US20200314319A1 - Image processing method and system based on adjustments performed according to environment - Google Patents
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- 238000012937 correction Methods 0.000 claims abstract description 70
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- 238000012545 processing Methods 0.000 claims abstract description 20
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- H—ELECTRICITY
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- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/60—Control of cameras or camera modules
- H04N23/667—Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
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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
- H04N23/74—Circuitry for compensating brightness variation in the scene by influencing the scene brightness using illuminating means
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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
- H04N23/71—Circuitry for evaluating the brightness variation
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- H—ELECTRICITY
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- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
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- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/70—Circuitry for compensating brightness variation in the scene
- H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
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Definitions
- the present disclosure relates to image processing technology and, more particularly, to an image processing method and system based on adjustments performed according to environment.
- a dashcam of a moving car records the car's location, condition, related data and captures a video of the surroundings. Therefore, the dashcam can provide video evidence in the event of a road accident.
- the conventional dashcam has an image-capturing device.
- the image-capturing device adjusts shutter speed and ISO sensitivity (ISO value) automatically with an automatic exposure unit such that the image has invariable brightness.
- ISO sensitivity ISO value
- the aforesaid way of recording an image with invariable brightness has a drawback: during nighttime, the car in the image obtained looks sharp, but the background in the image obtained is blurred and dim, thereby failing to ensure overall image quality.
- an image processing method based on adjustments performed according to environment includes: capturing an environmental parameter of an image; determining a scene mode of the image according to the environmental parameter; estimating a brightness correction parameter of the image according to the scene mode; and performing an image area determination to obtain an image area and an area brightness of the image area, followed by performing brightness correction on the image according to the image area, the area brightness and the brightness correction parameter.
- the brightness correction involves performing gamma correction on background in the image when the scene mode is a dark mode.
- an image processing system based on adjustments performed according to environment includes an image-capturing unit, a scene determining unit, an image area determination unit and an image correction unit.
- the image-capturing unit captures at least an image and obtains an environmental parameter of the image.
- the scene determining unit and the image area determination unit are in signal connection with the image-capturing unit.
- the scene determining unit determines a scene mode of the image according to the environmental parameter and generates a brightness correction parameter according to the scene mode.
- the image area determination unit performs an image area determination on the image to obtain an image area and an area brightness of the image area.
- the image correction unit is in signal connection with the scene determining unit and the image area determination unit to perform brightness correction on the image according to the image area, the area brightness and the brightness correction parameter.
- the brightness correction involves performing gamma correction on background in the image.
- a captured image varies with a variable environment. Therefore, the present disclosure is advantageous in that image processing is carried out to an image according to environment to perform brightness correction on each image appropriately, so as to ensure image quality.
- FIG. 1 is a schematic view of an image processing system according to an embodiment of the present disclosure
- FIG. 2 is a schematic view of a scene mode divided into four sectors according to a gamma value according to an embodiment of the present disclosure
- FIG. 3 is a schematic view of a process flow of an image processing method according to an embodiment of the present disclosure
- FIG. 4 is a schematic view of a process flow of the image processing method according to another embodiment of the present disclosure.
- FIG. 5 is a schematic view of a process flow of the image processing method according to yet another embodiment of the present disclosure.
- FIG. 6 is a graph of gamma correction according to an embodiment of the present disclosure.
- FIG. 7 is a graph of gamma correction according to another embodiment of the present disclosure.
- FIG. 1 is a schematic view of an image processing system according to an embodiment of the present disclosure.
- the image processing system 10 which is based on adjustments performed according to environment, includes an image-capturing unit 12 , a scene determining unit 14 , an image area determination unit 16 , an image correction unit 18 and an automatic exposure unit 20 .
- the image-capturing unit 12 captures at least an image from outside and obtains an environmental parameter of the image.
- the automatic exposure unit 20 is in signal connection with the image-capturing unit 12 .
