WO2007059671A1 - Dispositif de capture de signal video - Google Patents

Dispositif de capture de signal video Download PDF

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Publication number
WO2007059671A1
WO2007059671A1 PCT/CN2006/001672 CN2006001672W WO2007059671A1 WO 2007059671 A1 WO2007059671 A1 WO 2007059671A1 CN 2006001672 W CN2006001672 W CN 2006001672W WO 2007059671 A1 WO2007059671 A1 WO 2007059671A1
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WIPO (PCT)
Prior art keywords
module
gamma characteristic
correction
parameter
video signal
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PCT/CN2006/001672
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English (en)
Chinese (zh)
Inventor
Zhong Luo
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Huawei Technologies Co., Ltd.
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Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Publication of WO2007059671A1 publication Critical patent/WO2007059671A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/80—Camera processing pipelines; Components thereof
    • H04N23/82—Camera processing pipelines; Components thereof for controlling camera response irrespective of the scene brightness, e.g. gamma correction
    • H04N23/83—Camera processing pipelines; Components thereof for controlling camera response irrespective of the scene brightness, e.g. gamma correction specially adapted for colour signals

Definitions

  • the present invention relates to video communication technologies, and in particular, to a video signal acquisition device having a gamma characteristic correction function. Background technique
  • Video communication is currently being widely used with the rapid development of broadband networks.
  • video conferencing and video telephony services are becoming the basic services on NGN (Next Generation Network).
  • NGN Next Generation Network
  • Telecom operators in various countries also attach great importance to this market opportunity. It is expected that in the next few years, video communication services will become an important business growth point for operators.
  • a key issue in developing such a business is to improve the end-to-end user experience (User Experience, or Quality of Experience).
  • the distortion of the luminance signal caused by the gamma nonlinearity caused by each link also affects the end user experience. An important factor.
  • an optical signal from a scene (person, background, file, etc.) to be transmitted enters the camera/camera, and is converted into a digital image signal by A/D. After compression coding, it is transmitted to the other terminal and decompressed and decoded to restore the digital image signal, and then displayed on the display device. It turns into a light signal that is perceived by the human eye.
  • the image brightness signal Luminance, here is a generalized luminance signal, that is, the initial optical signal, the electrical signal, and then the digitized image luminance/gray signal, the signal of each stage contains the luminance signal. Information, in a broad sense, the luminance signal has gone through multiple steps).
  • Fig. 1 is a schematic diagram of the model of the link Gamma characteristic.
  • the Gamma characteristic is that the input/output relationship of the luminance signal of a link is not linear, but a nonlinearity.
  • the effect of the non-linear link distortion of Gamma is shown in Fig. 2.
  • the brightness of the above-mentioned row of gray squares is linearly increasing from 0.1 to 1.0.
  • the lower line is distorted by the Gamma nonlinear link, and the brightness is increased according to the power function.
  • the input and output luminance signals here are normalized in their respective coordinate spaces, that is, 0 ⁇ L. ut ⁇ l, 0 ⁇ L in ⁇ l.
  • Other types of displays such as liquid crystals, have different forms of Gamma functions, or although they are also power functions in form, but the parameters are different.
  • FIG. 3 is a schematic diagram of a gamma characteristic of a plurality of links (Cascading or tandem).
  • the total Gamma characteristic is equal to the composition of each Gamma function, and the formula 3 is satisfied.
  • G CT (.) G m (.).
  • CT indicates Cascaded Total, which is the meaning of cascading total Gamma.
  • the model of the correction link is the inverse model of the Gamma characteristic equivalent model. If the equivalent model can be expressed by a function relation, the function relation of the inverse model is its inverse function. Obviously, G g (.) and G e (.) are inverse functions of each other. In general, for a function, the inverse function does not necessarily have a solution (or even if the solution exists, it cannot be obtained by calculation).
  • the origin of the Gamma correction problem lies in the CRT display device with Gamma characteristics, and the camera/camera provides Gamma correction as a requirement.
  • high-end cameras generally provide Gamma correction, but a large number of low-end cameras are not available. If the camera is capable of providing Gamma correction, it means that the external Gamma characteristics of the camera as a whole are given by Equation 2.
  • the present invention provides a video signal acquisition device having a gamma characteristic correction function to solve the problem that the video signal acquisition device lacks adaptive correction capability for the gamma characteristic of the video signal in the prior art.
  • the video signal collecting device of the present invention includes a camera module that collects a video signal, and the video signal collecting device further includes:
  • control module parsing the correction control instruction and outputting a corresponding indication signal
  • the processing module acquires a related gamma characteristic parameter of the video signal according to the indication signal, and calculates and outputs a gamma characteristic correction parameter;
  • a correction generation module corrects a gamma characteristic of the video signal according to the gamma characteristic correction parameter.
