WO2000004716A1 - Dispositif d'analyse d'image - Google Patents

Dispositif d'analyse d'image Download PDF

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Publication number
WO2000004716A1
WO2000004716A1 PCT/JP1998/003215 JP9803215W WO0004716A1 WO 2000004716 A1 WO2000004716 A1 WO 2000004716A1 JP 9803215 W JP9803215 W JP 9803215W WO 0004716 A1 WO0004716 A1 WO 0004716A1
Authority
WO
WIPO (PCT)
Prior art keywords
compression
circuit
image information
state
interface
Prior art date
Application number
PCT/JP1998/003215
Other languages
English (en)
Japanese (ja)
Inventor
Hiroki Jinbo
Kenichi Munei
Kikuo Shioya
Hiroaki Takagishi
Original Assignee
Hitachi, Ltd.
Hitachi Tohbu Semiconductor, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to TW087111613A priority Critical patent/TW416229B/zh
Application filed by Hitachi, Ltd., Hitachi Tohbu Semiconductor, Ltd. filed Critical Hitachi, Ltd.
Priority to PCT/JP1998/003215 priority patent/WO2000004716A1/fr
Publication of WO2000004716A1 publication Critical patent/WO2000004716A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals

Definitions

  • the present invention relates to an imaging device such as a camera for sequentially transmitting captured moving image information to a host device.
  • an imaging device such as a camera for sequentially transmitting captured moving image information to a host device.
  • a host device For example, in a video conference system, a television telephone, or the like, an image is captured in a limited band.
  • technology related to technology that is effective when applied to a data processing system such as an image compression / decompression device that compresses image information with hardware or software and decompresses compressed data with software. Things. Background art
  • USB Universal Serial Bus
  • SCSI Serial Computer System Interface
  • IrDA Infrared Data Association
  • RS232C RS232C
  • USB is a standard for serial data transfer, and its data transfer rate is 12 Mbps.
  • the USB Standard (REV1.0) was published on November 13, 1995.
  • the frame rate of the image information is about 25 Hz.
  • the image size of one frame is 352 x 2888 pixels.
  • the image data format is 4: 2: 0 (the luminance data per pixel is 8 bits and the color difference data per pixel is 4 bits)
  • the amount of image information data to be transmitted Is about 29 M bps.
  • the USB data transfer rate is 12 Mb-ps, so when transmitting image information using a USB, image data captured by a monitor camera is compressed or thinned out. And so on. For example, if the compression ratio is reduced to 1/4, the data amount will be approximately 7.3 Mbps, which can satisfy the USB data transfer rate.
  • QCIF Quadrater Common Intermediate Format
  • the size of one frame is 1/4 of CIF
  • QCIF Quadrater Common Intermediate Format
  • the image information can be transferred to the host device via USB as it is, and decompression processing is unnecessary on the host device side, which is preferable because the data processing time is reduced and the load on the processor is reduced.
  • USB devices peripheral devices
  • USB devices can be connected to one host device via a hub.
  • USB specification when a USB device is connected to a port, various configuration information of the USB device is transferred to the host device. Then, the host device always schedules what kind of transfer and when to perform it in units of 1 ms. At this time, since the maximum data transfer rate per second is the above-mentioned 12 Mbps, multiple USB devices must be able to perform data transmission operation in time-division multiplexing without significantly impairing real-time performance. The total data transfer rate of all USB devices must be less than 12 Mbps.
  • the amount of information can be reduced by calculating the difference.
  • the difference is frequency-transformed by the discrete cosine transform.
  • the data after frequency conversion is quantized to reduce the information of high frequency components with a small amount of information.
  • variable-length coding assigns a short code length to a code with a high appearance frequency and a long code length to a code with a low appearance frequency.
  • difference data between frames is calculated in the order of variable length decoding, inverse quantization, and inverse discrete cosine transform. The difference is added to the past image information frame to reproduce the image.
  • Such a method is intended to reduce the amount of information by focusing on the temporal and spatial redundancy of the image.
  • An object of the present invention is to provide an image pickup apparatus capable of efficiently transmitting image information while maintaining good image quality in accordance with an image size (amount of information) and a band (a transfer capacity) of a transmission path. It is in.
