KR-20260064403-A - ELECTRONIC DEVICE, METHOD AND NON-TRANSITORY COMPUTER READABLE MEDIUM TO CORRECT FOR CONTRAST RATIO OF AN IMAGE

KR20260064403AKR 20260064403 AKR20260064403 AKR 20260064403AKR-20260064403-A

Abstract

An electronic device, a method, and a storage medium for correcting the contrast ratio of an image are provided. The electronic device includes at least one processor comprising a processing circuit and a memory storing instructions that are executed individually or collectively by at least one processor. The instructions stored in the memory are configured to cause the electronic device to obtain a first probability distribution function of luminance including a first plurality of Gaussian functions from a luminance histogram of an image. The instructions are configured to cause the electronic device to determine a threshold value from the first probability distribution function of luminance. The instructions are configured to cause the electronic device to determine a scale factor of luminance when the threshold value is less than or equal to a preset first value. The instructions are configured to cause the electronic device to perform a first luminance correction operation to correct luminance based on the scale factor. The instructions are configured to cause the electronic device to correct the luminance of each of a plurality of blocks into which the image is divided by a preset size. The instructions are configured to cause the electronic device to correct the luminance of the entire area of the image. The instructions are configured to cause the electronic device to determine a gamma parameter with a threshold applied based on the average luminance of the image. The command is configured to cause the electronic device to generate a corrected image by correcting the luminance based on the gamma parameter.

Inventors

김종철
신영준
김지원
황수현
고근수
고진원
김창수

Assignees

삼성전자주식회사
고려대학교 산학협력단

Dates

Publication Date: 20260507
Application Date: 20241118
Priority Date: 20241030

Claims (20)

In electronic devices, At least one processor including a processing circuit; and The above-mentioned memory for storing instructions executed individually or collectively by at least one processor; The instruction stored in the above memory causes the electronic device: A first probability distribution function of luminance including a first plurality of Gaussian functions is obtained from the luminance histogram of an image, and A threshold value is determined from the first probability distribution function of the above luminance, and If the above threshold value is less than or equal to a preset first value, the scale factor of the above luminance is determined, and A first brightness correction operation is performed to correct the brightness based on the above scale factor, and Correcting the brightness of each of the multiple blocks into which the above image is divided into preset sizes, and Corrects the brightness of the entire area of the above image, and Based on the average luminance of the above image, the gamma parameter to which the above threshold value is applied is determined, and An electronic device configured to generate a corrected image by correcting the brightness based on the above gamma parameters.
In paragraph 1, The above command causes the electronic device to: An electronic device configured to determine the lowest average among the averages of the first plurality of Gaussian functions as the threshold value.
In paragraph 1, The above command causes the electronic device to: An electronic device configured to skip the first brightness correction operation when the above threshold value exceeds a preset first value, wherein the preset first value includes 0.0649.
In paragraph 1, The above command causes the electronic device to: An electronic device configured to determine the scale factor to a preset second value when the ratio of the maximum luminance of the pixels of the above image is less than the above threshold value, and to determine the scale factor based on the ratio of the maximum luminance when the ratio of the maximum luminance is greater than or equal to the above threshold value and less than or equal to the above preset first value.
In paragraph 4, The above command causes the electronic device to: An electronic device configured to set the average of the ratios of the maximum luminances of a plurality of pixels of the above image as a weight, and to perform the first luminance correction operation based on the weight.
In paragraph 1, The above command causes the electronic device to: An electronic device configured to obtain the average and standard deviation of the luminance of each of the plurality of blocks, obtain a weight of the luminance of each of the plurality of blocks based on a function of the average of the luminance and a function of the standard deviation of the luminance, and correct the luminance of each of the plurality of blocks based on the weight.
In paragraph 6, The above command causes the electronic device to: An electronic device configured to set the minimum value of the standard deviation based on the entropy of the above image.
In paragraph 6, The above command causes the electronic device to: An electronic device configured to obtain a penalty for the luminance of each of the plurality of blocks based on the above average, and to correct the luminance of each of the plurality of blocks based on the above weight and the above penalty.
In paragraph 1, The above command causes the electronic device to: An electronic device configured to obtain a second probability distribution function of luminance including a second plurality of Gaussian functions from the luminance histogram, obtain a cumulative distribution function based on the second probability distribution function, obtain a global change curve based on the cumulative distribution function, and correct the luminance of the entire area based on the global change curve.
In paragraph 1, The above command causes the electronic device to: An electronic device configured to reduce the threshold value applied to the gamma parameter when the average brightness of the above image is less than a preset third value.
In a method for correcting the contrast ratio of an image, The operation of obtaining a first probability distribution function of luminance including a plurality of Gaussian functions from the luminance histogram of the above image; An operation to determine a threshold value from the first probability distribution function of the above luminance; An operation to determine the scale factor of the luminance when the above threshold value is less than or equal to a preset first value; An operation to perform a first brightness correction operation that corrects the brightness based on the above scale factor; An operation to correct the brightness of each of the plurality of blocks into which the above image is divided into preset sizes; An operation to correct the brightness of the entire area of the above image; An operation to determine a gamma parameter to which the threshold value is applied based on the average luminance of the above image; and A method comprising the operation of generating a corrected image by correcting the luminance based on the above gamma parameter.
In Paragraph 11, The operation of determining the above threshold value is, A method for determining the lowest average among the averages of the plurality of Gaussian functions as the threshold value.
In Paragraph 11, The operation of skipping the first brightness correction operation when the above threshold value exceeds a preset first value is further included. A method in which the first value previously set above includes 0.0649.
In Paragraph 11, The operation of determining the scale factor of the above luminance is, A method for determining the scale factor to a preset second value when the ratio of the maximum luminance of the pixels of the above image is less than the above threshold value, and determining the scale factor based on the ratio of the maximum luminance when the ratio of the maximum luminance is greater than or equal to the above threshold value and less than or equal to the above preset first value.
In Paragraph 14, The operation of performing the above-mentioned first brightness correction operation is, A method for setting the average of the ratios of the maximum luminances of a plurality of pixels of the above image as a weight, and performing the first luminance correction operation based on the weight.
In Paragraph 11, The operation of correcting the brightness of each of the above plurality of blocks is, A method for obtaining the average and standard deviation of the luminance of each of the plurality of blocks, obtaining a weight of the luminance of each of the plurality of blocks based on a function of the average of the luminance and a function of the standard deviation of the luminance, and correcting the luminance of each of the plurality of blocks based on the weight.
In Paragraph 16, The operation of correcting the brightness of each of the above plurality of blocks is, A method for setting the minimum value of the standard deviation based on the entropy of the above image.
In Paragraph 16, The operation of correcting the brightness of each of the above plurality of blocks is, A method for obtaining a penalty for the luminance of each of the plurality of blocks based on the above average, and correcting the luminance of each of the plurality of blocks based on the above weight and the above penalty.
In Paragraph 11, The operation of correcting the brightness of the entire area above is, A method for obtaining a second probability distribution function of luminance including a second plurality of Gaussian functions from the luminance histogram, obtaining a cumulative distribution function based on the second probability distribution function, obtaining a global change curve based on the cumulative distribution function, and correcting the luminance of the entire area based on the global change curve.
In a non-transient computer-readable storage medium on which a program for performing a method of correcting the contrast ratio of an image is recorded, The operation of obtaining a first probability distribution function of luminance including a plurality of Gaussian functions from the luminance histogram of the above image; An operation to determine a threshold value from the first probability distribution function of the above luminance; An operation to determine the scale factor of the luminance when the above threshold value is less than or equal to a preset first value; An operation to perform a first brightness correction operation that corrects the brightness based on the above scale factor; An operation to correct the brightness of each of the plurality of blocks into which the above image is divided into preset sizes; An operation to correct the brightness of the entire area of the above image; An operation to determine a gamma parameter to which the threshold value is applied based on the average luminance of the above image; and A non-transient computer-readable storage medium having a program recorded thereon that performs a method including the operation of generating a corrected image by correcting the brightness based on the above gamma parameters.

