CN107786814B - Wide dynamic image processing method and device and exposure circuit - Google Patents
Wide dynamic image processing method and device and exposure circuit Download PDFInfo
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- CN107786814B CN107786814B CN201610720722.3A CN201610720722A CN107786814B CN 107786814 B CN107786814 B CN 107786814B CN 201610720722 A CN201610720722 A CN 201610720722A CN 107786814 B CN107786814 B CN 107786814B
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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
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/741—Circuitry for compensating brightness variation in the scene by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/50—Control of the SSIS exposure
- H04N25/57—Control of the dynamic range
- H04N25/58—Control of the dynamic range involving two or more exposures
- H04N25/587—Control of the dynamic range involving two or more exposures acquired sequentially, e.g. using the combination of odd and even image fields
- H04N25/589—Control of the dynamic range involving two or more exposures acquired sequentially, e.g. using the combination of odd and even image fields with different integration times, e.g. short and long exposures
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management
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Abstract
The embodiment of the invention discloses an image processing method and device based on wide dynamic range and an exposure circuit, wherein the method comprises the following steps: each pixel point in the image processing system at least corresponds to a first pixel circuit for carrying out long exposure and a second pixel circuit for carrying out short exposure, and after receiving a corresponding long exposure reset signal and a corresponding short exposure reset signal, each first pixel circuit and each second pixel circuit start exposure at the same time to generate a first long exposure image and a first short exposure image, so that the time interval for starting exposure is reduced, and the problem of motion flaws in wide dynamic data is solved. And then, in order to form an image with good effect, overlapping the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point.
Description
Technical Field
The present invention relates to the field of image processing technologies, and in particular, to an image processing method and apparatus based on wide dynamic range, and an exposure circuit.
Background
The wide dynamic technology is a technology applied by making a camera see the characteristics of images under very strong contrast, and makes both bright details and dark details in a scene particularly clear. WDR (Wide Dynamic Range ) is the ratio of the brightest luminance signal value that an image can resolve to the darkest luminance signal value that can resolve. The larger the wide dynamic range is, the more abundant the level it can represent, and the more abundant the details of the bright part and the dark part can be recorded simultaneously.
The conventional wide dynamic technology is to use a multi-frame synthesis mechanism, i.e. to superimpose an exposure image formed by long exposure and an exposure image formed by short exposure to obtain wide dynamic data.
The image processing system utilizing the traditional wide dynamic technology performs twice exposure on each pixel, wherein the twice exposure comprises one long exposure and one short exposure, and then screening and overlapping are performed according to a long exposure image and a short exposure image generated by the twice exposure, so that an effective exposure image is obtained, and further, the subsequent image processing flow is performed. Wherein the exposure depends on the pixel circuit. In the prior art, each pixel corresponds to a pixel circuit. The conventional pixel circuit is shown in fig. 1, and the specific exposure process is as follows: when the pixel starts to be exposed, the image processor transmits a reset signal RST to the pixel circuit to start a reset operation so that the output voltage of the photodiode PD is set to 0; the photodiode PD absorbs the optical signal to accumulate the effective charge, and after reaching the exposure time threshold value, the accumulation of the effective charge is finished; the accumulated effective charges of the photodiode PD are converted into analog voltage signals through a source follower T1, so that photoelectric conversion is realized; the row strobe RS activates the address switch T2, and the converted analog voltage signal is outputted through the column line, and the analog voltage signal is subjected to analog-to-digital conversion to generate a digital signal (long exposure image) to complete one exposure. The next exposure is then performed to generate a short exposure image. Performing the exposure twice will have two RST reset operations and two photoelectric conversion processes. And superposing the exposure images formed by the two exposures to obtain an effective exposure image.
It can be seen that there is a time difference between the two RST reset operations, and motion flaws appear in the wide dynamic data synthesized by the exposure image formed by performing long exposure and the exposure image formed by performing short exposure for a moving object, and the larger the time interval of starting exposure time between the exposure images, the more obvious the motion flaws. The larger the time difference, the larger the time interval in which the pixel starts to be exposed, and the more obvious the motion flaws in the formed wide dynamic data.
Disclosure of Invention
The embodiment of the invention discloses an image processing method, an image processing device and an exposure circuit based on wide dynamic, which are used for reducing the time interval for starting exposure and solving the problem that motion flaws exist in wide dynamic data. The specific scheme is as follows:
in one aspect, an embodiment of the present invention provides a wide dynamic image processing method, which is applied to an image processing system, where each pixel point in the image processing system corresponds to at least one first pixel circuit for performing long exposure and one second pixel circuit for performing short exposure, and the method includes:
obtaining a long exposure reset signal and a short exposure reset signal for each pixel point;
Transmitting a long exposure reset signal and a short exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit at the same time, so that each first pixel circuit and each second pixel circuit start exposure at the same time, and a first long exposure image and a first short exposure image of each pixel point are generated;
and superposing the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point.
Optionally, the superimposing the first long exposure image and the first short exposure image to obtain an effective exposure image includes:
normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image;
comparing a second brightness value of the second exposure image with a preset threshold range;
determining the first short-exposure image as an available exposure image if the second luminance value is greater than a maximum value in the preset threshold range;
if the second brightness value is smaller than the minimum value in the preset threshold range, determining the first long exposure image as an available exposure image;
If the second brightness value is within a preset threshold value range, determining an available exposure image according to brightness information of the first long exposure image and the first short exposure image;
and processing the available exposure image by using a preset brightness homogenization mode to obtain an effective exposure image with homogenized brightness.
Optionally, the determining the available exposure image according to the brightness information of the first long exposure image and the first short exposure image includes:
and fusing the first long exposure image and the first short exposure image according to a preset proportion to obtain an available exposure image.
Optionally, normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image, including: obtaining a first luminance value of the first short exposure image; multiplying the first brightness value by the exposure ratio to obtain a second short exposure image consistent with the first long exposure image data amount.
Optionally, each pixel point in the image processing system corresponds to two first pixel circuits and two second pixel circuits; the pixel points are divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
Reset ends of the two first pixel circuits are connected;
and the reset ends of the two second pixel circuits are connected.