  • the video signal collecting device further includes a storage module connected between the control module and the processing module, configured to save a preset initial calibration parameter, and/or a target gamma of the video signal corrected by the correction generating module. Ma characteristic parameters.
  • the storage module includes:
  • An initial correction parameter storage submodule for saving the initial correction parameter
  • a target gamma characteristic parameter storage submodule configured to save the target gamma characteristic parameter.
  • the storage module further includes:
  • a camera module gamma characteristic parameter storage sub-module for saving a gamma characteristic parameter of the camera module
  • the control module includes:
  • a correction control instruction receiving submodule for receiving an external correction control instruction
  • the correction control instruction parsing sub-module is configured to parse the correction control instruction and output a corresponding indication signal to the processing module, specifically including one or any combination of the following:
  • the instruction processing module performs the following operations: receiving the camera module gamma characteristic parameter input by the control module and the gamma characteristic parameter of the subsequent module through which the video signal output by the correction generating module passes, according to the The camera module gamma characteristic parameter and the subsequent module gamma characteristic parameter calculate the gamma characteristic correction parameter, and calculate the target gamma characteristic parameter according to the camera module gamma characteristic parameter and the gamma characteristic correction parameter, and then the target The gamma characteristic parameter is stored in the target gamma parameter storage sub-module;
  • the instruction processing module performs the following operations: extracting the camera module gamma characteristic parameter from the camera module gamma characteristic parameter storage submodule, and receiving the subsequent module gamma characteristic parameter input by the control module, Calculating the gamma characteristic correction parameter according to the camera module gamma characteristic parameter and the subsequent module gamma characteristic parameter, and calculating the target gamma characteristic parameter according to the camera module gamma characteristic parameter and the gamma characteristic correction parameter, and then The target gamma characteristic parameter is stored in the target gamma parameter storage submodule;
  • the instruction processing module performs the following operations: receiving the camera module gamma characteristic parameter and the target gamma characteristic parameter input by the control module, and calculating the gamma characteristic parameter and the target gamma characteristic parameter according to the camera module Describe the gamma characteristic correction parameter, and then store the target gamma characteristic parameter into the target gamma parameter storage sub-module;
  • the instruction processing module performs the following operations: extracting the camera module gamma characteristic parameter from the camera module gamma characteristic parameter storage submodule, and receiving the current target correction gamma characteristic parameter input by the control module, according to The camera module gamma characteristic parameter and the current target correction gamma characteristic parameter calculate the gamma characteristic correction parameter, and store the target gamma characteristic parameter into the target gamma parameter storage sub-module;
  • the instruction processing module performs the following operations: receiving the camera module gamma characteristic parameter input by the control module, and extracting the fifth school from the calibration template parameter storage submodule Positively controlling the calibration template parameter indicated in the instruction, calculating the gamma characteristic correction parameter according to the camera module gamma characteristic parameter and the calibration template parameter, and storing the calibration template parameter in the target gamma parameter storage submodule;
  • the instruction processing module performs the following operations: extracting the camera module gamma characteristic parameter from the camera module gamma characteristic parameter storage submodule, and extracting the sixth correction control instruction from the calibration template parameter storage submodule The calibration template parameter indicated in the calculation, calculating the gamma characteristic correction parameter according to the camera module gamma characteristic parameter and the calibration template parameter, and storing the calibration template parameter in the target gamma parameter storage sub-module;
  • the instruction processing module Upon receiving the seventh correction control instruction, the instruction processing module performs the following operations: Extracting the initial correction parameters from the initial correction parameter storage module and inputting the correction generation module.
  • the control module further includes: a gamma characteristic parameter read/write sub-module, configured to receive an associated gamma parameter of the external command input and write the corresponding storage sub-module; or, read the parameter from the storage sub-module according to the external instruction. And output; or, according to an external instruction, delete the parameters in the corresponding storage sub-module.
  • a gamma characteristic parameter read/write sub-module configured to receive an associated gamma parameter of the external command input and write the corresponding storage sub-module; or, read the parameter from the storage sub-module according to the external instruction. And output; or, according to an external instruction, delete the parameters in the corresponding storage sub-module.
  • control module the gamma characteristic parameter storage module, the processing module, and the correction generation module are collectively set as independent entities, and:
  • the calibration generation module receives the video signal to be corrected through the first interface, and outputs the corrected video signal through the second interface;
  • the control module receives the associated gamma parameters and correction control commands of the external input through a third interface.
  • the camera module includes: a camera/camera, a video collection sub-module, and a video signal acquisition driver sub-module;
  • the calibration generation module is connected between the camera/camera and the video collection sub-module, or between the video acquisition sub-module and the video signal acquisition driver sub-module, or between the acquisition driver sub-module and the subsequent module.