  • Another object of the present invention is to reduce the cost of an image pickup apparatus that transmits image information efficiently and with good image quality according to the image size and the bandwidth of the transmission path.
  • An image pickup apparatus is used for image pickup means, compression means for compressing image information acquired via the image pickup means at a variable compression rate, and data transmission of compressed image information output from the compression means.
  • the compression means includes a plurality of compression logic means for respectively compressing image information, means for selecting a compression rate for processing using the compression logic means, and means for indicating a compression rate selected by the selection means. .
  • the compression rate is optimized according to the expansion processing capacity of the host device that receives the different image sizes, transfer capacities, and coded compressed image information. It becomes possible to do.
  • the compression logic is capable of completing the compression process within a single image information frame. In other words, the compression process can be completed with the data in the image information frame. Therefore, the cost of hardware for compressing an image can be reduced, and it is not necessary to have a frame memory for compression.
  • the plurality of compression logic means includes a thinning circuit for image information, ⁇ ⁇ ⁇ V circuit can be adopted. At this time, the selection means may select a state using only the thinning circuit, a state using only the AYUV circuit, a state using both the thinning circuit and the ⁇ YUV circuit, and a state using both the thinning circuit and the ⁇ YUV circuit. One state can be selected from among the states that allow image information to pass through as unused.
  • each image information can be compressed at the selected constant compression ratio, and it is easy to secure a constant frame rate. It is. As a result, it is possible to suppress the deterioration of the image quality of the image information that has undergone compression and expansion.
  • compression logic means consideration is given to decompression processing by software, and the emphasis is on algorithm simplicity rather than compression ratio.
  • compression for example, 1 / m decimation with a compression ratio of lZm, 1 / n decimation with a compression ratio of 1 / n, and a compression ratio of 1/111 ⁇ 1; And compress them in series to compress l / m, l / n, l / (m'n), and 1 / (m ⁇ m).
  • the algorithm of the compression process is easy, and the load on the software for performing the decompression process can be reduced.
  • a USB port of a host device to which a USB device having a USB interface function is connected has a large number of USB ports.
  • the maximum data transfer rate of the USB port of the host device is limited to 12 Mbps, and when multiple USB devices transfer data by time division multiplexing, At this time, since the image pickup device can select a compression ratio of image information, in the case of a USB device having a relatively high data transfer rate such as an image pickup device, The compression ratio of the image information can be varied in consideration of the number of other USB devices sharing the USB port and the data transfer rate.
  • the host device connected to the interface means gives the instruction, the host device refers to the compression ratio instruction at that time. The decompression process can be performed.
  • FIG. 1 is a block diagram showing an overall configuration of an image compression / decompression system including a monitoring camera and a host computer according to an embodiment of the present invention.
  • FIG. 2 is a block diagram showing an example of a variable compression section.
  • FIG. 3 is a schematic diagram illustrating a 1/2 thinning operation selected by the variable compression section.
  • FIG. 4 is a circuit diagram showing an example of a thinning circuit provided in the variable compression section.
  • FIG. 5 is a schematic diagram illustrating the 1/4 thinning operation selected by the variable compression unit.
  • FIG. -FIG. 6 is an explanatory diagram showing a specific example of a data conversion in the compression / decompression processing by the AYUV circuit.
  • FIG. 7 is an explanatory diagram showing a conversion table for converting difference data between adjacent images into transmission data in the AYUV circuit.
  • FIG. 8 is an explanatory diagram showing a conversion table for converting a received data into a difference data from an adjacent image in the AYUV circuit.
  • FIG. 9 is a flowchart showing an example of a compression data decompression process performed by the host computer.
  • FIG. 10 is a flowchart showing an example of realizing compression processing of image data by software.