Optionally, the processing the available exposure image by using a preset brightness homogenizing mode, and the formula used for obtaining the effective exposure image with uniform brightness is as follows:
Y＝X 1 *K 1 +X 2 *K 2 +X 3 *K 3 +X 4 *K 4 ；
wherein the Y represents the effective exposure image; the X is 1 And X 4 Respectively representing the brightness value and X of two areas on a diagonal line of the corresponding pixel point of the two first pixel circuits 2 And X 3 Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; the K is 1 、K 2 、K 3 And K 4 Respectively representing the X in advance 1 Said X 2 Said X 3 And said X 4 The set weight coefficient; wherein when the available exposure image is determined by the first short exposure image, the X 1 And X 4 Taking 0; when the available exposure image is determined by the first long exposure image, the X 2 And X 3 Taking 0; when the available exposure image is determined by the brightness information of the first long exposure image and the first short exposure image, the X 1 、X 2 、X 3 And X 4 Is the actual luminance value.
In another aspect, an embodiment of the present invention provides a wide dynamic image processing apparatus, which is applied to an image processing system, where each pixel point in the image processing system corresponds to at least one first pixel circuit for performing long exposure and one second pixel circuit for performing short exposure, and the apparatus includes:
A first obtaining module for obtaining a long-exposure reset signal and a short-exposure reset signal for each pixel point;
a transmitting module, configured to simultaneously transmit a long-exposure reset signal and a short-exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit, so that each first pixel circuit and each second pixel circuit simultaneously start exposure, and generate a first long-exposure image and a first short-exposure image;
and the second obtaining module is used for superposing the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point.
Optionally, the second obtaining module includes a normalization unit, a comparison unit, a first determination unit, a second determination unit, a third determination unit, and a processing unit;
the normalization unit is used for normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image;
the comparing unit is specifically configured to compare a second brightness value of the second exposure image with a preset threshold range;
The first determining unit is configured to determine the first short exposure image as an available exposure image if a second luminance value is greater than a maximum value in the preset threshold range;
the second determining unit is configured to determine the first long exposure image as an available exposure image if a second brightness value is smaller than a minimum value in the preset threshold range;
the third determining unit is used for determining an available exposure image according to the brightness information of the first long exposure image and the first short exposure image if the second brightness value is in a preset threshold range;
the processing unit is used for processing the available exposure image by utilizing a preset brightness homogenization mode to obtain an effective exposure image with homogenized brightness.
Optionally, the third determining unit is specifically configured to fuse the first long exposure image and the first short exposure image according to a predetermined ratio, so as to obtain an available exposure image.
Optionally, the normalization unit is specifically configured to obtain a first luminance value of the first short-exposure image; multiplying the first brightness value by the exposure ratio to obtain a second short exposure image consistent with the first long exposure image data amount.
Optionally, each pixel point in the image processing system corresponds to two first pixel circuits and two second pixel circuits; the pixel points are divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
reset ends of the two first pixel circuits are connected;
and the reset ends of the two second pixel circuits are connected.
Optionally, the processing the available exposure image by using a preset brightness homogenizing mode, and the formula used for obtaining the effective exposure image with uniform brightness is as follows:
Y＝X 1 *K 1 +X 2 *K 2 +X 3 *K 3 +X 4 *K 4 ；
wherein the Y represents the effective exposure image; the X is 1 And X 4 Respectively representing the brightness value and X of two areas on a diagonal line of the corresponding pixel point of the two first pixel circuits 2 And X 3 Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; the K is 1 、K 2 、K 3 And K 4 Respectively representing the X in advance 1 Said X 2 Said X 3 And said X 4 The set weight coefficient; wherein when the available exposure image is determined by the first short exposure image, the X 1 And X 4 Taking 0; when the available exposure image is determined by the first long exposure image, the X 2 And X 3 Taking 0; when the available exposure image is determined by the brightness information of the first long exposure image and the first short exposure image, the X 1 、X 2 、X 3 And X 4 Is the actual luminance value.
In another aspect, an embodiment of the present invention provides an exposure circuit including at least a first pixel circuit for performing long exposure and a second pixel circuit for performing short exposure;
each first pixel circuit is connected with the image processor, and receives a long exposure reset signal sent by the image processor to perform long exposure;
and each second pixel circuit is connected with the image processor and receives a short exposure reset signal sent by the image processor to perform short exposure.
Optionally, the exposure circuit corresponds to two first pixel circuits and two second pixel circuits; each pixel point is divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
reset ends of the two first pixel circuits are connected;
And the reset ends of the two second pixel circuits are connected.
Optionally, the first column lines of the two first pixel circuits are connected, and the first row strobe signal lines of the two first pixel circuits are connected;
the second column lines of the two second pixel circuits are connected, and the second row strobe signal lines of the two second pixel circuits are connected.
Optionally, the first pixel circuit includes a first photodiode, a first source follower and a first addressing switch;
the first photodiode is used for setting the output voltage to 0 after the first pixel circuit receives the long exposure reset signal sent by the image processor, and absorbing the optical signal to accumulate first effective charge;
the first source follower is used for converting the accumulated first effective photoelectric charge of the first photodiode into a first analog voltage signal;
the first addressing switch is used for outputting the first analog voltage signal converted by the first source follower through a first column line after receiving a first row strobe signal sent by the image processor;
the second pixel circuit comprises a second photodiode, a second source follower and a second addressing switch;
The second photodiode is configured to set an output voltage to 0 after the second pixel circuit receives a short exposure reset signal sent by the image processor, and absorb an optical signal to accumulate a second effective charge;
the second source follower is configured to convert a second effective photo-charge accumulated by the second photodiode into a second analog voltage signal;
the second addressing switch is configured to output the second analog voltage signal converted by the second source follower through a second column line after receiving a second row strobe signal sent by the image processor.
Optionally, the first pixel circuit further includes a first analog/digital converter;
the first analog/digital converter is configured to convert the first analog voltage signal output from the first column line into a first digital signal and output the first digital signal to the image processor;
the second pixel circuit also comprises a second analog-to-digital converter;
the second analog/digital converter is configured to convert the second analog voltage signal output from the second column line into a second digital signal and output the second digital signal to the image processor.
