Methods and imaging devices for acquiring digital images under low-light conditions

Abstract

The imaging device may include an optical lens; a sensor configured to convert light into one or more digital signals; a processor; and a non-transitory processor-readable storage medium including one or more programming instructions that, when executed, cause the processor to: determine an illuminance hue distribution and an average illuminance of the one or more digital signals; assign one or more RGB values ​​to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux; assign one or more saturation values ​​to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux; transform the hue distribution using a first gain control defined by a first lux gain ratio; and convert the transformed hue distribution into a digital image.

Description

Cross-references to related applications

[0001] This application claims the benefit of international application PCT / CN2024 / 132432 (GP202400747P) entitled “Method for acquiring digital images under low light conditions and imaging apparatus thereof”, filed on November 15, 2024. Technical Field

[0002] This specification generally relates to methods and imaging apparatus for acquiring digital images, and more specifically to methods and imaging apparatus for acquiring digital images under low light conditions. Background Technology

[0003] In complete darkness (0 lux to less than 0.001 lux) and low light conditions (from 0.001 lux to 100 lux), the use of conventional imaging equipment and digital imaging often suffers, where photographs or images are typically not bright enough to discern sufficient detail. Furthermore, introducing external light sources to increase brightness may not be a preferred solution, as external light sources can alert the observed subject, as is the case with observation instruments, binoculars, and security and wildlife cameras. Therefore, night vision optics is a significant area of ​​research aimed at improving photographs / videos or images taken or observed under these conditions without alerting the observed subject. Summary of the Invention

[0004] Traditional night vision devices utilize photoelectric image enhancement, where infrared light reflected from the observed object is amplified to generate an image, producing a typical green or red-toned image. However, what is generally desired is a method that produces sufficiently bright and full-color images of low-light objects or scenes, rather than the green or red-toned images of infrared imaging devices. Furthermore, a method that can generate images without an external light source, regardless of whether the light source is in the visible or infrared spectrum, is desired.

[0005] Gain is a method used to digitally enhance images in low-light conditions, making them bright enough for interpretation. Gain control can amplify the average brightness of objects and / or scenes, increasing the overall brightness of the tonal distribution and thus the overall brightness of the final digital image. However, uncontrolled gain can also lead to increased "grain" in the photograph, reducing the sharpness of the resulting digital image. Furthermore, too little gain can cause the image to become too dark, making it difficult to interpret. This becomes particularly problematic in low-light conditions where the initial brightness is already low. Therefore, it may be necessary to find a balance between the initial brightness of the image and the magnitude of the gain used to achieve an "optimal match" between the sharpness of the resulting image and the given initial brightness.

[0006] The embodiments described herein achieve the above objectives by utilizing an imaging device having at least an optical lens, a sensor, a processor, and a non-transitory processor-readable storage medium comprising one or more programming instructions that, when executed, cause the processor to perform a process. This process can transform a digital image using gain control with a defined lux gain ratio, thereby producing a digital image with improved sharpness compared to comparable imaging devices and algorithms. During the generation of the digital image, the gain control can be further adjusted to produce an adjusted digital image with further improved sharpness.

[0007] According to one embodiment of this disclosure, an imaging device may include: an optical lens configured to receive light from an object located downstream of the optical lens in an optical path; a sensor configured to convert light into one or more digital signals; a processor; and a non-transitory processor-readable storage medium communicating with the processor, including one or more programming instructions that, when executed, cause the processor to: determine an illuminance hue distribution and an average illuminance of the one or more digital signals; assign one or more RGB values ​​to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux; assign one or more saturation values ​​to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux; transform the hue distribution using a first gain control defined by a first lux gain ratio; and convert the transformed hue distribution into a digital image.