  • Fig. 1 shows the overall configuration of an image compression / decompression system equipped with a monitor camera and a host computer.
  • reference numeral 4 denotes a host computer such as a personal computer, for example, which has a USB interface function as an external interface, and is connected to a USB port located on a US host hub 20.
  • a device that supports USB can be connected to the port.
  • the USB host hub 20 is connected to an interface controller inside the host computer 4 and controls data transfer instructed by a data transfer command from a processor (not shown). This is performed in accordance with the provisions of the USB Function Specification (REV1.0).
  • REV1.0 USB Function Specification
  • the monitoring camera 21 is one of the USB devices.
  • the monitoring camera 21 is connected to the USB host hub 20 via an interface cable 10A.
  • USB host To the DSU (Digital Service Unit) and TA (Terminal Adapter) 23 which are typically shown as separate USB devices, via an interface cable 10B and an external hub 22.
  • Board 24 is connected.
  • the input image signal is converted into a luminance signal and a chrominance signal by the signal processing unit 5.c
  • the variable compression unit 6 compresses the luminance signal and the chrominance signal by varying the compression ratio.
  • Compressed data (compression The image information) is transmitted from the USB interface circuit 7 to the host computer 4 via the interface cable 1 OA.
  • the host computer 4 expands the received compressed image signal by software and displays it on a monitor.
  • the CCD 1 and the A / D converter 2 operate in synchronization with a signal generated by the timing control unit 8.
  • the image information from the CCD 1 is sequentially read out one pixel at a time for each scanning line, and supplied to the signal processing unit 5.
  • the camera 21 does not need to have a frame memory corresponding to image information such as CIF.
  • FIG. 2 shows a detailed circuit example of the variable compression section 6.
  • the variable compression section includes a 1/2 thinning circuit 11 for compressing the information amount of the captured image to 1/2, a 1/4 thinning circuit 12 for compressing the information amount of the captured image to 1/4, It has an AYUV circuit 13 for compressing the information amount of the image to half, and switch circuits 14 and 15 for selecting three kinds of compression circuits.
  • the switch states of the switch circuit 14 and the switch circuit 15 are controlled by an instruction from the general control unit (general control circuit) 9. By switching the switches 14 and 15, it is possible to set a path for outputting the input signal without compression and a path for compressing the compression ratio of 1/2, 1/4, and 1/8.
  • FIG. 3 schematically shows luminance (or color difference) signals arranged two-dimensionally.
  • the 1/2 thinning circuit compresses the above information amount to 1/2 by sampling 1/2 data and thinning out 1/2 data. However, if only 1/2 of the data is thinned out, the image may be distorted due to the effect of aliasing. Therefore, before thinning, the image is subjected to a two-dimensional LPF (Low Pass Filter) operation to reduce high frequency components.
  • Fig. 4 shows an example of LPF configuration.
  • the horizontal storage element 16 is a 7-pin filter and the vertical storage element 17 is a 3-tap FIR (Finite Impulse Response) type filter. You.
  • a luminance (or color difference) signal is input one pixel at a time in the horizontal direction, a product-sum operation is performed using coefficients 1 & A to 18J, and the operation result is replaced with the data of the center pixel.
  • the selection circuit 19 performs the thinning according to FIG. 3 to compress the information amount to half.
  • the ⁇ YUV circuit 13 will be described.
  • the AYUV method is a compression technology that has been put to practical use in car navigation and the like.
  • Figure 6 shows an example of conversion from original data to compressed data.
  • the dynamic range of luminance (or color difference) signal 0 to 255 is compressed to 16 to 235 by the conversion formula ⁇ 2 (y / 255) ⁇ 219 + 16.
  • Yn—Predicted value Pn Difference Dn is obtained.
  • the difference Dn is encoded according to the conversion table shown in FIG. 7, and the obtained ⁇ n is transmitted.
  • ⁇ Yn is re-converted according to the conversion template shown in Fig.
  • Pn + 1 is 16 or less or 235 or more, clip to 16 or 235.
  • the AYUV circuit 13 also reduces the amount of information by half.
  • variable compression section 6 the processing is completed in the image information frame, and there is no need to use a frame memory in the compression / expansion processing, and the cost of the image compression / expansion apparatus can be reduced. it can. Furthermore, there is no change in the number of processes due to the redundancy of the image information, the frame rate can be kept constant, and the smooth operation of the object of the reproduced image is guaranteed.