In the scheme, each pixel point in the image processing system at least corresponds to a first pixel circuit for carrying out long exposure and a second pixel circuit for carrying out short exposure, a long exposure reset signal and a short exposure reset signal for each pixel point are obtained and are simultaneously sent to each corresponding first pixel circuit and each corresponding second pixel circuit, so that each first pixel circuit and each corresponding second pixel circuit simultaneously start exposure to generate a first long exposure image and a first short exposure image, the time interval for starting exposure is reduced, the problem of motion flaws in wide dynamic data is solved, and then in order to form an image with good effect, the first long exposure image and the first short exposure image of each pixel point are overlapped, and an effective exposure image of each pixel point is obtained. Of course, it is not necessary for any one product or method of practicing the invention to achieve all of the advantages set forth above at the same time.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a conventional pixel circuit;
FIG. 2 is a schematic flow chart of an image processing method based on wide dynamic range according to an embodiment of the present invention;
FIG. 3 is a flowchart illustrating a specific implementation of step S203 shown in FIG. 2;
FIG. 4 is a schematic diagram of an image processing apparatus based on wide dynamic range according to an embodiment of the present invention;
FIG. 5 is a schematic diagram showing a specific structure of a second obtaining module in the apparatus shown in FIG. 4;
FIG. 6 is a schematic diagram of an exposure circuit according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of an exposure circuit according to an embodiment of the present invention;
fig. 8 is a schematic distribution diagram of a first pixel circuit and a second pixel circuit according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The embodiment of the invention provides an image processing method, an image processing device and an exposure circuit based on wide dynamic, which are used for reducing the time interval for starting exposure and solving the problem that motion flaws exist in wide dynamic data.
The following first describes an image processing method based on wide dynamic range provided by the embodiment of the present invention.
It should be noted that the image processing method based on wide dynamic provided by the embodiment of the invention can be applied to an image processing system, where each pixel point in the image processing system corresponds to at least one first pixel circuit for performing long exposure and one second pixel circuit for performing short exposure. The exposure time corresponding to each of the first pixel circuit and the second pixel circuit can be controlled by upper layer application software.
As shown in fig. 2, the image processing method based on wide dynamic range provided by the embodiment of the invention may include the following steps:
s201: obtaining a long exposure reset signal and a short exposure reset signal for each pixel point;
it will be appreciated that when the wide dynamic function is on, the image processing system obtains a long exposure reset signal and a short exposure reset signal for each pixel point, wherein the long exposure reset signal may be the same as or different from the short exposure reset signal. In one implementation, the long exposure reset signal and the short exposure reset signal may both be reset signals RST.
In addition, the long exposure reset signal and the short exposure reset signal can be obtained by adopting the prior art, and are not described herein.
S202: transmitting a long exposure reset signal and a short exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit simultaneously, so that each first pixel circuit and each second pixel circuit simultaneously start exposure, and a first long exposure image and a first short exposure image are generated;
in order to ensure that each first pixel circuit and each second pixel circuit can be exposed at the same time, the time interval for starting exposure is eliminated, and the problem that motion flaws exist in wide dynamic data is solved. The image processing system simultaneously transmits the obtained long-exposure reset signal and short-exposure reset signal to each corresponding first pixel circuit and each second pixel circuit. Each first pixel circuit and each second pixel circuit simultaneously start exposure to generate a first long exposure image and a first short exposure image.
The exposure of each first pixel circuit and each second pixel circuit is the same as that of the prior art, and a detailed description thereof is omitted herein.
S203: and superposing the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point.
It can be understood that, for the first short exposure image, the exposure time is short, and the underexposure phenomenon may occur in the pixel point, so that the image formed by the corresponding portion is too dark, and the details of the dark portion of the image are not well reflected. For the first long exposure image, the exposure time is long, the phenomenon of over-saturation exposure of the pixel point may occur, at this time, the image formed by the corresponding part is over-bright, and the bright part detail of the picture is not well reflected. In order to form an image with a better effect, the bright part details and the dark part details in the image can be fully and completely displayed, an effective exposure image needs to be determined according to the generated first long exposure image and the first short exposure image, and then a subsequent image processing flow is carried out. The overlapping of the first long-exposure image and the first short-exposure image of each pixel point may adopt the prior art, and will not be described herein.
By applying the embodiment of the invention, each pixel point in the image processing system at least corresponds to one first pixel circuit for carrying out long exposure and one second pixel circuit for carrying out short exposure, a long exposure reset signal and a short exposure reset signal aiming at each pixel point are obtained and simultaneously sent to each corresponding first pixel circuit and each corresponding second pixel circuit, so that each first pixel circuit and each corresponding second pixel circuit simultaneously start exposure, a first long exposure image and a first short exposure image are generated, the time interval for starting exposure is reduced, the problem of motion flaws in wide dynamic data is solved, and then the first long exposure image and the first short exposure image of each pixel point are overlapped to obtain an effective exposure image of each pixel point.
In a specific implementation manner, as shown in fig. 3, the overlapping the first long exposure image and the first short exposure image to obtain an effective exposure image (S203), includes:
s301: normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image;
S302: comparing a second brightness value of the second exposure image with a preset threshold range;
s303: determining the first short-exposure image as an available exposure image if the second luminance value is greater than a maximum value in the preset threshold range;
s304: if the second brightness value is smaller than the minimum value in the preset threshold range, determining the first long exposure image as an available exposure image;
s305: if the second brightness value is within a preset threshold value range, determining an available exposure image according to brightness information of the first long exposure image and the first short exposure image;
s306: and processing the available exposure image by using a preset brightness homogenization mode to obtain an effective exposure image with homogenized brightness.
Since the exposure time of the first short exposure image is different from that of the first long exposure image, the brightness of the presented images is different, so as to ensure that better available exposure images can be determined according to the first short exposure image and the first long exposure image. First, normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image, and converting the first short exposure image to the same data volume as the first long exposure image to obtain a second short exposure image. The exposure ratio of the first long exposure image and the first short exposure image may be determined according to the prior art, and will not be described herein. Also, the normalization of the first short-exposure image may be performed using the prior art. For example, before normalization, the corresponding amount of data may be 16 bits for the first long exposure image and 12 bits for the first short exposure image. And normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image with the data volume of 16 bits.