[0008] According to another embodiment of this disclosure, a method for acquiring a digital image under low-light conditions may include: providing an imaging device including an optical lens configured to receive light; a sensor configured to convert light into one or more digital signals; a processor; and a non-transitory processor-readable storage medium in communication with the processor; receiving light from an object located downstream of the optical path of the optical lens; converting the light into one or more digital signals; determining an illuminance hue distribution and an average illuminance of the one or more digital signals; assigning one or more RGB values ​​(HUES) to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux; assigning one or more saturation values ​​to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux; transforming the hue distribution using a first gain control defined by a first lux gain ratio; and converting the transformed hue distribution into a digital image. Attached Figure Description

[0009] The following detailed description of specific embodiments of this disclosure can be best understood when read in conjunction with the accompanying drawings, in which: Figure 1 An imaging apparatus according to one or more embodiments described herein is depicted; Figure 2 This depicts another perspective based on one or more embodiments described herein. Figure 1 Imaging equipment; Figure 3 This depicts yet another perspective based on one or more embodiments described herein. Figure 1 and Figure 2 Imaging equipment; Figure 4 One or more embodiments according to the description herein are depicted. Figures 1 to 3 One or more internal components of an imaging device; and Figure 5 A method for obtaining digital images under low-light conditions is illustrated according to one or more embodiments described herein. Detailed Implementation

[0010] Embodiments of this disclosure relate to methods and imaging apparatus for acquiring digital images, and more particularly to methods and imaging apparatus for acquiring digital images under low light conditions.

[0011] As previously stated, the embodiments herein relate to imaging devices for acquiring digital images. As used herein, "imaging device" can refer to various devices, including but not limited to binoculars, cameras, observation instruments, etc. For example, such as... Figures 1 to 3 As shown, the imaging device 100 may include a housing 102 having a light receiver 104 and a display 106, wherein the light receiver 104 may also be regarded as the "first end" and the display 106 may also be regarded as the "second end".

[0012] Now for reference Figure 4 , showed Figures 1 to 3 A depiction of one or more internal components of the imaging device 100. (e.g.) Figure 3 and Figure 4As shown, the imaging device 100 may further include an optical lens 108 positioned near the light receiver 104. The optical lens 108 may be configured to receive light from an object located downstream of the optical path between the optical lens 108 and the light receiver 104. As used herein, "upstream of the optical path" and "downstream of the optical path" refer to the relative positions of two locations or components along the optical path relative to the light source. For example, if a first component is closer to the light source along the path through which the light beam passes than a second component, then the first component is upstream of the optical path of the second component. The optical lens 108 may also be further configured to manipulate light to magnify the size of an object located downstream of the optical path of the optical lens 108. In other words, the optical lens 108 may be a magnifying lens.

[0013] For example Figure 4 As depicted, the imaging device 100 may also include a sensor 110 positioned downstream of the optical path of the optical lens 108 (i.e., between the optical lens 108 and the display end 106). The sensor 110 may be optically coupled to the optical lens 108. The sensor 110 may also be configured to convert light received by the optical lens 108 into one or more electrical signals; that is, the sensor 110 may also be considered an "image sensor." For example, in one embodiment, the sensor 110 may include a complementary metal-oxide-semiconductor (CMOS) sensor, but other possible sensors are also contemplated. A CMOS sensor may include a plurality of photodiodes (photodiodes) arranged in an array. Without being theoretically limited, when visible photons contact a pixel, they are converted into electrical charges, which are interpreted as electrical signals by the CMOS sensor.

[0014] The electrical signal can then be converted into a digital signal, where hue values ​​(illuminance in lux) are assigned to each pixel. These hue values ​​can then be arranged into an image histogram, commonly called a hue distribution. In the hue distribution, the range of hue values ​​is mapped onto one axis, while the frequency of hue values ​​between pixels is arranged onto another axis. In doing so, a relative measure of the illuminance (hue values) of the scene (and the resulting image) can be determined, where the density of illuminance values ​​at the far end of the hue values ​​indicates a bright scene, and the density of illuminance values ​​at the near end of the hue values ​​represents a dark image relative to the chosen scale.

[0015] As used herein, illuminance values ​​in the range of 0.001 lux to 100 lux represent low lighting conditions for image processing. Illuminance values ​​below 0.001 lux to 0 lux represent pitch-black conditions for image processing. Illuminance values ​​above 100 lux generally represent moderate to good lighting conditions for image processing. In embodiments, sensor 110 may have a pixel count of at least 200 megapixels, for example, 200 to 400 megapixels.

