335 results about "Automatic exposure control" patented technology

A multi-dimensional imaging device and method for automated exposure control that implement two distinct modules to control the exposure and gain settings in the imager so that processing can occur in a multi-tasking single CPU environment. The first module, referred to herein as the imager control module, controls the exposure and gain settings in the imager. The first module is typically implemented in a high priority routine, such as an interrupt service routine, to insure that module is executed on every captured frame. The second module, referred to herein as the histogram processing module, calculates a target contrast (the product of the targeted exposure and gain settings) based on feedback data from the first module and image data from memory. The second module is typically implemented in a low priority routine, such as a task level routine, to allow for the routine to be executed systematically in accordance with priority.

A method for optimizing the radiogram image of a subject is provided. The method provides for showing the location of automatic exposure control sensors on the radiograms, along with alignment and targeting projections to optimize the radiation exposure of the subject. By displaying the location of the automatic exposure control sensors on the radiograms along with the image of the subject, the observers can determine whether the radiogram image was taken with appropriate subject alignment. This method also serves as an educational aid in training radiography technicians.

An exposure control method and an image processing system are provided. The image processing system comprises: an image sensor module, configured to provide at least two types of source images in parallel, each type of the source images has different exposure setting; a pre-processing unit, configured to determine luminance distribution of the source images on block basis, perform a first exposure control according to the luminance distribution of the two types of source images, and generate output images according to the source images in RAW image domain, and a post-processing unit, configured to determine luminance distribution of the output images, and perform a second exposure control according to the luminance distribution of the output images in normal image domain; wherein exposure settings of the image sensor module is adjusted according to the first exposure control and the second exposure control.

An improved method for automatic exposure control at a digital camera is described. In response to a user request for capture of a digital image, image data is captured on the camera's image sensor. The captured image data includes pixel values of brightness of pixels of the image sensor. A histogram of pixel values is generated based upon brightness of pixels of the image sensor. The histogram that is generated is then evaluated to determine whether an image is overexposed or underexposed. Coarse exposure settings for capture of a digital image are automatically generated based upon scaling the histogram of pixel values towards the midpoint of a pre-selected interval. The coarse exposure settings and image data that have been captured are evaluated to determine whether light sources are present. In the event that light sources are determined not to be present, the coarse exposure settings are adjusted based upon not scaling said histogram beyond the largest histogram value.

A camera automatic exposure method and a control device, the method comprising the following steps: a. obtaining the average brightness value of the current frame image; b. comparing the current frame image average brightness value with a preset average brightness value, if the current frame image If the average brightness value of the current frame image is within the allowable range of the preset average brightness value, maintain the exposure time in the current exposure setting and return to step a, otherwise continue; c. If the average brightness value of the current frame image is greater than the preset average brightness value within the allowable range, adjust the shortening of the exposure time to obtain the new exposure time in the exposure setting; if the average brightness value of the current frame image is less than the allowable range of the preset average brightness value, then adjust the lengthening of the exposure time to obtain the exposure setting a new exposure time; and e, setting the image sensor according to the new exposure time. The present invention can realize automatic exposure at low cost, simply and quickly.

An imaging apparatus includes the functions of conducting automatic exposure control and of conducting shake correction with respect to digital image data acquired by an image pickup unit. The imaging apparatus includes: a determining unit that determines whether or not the shake correction is being implemented; and a switching unit which, when it has been determined by the determining unit that the shake correction is being implemented, switches the shutter speed such that the shutter speed is raised in comparison to when it has been determined by the determining unit that the shake correction is not being implemented. An imaging method determines whether or not the shake correction is being implemented, and when it has been determined that the shake correction is being implemented, switches the shutter speed such that the shutter speed is raised in comparison to when it has been determined that the shake correction is not being implemented.

An apparatus and method for performing automatic exposure and gain control while minimizing oscillations as well as providing a good response time, for example, a lag time or a settling time of about one frame. The automatic exposure and gain controls are performed not only on the image as a whole but on a weighted region of interest. If the contrast in the image exceeds the dynamic range of the sensor array, then the image in the region of interest will improve at the expense of the remainder of the image. A region of interest is a selected subset of tiles upon which automatic exposure and gain control will be based. The tiles are defined by a grid system having grid coordinates, which are programmable. Image sensors have to receive feedback with regular updates of exposure and gain settings based on ever changing light conditions.