  • the camera module includes: a camera/camera, a video signal interface acquisition board, and a video signal acquisition driver submodule;
  • the calibration generating module is connected between the camera/camera and the video signal interface acquisition board, or between the video signal interface acquisition board and the video signal acquisition driver submodule, or between the acquisition driver submodule and the subsequent module.
  • the subsequent modules specifically include:
  • the video signal passes through all links with gamma characteristics on the receiving terminal.
  • the correction generation module includes two or more.
  • the invention adds a Gamma correction link to the video signal acquisition device, thereby realizing the gamma correction applicable to any camera/camera and subsequent modules, which can be realized by a circuit and a hardware method, or can be realized by a software method, thereby improving the quality of the video user experience. ;
  • the video signal acquisition device of the present invention can set a plurality of correction modules in parallel, respectively connecting the display module of the video signal and the network output interface, respectively for using the camera.
  • the gamma characteristic correction function of the module and the display module corrects the locally displayed video signal, or corrects the gamma characteristic of the output video signal of the terminal by using the gamma characteristic of the communication terminal, thereby improving the gamma correction performance of the video communication system.
  • Figure 1 is a general model of the link Gamma characteristics
  • FIG. 2 is a schematic diagram of luminance signal distortion caused by link Gamma characteristics
  • Figure 3 is a general model of multi-link cascaded Gamma characteristics
  • Figure 4 is a schematic diagram of the Gamma characteristic for correcting a single link
  • Figure 5 is a schematic diagram of the Gamma characteristics for correcting a plurality of given links
  • Figure 6 is a schematic diagram of possible correction points when multiple Gamma links are cascaded
  • FIG. 7 is a schematic diagram of a general Gamma characteristic correction method when multiple Gamma links are cascaded;
  • FIG. 8 is a schematic diagram of an internal module structure of a multimedia communication terminal based on an independent hardware box;
  • 9 is an internal module structure of a multimedia communication terminal based on a general-purpose computer;
  • FIG. 10 is a schematic structural diagram of a video capture device according to the present invention, including the video signal correction subsystem of the present invention
  • FIG 11 is a schematic structural view of the control module of Figure 10. Detailed ways
  • the Gamma path of the video signal from the acquisition to the output includes N t cascaded Gamma links, and any two links can be selected as the correction point, and the correction link passes the image through the Gamma path.
  • the correction point includes > ⁇ links, and the correction points include N p links.
  • the equivalent integrated Gamma characteristics of the links and N p links are determined separately, and then the syndromes of the equivalent Gamma characteristics are respectively constructed, and then the two syndromes are combined and inserted into the correction points, and corrected.
  • the link is actually a combination of two syndromes, including the following steps:
  • the construction method of the correction link model includes one of the following:
  • Direct calculation method calculating the correction signal of the last output signal of the N a links by using the function relation of the first inverse model and the function relation of the second inverse model in real time;
  • Two-step calculation method Calculate the primary correction signal of the last output signal of the N a link in real time by using the functional relationship of the first inverse model, and calculate the secondary correction signal of the primary correction signal by using the functional relationship of the second inverse model, The secondary correction signal is used as the correction signal;
  • Checking table method calculating, according to the direct calculation method or the two-step calculation method, a correction value corresponding to a plurality of sample values in a value interval of the last output signal of the N a bad segments, and saving the correspondence relationship
  • the correction value of any value to be corrected is then determined by querying the data table in real time.
  • the equivalent model itself has no analytical form (for example, using the look-up table method, of course, the inverse function has no analytical form), then the inverse model is the inverse table of the data table, one table There are two columns and multiple rows.
  • the left column (input column) is the sampled value of the input signal, that is, the signal value to be corrected
  • the right column output column
  • the inverse table is the new data table obtained by adjusting the left and right columns.
  • the table lookup is the most practical method.
  • the terminal must be able to determine all the gamma features on the terminal.
  • the sender or receiver can determine the equivalent model of each gamma feature link at the local end. Its parameters.
  • the present invention also introduces a method for determining the equivalent model of each Gamma characteristic link and its parameters, including the following steps:
  • Equation 5 The domain of the function shown in Equation 5 (ie, the range of argument values) is the interval [ll/q, l], the range of values (the range of values of the function value) ) is the interval [(0,1].
  • Equation 6 Equation 6
  • Mathematical optimization techniques such as: hill climbing method, 0.618 method (Hua Luogen preferred method), steepest descent method or conjugate gradient method, etc.
  • This process is actually an iterative process.
  • the parameters p and ⁇ are constantly adjusted.
  • the function value F is decreasing.
  • the minimum point is considered to have been found.
  • the corresponding parameter and 01 are considered as the true parameters of the application environment model.