[0016] In one embodiment, the imaging device 100 may further include a shutter 111 positioned between the optical lens 108 and the sensor 110. The shutter 111 may be configured to be adjustable, allowing the sensor 110 to change its exposure time to light.

[0017] Still referencing Figure 4 The imaging device 100 may further include a processor 112 and a non-transitory processor-readable storage medium 113 positioned between a light receiver 104 and a display 106. The processor 112 may communicate with the sensor 110 and the non-transitory processor-readable storage medium 113. The processor 112 may also communicate with a shutter 111 and may be used to variably adjust the shutter 111, such that the exposure time of the sensor 110 to light may be variable, as explained in further detail herein.

[0018] The non-transitory processor-readable storage medium 113 may include one or more programming instructions that, when executed, cause a processor to perform a process of converting one or more digital signals into a digital image. The non-transitory processor-readable storage medium 113 may be configured to store one or more electrical signals, one or more digital signals, digital images, or combinations thereof. Without being theoretically limited, the processor 112 may be configured via machine-readable instructions to convert one or more digital signals into a single digital image, i.e., a snapshot, or a continuous sequence of digital images, i.e., video.

[0019] Now for reference Figure 2 and Figure 4 The imaging device 100 may also include a display 114. The display 114 may communicate with the processor 112 and may be configured to display digital images generated by the processor 112. The display 114 may be an LED (light-emitting diode) screen, but other possible displays are also possible.

[0020] Although not shown, imaging device 100 may also include one or more additional components. For example, in one embodiment, imaging device 100 may also include a transceiver. The transceiver may communicate with processor 112 or non-transitory processor-readable storage medium 113 or both, and may be configured to transmit signals including digital images via wired or wireless means. This signal may then be received by a second transceiver of a separate device, which may also include a second non-transitory processor-readable storage medium or a second display or both. This separate device may then store the digital image in the second non-transitory processor-readable storage medium and / or display the digital image on the second display in a manner similar to that of imaging device 100, non-transitory processor-readable storage medium 113, and display 114. In this configuration, imaging device 100 and the separate device may constitute a system for acquiring digital images under low-light conditions. Without being theoretically limited, the separate device may include any of a plurality of electronic devices capable of displaying images, including but not limited to printers, computers, smartphones, tablets, etc.

[0021] As previously described, the imaging device 100 may include one or more additional components. For example, such as Figure 1 As shown, the imaging device 100 may include a track 116 for mounting additional components, such as, but not limited to, a battery pack, an infrared torch, a laser sight, etc.

[0022] In embodiments, imaging device 100 may not include certain components that may be included in a comparative imaging device. For example, in embodiments, imaging device 100 may not include (i.e., may not utilize) external light sources or components for thermal imaging, such as external light sources or components for emitting visible light or infrared spectra. Similarly, the methods described herein may generate digital images without utilizing external light sources or thermal images.

[0023] As previously described, the non-transitory processor-readable storage medium 113 may include one or more programming instructions that, when executed, cause the processor 112 to perform a process in which the initial step may be determining the illuminance hue distribution of one or more digital signals. As previously described, the sensor 110 may convert light received by the optical lens 108 into one or more electrical signals, which may then be converted into one or more digital signals. The digital signals may have associated hue values ​​that can be mapped to a graph of the illuminance hue distribution in the one or more digital signals as a function of frequency.

[0024] Processor 112 may be further configured to assign one or more RGB values ​​(HUES) to the hue distribution, such as the individual digital signals of the hue distribution, when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux (i.e., the average illuminance of the object is under low illumination conditions). Similarly, processor 112 may be further configured to assign one or more saturation values ​​to the hue distribution, such as the individual digital signals of the hue distribution, when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux (i.e., the average illuminance of the object is under low illumination conditions). The assignment of one or more RGB values ​​and one or more saturation values ​​to the hue distribution is based on its correlation with a color and saturation chart adjusted for illuminance. However, if the average luminance of the hue distribution is less than 0.001 lux, processor 112 may be additionally or alternatively configured to generate a black and white image.

