Optical filter, camera module, camera device and electronic equipment

Abstract

The invention provides an optical filter, a camera module, a camera device and electronic equipment. The camera device comprises a first camera module, the first camera module comprises a lens, an optical filter and an image sensor which are sequentially arranged along an optical axis, and the optical filter is used for visible light to pass so as to acquire spectral information of a target object on the image sensor; the optical filter has a first transmittance curve obtained under a normal incidence condition and a second transmittance curve obtained under an oblique incidence condition; on the first transmittance curve, the wavelength corresponding to the 50% transmittance comprises a first wavelength, and the first wavelength is in the range of 600-660 nm; on the second transmittance curve, the wavelength corresponding to the 50% transmittance comprises a second wavelength, and the difference value between the first wavelength and the second wavelength is in the range of 0-20 nm. According to the technical scheme, the accuracy of the camera module for color calibration can be improved while the color restoration capability of the camera module is ensured.

Description

Technical Field

[0001] The present application relates to the field of camera technology, and more specifically, to a filter, a camera module, a camera device and an electronic device. Background Art

[0002] The multi-spectral camera module can obtain the information of radiation or reflection of multiple spectral bands of the photographed target through spectroscopy technology, and then obtain the characteristic spectrum of the photographed target, which can be used to restore the color of the photographed target.

[0003] Compared with the existing three-channel camera module, the multi-spectral camera module has stronger spectral perception ability, so the color restoration ability is strong, and the color of the collected image is closer to the real color. Therefore, in order to improve the quality of the output image of the three-channel camera module, the image obtained by the multi-spectral camera module can be used to perform color calibration on the image obtained by the three-channel camera module.

[0004] However, the color reproduction ability of the multi-spectral camera module is also affected by the two key optical components in the module, the optical lens and the filter. It is necessary to combine the chip, optical lens and filter to design the optical response of the module. Poor optical response design will lead to poor accuracy of color calibration of the multi-spectral camera module. Even if the multi-spectral camera module can obtain the real color, the three-channel camera module cannot accurately obtain color information from the multi-spectral camera module, resulting in a large deviation between the color performance of the three-channel camera module and the color seen by the human eye, and poor authenticity. Summary of the invention

[0005] The present application provides a filter, a camera module, a camera device and an electronic device, which can improve the accuracy of the camera module for color calibration while ensuring the color restoration capability of the camera module, thereby improving the color authenticity and consistency of the image.

[0006] In a first aspect, a camera device is provided, comprising a first camera module, the first camera module comprising an optical lens, a filter and an image sensor arranged in sequence along an optical axis direction, the optical lens being used to receive light from a target object, the filter being used to allow visible light in the light to pass through, the image sensor being used to receive the visible light to obtain spectral information of the target object, and the number of channels of the image sensor being greater than 3; wherein the filter has a first transmittance curve and a second transmittance curve, the first transmittance curve being a curve of a corresponding relationship between the wavelength of light normally incident on the filter and the transmittance, the second transmittance curve being a curve of a corresponding relationship between the wavelength of light incident on the filter at a first angle and the transmittance, the first angle being greater than 0° and less than or equal to 35°; on the first transmittance curve, the wavelength corresponding to 50% transmittance includes a first wavelength, the first wavelength being greater than or equal to 600nm and less than or equal to 660nm; on the second transmittance curve, the wavelength corresponding to 50% transmittance includes a second wavelength, and the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 20nm.

[0007] In the embodiment of the present application, the filter with the above parameters makes the spectral response curve of the first camera module have a high degree of similarity with the spectral response curves of the human eye and the three-channel camera module. Accordingly, after the spectral response curve of the first camera module is mapped from high dimension to low dimension, it can be close to or equal to the spectral response curves of the human eye and the three-channel camera module. Therefore, the color restoration ability of the first camera module and the accuracy of color correction of the three-channel camera module can be improved, the color cast problem can be reduced or avoided, and the color authenticity of the image of the three-channel camera module can be improved, thereby improving the user experience.

[0008] Specifically, at normal incidence, the first wavelength corresponding to the filter at a transmittance of 50% is in the range of 600nm-660nm, which is roughly equivalent to the corresponding wavelength range of the filter in the three-channel camera module, and can limit the spectral response range as a whole, which is conducive to making the spectral response curve of the first camera module approach the spectral response curve of the human eye and the spectral response curve of the three-channel camera module after dimensionality reduction from high dimension. In addition, the difference between the first wavelength and the second wavelength is in the range of 0-20nm, which can ensure that within the incident range of light, the transmittance curve of the filter can make the spectral response curve of the first camera module have a high degree of similarity with the spectral response curve of the human eye and the spectral response curve of the three-channel camera module, thereby reducing or avoiding the color cast problem and improving the color authenticity of the output image.

[0009] In addition, the difference between the first wavelength and the second wavelength is within the range of 0-20 nm, which can limit the angular offset of the transmittance curve of the filter, improve the color reproduction consistency between the center and the edge of the image, and reduce the chromatic aberration between the center and the edge of the image.

[0010] In combination with the first aspect, in a possible implementation, on the first transmittance curve, the wavelength corresponding to 50% transmittance includes a third wavelength, and the third wavelength is greater than or equal to 400nm and less than or equal to 440nm; on the second transmittance curve, the wavelength corresponding to 50% transmittance includes a fourth wavelength, and the difference between the third wavelength and the fourth wavelength is greater than or equal to 0 and less than or equal to 20nm.

[0011] At oblique incidence, the third wavelength range corresponding to the filter at a transmittance of 50% is 400nm-440nm, which is roughly equivalent to the corresponding wavelength range of the filter in the three-channel camera module. The spectral response range can be limited as a whole, so that the spectral response curve of the first camera module is highly similar to the spectral response curves of the human eye and the three-channel camera module, respectively, which is beneficial to improving the color restoration capability of the first camera module and the accuracy of color correction of the three-channel camera module, reducing or avoiding color cast problems, and improving the color authenticity of the three-channel camera module image.

[0012] The difference between the third wavelength and the fourth wavelength is in the range of 0-20 nm, which can limit the angular offset of the transmittance curve of the filter, improve the color reproduction consistency between the center and the edge of the image, and reduce the chromatic aberration between the center and the edge of the image.

[0013] In combination with the first aspect, in a possible implementation manner, the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 10 nm.

[0014] In combination with the first aspect, in a possible implementation method, on the first transmittance curve, the average transmittance in the 350nm~395nm band is less than or equal to 3%, and the average transmittance in the 700nm~780nm band is less than or equal to 2%; on the second transmittance curve, the average transmittance in the 350nm~395nm band is less than or equal to 4%, and the average transmittance in the 700nm~780nm band is less than or equal to 3%.

[0015] In the embodiment of the present application, the cutoff wavelength of the filter corresponds to the cutoff wavelength position of the visual response curve of the human eye. By filtering out light waves that exceed the sensing band of the human eye, the effective information has a better signal-to-noise ratio, which is beneficial to improving image quality.

[0016] In combination with the first aspect, in a possible implementation, on the first transmittance curve, the minimum transmittance of the 440nm~580nm band is greater than or equal to 70%, and the average transmittance of the 440nm~580nm band is greater than or equal to 80%; on the second transmittance curve, the minimum transmittance of the 440nm~580nm band is greater than or equal to 70%, and the average transmittance of the 440nm~580nm band is greater than or equal to 80%.

[0017] 440nm~580nm is the stable section of filter transmittance. By constraining the minimum value within this band, the filter can be prevented from having large transmittance fluctuations to ensure the consistency of the effect color. By constraining the average transmittance value of this band, the overall sensitivity of the multi-spectral camera module can be guaranteed, thereby improving the image quality.

[0018] In combination with the first aspect, in a possible implementation manner, the first wavelength and the second wavelength belong to a red light band, and the third wavelength and the fourth wavelength belong to a blue light band.

[0019] In combination with the first aspect, in a possible implementation, the camera device further includes at least one second camera module, the second camera module is a three-channel camera; the first camera module is a C-channel camera and C is greater than 3, and the similarity v between the spectral response curve of the first camera module and the spectral response curve of the human eye is 0 is greater than or equal to 0.93, and the similarity v′ between the spectral response curve of the first camera module and the spectral response curve of the second camera module is greater than or equal to 0.93; wherein,

[0020]

[0021] Q N×C is a spectral response matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the first camera module, P{Q N×C =Q N×C [Q N×C T Q N×C ]- 1 Q N×C T ;

[0022] is a spectral response matrix obtained by sampling N points in each of the three channels based on the spectral response curve of the human eye,

[0023] X′ N×3is a spectral response matrix obtained by sampling N points in each of the three channels based on the spectral response curve of the second camera,

[0024] Tr() is the trace.

[0025] When v 0 When it is greater than or equal to 0.93, the spectral response curve of the first camera module can be as close to the spectral response curve of the human eye as possible after dimensionality reduction from a high dimension. This can improve the color restoration ability of the multispectral camera module, reduce or avoid color cast problems, and improve the color authenticity or color parameter accuracy of the image output by the multispectral camera module.

[0026] When v′ is greater than or equal to 0.93, the spectral response curve of the first camera module can be as close as possible to the spectral response curve of the second camera module after dimensionality reduction from a high dimension. This can improve the accuracy of migrating the color parameters of the multi-spectral camera module to the second camera module, reduce or avoid the color cast problem caused by the migration error, and improve the color authenticity of the image output by the second camera module.

[0027] In combination with the first aspect, in a possible implementation, the spectral response matrix of the first camera module is

[0028] Q N×C =M N×C ⊙T N×1 ⊙L N×1

[0029] M N×C A matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the image sensor;

[0030] T N×1 is a matrix obtained by sampling N points based on the transmittance curve of the filter;

[0031] L N×1 It is a matrix obtained by sampling N points based on the transmittance curve of the optical lens.