At this time, the second luminance value of the second exposure image may be directly compared with the preset threshold range. Wherein the preset threshold range may be determined by prior art techniques. It can be understood that when the second brightness value is greater than the maximum value in the preset threshold range, the phenomenon that the corresponding pixel point in the first long exposure image may be over-saturated in exposure can be indicated, and in order to make the quality of the available exposure image better, the complete representation of the bright part detail of the exposure image can be ensured, and the first short exposure image can be determined to be the available exposure image; when the second brightness value is smaller than the minimum value in the preset threshold range, the phenomenon that the corresponding pixel point in the first short exposure image is possibly underexposed can be shown, and in order to ensure that the quality of the available exposure image is better, the complete representation of the dark part detail of the exposure image is ensured, and the first long exposure image can be determined to be the available exposure image; when the second brightness value is within the preset threshold value range, it can be indicated that the exposure of the pixel point corresponding to the first short exposure image is sufficient, and the exposure of the pixel point corresponding to the first long exposure image is not oversaturated, at this time, the available exposure image can be determined according to the brightness information of the first long exposure image and the brightness information of the first short exposure image, that is, the value of the pixel point corresponding to the available exposure image is determined according to the brightness information of the pixel point corresponding to the first long exposure image and the brightness information of the pixel point corresponding to the first short exposure image.
It should be noted that, when the second brightness value is within the preset threshold range, it may indicate that the pixel point exposure corresponding to the first short exposure image is sufficient, and the pixel point exposure corresponding to the first long exposure image is not supersaturated. At this time, the pixels corresponding to the first short exposure image and the first long exposure image may be fused according to a predetermined ratio, so as to obtain an available exposure image of each pixel.
For each pixel point, long and short exposure is carried out simultaneously, a first short exposure image is formed at the part of each pixel point, which is subjected to short exposure, and a first long exposure image is formed at the part of each pixel point, which is subjected to long exposure. It can be understood that, in the portion where long exposure is performed for each pixel point, since short exposure is not performed, no brightness is generated in the corresponding portion in the formed first short exposure image; in the portion where short exposure is performed for each pixel, since long exposure is not performed, no luminance is generated in the corresponding portion in the formed first long-exposure image. In order to ensure the integrity and brightness uniformity of the available exposure images determined according to the first long exposure image and the first short exposure image, the available exposure images can be processed by utilizing a preset brightness homogenization mode to obtain brightness homogenized effective exposure images.
It will be appreciated that there are three situations in which the available exposure image for each pixel is: when the second brightness value of the corresponding pixel point of the second short exposure image is larger than the maximum value in the preset threshold range, the value of the corresponding pixel point is the value of the corresponding pixel point of the first short exposure image; the second step is: when the second brightness value of the corresponding pixel point of the second short exposure image is smaller than the minimum value in the preset threshold range, the value of the corresponding pixel point is the value of the corresponding pixel point of the first long exposure image; the third is: when the second brightness value of the corresponding pixel point of the second short exposure image is in the preset threshold range, the value of the corresponding pixel point is determined according to the brightness information of the first long exposure image and the first short exposure image.
In a specific implementation manner, normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image, including:
obtaining a first luminance value of the first short exposure image; multiplying the first brightness value by the exposure ratio to obtain a second short exposure image consistent with the first long exposure image data amount.
Since the exposure time of the first short exposure image is different from that of the first long exposure image, the data amount of the brightness value of the corresponding pixel point will be different, in order to determine a better available exposure image, the exposure ratio of the first long exposure image and the first short exposure image can be determined by using the prior art, and the first short exposure image is converted into a second short exposure image consistent with the data amount of the first long exposure image, so as to facilitate screening of the available exposure image. For example, the first long exposure image data amount is 16 bits, the first short exposure image data amount is 12 bits, and the exposure ratio is 4:3 (16:12), multiplying the exposure ratio 4 by a first brightness value corresponding to the first short exposure image: and 3, obtaining a second short exposure image with the data quantity of 16 bits.
Alternatively, it is also possible to convert the first long-exposure image into a second long-exposure image corresponding to the first short-exposure image data amount, and then to determine the subsequent available exposure image based on the third luminance value corresponding to the second long-exposure image.
In a specific implementation manner, each pixel point in the image processing system corresponds to two first pixel circuits and two second pixel circuits; the pixel points are divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
Reset ends of the two first pixel circuits are connected;
and the reset ends of the two second pixel circuits are connected.
As shown in fig. 8, in order to equalize the exposure luminance in each pixel point, each pixel point may be divided into four areas on average, in which two areas (area 1 and area 4, or area 2 and area 3) are subjected to long exposure and two areas (area 2 and area 3, or area 1 and area 4) are subjected to short exposure. Two first pixel circuits for performing long exposure correspond to two areas on a diagonal line of a pixel point respectively, for example: in fig. 8, in the region 1 and the region 4, two second pixel circuits for performing short exposure correspond to two regions on the other diagonal of the pixel point, respectively, for example: region 2 and region 3 in fig. 8. And in order to ensure the synchronization of the exposure circuits, the reset terminals of the two first pixel circuits are connected, and the reset terminals of the two second pixel circuits are connected. And in order to reduce the time difference between the long exposure and the short exposure, the problem of motion flaws in the wide dynamic data is avoided, and the first pixel circuit and the second pixel circuit simultaneously receive reset signals and simultaneously start exposure.
In a specific implementation manner, the formula used for processing the available exposure image by using a preset brightness homogenization mode to obtain the effective exposure image with the homogenized brightness is as follows:
Y＝X 1 *K 1 +X 2 *K 2 +X 3 *K 3 +X 4 *K 4 ；
Wherein the Y represents the effective exposure image; the X is 1 And X 4 Respectively representing the brightness value and X of two areas on a diagonal line of the corresponding pixel point of the two first pixel circuits 2 And X 3 Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; the K is 1 、K 2 、K 3 And K 4 Respectively representing the X in advance 1 Said X 2 Said X 3 And said X 4 The set weight coefficient; wherein when the available exposure image is determined by the first short exposure image, the X 1 And X 4 Taking 0; when the available exposure image is determined by the first long exposure image, the X 2 And X 3 Taking 0; when the available exposure image is determined by the brightness information of the first long exposure image and the first short exposure image, the X 1 、X 2 、X 3 And X 4 Is the actual luminance value.
Wherein K is 1 、K 2 、K 3 And K 4 The setting may be performed according to actual conditions, and is not limited herein. It will be appreciated that in processing the available exposure image, luminance equalization is performed for each pixel separately.