[0025] In an embodiment, processor 112 may be further configured to transform the tone distribution using a first gain control defined by a lux gain ratio. As previously stated, and without being theoretically limited, gain control can amplify the brightness (i.e., illuminance) of each of one or more data signals, thereby increasing the overall brightness of the tone distribution and thus the overall brightness of the final digital image. However, uncontrolled gain can also lead to increased graininess in the photograph, thereby reducing the sharpness of the resulting digital image. Furthermore, too small a gain can cause the image to become dark, making it difficult to interpret. The latter becomes particularly problematic when the original brightness is already low, i.e., under low-light conditions. Therefore, it may be necessary to seek a balance between the initial brightness of the image and the magnitude of the gain used to achieve an "optimal match" between the sharpness of the resulting image and the given initial brightness. Therefore, and without being theoretically limited, the first gain control defined by the lux gain ratio (in particular, the lux gain ratio equation explained further below) can provide the desired balance.

[0026] In embodiments, the lux gain ratio, and thus the gain applied to the hue distribution, can vary with average illuminance; that is, the lux gain ratio can be controlled by a lux gain ratio equation that takes illuminance as an input variable (x) and the required gain as an output variable (y). In other words, the gain and lux gain ratio associated with the first gain control can be inversely proportional to the average illuminance, as shown in Table 1 below, and may resemble a power-law or logarithmic equation. For example, in at least one embodiment and based on the data in Table 1, a lux-gain equation resembling a power-law equation could be... (for a given a Add or subtract 0.5 to the component, and for a given kThe component is added to or subtracted by 0.04), where the gain can be subsequently adjusted starting from the initial gain, as explained in further detail herein. In at least one other embodiment and according to the data in Table 1, a Lux-gain equation similar to a logarithmic equation can be... (for a given a The gain can be adjusted by adding or subtracting 1 for the b component (and by adding or subtracting 1 for the b component), where the gain can be subsequently adjusted starting from the initial gain, as explained in further detail herein. The Lux gain ratio equation can also be controlled by various factors, including but not limited to the lens exposure time.

[0027] Table 1: Lux Gain Ratio

[0028] In an embodiment, the processor 112 may be further configured to synchronize the exposure time of the light pair sensor 110 with the adjustment of the hue distribution using a first gain control. In particular, as the exposure time increases, a smaller gain may be required for a given exposure.

[0029] In some embodiments, processor 112 may further be configured to convert the transformed tonal distribution into a digital image. However, in some embodiments, processor 112 may further be configured to apply a median filter to the transformed tonal distribution before converting it into a digital image. Without being theoretically limited, applying a median filter to the transformed tonal distribution can remove outlier tonal values ​​by having the median of the tonal values ​​surround them, thereby removing noise from the digital image. This type of noise is often referred to as "salt and pepper noise."

[0030] In an embodiment of the imaging device 100 including a display 114, the processor 112 may further be configured to display digital images on the display 114. In an embodiment of the imaging device 100 including a transceiver, the processor 112 may further be configured to transmit digital images to a separate device using the transceiver.

[0031] In embodiments, processor 112 may further be configured to utilize a second gain control to transform the tonal distribution, for example, when it is determined that the digital image does not have the desired sharpness or brightness, or both. The second gain control may be defined by a second lux gain ratio and / or a second gain, which is within 10%, 5%, or 1% of the first lux gain ratio and / or the first gain. Therefore, without being theoretically limited, the tonal distribution and the resulting digital image can be “fine-tuned” to obtain additional sharpness beyond the initial gain control. Following the second gain control, processor 112 may further be configured to convert the tonal distribution transformed based on the second gain control into an adjusted digital image. In embodiments, processor 112 may be configured to repeat the above steps multiple times as needed, for example, iteratively, to generate a digital image with the desired sharpness. Processor 112 may also be configured to incrementally iteratively execute the repeated steps to reduce the variance of subsequent gain controls (e.g., third, fourth, fifth gain controls, etc.) to “fine-tune” the final sharpness. In at least some embodiments, the iterative approach and / or fine-tuning of steps beyond the initial gain control may involve machine learning aspects.