[0032] In a second aspect, a filter is provided, which is applied to a camera module. The camera module also includes an optical lens and an image sensor. The filter is arranged between the optical lens and the image sensor. The optical lens is used to receive light from a target object. The filter is used to pass visible light in the light. The image sensor is used to receive the visible light to obtain spectral information of the target object. The number of channels of the image sensor is greater than 3. The filter has a first transmittance curve and a second transmittance curve. The first transmittance curve is the transmittance of the light incident on the filter. A curve of correspondence between wavelength and transmittance, wherein the second transmittance curve is a curve of correspondence between the wavelength and transmittance of light incident on the filter at a first angle, wherein the first angle is greater than 0° and less than or equal to 35°; on the first transmittance curve, the wavelength corresponding to 50% transmittance includes a first wavelength, wherein the first wavelength is greater than or equal to 600nm and less than or equal to 660nm; on the second transmittance curve, the wavelength corresponding to 50% transmittance includes a second wavelength, wherein the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 20nm.

[0033] In combination with the second aspect, in one possible implementation, on the first transmittance curve, the wavelength corresponding to 50% transmittance includes a third wavelength, and the third wavelength is greater than or equal to 400nm and less than or equal to 440nm; on the second transmittance curve, the wavelength corresponding to 50% transmittance includes a fourth wavelength, and the difference between the third wavelength and the fourth wavelength is greater than or equal to 0 and less than or equal to 20nm.

[0034] In combination with the second aspect, in a possible implementation manner, the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 10 nm.

[0035] In combination with the second aspect, in a possible implementation method, on the first transmittance curve, the average transmittance in the 350nm~395nm band is less than or equal to 3%, and the average transmittance in the 700nm~780nm band is less than or equal to 2%; on the second transmittance curve, the average transmittance in the 350nm~395nm band is less than or equal to 4%, and the average transmittance in the 700nm~780nm band is less than or equal to 3%.

[0036] In combination with the second aspect, in a possible implementation method, on the first transmittance curve, the minimum transmittance of the 440nm~580nm band is greater than or equal to 70%, and the average transmittance of the 440nm~580nm band is greater than or equal to 80%; on the second transmittance curve, the minimum transmittance of the 440nm~580nm band is greater than or equal to 70%, and the average transmittance of the 440nm~580nm band is greater than or equal to 80%.

[0037] In combination with the second aspect, in a possible implementation manner, the first wavelength and the second wavelength belong to a red light band, and the third wavelength and the fourth wavelength belong to a blue light band.

[0038] In a third aspect, a camera module is provided, comprising an optical lens, an image sensor, and the filter according to the second aspect and any one of the implementations of the second aspect, wherein the filter is arranged between the optical lens and the image sensor, the optical lens is used to receive light from a target object, the filter is used to allow visible light in the light to pass, the image sensor is used to receive the visible light to obtain spectral information of the target object, and the number of channels of the image sensor is greater than 3.

[0039] In a fourth aspect, an electronic device is provided, comprising an image processing chip and the camera module according to the third aspect, wherein the image processing chip is used to process images acquired by the camera module.

[0040] In a fifth aspect, an electronic device is provided, comprising an image processing chip and a camera device according to the first aspect and any one of the implementations of the first aspect, wherein the image processing chip is used to process images acquired by the camera device.

[0041] In combination with the fifth aspect, in a possible implementation, the camera device also includes at least one second camera module, which is a three-channel camera, and the image processing chip is used to correct the color of the target object obtained by the second camera module based on the spectral information of the target object obtained by the first camera module.

[0042] In combination with the fifth aspect, in one possible implementation, the second camera module is a wide-angle camera, a telephoto camera, or an ultra-wide-angle camera.

[0043] The beneficial effects of the devices described in the second to fifth aspects above refer to the beneficial effects described in the first aspect above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic structural diagram of an electronic device applicable to an embodiment of the present application.

[0045] Figure 2 It is a schematic exploded view of a camera module provided in an embodiment of the present application.

[0046] Figure 3 It is a schematic cross-sectional view of a camera module provided in an embodiment of the present application.

[0047] Figure 4 It is a schematic diagram of a transmittance curve of a filter provided in an embodiment of the present application.

[0048] Figure 5 It is a schematic diagram of a transmittance curve of another filter provided in an embodiment of the present application.

[0049] Figure 6 It is a schematic diagram of a transmittance curve of another filter provided in an embodiment of the present application.

[0050] Figure 7 It is a schematic diagram of a transmittance curve of another filter provided in an embodiment of the present application.

[0051] Figure 8 It is a schematic diagram of a transmittance curve of another filter provided in an embodiment of the present application.

[0052] Fig. 9 It is a schematic diagram of a transmittance curve of another filter provided in an embodiment of the present application.

[0053] Fig.10 It is a schematic flowchart of a camera module design method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0055] It should be noted that, in the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in this article is merely a way to describe the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0056] In the embodiments of the present application, the terms "first", "second", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two, "at least one" and "one or more" refer to one, two or more. The singular expressions "one", "a kind", "said", "above", "the", and "this" are intended to also include expressions such as "one or more", unless there is a clear indication to the contrary in the context.

[0057] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear at different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0058] In the description of the embodiments of the present application, the terms "upper", "lower", "inside", "outside", "vertical", "horizontal", etc. indicate orientations or positional relationships that are defined relative to the orientations or positions of the components schematically placed in the drawings. It should be understood that these directional terms are relative concepts. They are used for description and clarification relative to the drawings, rather than indicating or implying that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. It may change accordingly according to the change in the orientation of the components placed in the drawings, and therefore cannot be understood as a limitation on the present application. In addition, the "vertical" involved in the present application is not vertical in the strict sense, but is within the allowable error range. "Parallel" is not parallel in the strict sense, but is within the allowable error range.

[0059] In the embodiments of the present application, the same reference numerals are used to represent the same components or parts. In addition, the various parts in the drawings are not drawn according to the actual scale, and the sizes and dimensions of the parts shown in the drawings are only exemplary and should not be understood as limiting the present application.

[0060] For ease of understanding, the technical terms involved in this application are explained and illustrated below.

[0061] The optical axis is an imaginary line in an optical system, which can be understood as the direction in which the optical system transmits light. For a symmetrical transmission system, the optical axis generally coincides with the rotation centerline of the optical system. If the light coincides with the optical axis, the light will be transmitted along the optical axis in the optical system.

[0062] Auto focus (AF) uses the principle of light reflection from the object. The light reflected from the object is imaged and received on the image sensor after passing through the lens. After being processed by a computer, it drives the focus device to focus.

[0063] Optical image stabilization (OIS) refers to the use of optical components in imaging devices such as mobile phones or cameras to avoid or reduce the instrument jitter that occurs during the capture of optical signals in order to improve image quality. A common approach is to use a gyroscope to detect jitter, and then use the OIS motor to translate or rotate the entire lens in the opposite direction to compensate for image blur caused by imaging device jitter during exposure.

[0064] Color space, also known as color space, is a mathematical model for representing color and is used for color quantification. Common color spaces include Lab color space, Luv color space, LCh color space, Yxy color space, XYZ color space, CMYK color space, RGB color space, Hex color space, YUV color space, etc.

[0065] The parameters of the filter include: center wavelength, transmittance, peak transmittance, bandwidth, cut-off band, and incident angle.

[0066] The center wavelength (CWL) is the midpoint between wavelengths where the peak transmittance is 50%, also known as the midpoint of the full width at half maximum. Generally, the center wavelength is expressed as the peak transmission wavelength of a bandpass or narrowband filter, or the peak reflection wavelength of a notch filter.

[0067] Transmittance refers to the ratio of the light allowed to pass through the filter to the incident light, usually expressed as a percentage, generally indicating the loss of light after entering the filter. When the transmittance is 10% or less, it is considered cutoff.

[0068] Peak transmittance refers to the maximum transmittance value of the passband, that is, the highest value that can be transmitted after the filter loss. In the spectrum curve, the area where the light actually passes is usually called the passband.

[0069] Bandwidth (full width at half maximum, FWHM), also known as half-maximum full width, half-width, half-peak width, etc., is a wavelength range that represents the difference between the wavelength bands where the peak transmittance is halfway. Filters with a half-width of less than 20nm are called narrowband filters, and filters with a half-width of more than 20nm are called bandpass filters.

[0070] Cut-off wavelength refers to the range of the light cut-off wavelength of the filter.

[0071] The angle of incidence (AOI) refers to the angle between the incident light and the normal line of the filter surface. When the light is incident vertically, the angle of incidence is 0°.

[0072] An operator is a mapping that can transform one mathematical object into another. An operator can be understood as an operation that processes input according to certain rules and produces output.

[0073] The trace of a matrix is ​​the sum of the eigenvalues ​​of the matrix. For a square matrix, the trace is the sum of all the elements on the main diagonal of the matrix (the diagonal from the upper left to the lower right).

[0074] It should be noted that the introduction of the above terms and concepts is only used to facilitate understanding and should not be construed as a limitation on the embodiments of the present application.

[0075] Figure 1 A schematic structural diagram of an electronic device to which an embodiment of the present application is applicable is shown.

[0076] In the embodiments of the present application, the electronic devices involved are electronic devices with imaging functions, such as mobile phones, personal digital assistants (PDAs), tablet computers, laptop computers, laptop computers, cameras, video recorders, cameras, smart watches, smart wristbands, point of sales (POS), car machines, televisions (such as smart screens), wearable devices, etc. The embodiments of the present application do not impose any special restrictions on the specific form of the electronic device. For the convenience of explanation and understanding, the following description is based on the example of a mobile phone as an electronic device.

[0077] For example, Figure 1 (a) and (b) schematically show the front and back sides of the electronic device 100, respectively. Figure 1 As shown, the electronic device 100 may include a housing 101 , a display panel (DP) 102 , and a camera array 103 .

[0078] The housing 101 is formed with a storage space for accommodating components of the electronic device 100. The housing 101 can also protect the electronic device 100 and support the entire device. The display screen 102 and the camera array 103 are arranged in the storage space of the housing 101 and are connected to the housing 101. In some embodiments, the housing 101 may include a back cover arranged opposite to the display screen 102 and a middle frame arranged between the back cover and the display screen 102, and the display screen 102 and the camera array 103 may be fixed on the middle frame. The material of the housing 101 may be metal, plastic, ceramic or glass.

[0079] The display screen 102 is used to display images, for example, images captured by the camera array 103. The display screen 102 may be a liquid crystal display (LCD) screen, an organic light emitting diode (OLED) display screen, etc. The display screen 102 may be a regular screen, or may be a special-shaped screen, a folding screen, etc. The display screen 102 may be disposed on the front and / or back of the electronic device 100. Here, the front of the electronic device 100 may be understood as the side facing the user when the user uses the electronic device 100, and the back of the electronic device 100 may be understood as the side facing away from the user when the user uses the electronic device 100.