- the automatic exposure unit 20 performs automatic exposure on image-capturing environment to enable the image-capturing unit 12 to capture the image in the presence of supplemental light provided by the automatic exposure unit 20 and provide the environmental parameter to the image-capturing unit 12 .
- the image-capturing unit 12 is an image sensing component, such as a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS).
- CCD charge coupled device
- CMOS complementary metal-oxide-semiconductor
- the environmental parameter is a shutter speed and an ISO sensitivity for use in obtaining the image, that is, the actual values obtained as a result of automatic exposure performed by the automatic exposure unit 20 on the image-capturing environment at the moment when the image-capturing unit 12 obtains the image.
- the scene determining unit 14 is in signal connection with the image-capturing unit 12 to determine, according to the environmental parameter, a scene mode which the image is attributed to, and generate a brightness correction parameter according to the scene mode.
- the brightness correction parameter is a gamma correction value for restoring image brightness.
- the image area determination unit 16 is in signal connection with the image-capturing unit 12 .
- the image area determination unit 16 performs an image area determination on the captured image to obtain an image area and an area brightness of the image area.
- the image correction unit 18 is in signal connection with the scene determining unit 14 and the image area determination unit 16 such that the image correction unit 18 can perform brightness correction on the image according to the obtained image area, area brightness and brightness correction parameter.
- the brightness of the image is restored to be proportionate to that of the real scene and perceivable by the naked eye.
- the area brightness is the average brightness of the image area obtained by the image area determination unit 16
- the image area is the whole area of the image or a partial area of the image.
- the image correction unit 18 is an image signal processing chip (ISP).
- ISP image signal processing chip
- the image processing system 10 further has a light measurement unit 22 in signal connection with the image area determination unit 16 and the image correction unit 18 .
- the image area determination unit 16 provides the location and magnitude of the image area to the light measurement unit 22
- the light measurement unit 22 performs light measurement on the image area such that the image area is subjected to optimal exposure, so as to estimate brightness of the current frame according to the image area and thereby ensure optimal area brightness.
- the image correction unit 18 after being completely corrected by the image correction unit 18 , the image is compressed by an image compression unit 24 to become image data. Then, the image data is output to a storage unit or an external device for back-end storage.
- different scene modes are determined according to the environmental parameter, i.e., the shutter speed and the ISO sensitivity.
- the environmental parameter i.e., the shutter speed and the ISO sensitivity.
- both the exposure value and alpha ( ⁇ ) value are directly proportional to gamma ( ⁇ ) value or each exposure value corresponds to a gamma value, such that a look up table (LUT) is created.
- the alpha value is a conversion variable for correlating the exposure value with the gamma value, as shown in expressions below.
- the gamma value can be inferred from the shutter speed and the ISO sensitivity, using the expressions, and then a scene mode of the image is determined according to the gamma value.
- the scene mode is divided into four sectors according to the gamma value.
- the present disclosure is not restrictive of the number of the sectors. In practice, the more the sectors are, the better the efficacy is. To increase the number of the sectors, the number of the sectors can be adjusted according to a user or system.
- the dark mode occurs at night or any other circumstances where there is a lack of illumination (gamma ⁇ 0.65).
- the image correction unit 18 performs brightness correction by performing gamma correction on the background in the image rather than the image area in the image, so as to restore background brightness.
- the image area is determined to be a partial area, wherein the background in the image is outside the image area in the image, causing the image area determination unit 16 to obtain the image area and the area brightness of the image area, further causing the image correction unit 18 to perform brightness correction on the background in the image rather than the image area in the image according to the image area, the area brightness, and the brightness correction parameter, allowing the brightness surrounding the image area in the image to equal the brightness within the image area in the image. Therefore, the brightness of the whole image is restored to the brightness of the real scene to thereby eliminate any difference in brightness between the image area and the background; otherwise, the background is blurred and dim.
- the image-capturing unit 12 , the image correction unit 18 , the automatic exposure unit 20 , the light measurement unit 22 , and the image compression unit 24 are built-in components of an image-capturing device, such as a camera or a camcorder.