When a shutter release button of an image capturing apparatus is half pressed, an exposure time t is determined by a normal AE function. Then, if a shutter release button is fully pressed, an image is captured with the exposure time t, and the captured image is stored in a frame memory. At the same time, a color-coding circuit color-codes the captured image according to luminance thresholds, and the color-coded image is displayed on an LCD. If a user selects a color of an area equivalent to a main subject with reference to the color-coded image, a dynamic range, gamma characteristics, and the like of the image are determined so that the area in the selected color can have a correct luminance. The image is corrected accordingly, and image data acquired by the correction is stored in a recording part.

The image of a subject is attained by image sensing and the image of the subject is displayed on the display screen of a digital still camera. The image of a face is detected from within the image of the subject and a face frame is displayed so as to enclose the detected image of the face. Autofocus control and automatic exposure control is carried out using image data representing the image within the face frame. Image data representing the image of the subject in which the image of the face is in focus and has the appropriate brightness can be recorded on a memory card.

In an imaging apparatus capable of selectively performing an imaging operation in normal imaging mode and that in composite imaging mode, auto exposure control is stopped after the auto exposure control for long-time exposure image signals and short-time exposure image signals is temporarily completed in composite imaging mode and if, after the auto exposure control is stopped, a predetermined brightness change in images is detected continuously for a predetermined time or longer based on brightness values detected from the images obtained from a composite image signal, the imaging mode of the imaging apparatus is switched from the composite imaging mode to the normal imaging mode.

An image capturing apparatus having an auto focus function or an auto exposure function stores digital image data output from an A / D conversion unit as first image data directly or after performing predetermined processing, and stores the digital image data serving as a base of the first image data as second image data after performing predetermined processing for the digital image data. The apparatus then detects a face region from the second image data, and displays the image on the basis of the image data output from the A / D conversion unit while the face region is detected form the second image data. After completion of detection of the face region from the second image data, the apparatus extracts information for auto focus, auto exposure, or white balance by using, of the first image data, data at a portion corresponding to the face region that is detected by said face detection means, and performs auto focus control, auto exposure control, or white balance control.

On embodiment of the present invention sets forth a technique for automatically computing exposure parameters for a digital video camera (DVC) system. The exposure parameters include exposure gain, analog gain, and digital gain. Each frame is analyzed with respect to an image luma value. Exposure gain and analog gain are adjusted to reduce differences between a target image luma value and measured image luma values over sequential frames. Digital gain is adjusted with respect to each frame to reduce visually abrupt changes in sequentially captured video frames.

The invention provides an automatic exposure method based on an analogous column diagram, which has favourable exposure effect on various situations, such as dark background light target, target size uncertainty and the like in deep space exploration. An automatic exposure control system is a closed loop control system and mainly comprises three modules: target gray level statistics, comparative judgment with expected values and exposure time calculation; data statistics analysis is carried out by gray scale region division, gray scale value weighting average calculation and the like so as to determine exposure required by shooting. Because of having low requirement on hardware, the invention can be suitable for different hardware platforms by slightly modifying, and can balance calculation speed, logic resource use, system time sequence requirement and the like according to the practical situation so as to choose different control modes.

The technical scheme of the invention discloses an exposure control method and device. The exposure control method comprises the following steps: calculating an average brightness of a scene; performing scene recognition according to scene illumination evaluation, a histogram light region ratio and a histogram dark region ratio, so as to obtain a target brightness value of an adaptive scene; and adjusting parameters of an image sensor according to the average brightness of the scene and the target brightness value of the adaptive scene, so as to enhance or reduce the image brightness. The exposure control method and the device provided by the technical scheme of the invention adaptively adjust the complexity and diversity of the scene, and ensure the speed and stability of automatic exposure control.

An automatic exposure control method and compensation apparatus are disclosed. It includes a coordinate system having sub-ranges with different corresponding exposure compensation values. It includes the setting of bright and dark regions threshold values and the calculation of the ratios of the pixel count in an image where the luminance of each pixel is higher than the bright area threshold value for obtaining a bright area ratio, and also includes the calculation of the ratio of the pixel count in an image where the luminance of each pixel is lower than the dark area threshold value for obtaining a dark area ratio. Afterwards, the image position in the coordinate system is determined. When the image position in the coordinate system is fallen inside one of the sub-ranges, the corresponding exposure compensation value of the sub-range where the image is located is given to compensate the exposure value of the image.