[0080] The camera array 103 is used to capture still images or videos. The camera array 103 includes a plurality of camera modules (camera compact modules, CCM) (or simply cameras). Exemplarily, the camera array 103 includes at least one multispectral camera module (also referred to as a first camera module in this application) and at least one second camera module, wherein the second camera module is a telephoto camera, a wide-angle camera, an ultra-wide-angle camera, or a depth-of-field camera. When the camera array 103 includes a plurality of multispectral camera modules (or a plurality of second camera modules), the plurality of multispectral camera modules (or a plurality of second camera modules) may be completely the same or different, for example, the plurality of multispectral camera modules (or a plurality of second camera modules) may have different focal lengths, different optical structures, or different optical parameters.

[0081] In some embodiments, each of the at least one multi-spectral camera module is capable of independent imaging, and the captured images can be directly presented to the user for browsing.

[0082] In some embodiments, each of the at least one second camera module can independently image, and the captured images can be directly presented to the user for browsing. One or more of the at least one second camera module can be used as a main camera. Usually, the main camera is responsible for the main shooting task, usually has the highest pixel, can provide higher resolution and stronger sensor, so as to meet the user's photography needs in different scenes.

[0083] In some embodiments, the image acquired by the multispectral camera module can be used to perform color calibration on the image acquired by the second camera module. For example, the multispectral image of the first scene acquired by the multispectral camera module can be used as a reference to perform color calibration on the three-channel image (such as a red, green, blue (RGB) image or a red, yellow, blue (RYB) image, etc.) of the first scene acquired by the second camera module.

[0084] The second camera module is a three-channel camera module. Due to the limitations of material capabilities, its corresponding spectral response curve is somewhat different from that of the human eye, and the number of spectral bands that can be perceived is small, so the color restoration ability is weak, and the captured image is prone to color cast of certain colors. Compared with the second camera module, the difference between the spectral response curve corresponding to the multi-spectral camera module and the spectral response curve corresponding to the human eye can be made smaller, and the multi-spectral camera module has a stronger spectral perception ability (that is, the number of spectral bands that can be perceived is more than 3), so the color restoration ability is strong, and the color of the captured image is closer to the real color after restoration. Using the image captured by the multi-spectral camera module as a reference, color calibration of the second camera module can improve the color authenticity of the image output by the second camera module.

[0085] In some embodiments, the multispectral camera module or the second camera module may be an upright module or a folding module (or a periscope camera module). An upright camera module may be understood as light entering the camera module directly hitting the image sensor without bending the light path. A folding camera module may be understood as light entering the camera module needs to pass through optical elements such as reflectors, lenses, and prisms before hitting the image sensor, and the light path is folded.

[0086] In some embodiments, the camera array 103 can be arranged on the front and / or back of the electronic device 100. When the camera array 103 is arranged on the front of the electronic device 100, it can also be called a front camera. When the camera array 103 is arranged on the back of the electronic device 100, it can also be called a rear camera. In some embodiments, when the display screen 102 can be folded, the camera array 103 can be used as a front camera or a rear camera as the display screen 102 is folded. It can be understood that the setting position of the camera array 103 can be determined according to actual needs. Figure 1 The mounting positions shown are schematic only.

[0087] In some embodiments, the electronic device 100 may further include a protective lens 104 for protecting the camera module in the camera array 103. The protective lens 104 is disposed on the housing 101 and covers the camera module. For example, when the protective lens 104 is used to protect the front camera, the protective lens 104 may only cover the front camera module or cover the entire front of the electronic device 100. When the protective lens 104 covers the entire front of the electronic device 100, it can also be used to protect the display screen 102. At this time, the protective lens 104 is a cover glass (CG). For another example, when the protective lens 104 is used to protect the rear camera, the protective lens 104 may cover the entire back of the electronic device 100, or may be only disposed at a position corresponding to the rear camera module.

[0088] In some embodiments, the material of the protective lens 104 can be glass, sapphire, ceramic, etc., which is not specifically limited in the present application. Exemplarily, the protective lens 104 is transparent, and light outside the electronic device 100 can enter the camera module through the protective lens 104.

[0089] In some embodiments, the electronic device 100 may further include a circuit board and an image processor (not shown in the figure), the circuit board and the image processor are located in the accommodation space formed by the housing 101, and the image processor is fixed to the circuit board and electrically connected to the circuit board. The image processor is communicatively connected to the camera module (e.g., a multi-spectral camera module or a second camera module) in the camera array 103. The image processor is used to obtain image data from the camera module and process the image data. Among them, the communication connection between the camera module and the image processor may include data transmission through electrical connection methods such as wiring, and may also include data transmission through coupling and other methods. It is understandable that the camera module and the image processor can also achieve communication connection through other methods that can achieve data transmission.

[0090] In some embodiments, the electronic device 100 may further include an analog-to-digital converter (also referred to as an A / D converter, not shown in the figure). The analog-to-digital converter is connected between the camera module and the image processor. The analog-to-digital converter is used to convert the signal generated by the camera module into a digital image signal and transmit it to the image processor, and then the digital image signal is processed by the image processor, and finally the image or video is displayed on the display screen 102.

[0091] In some embodiments, the electronic device 100 may further include a memory (not shown in the figure), which is in communication with the image processor. The image processor processes the image digital signal and then transmits the image to the memory, so that when the image needs to be viewed later, the image can be searched from the memory at any time and displayed on the display screen 102. In some embodiments, the image processor also compresses the processed image digital signal and stores it in the memory to save memory space.

[0092] It should be understood that Figure 1 The structure illustrated in the figure does not constitute a specific limitation on the electronic device 100. The electronic device 100 may include more or fewer components than those shown in the figure. For example, the electronic device 100 may also include one or more components such as a battery, a flash, an earpiece, buttons, and a sensor. Alternatively, the electronic device 100 does not include the display screen 102, or the electronic device 100 may also be provided with a component arrangement different from that shown in the figure.

[0093] Figure 2 and Figure 3 The structure diagram of a camera module provided in an embodiment of the present application is shown. Figure 2 is a schematic exploded view of the camera module 200, Figure 3 is a schematic cross-sectional view of the camera module 200 . Figure 2 The camera module 200 may be Figure 1 An exemplary structure of a multi-spectral camera module or a second camera module in FIG. Figure 2 and Figure 3 The structure of the camera module 200 is briefly introduced.

[0094] For the convenience of description, the optical axis direction of the camera module 200 is defined as the Z direction, and the two directions perpendicular to the optical axis are the X direction and the Y direction, and the X direction is perpendicular to the Y direction. In the Z direction, the direction side where the object is located is the front side, and the direction side opposite to the object is the rear side; in the X direction and the Y direction, the direction close to the optical axis is the inner side, and the direction opposite to the optical axis is the outer side. In the embodiment of the present application, the optical axis direction is the direction in which the optical system conducts light.

[0095] Here, the definitions of the X, Y, Z directions and the front, rear, inside, and outside are also applicable to the drawings to be described later. It should be noted that the above definitions of the X, Y, Z directions and the front, rear, inside, and outside are only for the convenience of describing the positional relationship, connection relationship, or motion relationship between the various components in the embodiments of the present application, and should not be understood as limiting the embodiments of the present application.

[0096] like Figure 2 and Figure 3As shown, the camera module 200 may include a housing 210 , a lens assembly 220 , a lens assembly actuator 230 and a light sensing assembly 240 .

[0097] The housing 210 is formed with a receiving space for accommodating the lens assembly 220, the lens assembly actuator 230, the light sensing assembly 240, etc. In addition, the housing 210 can also play a protective and supporting role. It can be understood that Figure 2 and Figure 3 The structure of the housing 210 shown in the figure is merely exemplary and should not be construed as a limitation to the present application. Those skilled in the art may design the shape of the housing 210 accordingly according to actual needs.

[0098] The lens assembly 220 (or optical lens) mainly includes a lens group 221 and a lens barrel 222, and the lens group 221 is accommodated in the accommodation space formed by the lens barrel 222. The lens assembly 220 is used to image the scene on the object side onto the imaging surface on the image side. In some embodiments, the lens assembly 220 can also perform certain processing on the received imaging beam, such as correcting aberrations, eliminating chromatic aberrations, etc. Here, the imaging beam refers to a beam formed by the light incident on the camera module 200.

[0099] The lens group 221 may include at least one lens. The at least one lens may be different or at least partially the same. The embodiment of the present application does not specifically limit the number of lenses included in the lens group 221. Those skilled in the art may set the number of lenses accordingly according to actual needs, such as 1, 2, 3, 5, 8 or more.

[0100] The focal length of the lens group 221 can be fixed, and accordingly, the lens assembly 220 is a fixed-focus lens. The focal length of the lens group 221 can also be adjusted, and accordingly, the lens assembly 220 is a zoom lens. For example, the focal length of the lens group 221 can be adjusted by adjusting the relative positions of the lenses in the lens group 221.

[0101] The lens barrel 222 is formed with a receiving space, which is mainly used to receive the lens group 221. In some embodiments, the lens barrel 222 can be a whole, and the lens group 221 is received in the lens barrel 222 of the whole. In other embodiments, the lens barrel 222 can also include a plurality of lens barrel parts, and the lenses of the lens group 221 are grouped and arranged in the plurality of lens barrel parts, wherein each lens barrel part and the lenses received therein can be referred to as a lens group. Exemplarily, the relative positions between the plurality of lens barrel parts can be adjusted, and the relative positions between the lenses can be adjusted to achieve optical zoom.

[0102] Understandably, Figure 2 and Figure 3The structure of the lens barrel 222, the connection method between the lens group 221 and the lens barrel 222, etc. are merely exemplary and do not impose any limitation on the embodiments of the present application.

[0103] The lens group actuator 230 is used to drive the lens assembly 220 to move to achieve automatic focusing and / or optical image stabilization. In some embodiments, the lens group actuator 230 can also be called a lens group motor, or simply a motor.