- the scene determining unit 14 and the image area determination unit 16 are provided in a dashcam or an engine system of a car.
- the image-capturing unit 12 , the scene determining unit 14 , the image area determination unit 16 , the image correction unit 18 , the automatic exposure unit 20 , the light measurement unit 22 and the image compression unit 24 are integrated into the same image-capturing device.
- the image processing method based on adjustments performed according to environment includes the steps of: capturing an environmental parameter of an image with an image-capturing unit 12 (step S 10 ) and performing an automatic exposure process on the image with the automatic exposure unit 20 to obtain an environmental parameter of the image, such as shutter speed and ISO sensitivity; determining a scene mode of the image with the scene determining unit 14 according to the environmental parameter (step S 12 ), wherein the scene mode is exemplified by a glaring mode, a bright mode, a dim mode, and a dark mode; estimating a brightness correction parameter of the image with the scene determining unit 14 according to the scene mode (step S 14 ) to obtain a gamma correction value of each image; performing an image area determination with the image area determination unit 16 to obtain an image area of the image and an area brightness of the image area, followed by performing brightness correction on the image with the image correction unit 18 according to the image area, the area brightness and the brightness correction parameter (step S 16 ).
- an environmental parameter of an image with an image-capturing unit 12 step
- the image correction unit 18 performs brightness correction on the image according to the brightness correction parameter (step S 15 ) such that the brightness of the image is restored to be proportionate to that of the real scene and perceivable by the naked eye.
- the step of image area determination is performed (step S 16 ). The other steps are the same as those of the method in the embodiment illustrated by FIG. 3 and thus, for the sake of brevity, are not reiterated.
- the image area is configured to be a partial area where a preceding car is present and is known as preceding car area.
- the image processing method including the steps of capturing an environmental parameter of a plurality of images (step S 20 ), capturing the images sequentially with the image-capturing unit 12 , and performing an automatic exposure process on each image with the automatic exposure unit 20 to obtain the environmental parameter of the images, such as shutter speed and ISO sensitivity.
- the scene determining unit 14 determines the scene mode of the images according to the environmental parameter (step S 21 ).
- the scene mode is a glaring mode (which occurs at noon), a bright mode (which occurs in the morning and afternoon), a dim mode (which occurs at dawn and dusk), or a dark mode (which occurs at night), but the present disclosure is not limited thereto.
- the scene determining unit 14 always estimates the brightness correction parameter of each image according to the scene mode (step S 22 ) to obtain the gamma correction value of each image.
- the image correction unit 18 performs brightness correction on the whole frame of each image according to the brightness correction parameter (step S 23 ) such that the brightness of an image is restored to be proportionate to that of the real scene and perceivable by the naked eye.
- step S 24 involves determining whether an image is attributed to the dark mode.
- a negative determination causes termination of the process flow the correction processing of the image (step S 27 )
- an affirmative determination causes the image area determination unit 16 to perform a preceding car area determination (step S 25 ) and thereby obtain a preceding car area in the image and an area brightness of the preceding car area, wherein the area brightness is the average brightness of the preceding car area and can be obtained by the light measurement unit 22 .
- the image correction unit 18 performs background brightness correction on the image according to the preceding car area, area brightness and brightness correction parameter (step S 26 ), that is, performs gamma correction on the background area such that the brightness surrounding the preceding car area in the image equals the brightness within the preceding car area in the image, allowing the brightness of the image to be restored to be proportionate to that of the real scene and thereby precluding any difference in brightness between the preceding car area and the background (the brightness difference renders the car image sharp and the background image blurred).
- the process flow of the correction processing of the image terminates (step S 27 ).
- brightness correction involves performing gamma correction on the background in the image (to correct the brightness surrounding the preceding car area in the image.)