  • the objective function value F may continue to decrease, or fall again, or rise directly, regardless of the objective function value. What kind of change is F, then selecting the parameter corresponding to the minimum value as the measurement result will improve the accuracy of the parameter measurement to some extent.
  • the determination of the model type and the measurement of the parameters are performed simultaneously.
  • the type of the equivalent model is not limited to these two forms.
  • the above method can also be used to measure the multi-link integrated Gamma characteristic model and its parameters.
  • the measurement method steps are identical. It should be pointed out that, from the formal point of view, the functional relationship of multiple Gamma characteristic models cascaded by multiple Gamma links can still adopt Equation 6. And the two types shown in Equation 7, but in the first type of comprehensive characteristic model, according to the qualitative analysis results and the empirical values actually measured, the range of the index ⁇ becomes ⁇ > 0, and in the second comprehensive characteristic model, the index The range of ⁇ values becomes ⁇ >0.
  • the external optical signal enters the camera/camera, and is processed by each link, and finally the display of the local display is converted into an optical signal; or the compressed coding link is transmitted to the other terminal through the communication network, and then After decompression decoding, it is restored into an image, and then displayed on the multi-terminal display to be converted into an optical signal; or after the optical signal enters from the camera/camera, it is converted into an electrical signal, and then, after a certain process, is written to the file, and saved.
  • a storage device such as a hard disk.
  • the path through which each video signal passes can be regarded as a Gamma path as shown in Fig. 7, and the general method described above can be used to correct the Gamma characteristics.
  • the multimedia communication terminal structure of the present invention comprises: a camera/camera, a video acquisition module, an acquisition drive module, a local display/file storage module, a video pre-processing module and a video compression coding module, and the acquisition driver module has a built-in driver.
  • the multimedia communication terminal of the present invention can be divided into two categories:
  • the first type is shown in Figure 8, which is a terminal based on an independent hardware box, including: conference room type multimedia conference terminal, STB type videophone terminal, mobile terminal with multimedia video communication capability, mobile phone, home network In the multi-function terminal/home gateway, etc.;
  • the second type is shown in FIG. 9, which is a general-purpose computer-based terminal, such as a PC, a workstation, or the like.
  • Figure 8 Based on independent hardware box terminals, there are many specific product forms covered. From the perspective of the internal module structure, Figure 8 provides the most general case. In practice, it is possible that the video processing board and the main control board are integrated on one board (this can reduce the size and cost, especially for mobile terminals). And the camera can be built into the box.
  • the video signal acquisition interface card may not be required as an independent hardware card, but its logic function is definitely required, for those that can directly pass through the USB port and The camera connected to the computer, this part of the logic function is assigned to the camera inside and the video capture driver. Therefore, it is emphasized that the present invention is described at the functional logic level, and the method is applicable to any specific hardware and software implementation, and is not limited to one or some specific implementation forms.
  • the video collection devices of the present invention are respectively located in a dotted line frame.
  • the above general gamma correction method can be implemented in the camera/camera, and a plurality of selected correction points can be selected in the camera/camera. Because the camera/camera is strictly speaking, if it contains the capture card and driver software it carries as a whole (this integration process is reasonable, because from the signal flow direction, the video signal from the camera/camera is captured by the card. And the driver software obtains, and then inputs to other modules of the multimedia communication terminal, so as a whole) can be called a video signal collection device. Therefore, in the present invention, the video collection device is a functional logic concept, and does not necessarily correspond only to Actual camera/camera.
  • microprocessor chips possibly and control programs based on such chips
  • this is the specific location and physical basis for implementing the Gamma correction function.
  • the illuminating signal is equivalent to the following two links (here, the link having the gamma characteristic) after entering the camera/camera: 1.
  • the total Gamma characteristics of each subsequent link It is represented by G Rear (.), that is, the total Gamma characteristic formed by the cascade of Gamme characteristics of all the links with Gamma characteristics in the subsequent steps of the signal passing, hereinafter referred to as the subsequent Gamma characteristics.
  • the subsequent Gamma feature refers to the Gamma feature introduced by each Gamma link of the display module, wherein the Gamma characteristic of the display accounts for a major proportion, and in actual application, it is based on the camera/ The camera Gamma link and the display Gamma link characteristic parameters are corrected.
  • the implementation principle of the video capture device with the correction function of the present invention is as shown in FIG. 10, and a correction link is added between the above two links, and the multi-step cascaded Gamma characteristic correction method is used for correction, and the correction link actually It constitutes the Gamma correction subsystem in the video capture device.
  • a correction link is added between the above two links, and the multi-step cascaded Gamma characteristic correction method is used for correction, and the correction link actually It constitutes the Gamma correction subsystem in the video capture device.
  • the Gamma characteristic of the subsystem uses G c . r (.) indicates, where Cor represents the Correction correction.
  • G VA D(-). G Rear (.) G can) (.). G Cor (.). G Rear (.) (9).