[0104] like Figure 3 As shown, the lens group actuator 230 may include a motor 231 for moving the lens assembly 220 for AF (hereinafter referred to as the AF motor for ease of description) and / or a motor 232 for moving the lens assembly 220 for OIS (hereinafter referred to as the OIS motor for ease of description). Specifically, the AF motor 231 is used to move the lens assembly 220 in the Z direction for autofocus, and the OIS motor 232 is used to move the lens assembly 220 in the X direction and / or the Y direction for optical image stabilization. In some embodiments, the AF motor 231 and the OIS motor 232 may be two independent components, which independently drive the lens assembly 220 to perform AF and OIS. Alternatively, the AF motor 231 and the OIS motor 232 may also be integrated into one, and one motor drives the lens assembly 220 to perform AF and OIS. Figure 3 The lens group actuator 230 is exemplarily shown to include an independent AF motor 231 and an OIS motor 232 , but it should be understood that the embodiments of the present application are not limited thereto.

[0105] In some embodiments, the AF motor 231 or the OIS motor 232 can be used to move the entire lens assembly 220, or to move a portion of the lens assembly 220. For example, if a portion of the lens assembly 220 (such as the first lens group) is relatively fixed, and another portion (such as the second lens group) is movable, the AF motor 231 or the OIS motor 232 can drive the movable portion to move, so as to change the optical path and thereby achieve the desired function.

[0106] In some embodiments, the AF motor 231 or the OIS motor 232 may be a voice coil motor (VCM), a shape memory alloy (SMA) motor, a stepping motor, a piezoelectric motor, etc. It should be understood that the specific structure of the AF motor 231 or the OIS motor 232 may be designed and selected accordingly according to the selected driving mode, and the embodiments of the present application are not limited thereto.

[0107] The light sensing component 240 is disposed at the rear side of the lens component 220 and is mainly used for imaging. Exemplarily, the light sensing component 240 may include a filter 241 , an image sensor 242 , and a circuit board 243 .

[0108] The filter 241 is disposed between the lens assembly 220 and the image sensor 242. The filter 241 can eliminate unnecessary light projected onto the image sensor 242, and prevent the image sensor from having problems such as ghosting, stray light, and color cast when imaging. Exemplarily, the filter 241 can be an infrared cutoff filter (filtering out long-wave light except visible light), a bandpass filter (for passing light of a specific wavelength and cutting off light outside the passband), or a filter for filtering out light of other wavelengths, etc. For different usage scenarios, the filter 241 can have different ranges of action.

[0109] The image sensor 242 is a semiconductor chip used to convert the collected external light signals into electrical signals. Specifically, the surface of the image sensor 242 contains hundreds of thousands to millions of photodiodes, which generate charges when exposed to light, thereby converting the light signals collected by the lens assembly 220 into electrical signals. Exemplarily, the image sensor 242 can be a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS).

[0110] The image sensor 242 includes a plurality of photosensitive units, which can convert light signals into electric charges to form an electronic image corresponding to the scene. Each photosensitive unit corresponds to a pixel, and the more pixels there are, the clearer the imaging effect.

[0111] In the image sensor used in the three-channel camera module, each photosensitive unit includes three different filter channels, such as red, green, and blue filter channels, or red, yellow, and blue filter channels, etc. For example, different filter channels can be formed by placing three different color filters on the photosensitive unit.

[0112] In the image sensor used by the multispectral camera module (hereinafter referred to as the multispectral image sensor for the convenience of description), each photosensitive unit includes more filter channels (the number of filter channels is more than 3), for example, chemical dyes, coating interference, super-surface micro-nano structure, etc. can be used to realize differentiated filter arrays (color filter array, CFA) to form different filter channels. Therefore, the multispectral image sensor can extract the spectral information of multiple channels to collect images. Since the multispectral image sensor has more filter channels and stronger spectral perception ability, the color authenticity of the perceived multispectral image is higher. The multispectral image sensor can obtain multispectral images through multiple filter channels, and can pass the collected image information to the color restoration module for analysis to achieve color imaging or color information extraction.

[0113] Exemplarily, the multi-spectral image sensor may include a spectral modulation area and a photoelectric conversion area. The spectral modulation area forms multiple filter channels through multiple materials or optical structures to split the incident light. The photoelectric conversion area converts the split light signal into an electrical signal, and then outputs a digital signal or code through analog-to-digital conversion. A color restoration module (for example, an image signal processor) is electrically connected to the multi-spectral image sensor. The color restoration module can calculate the spectral information or color information based on the light signal and pixel position information input by the multi-spectral image sensor. Based on the color transformation matrix from the signals of multiple channels to the color space, the color restoration module can also convert the multi-spectral signal collected by the multi-spectral image sensor into the color space information of the image (for example, RGB information, XYZ three-stimulus values, or YUV information, etc.). Here, the color transformation matrix from the signals of multiple channels to the color space is established based on the visual response curve of the human eye (for example, the spectral three-stimulus value curve, including the response curve of the human eye to red, green, and blue light) and the spectral response curve of the multi-spectral camera module (including the spectral response curve of the multi-spectral camera module to different wavelengths). In some embodiments, the color restoration module can also use the spectral information obtained by the multi-spectral camera module to perform color calibration on other cameras. For example, based on the transformation relationship between the spectral response curve of the multi-spectral camera module and the spectral response curves of other camera modules, the color space information corresponding to the multi-spectral camera module is mapped to other camera modules to correct their colors, making the image colors of other camera modules more accurate.

[0114] In some embodiments, camera modules with different focal lengths may have their own image sensors, or camera modules with different focal lengths may share the same image sensor.

[0115] In some embodiments, the light sensing component 240 may include an image signal processing (ISP) module, which is used to process the signal collected by the image sensor 242, such as linear correction, noise elimination, automatic white balance, automatic exposure control, color correction, etc., and convert the raw data collected by the image sensor 242 into a format supported by the algorithm. Exemplarily, the image signal processing module can be integrated with the image sensor 242.

[0116] The circuit board 243 is used to transmit electrical signals, and may be a flexible printed circuit (FPC) or a printed circuit board (PCB). The image sensor 242 may be electrically connected to the circuit board 243 via a wire to achieve signal extraction.

[0117] In some embodiments, the light sensing component 240 may also include a microelectromechanical systems (MEMS) actuator 244, which is used to drive the image sensor 242 to move along the optical axis and / or in a direction perpendicular to the optical axis, thereby achieving autofocus and / or optical image stabilization. The driving mode of the MEMS actuator 244 may be electrostatic force drive, magnetoelectric drive, piezoelectric drive, thermoelectric drive, etc. It should be understood that the specific structure of the MEMS actuator 244 can be designed and selected accordingly according to the selected driving mode, and this application does not limit this.

[0118] It should be understood that Figure 2 and Figure 3 The structure shown in the figure does not constitute a specific limitation on the camera module 200. The camera module 200 may include more or fewer components than shown in the figure, for example, the camera module 200 may also include a connector and peripheral electronic components, or the camera module 200 may not include the lens group actuator 230, which will not be described in detail here.

[0119] As mentioned above, the spectral perception and color restoration capabilities of the multispectral camera module are stronger than those of the three-channel camera module. Therefore, the spectral information obtained by the multispectral camera module can be used to perform color calibration on the images obtained by the three-channel camera module. However, the accuracy of the current multispectral camera module for color calibration of the three-channel camera module still needs to be improved.

[0120] This is because the accuracy of the multi-spectral camera module when used for color calibration is not only related to the spectral perception ability and color restoration ability of the multi-spectral camera module itself, but also affected by the similarity (or equivalence) between the spectral response curve of the multi-spectral camera module and the spectral response curve of the three-channel camera module. Specifically, since the multi-spectral camera module perceives more spectral bands, the spectral perception function corresponding to the multi-spectral camera module can be converted from a high dimension to a spectral perception function corresponding to the three-channel camera module. The higher the degree of equivalence between the spectral response curve of the multi-spectral camera module and the spectral response curve of the three-channel camera module, the higher the conversion accuracy between the spectral response curve of the multi-spectral camera module and the spectral response curve of the three-channel camera module, that is, the more accurate the process of dimensionality reduction fitting from the spectral perception function of the multi-spectral camera module to the spectral perception function of the three-channel camera module, and accordingly, based on the more accurate dimensionality reduction conversion matrix between the two spectral perception functions, the three-channel camera module can more accurately obtain real color information from the multi-spectral camera module.

[0121] For example, if the spectral response curve of a multi-spectral camera module is completely equivalent to the spectral response curve of a three-channel camera module, then the spectral response curve of the multi-spectral camera module is exactly the same as the spectral response curve of the three-channel camera module after dimensionality reduction from a high dimension, that is, the chromaticity perception capability of the multi-spectral camera module is completely adapted to the chromaticity perception capability of the three-channel camera module, and the spectral perception function of the multi-spectral camera module can be linearly converted to the spectral perception function of the three-channel camera module. Accordingly, based on the dimensionality reduction conversion matrix between the two, direct conversion of the chromaticity space can be performed through linear transformation, and the color information obtained by the three-channel camera module is highly consistent with the color perceived by the multi-spectral camera module. When the color of the multi-spectral camera module is accurate, the three-channel camera module can obtain real color information.

[0122] On the contrary, if the similarity between the spectral response curve of the multi-spectral camera module and the spectral response curve of the three-channel camera module is lower, the difference between the spectral response curve of the multi-spectral camera module and the spectral response curve of the three-channel camera module after dimensionality reduction from a high dimension will be greater, that is, the accuracy of the dimensionality reduction fitting from the spectral perception function of the multi-spectral camera module to the spectral perception function of the three-channel camera module will be lower. Accordingly, based on the dimensionality reduction conversion matrix between the two, the three-channel camera module cannot accurately obtain the color information of the multi-spectral camera module.

[0123] Similar to the above principle, the multispectral camera module itself needs to achieve accurate color restoration, and the spectral response curve of the multispectral camera module and the spectral response curve of the human eye (such as the tristimulus value curve) must be as equivalent as possible. For example, when the spectral response curve of the multispectral camera module is completely identical to the tristimulus value curve of the human eye after dimensionality reduction from a high dimension, that is, the chromaticity perception ability of the multispectral camera module is completely adapted to the chromaticity perception ability of the human eye, the spectral perception function of the multispectral camera module can be linearly converted to the tristimulus value curve of the human eye. Accordingly, based on the dimensionality reduction conversion matrix between the two, the chromaticity space can be directly converted through linear transformation to obtain completely true color information.