- the dashed line denotes pre-adjustment background brightness
- the solid line denotes post-adjustment background brightness
- the preceding car area brightness L functioning as a standard
- the brightness of the input image is adjusted according to a brightness ratio, for example, increasing 25% brightness to 50% brightness, increasing 50% brightness to 90% brightness, so as to perform gamma correction according to the ratio.
- the dashed line denotes pre-adjustment background brightness
- the solid line denotes post-adjustment background brightness
- the preceding car area brightness L functioning as a standard
- the gamma value is a predetermined parameter, for example, a parameter predetermined according to measurement performed before installation.
- a captured image varies with a variable environment.
- the image processing method and system of the present disclosure are applied to a dashcam
- the environment of the captured image changes while the car is moving. Therefore, the present disclosure is advantageous in that image processing is carried out to an image according to environment to perform brightness correction on each image appropriately and thereby enhance image quality, so as to ensure image quality adaptively.
- the image processing system of the present disclosure ensures optimal efficacy. For instance, when applied to a dashcam mounted on a police car, the image processing system of the present disclosure ensures that all the captured images are sharp and the backgrounds are not blurred or dim such that the dashcam mounted on the police car can provide video evidence in the event of a road accident.
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Abstract
Description
- The present disclosure relates to image processing technology and, more particularly, to an image processing method and system based on adjustments performed according to environment.
- A dashcam of a moving car records the car's location, condition, related data and captures a video of the surroundings. Therefore, the dashcam can provide video evidence in the event of a road accident.
- The conventional dashcam has an image-capturing device. To capture an image, the image-capturing device adjusts shutter speed and ISO sensitivity (ISO value) automatically with an automatic exposure unit such that the image has invariable brightness. However, the aforesaid way of recording an image with invariable brightness has a drawback: during nighttime, the car in the image obtained looks sharp, but the background in the image obtained is blurred and dim, thereby failing to ensure overall image quality.
- In view of the aforesaid drawback of the prior art, it is an objective of the present disclosure to provide an image processing method and system based on adjustments performed according to environment, so as to ensure image quality adaptively.
- In an embodiment, an image processing method based on adjustments performed according to environment includes: capturing an environmental parameter of an image; determining a scene mode of the image according to the environmental parameter; estimating a brightness correction parameter of the image according to the scene mode; and performing an image area determination to obtain an image area and an area brightness of the image area, followed by performing brightness correction on the image according to the image area, the area brightness and the brightness correction parameter.
- In some embodiments, the brightness correction involves performing gamma correction on background in the image when the scene mode is a dark mode.
- In an embodiment, an image processing system based on adjustments performed according to environment includes an image-capturing unit, a scene determining unit, an image area determination unit and an image correction unit. The image-capturing unit captures at least an image and obtains an environmental parameter of the image. The scene determining unit and the image area determination unit are in signal connection with the image-capturing unit. The scene determining unit determines a scene mode of the image according to the environmental parameter and generates a brightness correction parameter according to the scene mode. The image area determination unit performs an image area determination on the image to obtain an image area and an area brightness of the image area. The image correction unit is in signal connection with the scene determining unit and the image area determination unit to perform brightness correction on the image according to the image area, the area brightness and the brightness correction parameter.
- In some embodiments, when the scene determining unit determines the scene mode of the image to be a dark mode, the brightness correction involves performing gamma correction on background in the image.
- In conclusion, a captured image varies with a variable environment. Therefore, the present disclosure is advantageous in that image processing is carried out to an image according to environment to perform brightness correction on each image appropriately, so as to ensure image quality.