  • Equation 9 As long as a given G eam (.) And G Rear (.), Then it can get G c. r (.), thus achieving gamma correction of the video image.
  • the Gamme property is parameterizable, in contrast to the parameterization of the function form (assuming that the Gamme property can be represented by a class of functions, so that the relevant parameters in the function expression can be used to characterize the Gamma property, ie a set of parameters. It is limited by the form of the function with a gamma characteristic, and the parameterization in the form of look-up table has a wide range of adaptability and versatility.
  • the general principle of the table lookup parameter method is as follows:
  • L. Ut and L in are signals, and each has a range of values.
  • the luminance signal in the current video communication technology, it is divided into 256 levels, and the luminance value is 0-255, which is represented by 8 bits (one byte). Normalization is to convert the value in the range 0-255 by 255 (if the maximum value is not 255, then divide by the corresponding maximum) into a normalized luminance signal in the interval [0,1].
  • the invention adopts the brightness signal to take a value of 0-255, and the normalization is mainly used in the function-based representation. If parameterization is used, the L can be established directly in the range of 0-255. The correspondence between ut and 1 ⁇ . This correspondence is shown in Table 1. Table 1. Schematic diagram of parameterization of table lookup It should be noted that the present invention is based on table parameterization, but some aspects also employ function parameterization, which will be described in detail later.
  • the present invention provides a correction subsystem in the video signal acquisition device defined in Figures 8 and 9, which enables adaptive Gamma correction that can be adjusted by external command control.
  • This correction subsystem can be implemented in the camera/camera, or in the video signal acquisition interface card (for general purpose computer terminals) or the video processing board video capture module (for independent hardware box terminals), or the video capture driver.
  • the method implemented may be based on hardware or software, or may be implemented by a mixture of hardware and software.
  • the calibration module is directly connected to the camera/camera for camera/camera
  • the output video data stream is corrected.
  • the correction generation module can be connected after any of the above three. Because the implementation position of the correction subsystem has many possibilities, such as implementation in the driver, then the input data should be the output of the capture card. But because the capture card and the driver itself do not introduce Gamma distortion, it is logical that the module is still "directly" connected to the camera/camera. That is to say, on the Gamma path, if some links in the middle have linear Gamma characteristics, then these links are considered to be absent in the sense of Gamma.
  • FIG. 10 it is a schematic structural diagram of a video capture device 100 according to the present invention, which includes a video signal acquisition module 101, which is a camera module, which may be a camera/camera, and a video signal acquisition module 101 is connected to the video of the present invention.
  • the signal correction subsystem wherein the correction subsystem includes the following modules:
  • the Data Storage 102 module can be divided into three smaller submodules:
  • the current G VAD (.) data storage sub-module 1021 stores the target gamma characteristic parameter G VAD (.) at the current time.
  • G VAD (.) may change, that is, the adjustment process, then the control and processing module Will be responsible for writing the latest current V VAD (.) to the current G VAD (.) data storage sub-module 1021;
  • G VAD (.) template data storage sub-module 1022 the template can be produced by the video capture device manufacturer (both It can be a camera/manufacturer, or a terminal manufacturer.
  • the two are preset at the time of shipment, or they can be added by external users afterwards, and of course, they can be deleted and modified.
  • the purpose of setting the G VAD (.) template data storage sub-module 1022 is to implement an approximation correction.
  • the user can use the external control command at any time to adjust the link Gamma
  • the parameters of the sex generation module 104 are reset to the factory default Gc. r (.).
  • the data storage 102 module can also include:
  • G cam (.) data storage sub-module 1023 used to save the camera/machine gamma characteristic data, for specific correction calculation, to avoid the user input G cara (.) multiple times.
  • the module is the core of the calibration subsystem and is responsible for the calculation and processing of the entire subsystem.
  • the specific calculations and processing according to the factory data can be divided into the following four categories:
  • the first type based on G cam (.) and G Rear (.), performs more accurate corrections to achieve the best results for the locally output video signal.
  • the specific correction calculations include the following:
  • G cam (.: ⁇ G Rear (.) are input from external commands;
  • G Cor (.)
  • G COT (.)
  • G eOT (.)
  • the Gamma feature is used to correct the video image, and GVAD(-)' is further calculated according to Equation 8 to write G vad (.) to the current G VAD (.) data storage sub-module 102.
  • G cam (.) is already built into the subsystem, G Rear (.) is input by an external command; first obtain G cam (.) from G cam (.) data storage sub-module 1023, and correct with Gamma G COT (.) should be calculated between the input and output, and G Cot (.) should be written into the correction link Gamma characteristic generation module 104.
  • the Gamma characteristic generation module 104 generates the corresponding Gamma characteristic according to the GCMG to correct the video.