[0124] However, the color restoration capability of the multispectral camera module is affected by the filters in the module. The difference in the transmittance of the filters to light causes the spectral information obtained by the multispectral camera module to easily deviate when the real image information is subsequently restored, resulting in a large deviation between the final image and the color seen by the human eye and poor image authenticity.

[0125] In view of this, an embodiment of the present application provides a filter, which, when applied to a multi-spectral camera module, can improve the accuracy of the multi-spectral camera module for color calibration while ensuring the color restoration capability of the multi-spectral camera module, thereby improving the color authenticity and consistency of the image.

[0126] The filter provided in the embodiment of the present application is applied to the first camera module, and the first camera module is a multi-spectral camera module. The first camera module also includes an optical lens and an image sensor, and the filter is arranged between the optical lens and the image sensor. The optical lens is used to receive light from a target object. The filter is used to filter out light other than visible light in the light, that is, to allow visible light in the light to pass. The image sensor is a multi-spectral image sensor, wherein the number of channels of the image sensor is greater than 3.

[0127] The filter has a first transmittance curve and a second transmittance curve. The first transmittance curve is a curve of the corresponding relationship between the wavelength of the light incident on the filter and the transmittance. The second transmittance curve is a curve of the corresponding relationship between the wavelength of the light incident on the filter at a first angle and the transmittance, and the first angle is greater than 0° and less than or equal to 35°.

[0128] On the first transmittance curve, the wavelength corresponding to 50% transmittance includes a first wavelength, and the first wavelength is greater than or equal to 600nm and less than or equal to 660nm. On the second transmittance curve, the wavelength corresponding to 50% transmittance includes a second wavelength, and the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 20nm.

[0129] It can be understood that the first transmittance curve is obtained under normal incidence conditions, where the incident angle of the light incident on the filter is 0°. The second transmittance curve is obtained under oblique incidence conditions, where the incident angle of the light incident on the filter is the first angle. The first transmittance curve and the second transmittance curve of the filter can be obtained through optical experiments or simulation experiments, and this application does not make specific restrictions on this.

[0130] It can be understood that the filter set in the camera module usually has a high transmittance for visible light. Based on this characteristic, the transmittance curve of the filter (the horizontal axis is the wavelength and the vertical axis is the transmittance) usually has the following common characteristics: as the wavelength enters the visible light band from the ultraviolet band, at least part of the transmittance curve shows an upward trend. For the convenience of description, this part of the curve is called the rising edge of the transmittance curve; and as the wavelength enters the infrared band from the visible light band, at least part of the transmittance curve shows a downward trend. For the convenience of description, this part of the curve is called the falling edge of the transmittance curve. It should be noted that there may be local small-scale fluctuations in the rising edge or falling edge of the transmittance curve, and such small-scale fluctuations do not affect the overall change trend of the rising edge or the falling edge.

[0131] In the embodiment of the present application, the first wavelength is greater than or equal to 600nm and less than or equal to 660nm, the first wavelength is located at the falling edge of the first transmittance curve, and the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 20nm, the first wavelength and the second wavelength are close to each other, and the second wavelength is located at the falling edge of the second transmittance curve. Therefore, it can also be understood that the first wavelength corresponding to 50% transmittance in the falling edge of the first transmittance curve is greater than or equal to 600nm and less than or equal to 660nm. The difference between the first wavelength corresponding to 50% transmittance in the falling edge of the first transmittance curve and the second wavelength corresponding to 50% transmittance in the falling edge of the second transmittance curve is greater than or equal to 0 and less than or equal to 20nm.

[0132] The filter with the above parameters provided in the embodiment of the present application, when applied to a multi-spectral camera module, can make the spectral response curve of the multi-spectral camera module have a high degree of equivalence with the spectral response curves of the human eye and the three-channel camera module. Accordingly, after the spectral response curve of the multi-spectral camera module is mapped from high dimension to low dimension, it can be close to or equivalent to the spectral response curves of the human eye and the three-channel camera module, respectively. Therefore, the color restoration capability of the multi-spectral camera module and the accuracy of color correction of the three-channel camera module can be improved, the color cast problem can be reduced or avoided, the color authenticity of the output image of the three-channel camera module can be improved, and the user experience can be improved.

[0133] Specifically, at normal incidence, the range of the first wavelength corresponding to the filter at a transmittance of 50% is roughly equivalent to the corresponding wavelength range of the filter in the three-channel camera module, which can limit the spectral response range as a whole, and is conducive to making the spectral response curve of the multi-spectral camera module approach the spectral response curve of the human eye and the spectral response curve of the three-channel camera module after dimensionality reduction from high dimensions. In addition, the difference between the first wavelength and the second wavelength is within the range of 0-20nm, which can ensure that within the incident range of light, the transmittance curve of the filter can make the spectral response curve of the first camera module have a high degree of similarity with the spectral response curve of the human eye and the three-channel camera module, thereby reducing or avoiding color cast problems and improving the color authenticity of the output image.

[0134] In addition, compared to normal incidence, when the light incident on the surface of the filter has an angle, the optical path of the light in the filter film layer will increase, causing the transmittance of the same wavelength of light in the filter to change, resulting in an angle drift phenomenon of the transmittance curve (drifting towards the short-wave direction). That is, due to the change in the angle of the incident light, the transmittance curve of the filter is offset. Generally, the larger the angle of the incident light, the greater the offset of the transmittance curve. In an embodiment of the present application, the difference between the first wavelength under normal incidence and the second wavelength under oblique incidence is in the range of 0-20nm, so that when the incident angle of the light changes within the range of a first angle (for example, 35°), the transmittance curve of the filter can satisfy the high similarity between the spectral response curve of the multi-spectral camera module and the spectral response curve of the human eye and the three-channel camera module even if it is offset. In other words, a shift of the transmittance curve of the filter within 20nm can make the spectral response curve of the multi-spectral camera module more similar to the spectral response curves of the human eye and the three-channel camera module, thereby reducing or avoiding color cast problems and improving the consistency of color reproduction in the center and edges of the image.

[0135] Generally, infrared light will form a virtual image on the target surface of visible light imaging, affecting the color and quality of the image. The difference between the first wavelength and the second wavelength in the embodiment of the present application is within the range of 0-20nm, which ensures that the filter has a good cutoff effect on infrared light within the incident angle range, which is conducive to improving imaging quality and reducing the risk of false color.

[0136] In addition, the difference between the first wavelength and the second wavelength is within the range of 0-20, which constrains the angular offset of the transmittance curve and can reduce the color difference (color shading) of the module. Specifically, the incident angles of light at the center and edge of the filter are different, resulting in the transmittance curve at the edge of the filter being offset compared to the transmittance curve at the center. Accordingly, the spectral response curves at the center and edge of the multi-spectral camera module deviate, resulting in color difference between the center and edge of the image. The multi-spectral camera module has more spectral channels than the ordinary three-channel camera module, and it is more difficult to perform additional corrections. The filter provided in the present application has a small angular offset of the transmittance curve, which can reduce the deviation of the spectral response curve of the camera module at the center and edge at the source, thereby reducing the color difference between the center and edge of the image. Therefore, the color shading of the multi-spectral camera module can be reduced without additional correction to ensure the accuracy of the color restoration of the entire picture and the accuracy when used for color correction.

[0137] In some embodiments, on the first transmittance curve, the wavelength corresponding to 50% transmittance includes a third wavelength, the third wavelength is greater than or equal to 400nm and less than or equal to 440nm. On the second transmittance curve, the wavelength corresponding to 50% transmittance includes a fourth wavelength, the difference between the third wavelength and the fourth wavelength is greater than or equal to 0 and less than or equal to 20nm.

[0138] In the embodiment of the present application, the third wavelength is greater than or equal to 400nm and less than or equal to 440nm, the third wavelength is located at the rising edge of the first transmittance curve, and the fourth wavelength is located at the rising edge of the second transmittance curve. Therefore, it can also be understood that the third wavelength corresponding to 50% transmittance in the rising edge of the first transmittance curve is greater than or equal to 400nm and less than or equal to 440nm. The difference between the third wavelength corresponding to 50% transmittance in the rising edge of the first transmittance curve and the fourth wavelength corresponding to 50% transmittance in the rising edge of the second transmittance curve is greater than or equal to 0 and less than or equal to 20nm.

[0139] At oblique incidence, the third wavelength range corresponding to the filter at a transmittance of 50% is 400nm-440nm, which is roughly equivalent to the corresponding wavelength range of the filter in the three-channel camera module. The spectral response range can be limited as a whole, so that the spectral response curve of the first camera module is highly similar to the spectral response curves of the human eye and the three-channel camera module, respectively, which is beneficial to improving the color restoration capability of the first camera module and the accuracy of color correction of the three-channel camera module, reducing or avoiding color cast problems, and improving the color authenticity of the three-channel camera module image.

[0140] The difference between the third wavelength and the fourth wavelength is in the range of 0-20 nm, which can limit the angular offset of the transmittance curve of the filter, improve the color reproduction consistency between the center and the edge of the image, and reduce the chromatic aberration between the center and the edge of the image.

[0141] In the embodiment of the present application, the angle of incidence refers to the angle between the light incident on the surface of the filter and the normal line of the surface of the filter. 50% transmittance refers to the position on the transmittance curve where the transmittance is 50%. The rising edge is the section on the transmittance curve where the transmittance shows an overall upward trend with the increase of wavelength, for example, the section where the transmittance rises from the lowest value to the highest value with the increase of wavelength, or the section where the transmittance rises from 5% to 80%. The falling edge is the section on the transmittance curve where the transmittance shows an overall downward trend with the increase of wavelength, for example, the section where the transmittance drops from the highest value to the lowest value with the increase of wavelength, or the section where the transmittance drops from 80% to 5%. The band corresponding to the rising edge overlaps with the blue light band (approximately 435nm to 450nm), and the band corresponding to the falling edge overlaps with the red light band (approximately 622nm to 760nm).

[0142] In some embodiments, the first wavelength and the second wavelength belong to the red light band.

[0143] In some embodiments, the third wavelength and the fourth wavelength belong to a blue light band.

[0144] In some embodiments, the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 10 nm. That is, the difference between the wavelength corresponding to 50% transmittance of the first transmittance curve in the falling edge and the wavelength corresponding to 50% transmittance of the second transmittance curve in the falling edge is greater than or equal to 0 and less than or equal to 10 nm.