Corresponding to the above-mentioned method embodiments, the embodiments of the present invention provide a wide dynamic image processing apparatus, which may be applied to an image processing system, where each pixel point in the image processing system corresponds to at least one first pixel circuit for performing long exposure and one second pixel circuit for performing short exposure, as shown in fig. 4, and the apparatus may include:
A first obtaining module 401 for obtaining a long-exposure reset signal and a short-exposure reset signal for each pixel point;
a transmitting module 402, configured to simultaneously transmit a long-exposure reset signal and a short-exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit, so that each first pixel circuit and each second pixel circuit simultaneously start exposure, and generate a first long-exposure image and a first short-exposure image;
the second obtaining module 403 is configured to superimpose the first long exposure image and the first short exposure image of each pixel point, and obtain an effective exposure image of each pixel point.
By applying the embodiment of the invention, each pixel point in the image processing system at least corresponds to one first pixel circuit for carrying out long exposure and one second pixel circuit for carrying out short exposure, a long exposure reset signal and a short exposure reset signal aiming at each pixel point are obtained and simultaneously sent to each corresponding first pixel circuit and each corresponding second pixel circuit, so that each first pixel circuit and each corresponding second pixel circuit simultaneously start exposure, a first long exposure image and a first short exposure image are generated, the time interval for starting exposure is reduced, the problem of motion flaws in wide dynamic data is solved, and then the first long exposure image and the first short exposure image of each pixel point are overlapped to obtain an effective exposure image of each pixel point.
In a specific implementation manner, as shown in fig. 5, the second obtaining module 403 includes a normalization unit 501, a comparison unit 502, a first determining unit 503, a second determining unit 504, a third determining unit 505, and a processing unit 506;
the normalizing unit 501 is configured to normalize the first short-exposure image according to the exposure ratio of the first long-exposure image and the first short-exposure image, to obtain a second short-exposure image consistent with the data amount of the first long-exposure image;
the comparing unit 502 is specifically configured to compare the second brightness value of the second exposure image with a preset threshold range;
the first determining unit 503 is configured to determine the first short exposure image as an available exposure image if the second luminance value is greater than a maximum value in the preset threshold range;
the second determining unit 504 is configured to determine the first long exposure image as an available exposure image if a second brightness value is smaller than a minimum value in the preset threshold range;
the third determining unit 505 is configured to determine an available exposure image according to the brightness information of the first long exposure image and the first short exposure image if the second brightness value is within a preset threshold range;
The processing unit 506 is configured to process the available exposure image by using a preset brightness homogenization manner, so as to obtain a brightness homogenized effective exposure image.
In a specific implementation manner, the third determining unit 505 is specifically configured to fuse the first long exposure image and the first short exposure image according to a predetermined ratio, so as to obtain an available exposure image.
In a specific implementation, the normalization unit 501 is specifically configured to obtain a first luminance value of the first short-exposure image;
multiplying the first brightness value by the exposure ratio to obtain a second short exposure image consistent with the first long exposure image data amount.
In a specific implementation manner, each pixel point in the image processing system corresponds to two first pixel circuits and two second pixel circuits; the pixel points are divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
reset ends of the two first pixel circuits are connected;
and the reset ends of the two second pixel circuits are connected.
In a specific implementation manner, the formula used for processing the available exposure image by using a preset brightness homogenization mode to obtain the effective exposure image with the homogenized brightness is as follows:
Y＝X 1 *K 1 +X 2 *K 2 +X 3 *K 3 +X 4 *K 4 ；
wherein the Y represents the effective exposure image; the X is 1 And X 4 Respectively representing the brightness value and X of two areas on a diagonal line of the corresponding pixel point of the two first pixel circuits 2 And X 3 Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; the K is 1 、K 2 、K 3 And K 4 Respectively representing the X in advance 1 Said X 2 Said X 3 And said X 4 The set weight coefficient; wherein when the available exposure image is determined by the first short exposure image, the X 1 And X 4 Taking 0; when the available exposure image is determined by the first long exposure image, the X 2 And X 3 Taking 0; when the available exposure image is determined by the brightness information of the first long exposure image and the first short exposure image, the X 1 、X 2 、X 3 And X 4 Is the actual luminance value.
By applying the embodiment of the invention, each first pixel circuit and each second pixel circuit can start exposure at the same time, and an effective exposure image with uniform brightness can be obtained.
Corresponding to the above-described method embodiment, an embodiment of the present invention provides an exposure circuit, as shown in fig. 6, which includes at least one first pixel circuit 610 for performing long exposure and one second pixel circuit 620 for performing short exposure;
each first pixel circuit 610 is connected to the image processor 600, and receives a long exposure reset signal sent by the image processor 600 to perform long exposure;
each of the second pixel circuits 620 is connected to the image processor 600, and receives a short exposure reset signal sent by the image processor 600 to perform short exposure.
It should be noted that, the connection between each first pixel circuit 610 and the image processor 600 and the connection between each second pixel circuit 620 and the image processor 600 shown in fig. 6 are only used to indicate that a communication connection relationship exists, and do not represent a physical connection. The exposure circuit provided by the invention can be correspondingly applied to each pixel point.
In a circuit realizing a wide dynamic function, it is necessary to perform long exposure and short exposure of a target object twice, respectively. The image processor 600 in the embodiment of the present invention starts each first pixel circuit 610 to perform long exposure by sending a long exposure reset signal to each first pixel circuit 610, starts each second pixel circuit 620 to perform short exposure by sending a short exposure reset signal to each second pixel circuit 620. Wherein the long exposure reset signal and the short exposure reset signal may be the same or different. In one particular implementation, the long exposure reset signal and the short exposure reset signal may both be reset signals RST.
Note that, the reset signal RST may be active high, that is, each first pixel circuit 610 or each second pixel circuit 620 starts to perform exposure when the reset signal RST is active high; it may be active low, i.e., each first pixel circuit 610 or each second pixel circuit 620 starts to perform exposure when the reset signal RST is active low.
In addition, it is understood that the image processor 600 may simultaneously transmit corresponding long-exposure reset signals and short-exposure reset signals to each of the first pixel circuits 610 and each of the second pixel circuits 620. So that each first pixel circuit 610 and each second pixel circuit 620 start exposure at the same time, the start exposure time difference between the long exposure and the short exposure is eliminated.
The image processor 600 may employ an SOC image processing chip. It will be appreciated that when the wide dynamic function is not turned on, the pins of the image processor 600 outputting the long-exposure reset signal or the short-exposure reset signal may be in a floating or grounded state, and when the wide dynamic function is turned on, the pins of the image processor 600 outputting the long-exposure reset signal are connected to each of the first pixel circuits 610, and the pins of the short-exposure reset signal are connected to each of the second pixel circuits 620. The access mode of each pin can be the same as the existing access mode. In addition, it should be emphasized that "first" of the "first pixel circuits" and "second" of the "second pixel circuits" in the embodiments of the present invention are merely used to distinguish different pixel circuits from each other in terms of naming, and are not meant to be limiting in any way.