[0032] Now for reference Figure 5 As previously described, embodiments herein may also include a method 200 for acquiring a digital image under low-light conditions. This method may include any steps that the processor 112 is configured to execute. Method 200 may include an initial step of providing an imaging device 100, which may be any imaging device 100 described above. Method 200 may then include converting light receivable from an optical lens 108 into one or more digital signals.

[0033] Then, method 200 may include determining an illuminance hue distribution of one or more digital signals. Method 200 may further include assigning one or more RGB values ​​(HUES) to the hue distribution and / or assigning one or more saturation values ​​to the hue distribution when the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux. However, if the average illuminance is determined to be less than 0.001 lux, method 200 may further include generating a black and white image.

[0034] Method 200 may then include transforming the tone distribution using a first gain control defined by a first lux gain ratio, and / or adjusting the exposure time of light to sensor 110 before, simultaneously with, or after adjusting the tone distribution using the first gain control. When it is determined that the digital image does not have the desired sharpness, method 200 may further include transforming the tone distribution using a second gain control defined by a second lux gain ratio within 10%, 5%, or 1% of the first lux gain ratio. Method 200 may also optionally include denoising the transformed tone distribution, for example by applying a median filter to the transformed tone distribution before converting it to a digital image, which may be performed iteratively multiple times until the desired sharpness is achieved. Method 200 may then include converting the transformed tone distribution to a digital image.

[0035] In method 200, which includes imaging apparatus 100 having a display 114, method 200 may further include displaying a digital image on the display 114. In method 200, which includes imaging apparatus 100 having a transceiver, method 200 may further include transmitting the digital image to a separate device using the transceiver, wherein the digital image may be displayed on a second display of the separate device, or the digital image may be stored in a second non-transitory processor-readable storage medium of the separate device, or both.

[0036] For the purposes of describing and defining embodiments, it should be noted that the variables mentioned herein as "functions" of parameters or other variables do not imply that the variable is the only function of the listed parameters or variables. Rather, the references herein to variables as "functions" of listed parameters are intended to be open-ended, allowing the variable to be a function of a single parameter or multiple parameters.

[0037] Unless otherwise expressly stated, it is never intended to interpret any method described herein as requiring its steps to be performed in a particular order, nor any particular orientation of any apparatus. Therefore, it is never intended to infer any order or orientation in any respect where a method claim does not actually describe the order in which its steps are followed, or where any apparatus claim does not actually describe the order or orientation of the various components, or where the claims or description do not otherwise specifically state that the steps will be limited to a particular order, or where a particular order or orientation of the components of the apparatus is not described. This applies to any possible non-explicit basis of interpretation, including: logical questions concerning the arrangement of steps, the flow of operations, the order of components, or the orientation of components; the general meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0038] As used herein, the singular forms “a,” “an,” and “the” include plural references unless the context clearly indicates otherwise. Thus, for example, a reference to a component “a” includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0039] As used herein, unless otherwise explicitly stated, numerical ranges include the endpoints. Thus, for example, the statement "the pixel count can be in the range of 200 megapixels to 400 megapixels" means that the wavelength can be 200 megapixels, can be 4 megapixels, or can be any integer between 200 and 400 megapixels.

[0040] It will be apparent to those skilled in the art that various modifications and alterations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, this specification is intended to cover modifications and alterations to the various embodiments described herein, provided that such modifications and alterations are within the scope of the appended claims and their equivalents.

Claims

1. An imaging device, comprising: An optical lens configured to receive light from an object located downstream of the optical path of the optical lens; A sensor configured to convert the received light into one or more digital signals; processor; and A non-transitory processor-readable storage medium, which communicates with the processor, includes one or more programming instructions that, when executed, cause the processor to: Determine the illuminance hue distribution and average illuminance of the one or more digital signals. When the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux, one or more RGB values ​​are assigned to the hue distribution. When the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux, one or more saturation values ​​are assigned to the hue distribution. The hue distribution is transformed using a first gain control, defined by a first lux gain ratio, and... The tonal distribution of the transformation is converted into a digital image.

