 52 and the step 53 are repeated, the image data for display of one frame is created. Sometimes the created image data for display is compressed after that, and other times the created image data for display is not compressed after that. For example, every time three files of image data for display are created, one file among them is compressed. In step 55, the uncompressed image data for display is displayed on the display unit. In steps 56 to 58, one file among them is JPEG-compressed. At first, in the step 56, the discrete cosine transformation is performed for each data block 63 composed of 8×8 image data, and the data describing brightness and color is converted into the data of the frequency band. Next, in the step 57, quantization is performed and the data block 63 converted into the frequency information is smoothed by the quality factor 64 and the quantization table 65. Every time the image data for display of a new frame reaches the step 57, a different quality factor 64 or a different quantization table 65 are used. In other words, every time the image data for display of a new frame reaches the steps 56 to 58, this image data is compressed at different compression rates. In this example, the description is provided assuming that the quantization table 65 is fixed and the quality factor 64 only is changed. In the last step 58 of the compression process, the Huffman coding is carried out and the JPEG compression is completed. In the step 59, the sizes of the display data files resulting from the use of the different quality factors are compared with each other with and the quality factor which gives the desired data size is decided upon. In step 60, the compressor is set at the estimated quality factor.
Here, since the estimated compression parameter is acquired by compressing image data for display with a low resolution, sometime it is not proper to use the estimated parameter as it is for the image data for photographing with a high resolution. It is known that the image with the higher resolution is generally compressed more effectively in the case of using the same compression parameter. Accordingly, sometimes it is preferable that a parameter QW′ which gives a compression rate higher than the quality factor QW estimated as the equation 1 is used. In addition, the smaller the value of the quality factor, the lower the image quality and thus the higher the compression rate. Therefore, QW′=QW×S (S<1.0) may be decided on the basis of the difference of the resolution between the display image and the photographed image and judgment gained from experience. In the step 59, by using a compression rate estimation table indicating a relation between such a correction amount S and a corrected quality factor, a desired quality factor may be decided. An example of the compression rate estimation table is indicated in Table 1 as follows.
Value of quality factor Correction Quantity after correction
th1 < = QW < th2 s1 QQW = s1 × QW
th2 < = QW < th3 s2 QQW = s2 × QW
th3 < = QW < th4 s3 QQW = s3 × QW
Next, with reference to FIG. 5, the flow of the processing in the photograph mode of the digital photographic device according to the present invention will be described below. At first, in step 71, the photograph mode is started. The photograph mode is started, for example, by completely pressing the functional button 4 in FIG. 1. In step 72, the data collection due to the solid-state image pickup device 13 is carried out and the conversion into the optical electric signal is performed by the solid-state image pickup device 13. In step 73, the image data for saving is sequentially created one line or several lines at a time. In step 74, the discrete cosine transformation is performed for each data block composed of the image data of 8×8 and the data describing brightness and a color is converted into the data of the frequency band. Next, in step 75, quantization is performed using the quality factor 80 the quantization table 81 decided by the flow of the processing shown in FIG. 4. In step 76, the Huffman coding is carried out and the JPEG-compressed image data for saving is sequentially created for each data block composed of the image data of 8×8. In step 77, the compressed image data for saving is saved in the recording medium. At last, in step 78, the calculation and the display of the number of images which still can be shot are carried out based on the remaining capacity of the recording medium and the data size per image data (one frame).
JP2000114980A Title not available
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1 Japanese Office Action dated Oct. 15, 2007 issued in corresponding Application No. 2005-503210.
U.S. Classification 382/232, 375/E07.157, 382/253, 375/E07.138, 375/E07.226, 375/E07.131, 375/E07.167
International Classification G06K9/36, H04N1/333, H04N7/30, H04N7/24, H04N1/41, G06K9/38, G06K9/46, H04N7/26, H04N5/92
Cooperative Classification H04N19/154, H04N19/197, H04N19/149, H04N19/196, H04N19/194, H04N19/60, H04N2201/33357, H04N1/33307, H04N2101/00
European Classification H04N19/00A4P1, H04N7/26A4P, H04N1/333B, H04N7/30, H04N7/26A6E4E, H04N7/26A6Q, H04N7/26A10T2
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ATSUMI, EIJI;SHIN, KAZUNOBU;TORIUMI, YUSUKE;REEL/FRAME:017562/0293;SIGNING DATES FROM 20060316 TO 20060417