By applying the embodiment of the invention, the exposure circuit at least comprises a first pixel circuit for carrying out long exposure and a second pixel circuit for carrying out short exposure; each first pixel circuit is connected with the image processor, and receives a long exposure reset signal sent by the image processor to perform long exposure; each second pixel circuit is connected with the image processor and receives a short exposure reset signal sent by the image processor to perform short exposure, and each first pixel circuit and each second pixel circuit can perform exposure simultaneously so as to reduce the time difference between the two exposures.
In a specific implementation, as shown in fig. 7, the exposure circuits correspond to two first pixel circuits 610 and two second pixel circuits 620; each pixel point is divided into four areas on average; the two first pixel circuits 610 respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits 620 respectively correspond to two areas on the other diagonal of the pixel point;
reset ends of the two first pixel circuits are connected;
and the reset ends of the two second pixel circuits are connected.
In order to equalize the exposure luminance in each pixel, each pixel may be divided into four areas on average, wherein two areas are subjected to long exposure and two areas are subjected to short exposure. The two first pixel circuits 610 performing long exposure correspond to two areas on one diagonal of the pixel point, respectively, and the two second pixel circuits 620 performing short exposure correspond to two areas on the other diagonal of the pixel point, respectively. And in order to ensure synchronization of the exposure circuit to start exposure, the reset terminals of the two first pixel circuits 610 are connected and the reset terminals of the two second pixel circuits 620 are connected. And in order to reduce the time difference between the long exposure and the short exposure, the image processor 600 may simultaneously transmit the corresponding long exposure reset signal and short exposure reset signal to each of the first pixel circuits 610 and each of the second pixel circuits 620, and each of the first pixel circuits 610 and each of the second pixel circuits 620 may simultaneously receive the respective corresponding long exposure reset signal and short exposure reset signal, thereby simultaneously starting exposure. Wherein, it can be understood that the reset terminal is a reset signal input terminal.
In addition, the above-described embodiment is only one example of the present invention, and the pixel may be divided into two areas, eight areas, ten areas, or the like on average, which is all that is possible.
In a specific implementation manner, the first column lines of the two first pixel circuits 610 are connected, and the first row strobe signal lines of the two first pixel circuits 610 are connected;
the second column lines of the two second pixel circuits 620 are connected, and the second row gate signal lines of the two second pixel circuits 620 are connected.
For each first pixel circuit 610, since the exposure positions of the pixel points corresponding to each first pixel circuit 610 are different, after the long exposure is performed, the long exposure signals can be formed together, the first column lines of the two first pixel circuits 610 are connected, and the obtained long exposure signals are output as a complete result. Similarly, for each second pixel circuit 620, since the exposure positions of the pixel points corresponding to each second pixel circuit 620 are different, after the short exposure is performed, the short exposure signals can be formed together, and the second column lines of the two second pixel circuits 620 are connected, and the obtained short exposure signals are output as a complete result.
In this case, as known in the art, after the address switch is activated by the row strobe signal, the long exposure signal (or the short exposure signal) is outputted from the first column line (the second column line). In order to ensure that the exposure signal formed in each exposure circuit can simultaneously output the first row gate signal lines of the two first pixel circuits 610, the second row gate signal lines of the two second pixel circuits 620 may be connected.
In a specific implementation manner, as shown in fig. 7, the circuit structure of each first pixel circuit 610 and each second pixel circuit 620 included in an exposure circuit according to an embodiment of the present invention may be the same as the circuit structure of a conventional pixel circuit. The first pixel circuit 610 includes a first photodiode PD1, a first source follower T1, and a first address switch T2;
the first photodiode PD1 is configured to set an output voltage to 0 after the first pixel circuit 610 receives the long exposure reset signal sent by the image processor 600, and absorb an optical signal to accumulate a first effective charge;
the first source follower T1 is configured to convert the first effective photo-charge accumulated by the first photodiode PD1 into a first analog voltage signal;
The first addressing switch T2 is configured to output the first analog voltage signal converted by the first source follower T1 through a first column line after receiving a first row strobe signal sent by the image processor 600;
the second pixel circuit comprises a second photodiode PD2, a second source follower T3 and a second addressing switch T4;
the second photodiode PD2 is configured to set an output voltage to 0 after the second pixel circuit 620 receives the short-exposure reset signal sent by the image processor 600, and absorb an optical signal to accumulate a second effective charge;
the second source follower T3 is configured to convert the second effective photo-charge accumulated by the second photodiode PD2 into a second analog voltage signal;
the second addressing switch T4 is configured to output the second analog voltage signal converted by the second source follower T3 through a second column line after receiving a second row strobe signal sent by the image processor 600.
Wherein the exposure time of each first pixel circuit 610 and each second pixel circuit 620 may be controlled by the image processor 600. Taking the first pixel circuit 610 as an example: the first pixel circuit 610 starts long exposure after receiving the long exposure reset signal sent from the image processor 600. Also, the time of outputting the respective exposure signals of each of the first pixel circuits 610 and each of the second pixel circuits 620 may also be controlled by the image processor 600. Taking the first pixel circuit 610 as an example: after receiving the first row strobe signal sent by the image processor 600, the first pixel circuit 610 outputs the first analog voltage signal converted by the first source follower T1 through the corresponding first column line.
In order to ensure that the exposure signals formed by each of the first pixel circuits 610 and each of the second pixel circuits 620 can be simultaneously output, the image processor 600 may simultaneously transmit the first line strobe signal and the second line strobe signal. This is also possible. In addition, in a specific implementation, the first row strobe signal and the second row strobe signal may be the same or different, and the first row strobe signal and the second row strobe signal may be both row strobe pulses RS, where the first row strobe signal (the second row strobe signal) may be active at a high level, that is, the first address switch (the second address switch) is turned on when at a high level; or the first addressing switch (second addressing switch) is turned on when the active level is low, namely the active level is low; or it is also possible that either the first row strobe signal or the second row strobe signal is active high and active low.
It should be emphasized that when the output voltage is set to 0 after each of the first pixel circuits 610 and each of the second pixel circuits 620 are reset, there may be an actual voltage offset due to the influence of each device in the circuit, and at this time, effective charges need to be accumulated to avoid the influence of the offset voltage on the exposure signal.