-
FIG. 1 is a schematic view of an image processing system according to an embodiment of the present disclosure; -
FIG. 2 is a schematic view of a scene mode divided into four sectors according to a gamma value according to an embodiment of the present disclosure; -
FIG. 3 is a schematic view of a process flow of an image processing method according to an embodiment of the present disclosure; -
FIG. 4 is a schematic view of a process flow of the image processing method according to another embodiment of the present disclosure; -
FIG. 5 is a schematic view of a process flow of the image processing method according to yet another embodiment of the present disclosure; -
FIG. 6 is a graph of gamma correction according to an embodiment of the present disclosure; and -
FIG. 7 is a graph of gamma correction according to another embodiment of the present disclosure. -
FIG. 1 is a schematic view of an image processing system according to an embodiment of the present disclosure. Referring toFIG. 1 , theimage processing system 10, which is based on adjustments performed according to environment, includes an image-capturingunit 12, ascene determining unit 14, an imagearea determination unit 16, animage correction unit 18 and anautomatic exposure unit 20. - The image-capturing
unit 12 captures at least an image from outside and obtains an environmental parameter of the image. Theautomatic exposure unit 20 is in signal connection with the image-capturingunit 12. Theautomatic exposure unit 20 performs automatic exposure on image-capturing environment to enable the image-capturingunit 12 to capture the image in the presence of supplemental light provided by theautomatic exposure unit 20 and provide the environmental parameter to the image-capturingunit 12. In some embodiments, the image-capturingunit 12 is an image sensing component, such as a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). - In some embodiments, the environmental parameter is a shutter speed and an ISO sensitivity for use in obtaining the image, that is, the actual values obtained as a result of automatic exposure performed by the
automatic exposure unit 20 on the image-capturing environment at the moment when the image-capturingunit 12 obtains the image. - The
scene determining unit 14 is in signal connection with the image-capturingunit 12 to determine, according to the environmental parameter, a scene mode which the image is attributed to, and generate a brightness correction parameter according to the scene mode. In an embodiment, the brightness correction parameter is a gamma correction value for restoring image brightness. The imagearea determination unit 16 is in signal connection with the image-capturingunit 12. The imagearea determination unit 16 performs an image area determination on the captured image to obtain an image area and an area brightness of the image area. Theimage correction unit 18 is in signal connection with thescene determining unit 14 and the imagearea determination unit 16 such that theimage correction unit 18 can perform brightness correction on the image according to the obtained image area, area brightness and brightness correction parameter. Therefore, the brightness of the image is restored to be proportionate to that of the real scene and perceivable by the naked eye. In some embodiments, the area brightness is the average brightness of the image area obtained by the imagearea determination unit 16, and the image area is the whole area of the image or a partial area of the image. - In some embodiments, the
image correction unit 18 is an image signal processing chip (ISP). - The
image processing system 10 further has alight measurement unit 22 in signal connection with the imagearea determination unit 16 and theimage correction unit 18. When the imagearea determination unit 16 provides the location and magnitude of the image area to thelight measurement unit 22, thelight measurement unit 22 performs light measurement on the image area such that the image area is subjected to optimal exposure, so as to estimate brightness of the current frame according to the image area and thereby ensure optimal area brightness. - In some embodiments, after being completely corrected by the
image correction unit 18, the image is compressed by animage compression unit 24 to become image data. Then, the image data is output to a storage unit or an external device for back-end storage. - In some embodiments, different scene modes are determined according to the environmental parameter, i.e., the shutter speed and the ISO sensitivity. Referring to
FIG. 2 , since both the shutter speed and the ISO sensitivity are directly proportional to the exposure value, both the exposure value and alpha (α) value are directly proportional to gamma (γ) value or each exposure value corresponds to a gamma value, such that a look up table (LUT) is created. In the LUT, the alpha value is a conversion variable for correlating the exposure value with the gamma value, as shown in expressions below. -
shutter speed (second)×ISO sensitivity=exposure value -
exposure value×alpha value=gamma value or LUT (exposure value)=gamma value - The gamma value can be inferred from the shutter speed and the ISO sensitivity, using the expressions, and then a scene mode of the image is determined according to the gamma value. Referring to