[0145] In some embodiments, the difference between the third wavelength and the fourth wavelength is greater than or equal to 0 and less than or equal to 10 nm. That is, the difference between the wavelength corresponding to 50% transmittance of the first transmittance curve in the rising edge and the wavelength corresponding to 50% transmittance of the second transmittance curve in the rising edge is greater than or equal to 0 and less than or equal to 10 nm.

[0146] As mentioned above, when the angle of the incident light changes, the transmittance curve of the filter will drift. By limiting the difference between the first wavelength and the second wavelength to within 10nm, when the incident angle changes within the first angle (for example, 35°), the transmittance curve of the filter can be offset to meet the high similarity between the spectral response curve of the multi-spectral camera module and the spectral response curve of the human eye and the three-channel camera module, further improving the consistency of color reproduction at the center and edges of the image. In addition, by limiting the difference range, the colorshading of the module can also be reduced, further improving the accuracy of color reproduction of the entire picture and the accuracy when used for color correction.

[0147] In some embodiments, on the first transmittance curve, the average transmittance in the 350 nm to 395 nm band is less than or equal to 3%, and the average transmittance in the 700 nm to 780 nm band is less than or equal to 2%.

[0148] In some embodiments, on the second transmittance curve, the average transmittance in the 350 nm to 395 nm band is less than or equal to 4%, and the average transmittance in the 700 nm to 780 nm band is less than or equal to 3%.

[0149] The color restoration of the multi-spectral camera module is aimed at the human eye. Generally, the wavelength range perceived by the human eye is between 400nm and 700nm. Light with wavelengths exceeding the sensing range of the human eye is a meaningless signal for the multi-spectral camera module. In the embodiment of the present application, the cut-off wavelength of the filter corresponds to the cut-off wavelength position of the visual response curve of the human eye. By filtering out light waves that exceed the sensing band of the human eye, the effective information has a better signal-to-noise ratio, which is conducive to improving image quality.

[0150] In some embodiments, on the first transmittance curve, the minimum transmittance in the 440nm-580nm band is greater than or equal to 70%, and the average transmittance in the 440nm-580nm band is greater than or equal to 80%.

[0151] In some embodiments, on the second transmittance curve, the minimum transmittance in the 440 nm to 580 nm band is greater than or equal to 70%, and the average transmittance in the 440 nm to 580 nm band is greater than or equal to 80%.

[0152] 440nm~580nm is the stable section of filter transmittance. By constraining the minimum value within this band, the filter can be prevented from having large transmittance fluctuations. Because the design of large transmittance fluctuations in the stable section is easy to cause inconsistent transmittance of different filters in actual production, affecting the consistency of the effect of the multi-spectral camera module in the application, thereby affecting the consistency of the effect color. By constraining the average transmittance value of the 440nm~580nm band, the image quality can be improved. Because too low transmittance will affect the overall sensitivity of the multi-spectral camera module, the camera will need a longer exposure time under the same environment, which is prone to image smear and blur, affecting the image quality.

[0153] In some embodiments, the material of the filter may be resin or glass. The embodiment of the present application may obtain the filter in the aforementioned embodiment of the present application by adjusting the thickness of the filter, the type and / or thickness of the coating, adding an organic material with specific spectral absorption characteristics to the filter, and the present application does not limit the specific implementation of the filter.

[0154] For further understanding, Figures 4 to 9 Schematic diagrams of transmittance curves of several filters provided in the embodiments of the present application are shown respectively.

[0155] refer to Figures 4 to 9 In the figure, λ1 represents the first wavelength corresponding to 50% transmittance at the falling edge of the first transmittance curve, λ3 represents the third wavelength corresponding to 50% transmittance at the rising edge of the first transmittance curve. λ2 represents the second wavelength corresponding to 50% transmittance at the falling edge of the second transmittance curve, and λ4 represents the fourth wavelength corresponding to 50% transmittance at the rising edge of the second transmittance curve.

[0156] For example, refer to Figures 4 to 9 , the approximate values ​​of the corresponding parameters are shown in Table 1 below.

[0157] Table 1

[0158]

[0159] It can be understood that on the first transmittance curve, if the falling edge fluctuates near 50% transmittance, the wavelength corresponding to 50% transmittance may include multiple wavelengths in the range of 600nm to 660nm, and the first wavelength λ1 may be any one of the multiple wavelengths in the range of 600nm to 660nm, for example, the shortest / longest / roughly centered one of the multiple wavelengths in the range of 600nm to 660nm. On the first transmittance curve, if the rising edge fluctuates near 50% transmittance, the wavelength corresponding to 50% transmittance may include multiple wavelengths in the range of 400nm to 440nm, and the third wavelength λ3 may be any one of the multiple wavelengths in the range of 400nm to 440nm, for example, the shortest / longest / roughly centered one of the multiple wavelengths in the range of 400nm to 440nm.

[0160] Similarly, on the second transmittance curve, if the falling edge fluctuates near the 50% transmittance, the wavelength corresponding to the 50% transmittance may include multiple wavelengths whose difference with the first wavelength λ1 meets the requirement, and the second wavelength λ2 may be any one of the multiple wavelengths whose difference with the first wavelength λ1 meets the requirement, for example, the one farthest / closest to the first wavelength λ1. On the second transmittance curve, if the rising edge fluctuates near the 50% transmittance, the wavelength corresponding to the 50% transmittance may include multiple wavelengths whose difference with the third wavelength λ3 meets the requirement, and the fourth wavelength λ4 may be any one of the multiple wavelengths whose difference with the third wavelength λ3 meets the requirement, for example, the one farthest / closest to the third wavelength λ3.

[0161] Proven, Figures 4 to 9 The filters shown can make the spectral response curve of the multi-spectral camera module have a high degree of similarity with the spectral response curves of the human eye and the three-channel camera module.

[0162] The effect of the filter provided in this application can be verified through experimental measurement, simulation, etc.

[0163] For example, in a method based on experimental measurement, the spectral response curve of a multi-spectral camera module (including the filter provided by the present application) (hereinafter referred to as the first spectral response curve for ease of description) and the spectral response curve of a three-channel camera module (hereinafter referred to as the second spectral response curve for ease of description) can be measured experimentally. The spectral response curve of the human eye (hereinafter referred to as the third spectral response curve for ease of description) can adopt the existing spectral three-stimulus value curve. Based on the transformation relationship between the first spectral response curve and the third spectral response curve, the color information of the target object photographed by the multi-spectral camera module can be obtained, and the color restoration ability of the multi-spectral camera module can be judged by the human eye. Based on the transformation relationship between the first spectral response curve and the second spectral response curve, the color space information corresponding to the multi-spectral camera module can be mapped to the three-channel camera module, and the human eye can judge whether the image presented by the three-channel camera module has a color cast problem, so as to judge the accuracy of the color correction of the multi-spectral camera module.

[0164] For example, in a simulation-based method, a first spectral response curve can be obtained by simulation, and a second spectral response curve can be obtained by simulation or experiment. The third spectral response curve can be a spectral tristimulus value curve. The dimensionality reduction fitting accuracy between the first spectral response curve and the second spectral response curve and the dimensionality reduction fitting accuracy between the first spectral response curve and the third spectral response curve can be calculated by computer simulation. The color restoration capability of the multi-spectral camera module can be judged based on the dimensionality reduction fitting accuracy between the first spectral response curve and the third spectral response curve, and the accuracy of the multi-spectral camera module for color correction of the three-channel camera module can be judged based on the dimensionality reduction fitting accuracy between the first spectral response curve and the second spectral response curve.

[0165] For ease of understanding, the effect of the filter provided in this application can also be verified by formula deduction, which is described in detail below.

[0166] In some embodiments, the equivalence (or similarity) of the spectral response curves of two camera modules (which can be regarded as a special three-channel camera module by the human eye) can be described by Vora-Value. Vora-Value is a number between 0 and 1. When Vora-Value is 1, it means that the spectral response curves of the two camera modules are completely equivalent, and their spectral perception functions (or spectral response matrices) can be linearly converted. For ease of quantification and expression, Vora-Value is defined as v below. For different comparison objects, the superscript or subscript of v is different.

[0167] In some embodiments, the similarity between the spectral response curve of the multi-spectral camera module and the spectral response curve of the human eye is expressed as v0 Specifically, it can be:

[0168]

[0169] In formula (1):

[0170] Q N×C is a spectral response matrix of the multi-spectral camera module, which is obtained based on the spectral response curve of the multi-spectral camera module;

[0171] is a spectral response matrix of a human eye, which is obtained based on a spectral response curve of the human eye;

[0172] P{} is an operator. For any matrix A, P{A}=A[A T A]- 1 A T ;

[0173] Its order is N×N;

[0174] Its order is N×N;

[0175] Tr() is the trace operation of a square matrix, that is, the sum of all elements on the main diagonal of the square matrix;

[0176] N is equal to the number of sampling points, and C is equal to the number of channels of the multispectral camera module.

[0177] The multi-spectral camera module has more channels and can reduce the dimension from high dimension to close to the spectral response curve of the human eye. When the spectral response curve of the multi-spectral camera module is suitable, v 0 As close to 1 as possible. Accordingly, in the color restoration process, the accuracy of the conversion result when the multispectral camera module and the human eye perform color space conversion is getting higher and higher, which means that the multispectral camera module has better color restoration capabilities and can reduce or avoid the occurrence of color cast problems.

[0178] When v 0 When =1, it indicates that the spectral response curve of the multispectral camera module is completely equivalent to the spectral response curve of the human eye, and the chromaticity perception ability of the multispectral camera module is completely adapted to the chromaticity perception ability of the human eye. The chromaticity space can be directly converted through linear transformation (such as matrix addition and multiplication). Accordingly, the multispectral camera module can accurately restore the colors seen by the human eye without color cast.

[0179] For the existing three-channel camera module, due to the limitation of the film material, its spectral response curve cannot be exactly the same as the spectral response curve of the human eye. Therefore, the similarity between the spectral response curve of the existing three-channel camera module and the spectral response curve of the human eye is usually less than 0.9, which means that the color reproduction ability of the existing three-channel camera module is weak and certain colors are prone to color cast.