Description

Electronic device, method and non-transit computer readable medium to correct contrast ratio of an image The embodiments of this document relate to electronic devices, methods, and storage media, and, for example, to electronic devices, methods, and storage media for correcting the contrast ratio of an image. The dynamic range that humans can perceive with their eyes can be much larger than the dynamic range that can be represented by a typical display. To display images similar to real scenes, tone mapping technology is being proposed to convert images with a wide dynamic range into images with a limited dynamic range. For example, tone mapping technology can be a technique that maps a high dynamic range (HDR) image with a wide 16-bit dynamic range into a low dynamic range (LDR) image with an 8-bit range that can be represented by a display. Tone mapping technology can minimize information loss that occurs during the mapping process to a smaller range and provide users with images that closely approximate the human visual experience. The information described above may be provided merely as related art to aid in understanding the present disclosure. None of the foregoing is to be claimed as prior art related to the present disclosure or to be used in determining prior art. An electronic device according to various embodiments of this document may include at least one processor comprising a processing circuit and a memory that stores instructions executed individually or collectively by said at least one processor. Instructions stored in said memory may be configured to cause the electronic device to obtain a first probability distribution function of luminance including a first plurality of Gaussian functions from a luminance histogram of an image. The instructions may be configured to cause the electronic device to determine a threshold value from said first probability distribution function of luminance. The instructions may be configured to cause the electronic device to determine a scale factor of the luminance when the threshold value is less than or equal to a preset first value. The instructions may be configured to cause the electronic device to perform a first luminance correction operation that corrects the luminance based on said scale factor. The instructions may be configured to cause the electronic device to correct the luminance of each of a plurality of blocks into which the image is divided by a preset size. The instructions may be configured to cause the electronic device to correct the luminance of the entire area of the image. The above command may be configured to cause the electronic device to determine the gamma parameter to which the threshold value is applied based on the average luminance of the image. The above command may be configured to cause the electronic device to correct the luminance based on the gamma parameter to generate a corrected image. A method for correcting the contrast ratio of an image according to various embodiments of the present document may include an operation of obtaining a first probability distribution function of luminance including a plurality of Gaussian functions from a luminance histogram of the image. The method may include an operation of determining a threshold value from the first probability distribution function of luminance. If the threshold value is less than or equal to a preset first value, the method may include an operation of determining a scale factor of the luminance. The method may include an operation of performing a first luminance correction operation to correct the luminance based on the scale factor. The method may include an operation of correcting the luminance of each of a plurality of blocks into which the image is divided by a preset size. The method may include an operation of correcting the luminance of the entire area of the image. The method may include an operation of determining a gamma parameter to which the threshold value is applied based on the average luminance of the image. The method may include an operation of generating a corrected image by correcting the luminance based on the gamma parameter. A non-transient computer-readable storage medium having a program recorded thereon for performing a method of correcting the contrast ratio of an image according to various embodiments of this document may perform an operation of obtaining a first probability distribution function of luminance including a plurality of Gaussian functions from a luminance histogram of the image. The storage medium may perform an operation of determining a threshold value from the first probability distribution function of luminance. If the threshold value is less than or equal to a preset first value, the storage medium may perform an operation of determining a scale factor of the luminance. The storage medium may perform an operation of performing a first luminance correction operation to correct the luminance based on the scale facto