  • the image calculates G VAD (.) according to Equation 8, and writes G VAD (.) into the current GVAD (.) data storage sub-module 1021.
  • the second type using G cam (.) and the user setting target G VAD (.) to perform predetermined correction, so that the corrected video image has predetermined gamma characteristics, including the following cases: N2006/001672
  • G eam (.) and target G VAD (.) are input from external commands;
  • G cam (.) is already built in the subsystem, target GVADC) is input by an external command; first obtain G cam (.) from G cam (.) data storage sub-module 1023, and calculate using formula 8.
  • G c . r (.) will be described in detail below.
  • G c . r (.) is written into the correction link Gamma characteristic generation module 104, which is based on Gc; by the Gamma characteristic generation module 104. .) Generate the corresponding Gamma feature to correct the video image, and then write the target G VAD 0 directly to the current G VAD (.) data storage sub-module 1021.
  • the third category using the template for approximate correction, includes the following situations:
  • G EAM (.) is written from the outside, and G VAD (.) is selected from the pre-stored GVAD (.) template data storage sub-module 1022 according to an external command;
  • the specified G VAD (.) template data is obtained from the pre-stored G VAD (.) template data storage sub-module 1022, and G c is calculated using Equation 8. r (.), will G c . r (.) is written into the correction link Gamma characteristic generation module 104, and the Gamma characteristic generation module 104 generates a corresponding Gamma characteristic according to Gc OT (.) to correct the video image, and then writes the selected G VAD (.) template data to the current G VAD (.) data storage sub-module 1021.
  • G CAM (.) is built in the subsystem, GVADC) is selected from the pre-stored G VAD (.) template data storage sub-module 1022 according to an external instruction;
  • G cam (.) from G cam ⁇ factory data storage sub-module 1023, obtain the specified G VAD (.) template data from the pre-stored G VAD (. j3 ⁇ 4 board data storage sub-module 1022, calculate G by formula 8 c. r (.), write G c . r (.) into the correction link Gamma characteristic generation module 104, and the Gamma characteristic generation module 104 generates a corresponding Gamma characteristic to correct the video image, and then the target G VAD (.) Directly write to the current G V AD(.) data storage sub-module 1021.
  • the user can select the G VAD (.) template to observe the locally output video image, and finally determine the better correction mode.
  • the fourth category is based directly on G c .
  • the factory standard data of r (.) is built into the subsystem;
  • the control and processing module 103 can also read the G COT (.) factory data from the G COT (.) factory data storage sub-module 1024 according to an external input command, and then directly write the correction link Gamma characteristic generation module 104, which will be G c .
  • the r (.) write correction correction Gamma characteristic generation module 104 is based on G c by the Gamma characteristic generation module 104. r (.) generates the corresponding gamma characteristic to correct the video image, and the above process does not need to be calculated.
  • the above seven correction scenarios actually correspond to seven commonly used correction control mode commands, from which the user can select and input the corresponding control commands, and also set the default mode at power-on or save the control mode applied when the user was last turned off. .
  • the Gamma characteristic occurs when a given Gamma characteristic parameter (function parameterization or table lookup parameterization) is generated, and a corresponding Gamma characteristic is generated between the input and the output, that is, the output is calculated according to the input using a given Gamma characteristic parameter, so that The relationship between the output and the input is consistent with the given Gamma characteristics and is a simulation of a nonlinear relationship.
  • a given Gamma characteristic parameter function parameterization or table lookup parameterization
  • the control module 105 is configured to receive a control command and a data read/write command, including a correction control command and a data read/write operation instruction:
  • the correction control instruction includes the foregoing seven mode instructions, and the control module 105 needs to parse the received correction control instruction and input a corresponding indication signal to the processing module 103, and the processing module 103 performs a specific correction mode;
  • the data read and write operation instructions specifically include:
  • the purpose of reading is that it may be necessary to know a Gamma characteristic of the entire acquisition device as a whole, For inspection and diagnosis, for example, the user has chosen one
  • the G VAD (.) template is sent to the acquisition device. If the device works correctly, the read G VAD (.), the issued G VAD (.) template, and the actual measured Gamma characteristics should be consistent. Otherwise The device is not working properly.
  • the present invention enables the subsystem to exhibit any given Gamma characteristic, achieving any tunable Gamma correction, rather than correcting some or some of the conditions as in the prior art;
  • the gamma characteristic correction of the video image displayed on the local end is to make the local display have no gamma distortion as much as possible. In this case, for the code stream sent to the peer end, it is necessary to add a correction link at a later place, or to be corrected by the other party.
  • G VAD G VAD
  • G VAD G VAD
  • a terminal can have multiple cameras/cameras connected to it. For example, a camera/camera is specifically for the far end. At this time, its calibration target G VAD (.) can be as far as possible.
  • the Gamma path on the side is set.