2. The imaging device of claim 1, wherein, The processor is also configured to synchronize the exposure time of the light to the sensor with the adjustment of the hue distribution using the first gain control.

3. The imaging device of claim 1, wherein, The processor is also configured to: When it is determined that the digital image does not have the desired sharpness, a second gain control is used to transform the tone distribution, the second gain control being defined by a second lux gain ratio, which is within 10% of the first lux gain ratio; as well as The tonal distribution of the transformation based on the second gain control is converted into an adjusted digital image.

4. The imaging device of claim 1, wherein, The processor is also configured to generate a black and white image when the average illuminance of the determined tone distribution is less than 0.001 lux.

5. The imaging device of claim 1, wherein, The processor is also configured to apply a median filter to the tonal distribution of the transformation.

6. The imaging device according to claim 1, wherein, The assignment of the one or more RGB values ​​and the one or more saturation values ​​to the hue distribution is based on the correlation with the color and saturation chart adjusted for illumination.

7. The imaging device of claim 1, wherein, The sensor is a complementary metal-oxide-semiconductor (CMOS) sensor.

8. The imaging device of claim 1, further comprising a display configured to display the digital image, and wherein, The processor is also configured to display the digital image on the display.

9. The imaging device according to claim 8, wherein: The imaging device also includes a housing with a light receiving end and a display end; The optical lens is positioned near the light receiver; and The display screen is positioned near the display end.

10. The imaging device of claim 9, wherein, The optical lens is also configured to manipulate the light to magnify the size of the object located downstream of the optical path of the optical lens.

11. The imaging device of claim 1, wherein, The imaging device does not utilize thermal imaging or an external light source.

12. The imaging device according to claim 1, wherein: The imaging device also includes a transceiver configured to transmit signals including the digital image; The processor communicates with the transceiver; and The processor is also configured to use the transceiver to transmit the signal to a separate device including a second transceiver for display on the separate device.

13. A method for acquiring digital images under low-light conditions, the method comprising: An imaging device is provided, the imaging device including an optical lens configured to receive light; A sensor configured to convert the light into one or more digital signals; a processor; and a non-transitory processor-readable storage medium in communication with the processor; Receives light from an object located downstream of the optical path of the optical lens; Convert the light into one or more digital signals; Determine the illuminance hue distribution and average illuminance of the one or more digital signals; When the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux, one or more RGB values ​​(HUES) are assigned to the hue distribution; When the average illuminance of the hue distribution is determined to be between 0.001 lux and 100 lux, one or more saturation values ​​are assigned to the hue distribution; The hue distribution is transformed using a first gain control, defined by BLANK's first lux gain ratio, and... The tonal distribution of the transformation is converted into a digital image.

14. The method of claim 13, further comprising synchronizing the exposure time of the light to the sensor with the adjustment of the hue distribution using the first gain control.

15. The method of claim 13, further comprising: When it is determined that the digital image does not have the desired sharpness, a second gain control is used to transform the tone distribution, the second gain control being defined by a second lux gain ratio, which is within 10% of the first lux gain ratio; as well as The tonal distribution of the transformation based on the second gain control is converted into an adjusted digital image.

16. The method of claim 13, further comprising generating a black and white image when the average illuminance of the hue distribution is determined to be less than 0.001 lux.

17. The method of claim 13, further comprising displaying the digital image on a display of the imaging device.

18. The method of claim 13, further comprising: The transceiver of the imaging device transmits a signal including the digital image to a second transceiver of a separate device, the transceiver of the imaging device communicating with the processor; The digital image is stored in a second non-transitory processor-readable storage medium of the separate device; as well as The digital image is displayed on a second display of the separate device.

19. The method of claim 13, wherein the method does not utilize thermal imaging or an external light source to generate the digital image.

20. The method of claim 13, wherein, The assignment of the one or more RGB values ​​and the one or more saturation values ​​to the hue distribution is based on the correlation with the color and saturation chart adjusted for illumination.

Images