The invention relates to a digital X-ray machine automatic exposure control method and device, and belongs to the technical field of digital radiography. The method mainly includes the steps of processing a pre-exposure image in secondary exposure and optimizing exposure parameters in a self-adaptive mode. The optimal threshold value is correspondingly found according to positions through gray stretch of the pre-exposure image, the image is divided into different areas, areas of interest with different components are extracted, the average gray level, the signal to noise ratio and the contrast ratio are calculated respectively, and then the main exposure parameters (mA, s and KV) are optimized in the self-adaptive mode; the precise time sequence is provided for the exposure process and data acquisition through a synchronous control unit, and the imaging effect is prevented from being influenced by time delay or antedating reaction. By the adoption of the multiple components, multiple target areas and multiple image standards, the exposure parameters are adjusted through a self-adaptive algorithm, and the top-quality image can be obtained through a small exposure dose when exposure is conducted under the synchronous control.

The invention discloses an automatic exposure adjustment method and a control system, comprising the following steps: first, setting the initial exposure parameters and determining the scope of the target brightness; secondly, judging whether the average brightness value of the image in the initial state is within the target brightness scope, and if so, do not change the exposure time and the gain value; the invention is characterized in that if the average brightness value of the image in the initial state is not within the target brightness scope, the exposure time is divided into n-levels, gained in each level and gradually adjusted based on a certain step length; the exposure time jumps from one level to another level on the equal-brightness curves so as to achieve the optimal exposure effect through the method of gradually adjusting the gain and the exposure time. The control system comprises a sensor (101), an interface module (102), an automatic exposure control module (103) and a brightness characteristic value calculation module (104); the method and the system are simple and flexible to realize so as to reduce the chip cost; and the adjustment on the equal-brightness curves enables the entire automatic exposure process to be very smooth, without the brightness-darkness staggered flashing situations.

An apparatus and method for radiation detection is herein described. The apparatus consists of two radiation-detection arrays: A primary radiation-detection array, based on scintillator-CMOS design, and a secondary radiation-detection array, mounted on the back of said primary array. A method of controlling the detection operation is described, where output of the secondary array is exploited for controlling the acquisition-start and acquisition-stop of the primary array. Further, the apparatus is equipped with fast memory for storage of correction tables, and with a processor for fast computation of the correction. A method of calibration is also describes with tables for: offset correction, gain correction, and for defect-pixel correction. These tables are evaluated by the fast processor and stored on the fast memory. A method of real-time evaluation of the signal corrections is described, which depends on the acquisition-start and acquisition-stop timings and which results a clean, artifact-free image.

The invention discloses an automatic exposure control method for a digital photographic device. According to the automatic exposure control method, a partitioning counted brightness weight model corresponding to a photographing application scenario of the digital photographic device, the target brightness of a target frame image of the photographing application scenario and an exposure curved line corresponding to the photographing application scenario are selected, and the brightness of a current image is calculated in a partitioned mode; then, the average brightness of whole images is calculated, an environment photometry compensation coefficient is determined according to the average brightness, a difference value Delta Bv between the brightness of an image of a current frame and the target brightness serves as an adjustment condition, and the exposure time and an aperture value of a next frame are determined. According to the automatic exposure control method, image brightness estimation is carried out in the manner of adjusting different weight coefficients in a self-adaptation mode according to different scenarios and different collection targets, and photographing scenarios in actual application can be represented better; under the condition of not increasing the software cost and the hardware cost, accurate control over automatic exposure is achieved through simple calculation, and the photographing quality can be effectively improved.

A method, apparatus, and system for dynamic range estimation of imaged scenes for automatic exposure control. For a given exposure time setting, certain areas of a scene may be brighter than what a camera can capture. In cameras, including those experiencing substantial lens vignetting, a gain stage may be used to extend dynamic range and extract auto-exposure data from the extended dynamic range. Alternatively, dynamic range can be extended using pre-capture image information taken under reduced exposure conditions.