In one specific implementation, as shown in fig. 7, the first pixel circuit 610 may further include a first analog-to-digital converter;
the first analog-to-digital converter is used for converting the first analog voltage signal into a first digital signal;
the second pixel circuit 620 may further include a second analog/digital converter therein;
the second analog-to-digital converter is configured to convert the second analog voltage signal into a second digital signal.
Further, after the first analog voltage signal (the second analog voltage signal) is output through the corresponding first column line (the second column line), the first analog voltage signal (the second analog voltage signal) may be directly input into the connected first analog-to-digital converter (the second analog-to-digital converter), and the first analog voltage signal (the second analog voltage signal) is converted into the first digital signal (the second digital signal) by the first analog-to-digital converter (the second analog-to-digital converter) and then output to the image processor 600. Alternatively, the image may be directly input to the image processor 600 for subsequent image processing.
The first analog-to-digital converter (second analog-to-digital converter) is connected to the output end of the exposure circuit provided by the embodiment of the invention. Wherein, as shown in fig. 7, the first analog-to-digital converter and the second analog-to-digital converter can be represented by a/D converters.
By applying the embodiment of the invention, each first pixel circuit and each second pixel circuit can be simultaneously exposed to reduce the time difference between two exposures, and the first analog voltage signal and the second analog voltage signal can be simultaneously subjected to analog/digital conversion.
For system/device embodiments, the description is relatively simple as it is substantially similar to method embodiments, with reference to the description of method embodiments in part.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Those of ordinary skill in the art will appreciate that implementing all or part of the steps in the above-described method embodiments may be accomplished by programming instructions in a computer readable storage medium, such as: ROM/RAM, magnetic disks, optical disks, etc.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.
Claims (10)
1. An image processing method based on wide dynamic range, which is applied to an image processing system, wherein each pixel point in the image processing system corresponds to at least one first pixel circuit for performing long exposure and one second pixel circuit for performing short exposure, and the method comprises the following steps:
obtaining a long exposure reset signal and a short exposure reset signal for each pixel point;
transmitting a long exposure reset signal and a short exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit at the same time, so that each first pixel circuit and each second pixel circuit start exposure at the same time, and a first long exposure image and a first short exposure image of each pixel point are generated;
Superposing the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point;
the step of superposing the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point comprises the following steps:
normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image;
comparing a second brightness value of the second short exposure image with a preset threshold range;
determining the first short-exposure image as an available exposure image if the second luminance value is greater than a maximum value in the preset threshold range;
if the second brightness value is smaller than the minimum value in the preset threshold range, determining the first long exposure image as an available exposure image;
if the second brightness value is within a preset threshold value range, determining an available exposure image according to brightness information of the first long exposure image and the first short exposure image;
processing the available exposure image by using a preset brightness homogenization mode to obtain an effective exposure image with homogenized brightness;
Each pixel point in the image processing system corresponds to two first pixel circuits and two second pixel circuits; the pixel points are divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
reset ends of the two first pixel circuits are connected;
reset ends of the two second pixel circuits are connected;
the available exposure image is processed by using a preset brightness homogenization mode, and an effective exposure image with the homogenized brightness is obtained by using the following formula:wherein said->Representing the effectively exposed image; said->And->Respectively representing brightness values of two areas on a diagonal line of the pixel point respectively corresponding to the two first pixel circuits, < >>And->Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; said->、/>、/>And->Respectively represent the aboveSaid->Said->Said->The set weight coefficient; wherein when said available exposure image is determined by said first short exposure image, said +. >And->Taking 0; when said available exposure image is determined by said first long exposure image, said +.>And->Taking 0; when the available exposure image is determined from the luminance information of the first long exposure image and the first short exposure image, the +.>、/>、/>And->Is the actual luminance value.
2. The method of claim 1, wherein determining an available exposure image from luminance information of the first long exposure image and the first short exposure image comprises:
and fusing the first long exposure image and the first short exposure image according to a preset proportion to obtain an available exposure image.
3. The method of claim 1, wherein normalizing the first short-exposure image based on the exposure ratio of the first long-exposure image and the first short-exposure image to obtain a second short-exposure image consistent with the first long-exposure image data amount comprises:
obtaining a first luminance value of the first short exposure image;
multiplying the first brightness value by the exposure ratio to obtain a second short exposure image consistent with the first long exposure image data amount.
4. An image processing apparatus based on wide dynamic range, which is applied to an image processing system in which each pixel corresponds to at least one first pixel circuit for performing long exposure and one second pixel circuit for performing short exposure, the apparatus comprising:
A first obtaining module for obtaining a long-exposure reset signal and a short-exposure reset signal for each pixel point;
a transmitting module, configured to simultaneously transmit a long-exposure reset signal and a short-exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit, so that each first pixel circuit and each second pixel circuit simultaneously start exposure, and generate a first long-exposure image and a first short-exposure image;
the second obtaining module is used for superposing the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point;
the second obtaining module comprises a normalization unit, a comparison unit, a first determining unit, a second determining unit, a third determining unit and a processing unit;
the normalization unit is used for normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image;
the comparison unit is specifically configured to compare a second brightness value of the second short exposure image with a preset threshold range;
The first determining unit is configured to determine the first short exposure image as an available exposure image if a second luminance value is greater than a maximum value in the preset threshold range;
the second determining unit is configured to determine the first long exposure image as an available exposure image if a second brightness value is smaller than a minimum value in the preset threshold range;
the third determining unit is used for determining an available exposure image according to the brightness information of the first long exposure image and the first short exposure image if the second brightness value is in a preset threshold range;
the processing unit is used for processing the available exposure image by utilizing a preset brightness homogenization mode to obtain a brightness homogenized effective exposure image;
each pixel point in the image processing system corresponds to two first pixel circuits and two second pixel circuits; the pixel points are divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
reset ends of the two first pixel circuits are connected;
Reset ends of the two second pixel circuits are connected;
the available exposure image is processed by using a preset brightness homogenization mode, and an effective exposure image with the homogenized brightness is obtained by using the following formula:wherein said->Representing the effectively exposed image; said->And->Respectively representing brightness values of two areas on a diagonal line of the pixel point respectively corresponding to the two first pixel circuits, < >>And->Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; said->、/>、/>And->Respectively represent the aboveSaid->Said->Said->The set weight coefficient; wherein when said available exposure image is determined by said first short exposure image, said +.>And->Taking 0; when said available exposure image is determined by said first long exposure image, said +.>And->Taking 0; when the available exposure image is determined from the luminance information of the first long exposure image and the first short exposure image, the +.>、/>、/>And->Is the actual luminance value.