FIG. 2 , the scene mode is divided into four sectors according to the gamma value. However, the present disclosure is not restrictive of the number of the sectors. In practice, the more the sectors are, the better the efficacy is. To increase the number of the sectors, the number of the sectors can be adjusted according to a user or system. In this embodiment, the four sectors are, from low to high gamma values, glaring mode (gamma=0.35, noon), bright mode (gamma=0.45, morning and afternoon), dim mode (gamma=0.55, dawn and dusk), and dark mode (gamma=0.65, night). The dark mode occurs at night or any other circumstances where there is a lack of illumination (gamma ≥0.65). - When the
scene determining unit 14 determines the scene mode of the image to be the dark mode, theimage correction unit 18 performs brightness correction by performing gamma correction on the background in the image rather than the image area in the image, so as to restore background brightness. In an embodiment, when the scene mode is determined to be the dark mode, the image area is determined to be a partial area, wherein the background in the image is outside the image area in the image, causing the imagearea determination unit 16 to obtain the image area and the area brightness of the image area, further causing theimage correction unit 18 to perform brightness correction on the background in the image rather than the image area in the image according to the image area, the area brightness, and the brightness correction parameter, allowing the brightness surrounding the image area in the image to equal the brightness within the image area in the image. Therefore, the brightness of the whole image is restored to the brightness of the real scene to thereby eliminate any difference in brightness between the image area and the background; otherwise, the background is blurred and dim. - In some embodiments, the image-capturing
unit 12, theimage correction unit 18, theautomatic exposure unit 20, thelight measurement unit 22, and theimage compression unit 24 are built-in components of an image-capturing device, such as a camera or a camcorder. Thescene determining unit 14 and the imagearea determination unit 16 are provided in a dashcam or an engine system of a car. In some further embodiments, the image-capturingunit 12, thescene determining unit 14, the imagearea determination unit 16, theimage correction unit 18, theautomatic exposure unit 20, thelight measurement unit 22 and theimage compression unit 24 are integrated into the same image-capturing device. - Referring to
FIG. 1 throughFIG. 3 , the image processing method based on adjustments performed according to environment includes the steps of: capturing an environmental parameter of an image with an image-capturing unit 12 (step S10) and performing an automatic exposure process on the image with theautomatic exposure unit 20 to obtain an environmental parameter of the image, such as shutter speed and ISO sensitivity; determining a scene mode of the image with thescene determining unit 14 according to the environmental parameter (step S12), wherein the scene mode is exemplified by a glaring mode, a bright mode, a dim mode, and a dark mode; estimating a brightness correction parameter of the image with thescene determining unit 14 according to the scene mode (step S14) to obtain a gamma correction value of each image; performing an image area determination with the imagearea determination unit 16 to obtain an image area of the image and an area brightness of the image area, followed by performing brightness correction on the image with theimage correction unit 18 according to the image area, the area brightness and the brightness correction parameter (step S16). In an embodiment, in the step of obtaining the area brightness, the imagearea determination unit 16 operates in conjunction with thelight measurement unit 22 to estimate the average brightness of the image area such that the estimated average brightness of the image area is regarded as the area brightness. - In some embodiments, as shown in
FIG. 4 , after the step of obtaining the brightness correction parameter (gamma correction value) of the image (step S14), theimage correction unit 18 performs brightness correction on the image according to the brightness correction parameter (step S15) such that the brightness of the image is restored to be proportionate to that of the real scene and perceivable by the naked eye. Afterward, the step of image area determination is performed (step S16). The other steps are the same as those of the method in the embodiment illustrated byFIG. 3 and thus, for the sake of brevity, are not reiterated. - In some embodiments, to clarify the complete process flow of the image processing method, the image area is configured to be a partial area where a preceding car is present and is known as preceding car area. The following embodiment is exemplified by the preceding car area and described in detail. Referring to