  • the video signal collection device of the present invention may be configured to set a plurality of correction modules in parallel, respectively connecting the display module of the video signal and the network output interface, respectively
  • the local display video signal is corrected by using the gamma characteristic of the camera module and the display module, or the gamma characteristic of the output video signal of the terminal is corrected by using the gamma characteristic of the communication terminal, thereby improving the gamma correction performance of the video communication system.
  • the subsystem can calculate the optimal G VAD (.) and G COT (.), complete the adjustment to achieve complete gamma correction; d, write G Rear ( .) parameter instructions;
  • G Rear (.) parameter Used to write the G Rear (.) parameter to the subsystem.
  • G Cam (.) parameter instruction if the subsystem has built-in G Cam (.), there is no need to write externally, the subsystem can calculate the optimal GVADC) and G c . r (.), complete the adjustment to achieve full gamma correction;
  • G VAD used to read out previously preset G VAD (.) template parameters from the subsystem. You can read one template at a time, or you can read multiple templates in batches.
  • G VAD G VAD
  • G VAD Used to write G VAD (.) template parameters to the subsystem, replacing some / some old templates. You can write one template at a time, or you can write multiple templates in batches;
  • control module 105 includes specific sub-modules:
  • the Gamma characteristic parameter read/write submodule 1051 is configured to receive and execute an external data operation instruction, including writing the related Gamma parameter to the corresponding storage submodule; or reading the parameter from the storage submodule and outputting the parameter;
  • a correction control instruction receiving submodule 1052 configured to receive an external correction control instruction
  • the correction control instruction parsing sub-module 1053 is configured to parse the correction control instruction and output a corresponding indication signal to the processing module 103, which specifically includes the following seven types:
  • the instruction processing module 103 When receiving the first correction control instruction, the instruction processing module 103 performs the following operations: receiving the camera module Gamma characteristic parameter input by the control module 105 and the gamma characteristic parameter of the subsequent module through which the video signal output by the correction generation module 104 passes, according to the The camera module Gamma characteristic parameter and the subsequent module gamma characteristic parameter calculate the gamma characteristic correction parameter, and calculate the target gamma according to the gamma gamma characteristic parameter and the gamma characteristic correction parameter Characteristic parameter, then the target gamma characteristic parameter is stored in the target gamma parameter storage sub-module, that is, the current G VAD (.) data storage sub-module 1021;
  • the instruction processing module 103 Upon receiving the second correction control instruction, the instruction processing module 103 performs the following operations: extracting the camera module Gamma characteristic parameter from the camera module gamma characteristic parameter storage sub-module 102, and receiving the subsequent module gamma characteristic input by the control module 105 a parameter, calculating the gamma characteristic correction parameter according to the camera module Gamma characteristic parameter and a subsequent module gamma characteristic parameter, and calculating the target gamma characteristic parameter according to the camera module gamma characteristic parameter and the gamma characteristic correction parameter, and then the target gamma
  • the characteristic parameter is stored in the target Gamma parameter storage sub-module, that is, the current G VA D (.) data storage sub-module 1021;
  • the instruction processing module 103 When receiving the third correction control instruction, the instruction processing module 103 performs the following operations: receiving the camera module Gamma characteristic parameter and the target gamma characteristic parameter input by the control module 105, and calculating the Gamma according to the camera module Gamma characteristic parameter and the target gamma characteristic parameter Characteristic correction parameters, and then the target gamma characteristic parameters are stored in the target gamma parameter storage sub-module, that is, the current G VAD (.) data storage sub-module 1021;
  • the instruction processing module 103 When receiving the fourth correction control instruction, the instruction processing module 103 performs the following operations: extracting the gamma gamma characteristic parameter from the camera module Gamma characteristic parameter storage submodule, that is, the G cam (.) factory data storage submodule 1023, and Receiving the current target corrected gamma characteristic parameter input by the control module 105, calculating the gamma characteristic correction parameter according to the camera module gamma characteristic parameter and the current target corrected gamma characteristic parameter, and storing the target gamma characteristic parameter in the target gamma parameter storage submodule
  • the current G VAD (.) data storage sub-module 1021 when receiving the fifth correction control instruction, instructs the processing module 103 to perform the following operations: receiving the camera module Gamma characteristic parameter input by the control module 105, and storing the sub-module from the calibration template parameter
  • the GVAD (.) template data storage sub-module 1022 extracts the calibration template parameter indicated in the fifth correction control instruction, and calculates the Gam
  • the instruction processing module 103 When receiving the sixth correction control instruction, the instruction processing module 103 performs the following operations: The module gamma characteristic parameter storage sub-module, that is, the G cam (.) factory data storage sub-module 1023 extracts the camera module gamma characteristic parameter, and the calibration template parameter storage sub-module, that is, the G VAD (.) template data storage sub-module The module 1022 extracts the calibration template parameter indicated in the sixth correction control instruction, calculates the gamma characteristic correction parameter according to the camera module gamma characteristic parameter and the calibration template parameter, and stores the calibration template parameter in the target gamma parameter storage. Module, the current G VAD (.) data storage sub-module 1021;
  • the instruction processing module 103 Upon receiving the seventh correction control instruction, the instruction processing module 103 performs the following operations: The sub-module, that is, G c , is stored from the initial correction parameter. The initial correction parameters are extracted from the r (.) factory data storage sub-module 1024 and input to the correction generation module 104.