  • compression processing is necessary (S10), it is determined whether or not compression by thinning is possible (S11) based on the compression ratio instructed from the host computer.
  • S11 it is determined whether it is 1/2 thinning or 1/4 thinning (S12), and select either 1/2 thinning processing (S13) or 1/4 thinning processing (S14). Or execute.
  • AYUV is required
  • S16 If neither compression is necessary, the luminance (color difference) signal is output through.
  • thinning 1/4 and thinning 1/2 and AYUV are two methods: thinning 1/4 and thinning 1/2 and AYUV. Either method can be selected depending on the image quality and the processing capability of the decompressing software.
  • the compressed image information is displayed as it is from the interface cable 10 on the display means (host computer 4). It is possible to display reduced-size images without using YUV decoding means.
  • Host computer 4 can be connected via interface cable 1 OA
  • the control information is given to the variable compression section 6 to indicate the compression ratio.
  • the host computer 4 stores the control information and, when decompressing the received compressed data, refers to the stored control information and performs processing according to the flowchart of FIG. .
  • the host computer 4 refers to the control information to determine whether compression by AYUV has been performed (S1), and if compression by AYUV has been performed, performs expansion processing by ⁇ YUV (S2). .
  • the host computer 4 refers to the control information to determine whether compression by thinning has been performed (S3), and if so, determines whether it is 1/2 thinning or 1/4 thinning. Yes (S4). If 1/2 has been thinned out, a filter operation for interpolating the data thinned out in the double interpolation processing (S5) is performed. If 1/4 thinning has been performed, it is determined whether decompression processing is possible (S6). If the display screen size by the host computer 4 is 1/4 of the screen size before compression, the decompression process is omitted. Performs a filter calculation. When the decompression process is completed, the image is displayed (S8).
  • the compression method of image information is a variable compression ratio, it is possible to cope with a case where priority is given to either the compression ratio or the image quality, which are in opposite relations. Since each frame is compressed at a predetermined compression ratio, the amount of operation of each compression algorithm is small, and multiple frame memories are not required, the USB port of the c host computer 4 that can realize a system at low cost has many USB devices share.
  • the maximum data transfer rate of the USB port of the host computer 4 has a limit of 12 Mbps, and when multiple USB devices transfer data by time division multiplexing, the limit must be satisfied. .
  • the monitor camera 21 can select the compression ratio of the image information, the USB data having a relatively large data transfer rate like the camera camera 21 is used.
  • the compression rate of image information can be varied in consideration of the transfer rate of several USB devices sharing the USB port. For example, if the imaging frame rate of CCD 1 is 25 Hz, the image data format is 4: 2: 0, and the image size is CIF, the number of USB devices connected to the USB host hub 20 When the number of other USB devices is increasing, the compression ratio can be set to 1/8.
  • the compression ratio can be set to 1/2 or 1/4.
  • the monitor camera 21 having the USB interface function has a large data transfer amount, the number of other USB devices sharing the USB port and the data transfer rate are taken into consideration.
  • the compression ratio of image information can be varied, making it ideal for USB interface.
  • the interface means is not limited to USB, but may be another serial interface or a parallel interface.
  • the image format of the luminance signal and the color difference signal may be 4: 2: 2.
  • the image frame rate of the image information picked up by the image pickup means is not limited to 25 Hz, but may be 30 Hz or the like.
  • the image size of the image information imaged by the imaging means is not limited to CIF and QCIF.
  • the settings of the overall control unit 9 are set from the host computer 4, but items that do not require external setting changes may be fixed in advance. Industrial applicability
  • the present invention can be widely applied to a monitor camera, a video conference system, a video phone, and the like which are used by being connected to a personal computer.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