[0180] In the embodiment of the present application, the above formula (1) can be used to calculate v 0 , through v 0 The value of can determine the color restoration capability of the multi-spectral camera module. For example, if v 0 If it is greater than or equal to a certain threshold (for example, 0.93), it means that the spectral response curve of the multi-spectral camera module can be as close as possible to the spectral response curve of the human eye after dimensionality reduction from a high dimension, which means that the color restoration ability of the multi-spectral camera module is relatively high.

[0181] In some embodiments, the similarity between the spectral response curve of the multi-spectral camera module and the spectral response curve of the three-channel camera module is represented by v′, which can be specifically:

[0182]

[0183] In formula (2):

[0184] Q N×C is a spectral response matrix of the multi-spectral camera module, which is obtained based on the spectral response curve of the multi-spectral camera module;

[0185] X′ N×3 is a spectral response matrix of a three-channel camera module, which is obtained based on a spectral response curve of the three-channel camera module;

[0186] P{} is an operator. For any matrix A, P{A}=A[A T A]- 1 A T ;

[0187] P{Q N×C =Q N×C [Q N×C T Q N×C ]- 1 Q N×C T , whose order is N×N;

[0188] P{X′ N×3} = X′ N×3 [X′ N×3 T X′ N×3 ]-1 X′ N×3 T , whose order is N×N;

[0189] Tr() is the trace operation of a square matrix, that is, the sum of all elements on the main diagonal of the square matrix;

[0190] N is equal to the number of sampling points, and C is equal to the number of channels of the multispectral camera module.

[0191] For example, if the camera device or electronic device includes i three-channel camera modules, different three-channel camera modules have their own spectral response curves and spectral response matrices. To distinguish the spectral response matrices of different three-channel camera modules, for i=1, 2, 3, ..., n, where n is an integer greater than or equal to 1, the spectral response matrices of the three-channel camera modules can be respectively expressed as Different values ​​of i represent different three-channel camera modules. For example, taking the three-camera scene as an example, i = 1, 2, 3, which can represent the wide-angle camera module, telephoto camera module, and ultra-wide-angle camera module respectively, and the corresponding spectral response matrices are Similarly, the similarity v′ between the spectral response curve of the multi-spectral camera module and the spectral response curve of each three-channel camera module can be expressed as v 1 , v 2 , v 3 ,…,vn, when calculating, X′ in formula (2) N×3 Replace them with

[0192] The multi-spectral camera module has more channels and can be transformed from high-dimensionality to a spectral response curve close to that of the three-channel camera module. When the spectral response curve of the multi-spectral camera module is appropriate, v′ can be made as close to 1 as possible. Accordingly, in the color correction process, the multi-spectral camera module can be more accurately mapped from high-dimensionality to the three-channel camera module, so that the three-channel camera module can accurately obtain the real color information and avoid color cast problems.

[0193] When v′=1, it indicates that the spectral response curve of the multi-spectral camera module is completely equivalent to the spectral response curve of the three-channel camera module, and the chromaticity perception ability of the multi-spectral camera module is completely adapted to the chromaticity perception ability of the three-channel camera module, and the chromaticity space can be directly converted through linear transformation. Accordingly, the three-channel camera module can accurately obtain the color of the multi-spectral camera module, and when the color of the multi-spectral camera module is accurate, the three-channel camera module will not have color cast.

[0194] In the embodiment of the present application, v' can be calculated using the above formula (2), and the color correction capability of the multi-spectral camera module can be determined by the value of v'. For example, if v' is greater than or equal to a certain threshold (e.g., 0.93), it can be shown that the spectral response curve of the multi-spectral camera module can be as close as possible to the spectral response curve of the three-channel camera module after dimensionality reduction from a high dimension, and it can also be shown that the accuracy of the multi-spectral camera module in color correction of the three-channel camera module is high.

[0195] For Q in formula (1) and formula (2), N×C , which can be obtained in the following ways.

[0196] In one example, the spectral response curve of the multi-spectral camera module can be obtained first. The spectral response curve of the multi-spectral camera module is obtained by directly measuring or simulating the entire module, and includes spectral response curves of C channels, wherein the spectral response curve of each channel takes into account the influence factors of the optical lens, filter and image sensor. Then, based on the spectral response curve of the multi-spectral camera module, the spectral response curve of each channel in the C channels is sampled at N points to obtain Q N×C .

[0197] In another example, instead of obtaining the spectral response curve of the multi-spectral camera module, the entire module can be directly measured or simulated using discrete wavelengths of light to obtain the response value of each channel to each wavelength of light, thereby obtaining Q N×C .

[0198] In another example, Q can be obtained based on the following formula (3): N×C :

[0199] Q N×C =M N×C ⊙T N×1 ⊙L N×1 (3)

[0200] In formula (3):

[0201] M N×C A matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the image sensor;

[0202] T N×1 is a matrix obtained by sampling N points based on the transmittance curve of the filter;

[0203] L N×1 is a matrix obtained by sampling N points based on the transmittance curve of the optical lens;

[0204] ⊙ is the dot product.

[0205] In an embodiment of the present application, a multi-spectral camera module includes an optical lens, a filter and an image sensor, wherein the optical lens is used to focus light from a target object onto the image sensor, and the filter is located between the optical lens and the image sensor for filtering. The image sensor is a multi-spectral image sensor having multiple response channels (i.e., multiple filter channels, also referred to as channels), which can respond to light within a continuous wavelength range, wherein each channel can obtain a corresponding spectral response curve, and the set formed by the spectral response curves of each channel is a spectral response curve corresponding to the image sensor. Both the optical lens and the filter are optical elements, which will affect the spectrum reaching the image sensor. Therefore, the spectral response characteristics of the multi-spectral camera module need to comprehensively consider the transmittance curve of the optical lens, the transmittance curve of the filter, and the spectral response curve of the image sensor.

[0206] In the embodiment of the present application, the transmittance curve of the optical lens is a curve of the correspondence between the transmittance of the optical lens and the wavelength, the transmittance curve of the filter is a curve of the correspondence between the transmittance of the filter and the wavelength, and the spectral response curve of the image sensor is a curve of the correspondence between the spectral response of the image sensor and the wavelength. The transmittance curve of the optical lens, the transmittance curve of the filter, and the spectral response curve of the image sensor are measured separately. The spectral response curve of the multi-spectral camera module can be indirectly obtained through the transmittance curve of the optical lens, the transmittance curve of the filter, and the spectral response curve of the image sensor.

[0207] It can be understood that the spectral response curve of the image sensor includes the spectral response curve corresponding to each of the C channels. It can also be said that the spectral response curve of the image sensor is a collection of spectral response curves of the C channels.

[0208] In some embodiments, by performing N-point discrete sampling on the transmittance curve of the optical lens, the transmittance matrix L of the optical lens can be obtained, and its order is N×1, that is, N rows and 1 column, that is, L in formula (3): N×1 By performing N-point discrete sampling on the transmittance matrix of the filter, the transmittance matrix T of the filter can be obtained, whose order is N×1, that is, T in formula (3) N×1 By performing N-point discrete sampling on the spectral response curve corresponding to each of the C channels of the image sensor, the spectral response matrix M of the image sensor can be obtained, whose order is N×C (i.e., N rows and C columns), which is M in formula (3): N×C .

[0209] Here, the N sampling points selected when discrete sampling is performed on the transmittance curve of the filter, the N sampling points selected when discrete sampling is performed on the transmittance curve of the optical lens, and the N sampling points selected when discrete sampling is performed on each channel of the image sensor are the same, that is, the sampling positions are the same. For example, within the preset wavelength range, every 5 nanometers is used as a sampling point.

[0210] For X′ in formula (2) N×3 , which can be obtained in the following ways.

[0211] In one example, the spectral response curve of the three-channel camera module can be obtained first. The spectral response curve of the three-channel camera module is obtained by directly measuring or simulating the entire module, which includes the spectral response curves of three channels, wherein the spectral response curve of each channel takes into account the influence factors of the optical lens, filter and image sensor in the module. Then, based on the spectral response curve of the three-channel camera module, the spectral response curve of each channel in the three channels is sampled at N points to obtain X′ N×3 .

[0212] In another example, instead of obtaining the spectral response curve of the three-channel camera module, the entire module can be directly measured or simulated using discrete wavelengths of light to obtain the response value of each channel to each wavelength of light, thereby obtaining X′ N×3 .

[0213] In yet another example, similar to formula (3), X′ N×3 It can be obtained by multiplying the transmittance matrix of the optical lens in the three-channel camera module (obtained by sampling at N points on the transmittance curve of the optical lens), the transmittance matrix of the filter in the three-channel camera module (obtained by sampling at N points on the transmittance curve of the filter), and the spectral response matrix of the image sensor in the three-channel camera module (obtained by sampling at N points in each channel of the spectral response curve of the image sensor). Among them, the transmittance curve of the optical lens, the transmittance curve of the filter, and the spectral response curve of the image sensor in the three-channel camera module are obtained by measurement respectively.

[0214] It can be understood that the spectral response curve of the image sensor of the three-channel camera module includes the spectral response curve corresponding to each of the three channels, or it can be said that its spectral response curve is a collection of spectral response curves of the three channels. In addition, when discretely sampling the corresponding curves, the selected N sampling points are the same, that is, the sampling positions are the same.

[0215] The human eye can be equated to a special three-channel camera module. The spectral response matrix of the human eye can be obtained by discrete sampling of the spectral response curve corresponding to the human eye. Its order is N×3 (i.e. N rows and 3 columns). It can also be expressed as X 0 . Specifically, It can be obtained by sampling N points in each of the three channels based on the spectral response curve of the human eye. That is, the spectral response curve of the human eye includes the spectral response curves corresponding to the three channels respectively. It is obtained by sampling N points on three curves respectively.

[0216] It should be noted that the sampling positions selected when sampling the spectral response curve of the three-channel camera module and the spectral response curve of the human eye are the same as the sampling positions selected when sampling the multi-spectral camera module. For example, within the same wavelength range, every 5 nanometers is used as a sampling point.

[0217] Still refer to Figures 4 to 9 According to formula (1) and formula (2), the similarity between the spectral response curve of the multi-spectral camera module and the spectral response curve of the human eye and the three-channel camera module is calculated as follows.