5. The apparatus according to claim 4, wherein the third determining unit is specifically configured to fuse the first long exposure image and the first short exposure image according to a predetermined ratio, so as to obtain an available exposure image.
6. The apparatus according to claim 4, wherein the normalization unit is configured to obtain a first luminance value of the first short-exposure image;
multiplying the first brightness value by the exposure ratio to obtain a second short exposure image consistent with the first long exposure image data amount.
7. An exposure circuit comprising at least a first pixel circuit for performing a long exposure and a second pixel circuit for performing a short exposure;
each first pixel circuit is connected with the image processor, receives a long exposure reset signal sent by the image processor to carry out long exposure, and generates a first long exposure image of each pixel point; the image processor sends a long exposure reset signal and a short exposure reset signal to each corresponding first pixel circuit and each corresponding second pixel circuit at the same time; each first pixel circuit and each second pixel circuit simultaneously start exposure;
each second pixel circuit is connected with the image processor, receives a short exposure reset signal sent by the image processor to perform short exposure, and generates a first short exposure image of each pixel point, so that the image processor overlaps the first long exposure image and the first short exposure image of each pixel point to obtain an effective exposure image of each pixel point;
The image processor superimposes the first long exposure image and the first short exposure image of each pixel point, and the step of obtaining the effective exposure image of each pixel point comprises the following steps:
normalizing the first short exposure image according to the exposure ratio of the first long exposure image and the first short exposure image to obtain a second short exposure image consistent with the data amount of the first long exposure image;
comparing a second brightness value of the second short exposure image with a preset threshold range;
determining the first short-exposure image as an available exposure image if the second luminance value is greater than a maximum value in the preset threshold range;
if the second brightness value is smaller than the minimum value in the preset threshold range, determining the first long exposure image as an available exposure image;
if the second brightness value is within a preset threshold value range, determining an available exposure image according to brightness information of the first long exposure image and the first short exposure image;
processing the available exposure image by using a preset brightness homogenization mode to obtain an effective exposure image with homogenized brightness;
the exposure circuit corresponds to two first pixel circuits and two second pixel circuits; each pixel point is divided into four areas on average; the two first pixel circuits respectively correspond to two areas on a diagonal line of the pixel point; the two second pixel circuits respectively correspond to two areas on the other diagonal line of the pixel point;
Reset ends of the two first pixel circuits are connected;
reset ends of the two second pixel circuits are connected;
the available exposure image is processed by using a preset brightness homogenization mode, and an effective exposure image with the homogenized brightness is obtained by using the following formula:wherein said->Representing the effectively exposed image; said->And->Respectively representing brightness values of two areas on a diagonal line of the pixel point respectively corresponding to the two first pixel circuits, < >>And->Respectively representing brightness values of two areas on a diagonal line of the pixel point corresponding to the two second pixel circuits; said->、/>、/>And->Respectively represent pre-formsThe first is thatSaid->Said->Said->The set weight coefficient; wherein when said available exposure image is determined by said first short exposure image, said +.>And->Taking 0; when said available exposure image is determined by said first long exposure image, said +.>And->Taking 0; when the available exposure image is determined from the luminance information of the first long exposure image and the first short exposure image, the +.>、/>、/>And->Is the actual luminance value.
8. The exposure circuit according to claim 7, wherein,
The first column lines of the two first pixel circuits are connected, and the first row strobe signal lines of the two first pixel circuits are connected;
the second column lines of the two second pixel circuits are connected, and the second row strobe signal lines of the two second pixel circuits are connected.
9. The exposure circuit according to claim 8, wherein the first pixel circuit includes therein a first photodiode, a first source follower, and a first addressing switch;
the first photodiode is used for setting the output voltage to 0 after the first pixel circuit receives the long exposure reset signal sent by the image processor, and absorbing the optical signal to accumulate first effective charge;
the first source follower is used for converting the accumulated first effective photoelectric charge of the first photodiode into a first analog voltage signal;
the first addressing switch is used for outputting the first analog voltage signal converted by the first source follower through a first column line after receiving a first row strobe signal sent by the image processor;
the second pixel circuit comprises a second photodiode, a second source follower and a second addressing switch;
The second photodiode is configured to set an output voltage to 0 after the second pixel circuit receives a short exposure reset signal sent by the image processor, and absorb an optical signal to accumulate a second effective charge;
the second source follower is configured to convert a second effective photo-charge accumulated by the second photodiode into a second analog voltage signal;
the second addressing switch is configured to output the second analog voltage signal converted by the second source follower through a second column line after receiving a second row strobe signal sent by the image processor.
10. The exposure circuit according to claim 8, wherein the first pixel circuit further comprises a first analog-to-digital converter therein;
the first analog/digital converter is used for converting a first analog voltage signal output from the first column line into a first digital signal and outputting the first digital signal to the image processor;
the second pixel circuit also comprises a second analog-to-digital converter;
the second analog/digital converter is configured to convert a second analog voltage signal output from the second column line into a second digital signal and output the second digital signal to the image processor.
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| US11062436B2 (en) * | 2019-05-10 | 2021-07-13 | Samsung Electronics Co., Ltd. | Techniques for combining image frames captured using different exposure settings into blended images |
| CN110460781B (en) * | 2019-08-26 | 2021-10-12 | Oppo广东移动通信有限公司 | Image sensor, image processing method and storage medium |
| CN111491110B (en) * | 2020-04-17 | 2021-09-17 | Oppo广东移动通信有限公司 | High dynamic range image processing system and method, electronic device, and storage medium |
| CN114513610A (en) * | 2020-11-17 | 2022-05-17 | 浙江大华技术股份有限公司 | Image processing method, image processing apparatus, and storage apparatus |
| WO2022140897A1 (en) * | 2020-12-28 | 2022-07-07 | 深圳元戎启行科技有限公司 | Image generation method and apparatus, and computer device and storage medium |
| CN116095502B (en) * | 2023-04-13 | 2023-07-25 | 芯动微电子科技(珠海)有限公司 | Method and device for fusing multiple exposure images |
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