A photographic flash unit comprises a direct flash unit and a bounce flash unit rotatably connected to the direct flash unit. Status and control lines coupled between a hot shoe and each flash unit enable independent triggering and control of each flash unit. The direct and bounce flash units may be a part of a digital camera adapted to make a first test exposure using direct flash illumination and second test exposure using bounce flash illumination, then computing an attenuation factor for compensating a selected flash exposure parameter by dividing the selected parameter by the attenuation factor. Steps in a method embodiment include making a first test image, making a second test image, selecting regions in the first and second test images, computing an attenuation factor from luminosity values for the first and second test images, and compensating settings for a final bounce flash image by the attenuation factor.

The present invention discloses a method for acquiring automatic exposure control parameters and a method for controlling automatic exposure control parameters and an imaging device. The core idea is to take the brightness weighted average value obtained according to brightness distribution weighted statistics of the image as the exposure control parameter. Then through adjusting the weighted coefficient of pixels in different brightness regions, control the influence of the pixel concentrated brightness regions on the brightness average value. Because the brightness distribution is the basis for determining weighted statistics, the control method of the present invention is not influenced by the scene assumption. Rather it can be universally adapted to a variety of different scenes, and the exposure control effect is not influenced by the position of scenes in the actual bright region / dark region and block distribution.

A method and system for digital cameras provides improved automatic exposure control, improved automatic white balance, improved color interpolation, improved automatic gamma correction, and improved progressive edge enhancement. These improvements are preferably implemented in CMOS semiconductor technology for faster speed.

In exposure control of a digital image, a signal is obtained from an image sensor. One or more color channels are obtained from the signal. A mean value from one or more of the color channels is determined. A target exposure level is obtained. The difference between the mean value and the target exposure level is determined. An exposure correction is determined based upon the difference. The exposure correction is fed back to the image sensor, and one or more settings of the image sensor are adjusted corresponding to the exposure correction.

An auto-exposure control method includes: creating an exposure table and an analog gain table including an exposure time and an analog gain of an image sensor set according to an index, respectively; calculating an average luminance value of an image frame obtained by the image sensor; checking whether or not the average luminance value is within a pre-set range including a prescribed final target value; if the average luminance value is not within the pre-set range, determining a shift step from indexes which have been applied to a current image frame according to the difference between the average luminance value and the final target value in order to determine indexes of the exposure table and the analog gain table to be applied to a next image frame; and repeatedly performing of reading an exposure time and an analog gain corresponding to the indexes shifted by the shift step determined from the indexes applied to the current image frame, from the exposure table and the analog gain table, applying the same to the image sensor, obtaining a next image frame, and calculating an average luminance value.

The invention relates to an automatic exposure control method and device based on an FPGA and suitable for space exploration imaging. The method includes the steps that the current-frame image average brightness is acquired through the main current-frame image average brightness, time of exposure is adaptively selected according to whether a difference value between the current-frame image average brightness and the expected image average brightness is positive or negative and is large or small, continuous frames are adopted for continuous loop iteration, and therefore the current-frame image average brightness reaches the expected image average brightness. The automatic exposure control device for conducting the automatic exposure control method comprises an optical lens, an APS sensor and the exposure control FPGA. According to the method and device, the technical problems existing in excessive exposure of a target image, segmentation of the target image and balance between the automatic exposure speed and stability in the existing space exploration imaging technology are solved, the image contrast ratio is increased, faster, more stable and more accurate automatic exposure control can be conducted in various space exploration light environments, and adaptive ability in the space exploration environment imaging process is improved.

An adapter device for an interchangeable lens of a camera having a signal conversion circuit for converting an automatic exposure control signal generated from the output from a video signal processing circuit of a video camera which is capable of performing an automatic exposure control into an automatic exposure control signal which is adapted to an interchangeable lens system for a still camera capable of performing an automatic exposure control.

An automatic exposure control camera always permits a subject to be photographed with appropriate brightness regardless of a front-lighted, back-lighted, or over-front-lighted condition. The area to be photographed is divided into 64 regions. The camera determines the average Yav64 of brightness over all the regions, the average YavU32 of brightness in the regions constituting the upper half, the average YavL32 of brightness in the regions constituting the lower half, the average YavD1 of brightness in regions in which brightness is lower than the average Yav64, the average YavD2 of brightness in regions in which brightness is lower than the average YavD1, the average YavB1 of brightness in regions in which brightness is higher than the average Yav64, and the average YavB2 of brightness in regions in which brightness is higher than the average YavB1. Based on the ratios between these averages, the camera distinguishes among a front-lighted, a back-lighted, and an over-front-lighted condition and controls the exposure of an image sensor accordingly.