  • the external interface 1061 (or ⁇ : reference point) of the gamma correction subsystem has three totals: II: Interface from the camera/camera
  • Gamma link 1061 This interface is mainly used to receive video data input from the camera/camera. If the subsystem is located inside the camera/camera, then this interface is the interface with the imaging unit (referred to as the CCD unit or CMOS unit, etc.) and its associated circuits; if the subsystem is located in the video signal acquisition interface On the card, then this interface is the interface with some other module on the video signal acquisition interface card. If the subsystem is implemented in the video capture driver, then this interface is the interface with some other module in the driver. .
  • the video signal format transmitted via this interface may be:
  • the corresponding video signal format transmitted via the 12 interface may be:
  • Interface 1063 between external control hosts Implement instruction-based control and data input/output.
  • control commands and data manipulation instructions are input in various ways.
  • the user can input commands through the interface control elements (menu, buttons, even command lines, etc.) on the user interface, obviously the interface control elements and the definitions herein Instructions do not correspond one-to-one.
  • Some instructions may not necessarily be sent by the user through the interface control, but are required for the program to run, for diagnostic purposes, such as reading V VAD (.) for diagnostic purposes, etc., with program code control. In either case, those skilled in the art can implement the information according to the disclosure of the present invention.
  • the present invention provides the following two approximate solutions:
  • the reason for the above two templates is that in most cases, a good approximation effect can be achieved.
  • the display does not have other Gamma links, and the display is a CRT display and has the standard Gamma characteristics, then the above two are used.
  • the necessary templates can achieve a good correction.
  • templates are selected by the user according to prior knowledge, or by human-computer interaction: that is, each template is tested in turn, the user observes the user experience of the actual video, and finally selects the best template for the user experience. Templates can be added to suit different application scenarios and devices. Templates that are not used for a long time can be deleted to save storage space.
  • the application of the present invention in a reasonable hypothetical environment can achieve good correction results: 1.
  • the camera/camera has or does not have the standard Gamma characteristics given by Equation 2;

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)
  • Studio Devices (AREA)
  • Processing Of Color Television Signals (AREA)
  • Transforming Electric Information Into Light Information (AREA)

Abstract

La présente invention concerne un dispositif de capture de signal vidéo appliqué au domaine de la vidéocommunication. A la différence des dispositifs de l'art antérieur, le dispositif décrit dans cette invention est doté d'une capacité de correction adaptative de la caractéristique gamma du signal. Le dispositif de capture de signal vidéo (100) susmentionné comprend des unités parmi lesquelles: un module caméra (101) qui capture le signal vidéo; un module de commande (105) qui analyse l'instruction de commande de correction et produit le signal d'instruction correspondant; un module de traitement (103) qui obtient le paramètre pertinent de la caractéristique gamma du signal vidéo d'après le signal d'instruction, puis calcule et produit le paramètre de correction de la caractéristique gamma; un module de correction (104) qui corrige la caractéristique gamma du signal vidéo d'après le paramètre de correction de la caractéristique gamma. Le mode de réalisation décrit dans cette invention consiste à ajouter un processus de correction du gamma dans le dispositif de capture de signal vidéo, permettant ainsi d'obtenir une correction du gamma applicable à n'importe quelle tête de caméra/lecture ou module ultérieur. Le dispositif décrit dans cette invention peut être obtenu à l'aide d'un circuit et d'un équipement, mais également à l'aide d'un logiciel, ce qui permet d'améliorer la qualité d'utilisation pour l'utilisateur.
PCT/CN2006/001672 2005-11-28 2006-07-14 Dispositif de capture de signal video WO2007059671A1 (fr)

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JPH06165167A (ja) * 1992-11-17 1994-06-10 Canon Inc 画像伝送システム、画像送信装置及び画像受信装置
CN1132975A (zh) * 1993-12-29 1996-10-09 三星电子株式会社 电视摄像机的γ校正装置
JPH1079886A (ja) * 1996-09-03 1998-03-24 Sony Corp ビデオカメラおよび非直線性ひずみ補正方法
JP2002199246A (ja) * 2001-11-05 2002-07-12 Konica Corp 撮像装置

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