L'invention concerne un dispositif d'analyse d'image constitué d'un moyen de compression (6, 9) qui comprime les informations images obtenues par un moyen d'analyse d'image (1) selon une compressibilité variable. Les informations images comprimées produites en sortie par le moyen de compression sont envoyées à un dispositif central (4) par l'intermédiaire d'un moyen d'interface (7). La compressibilité est spécifiée par le moyen de compression en fonction d'informations de commande envoyées par le moyen d'interface et la compression peut être effectuée par le moyen de compression dans un seule trame d'informations images. Ainsi, la compressibilité peut être optimisée en fonction de la capacité de décompression du dispositif central qui reçoit différentes tailles d'image, capacités de transfert et informations images comprimées. Par ailleurs, étant donnée que la compression peut être assurée par des données dans la trame d'informations images, le coût du matériel pour la compression d'images peut être réduit et une mémoire de trames pour la compression n'est pas nécessaire.
PCT/JP1998/003215 1998-07-17 1998-07-17 Dispositif d'analyse d'image WO2000004716A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
TW087111613A TW416229B (en) 1998-07-17 1998-07-16 Photographing apparatus
PCT/JP1998/003215 WO2000004716A1 (fr) 1998-07-17 1998-07-17 Dispositif d'analyse d'image

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP1998/003215 WO2000004716A1 (fr) 1998-07-17 1998-07-17 Dispositif d'analyse d'image

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WO2000004716A1 true WO2000004716A1 (fr) 2000-01-27

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PCT/JP1998/003215 WO2000004716A1 (fr) 1998-07-17 1998-07-17 Dispositif d'analyse d'image

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WO (1) WO2000004716A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004112396A1 (fr) * 2003-06-13 2004-12-23 Nokia Corporation Dispositif electronique de compression de donnees d'images et de creation d'images reduites, processeur d'images, et structure de donnees
JP2007124212A (ja) * 2005-10-27 2007-05-17 Megachips Lsi Solutions Inc 画像処理装置および画像処理装置に接続される装置
CN1320809C (zh) * 2001-08-29 2007-06-06 佳能株式会社 图像处理装置与方法
JP2011155693A (ja) * 2011-04-27 2011-08-11 Mega Chips Corp 画像処理装置および画像処理装置に接続される装置

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Publication number Priority date Publication date Assignee Title
JPH0262856U (fr) * 1988-10-27 1990-05-10
JPH07264092A (ja) * 1994-03-17 1995-10-13 Fujitsu Ltd 情報提供装置
JPH08289251A (ja) * 1995-04-18 1996-11-01 Tec Corp マルチメディア処理装置

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Publication number Priority date Publication date Assignee Title
JPH0262856U (fr) * 1988-10-27 1990-05-10
JPH07264092A (ja) * 1994-03-17 1995-10-13 Fujitsu Ltd 情報提供装置
JPH08289251A (ja) * 1995-04-18 1996-11-01 Tec Corp マルチメディア処理装置

Non-Patent Citations (2)

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Title
M. WRIGHT: "Digital-camera interfaces lead to ubiquitous deployment", EDN, vol. 43, no. 2, 1998, US, pages 63 - 64, 66, 68, 70, 72-73, XP002927439 *
SATOSHI FUKINO: "Practical Theory on USB (in Japanse)", ELECTRONICS, vol. 43, no. 5, 1998, TOKYO, pages 31 - 51, XP002927440 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1320809C (zh) * 2001-08-29 2007-06-06 佳能株式会社 图像处理装置与方法
WO2004112396A1 (fr) * 2003-06-13 2004-12-23 Nokia Corporation Dispositif electronique de compression de donnees d'images et de creation d'images reduites, processeur d'images, et structure de donnees
JPWO2004112396A1 (ja) * 2003-06-13 2006-07-27 ノキア コーポレイション 画像データの圧縮とサムネール画像の作成を行う電子機器、画像処理装置、データ構造
US7362970B2 (en) 2003-06-13 2008-04-22 Nokia Corporation Electronic device for compressing image data and producing thumbnail image, image processing apparatus, and data structure
JP4571074B2 (ja) * 2003-06-13 2010-10-27 ノキア コーポレイション 画像データの圧縮とサムネール画像の作成を行う電子機器、画像処理装置、データ構造
JP2007124212A (ja) * 2005-10-27 2007-05-17 Megachips Lsi Solutions Inc 画像処理装置および画像処理装置に接続される装置
JP2011155693A (ja) * 2011-04-27 2011-08-11 Mega Chips Corp 画像処理装置および画像処理装置に接続される装置

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