FIG. 1 ,FIG. 2 andFIG. 5 , the image processing method including the steps of capturing an environmental parameter of a plurality of images (step S20), capturing the images sequentially with the image-capturingunit 12, and performing an automatic exposure process on each image with theautomatic exposure unit 20 to obtain the environmental parameter of the images, such as shutter speed and ISO sensitivity. Thescene determining unit 14 determines the scene mode of the images according to the environmental parameter (step S21). For instance, the scene mode is a glaring mode (which occurs at noon), a bright mode (which occurs in the morning and afternoon), a dim mode (which occurs at dawn and dusk), or a dark mode (which occurs at night), but the present disclosure is not limited thereto. Whatever the scene mode, thescene determining unit 14 always estimates the brightness correction parameter of each image according to the scene mode (step S22) to obtain the gamma correction value of each image. After the brightness correction parameter of each image has been obtained, theimage correction unit 18 performs brightness correction on the whole frame of each image according to the brightness correction parameter (step S23) such that the brightness of an image is restored to be proportionate to that of the real scene and perceivable by the naked eye. Since the scene mode of each image is determined in step S21, step S24 involves determining whether an image is attributed to the dark mode. In step S24, a negative determination causes termination of the process flow the correction processing of the image (step S27), whereas an affirmative determination causes the imagearea determination unit 16 to perform a preceding car area determination (step S25) and thereby obtain a preceding car area in the image and an area brightness of the preceding car area, wherein the area brightness is the average brightness of the preceding car area and can be obtained by thelight measurement unit 22. Afterward, theimage correction unit 18 performs background brightness correction on the image according to the preceding car area, area brightness and brightness correction parameter (step S26), that is, performs gamma correction on the background area such that the brightness surrounding the preceding car area in the image equals the brightness within the preceding car area in the image, allowing the brightness of the image to be restored to be proportionate to that of the real scene and thereby precluding any difference in brightness between the preceding car area and the background (the brightness difference renders the car image sharp and the background image blurred). Upon completion of the step of background brightness correction performed on each image in the dark mode, the process flow of the correction processing of the image terminates (step S27). - In some embodiments, when the image is determined to be attributed to the dark mode, brightness correction involves performing gamma correction on the background in the image (to correct the brightness surrounding the preceding car area in the image.) Referring to
FIG. 6 , the dashed line denotes pre-adjustment background brightness, whereas the solid line denotes post-adjustment background brightness, with the preceding car area brightness L functioning as a standard, the brightness of the input image is adjusted according to a brightness ratio, for example, increasing 25% brightness to 50% brightness, increasing 50% brightness to 90% brightness, so as to perform gamma correction according to the ratio. Referring toFIG. 7 , the dashed line denotes pre-adjustment background brightness, whereas the solid line denotes post-adjustment background brightness, with the preceding car area brightness L functioning as a standard, the brightness of the input image is increased according to the gamma curve (gamma value γ=0.3), so as to perform gamma correction according to the gamma value, thereby adjusting the background brightness. In an embodiment, the gamma value is a predetermined parameter, for example, a parameter predetermined according to measurement performed before installation. - Therefore, a captured image varies with a variable environment. For instance, when the image processing method and system of the present disclosure are applied to a dashcam, the environment of the captured image changes while the car is moving. Therefore, the present disclosure is advantageous in that image processing is carried out to an image according to environment to perform brightness correction on each image appropriately and thereby enhance image quality, so as to ensure image quality adaptively. Furthermore, when applied to special use, the image processing system of the present disclosure ensures optimal efficacy. For instance, when applied to a dashcam mounted on a police car, the image processing system of the present disclosure ensures that all the captured images are sharp and the backgrounds are not blurred or dim such that the dashcam mounted on the police car can provide video evidence in the event of a road accident.
- The features and advantages of the present disclosure are illustrated by the embodiments of the present disclosure to enable persons skilled in the art to gain insight into the technical disclosure in the present disclosure and implement the present disclosure accordingly. The embodiments of the present disclosure are not restrictive of the claims of the present disclosure. Equivalent changes or modifications made to the embodiments of the present disclosure in accordance with the spirit embodied in the present disclosure must be deemed falling within the scope of the present disclosure.
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