[0218] Figures 4 to 9 The transmittance curves of the filters shown include the transmittance curves when the AOI is 0° and the transmittance curves when the AOI is 35°. Taking i=1, 2, 3 in formula (2) as an example, i=1, 2, 3 represent the wide-angle camera module, telephoto camera module and ultra-wide-angle camera module respectively, the corresponding spectral response matrices are The similarity calculated according to formula (2) can be expressed as v 1 , v 2 , v 3 The spectral response matrix of the human eye is The similarity calculated according to formula (1) can be expressed as v 0 .

[0219] Proven, Figure 4 The transmittance curve of the filter (made of glass) shown can make the Vora value between the multi-spectral camera module and the human eye, wide-angle camera module, telephoto camera module and ultra-wide-angle camera module as follows:

[0220] When AOI = 0°, v 0 =0.9933; v 1 =0.9935; v 2 =0.9960; v 3 =0.9926.

[0221] When AOI = 35°, v 0 =0.9835; v 1 =0.9950; v 2 =0.9891; v 3 =0.9882.

[0222] It can be seen that within the incident angle range of the filter, v 0 、v 1 、v 2 、v 3 Both are greater than 0.98.

[0223] Proven, Figure 5 The transmittance curve of the filter shown can make the Vora value between the multi-spectral camera module and the human eye, wide-angle camera module, telephoto camera module and ultra-wide-angle camera module as follows:

[0224] When AOI = 0°, v 0 =0.9799; v 1 =0.9958; v 2 =0.9866; v 3 =0.9893.

[0225] When AOI = 35°, v 0 =0.9743; v 1 =0.9933; v 2 =0.9809; v 3 =0.9774.

[0226] It can be seen that within the incident angle range of the filter, v 0 、v 1 、v 2 、v 3 Both are greater than 0.97.

[0227] Proven, Figure 6 The transmittance curve of the filter shown can make the Vora value between the multi-spectral camera module and the human eye, wide-angle camera module, telephoto camera module and ultra-wide-angle camera module as follows:

[0228] When AOI = 0°, v 0 =0.9786; v 1 =0.9911; v 2 =0.9904; v 3 =0.9939.

[0229] When AOI = 35°, v 0 =0.9697; v 1=0.9941; v 2 =0.9798; v 3 =0.9839.

[0230] It can be seen that within the incident angle range of the filter, v 0 、v 1 、v 2 、v 3 Both are greater than 0.96.

[0231] Proven, Figure 7 The transmittance curve of the filter (made of resin) shown can make the Vora value between the multi-spectral camera module and the human eye, wide-angle camera module, telephoto camera module and ultra-wide-angle camera module as follows:

[0232] When AOI = 0°, v 0 =0.9841; v 1 =0.9865; v 2 =0.9942; v 3 =0.9899.

[0233] When AOI = 35°, v 0 =0.9768; v 1 =0.9952; v 2 =0.9845; v 3 =0.9880.

[0234] It can be seen that within the incident angle range of the filter, v 0 、v 1 、v 2 、v 3 Both are greater than 0.97.

[0235] Proven, Figure 8 The transmittance curve of the filter shown can make the Vora value between the multi-spectral camera module and the human eye, wide-angle camera module, telephoto camera module and ultra-wide-angle camera module as follows:

[0236] When AOI = 0°, v 0 =0.9824; v 1 =0.9872; v 2 =0.9933; v 3 =0.9907.

[0237] When AOI = 35°, v 0 =0.9744; v 1 =0.9947; v 2 =0.9832; v 3 =0.9828.

[0238] It can be seen that within the incident angle range of the filter, v 0 、v 1 、v 2 、v 3 Both are greater than 0.97.

[0239] Proven, Fig. 9 The transmittance curve of the filter shown can make the Vora value between the multi-spectral camera module and the human eye, wide-angle camera module, telephoto camera module and ultra-wide-angle camera module as follows:

[0240] When AOI = 0°, v 0 =0.9799; v 1 =0.9958; v 2 =0.9866; v 3 =0.9893.

[0241] When AOI = 35°, v 0 =0.9727; v 1 =0.9892; v 2 =0.9768; v 3 =0.9690.

[0242] It can be seen that within the incident angle range of the filter, v 0 、v 1 、v 2 、v 3 Both are greater than 0.96.

[0243] According to v 0 From the value of , we can know that the spectral response curve of the multispectral camera module can be as close to the spectral response curve of the human eye as possible after dimensionality reduction from high dimension. Therefore, the color restoration ability of the multispectral camera module can be improved, and the color cast problem can be reduced or avoided, thereby improving the color authenticity of the output image of the multispectral camera module.

[0244] According to v 1 、v 2 、v 3 From the value of , we can know that the spectral response curve of the multi-spectral camera module can be as close as possible to the spectral response curve of the three-channel camera module after dimensionality reduction from high dimension. Therefore, the accuracy of color correction of the three-channel camera module by the multi-spectral camera module can be improved, the color cast problem can be reduced or avoided, and the color authenticity of the output image of the three-channel camera module can be improved.

[0245] It is difficult for existing three-channel camera modules to achieve consistent spectral response curves. Therefore, there are color differences between the images output by different camera modules for the same scene, and the color consistency is poor, which affects the switching experience. In this application, different three-channel camera modules can correspond to good Vora-Values, that is, the spectral response curve of the multi-spectral camera module can be as close as possible to the spectral response curve of each three-channel camera module after dimensionality reduction from high dimensions. In this way, when the color information of the multi-spectral camera module is uniformly mapped to different three-channel camera modules, it can be ensured that different three-channel camera modules are aligned to the same standard, that is, color information is obtained from the multi-spectral camera module, which can improve the color consistency of the images output by multiple three-channel camera modules.

[0246] In addition, within the incident angle range of the filter, even if the transmittance curve of the filter drifts, it can still meet a higher Vora value. This can reduce the deviation between the spectral response curve at the center and the spectral response curve at the edge of the multi-spectral camera module, ensuring the accuracy of color reproduction of the entire picture.

[0247] An embodiment of the present application also provides a camera module, which includes an optical lens, an image sensor and the aforementioned filter, wherein the filter is arranged between the optical lens and the image sensor, the optical lens is used to receive light from the target object, the filter is used to pass visible light in the light, and the image sensor is used to receive visible light to obtain spectral information of the target object, wherein the number of channels of the image sensor is greater than 3.

[0248] The camera module is a multispectral camera module, which may also be referred to as a multispectral module.

[0249] It can be understood that the number of channels of the camera module is determined based on the number of channels of the image sensor. Specifically, the optical lens and the filter each have one channel, so the number of channels of the camera module is the same as the number of channels of the image sensor. Accordingly, if the number of channels of the image sensor is greater than 3, the number of channels of the camera module is also greater than 3. For example, if the number of channels is C, then the camera module is a C-channel camera.

[0250] In some embodiments, the filter is coated with an infrared cut-off film.

[0251] The embodiment of the present application also provides a camera device, which includes a first camera module, which includes an optical lens, a filter and an image sensor arranged in sequence along the optical axis direction, the optical lens is used to receive light from the target object, the filter is used to pass visible light in the light, the image sensor is used to receive visible light to obtain spectral information of the target object, and the number of channels of the image sensor is greater than 3. The filter is the filter in the above embodiment.

[0252] In some embodiments, the camera device further comprises at least one second camera module, the second camera module is a three-channel camera, the first camera module is a C-channel camera and C is greater than 3, and the similarity v between the spectral response curve of the first camera module and the spectral response curve of the human eye is 0 is greater than or equal to 0.93, and the similarity v′ between the spectral response curve of the first camera module and the spectral response curve of the second camera module is greater than or equal to 0.93; wherein,

[0253]

[0254] Q N×C is a spectral response matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the first camera module, P{Q N×C =Q N×C [Q N×C T Q N×C ]- 1 Q N×C T ;

[0255] is a spectral response matrix obtained by sampling N points in each of the three channels based on the spectral response curve of the human eye,

[0256] X′ N×3 is a spectral response matrix obtained by sampling N points in each of the three channels based on the spectral response curve of the second camera, P{X′ N×3} = X′ N×3 [X′ N×3 T X′ N×3 ]- 1 X′ N×3 T ;

[0257] Tr() is the trace.

[0258] About v 0 The specific calculation method of and v′ and the related contents of each parameter can be referred to the description of formula (1) and formula (2). For the sake of brevity, they will not be described in detail here.

[0259] In some embodiments, Q N×C The spectral response curve of the entire first camera module can be measured and then obtained by discrete sampling of the spectral response curve of the module.

[0260] In other embodiments, Q N×C =MN×C ⊙T N×1 ⊙L N×1 ,in:

[0261] M N×C A matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the image sensor;

[0262] T N×1 is a matrix obtained by sampling N points based on the transmittance curve of the filter;

[0263] L N×1 It is a matrix obtained by sampling N points based on the transmittance curve of the optical lens.

[0264] That is to say, the spectral response curve of the image sensor, the transmittance curve of the filter, and the transmittance curve of the optical lens can be measured respectively, and then discrete sampling can be performed to obtain M N×C , L N×1 、T N×1 , and then obtain Q by the dot product of the three N×C .

[0265] About Q N×C The specific calculation method and related contents of each parameter can be referred to the description of formula (3), which will not be described in detail here for the sake of brevity.

[0266] In some embodiments, X′ N×3 The spectral response curve of the entire second camera module can be measured and then obtained by discrete sampling of the spectral response curve of the module. Alternatively, the spectral response curve of the image sensor in the second camera module, the transmittance curve of the filter and the transmittance curve of the optical lens can be measured respectively, and then discrete sampling can be performed to obtain the corresponding matrix, and then X′ can be obtained by the dot product of the three matrices. N×3 .

[0267] In some embodiments, It can be obtained by discrete sampling of the spectral response curve of the human eye.

[0268] In some embodiments, the second camera module may be a telephoto camera module, a wide-angle camera module, or an ultra-wide-angle camera module. If the camera device includes multiple second camera modules, the focal lengths of the multiple second camera modules may be the same or different. Exemplarily, the multiple second camera modules may achieve full focal length coverage.

[0269] In an embodiment of the present application, the second camera module includes a filter, for example, the filter is used to filter out other bands except visible light, and accordingly, the second camera module can output a visible light image.

[0270] An embodiment of the present application also provides an electronic device, which includes an image processing chip and the multispectral image head module involved in the aforementioned embodiment (that is, the aforementioned first camera module), and the image processing chip is used to process images acquired by the multispectral camera module.

[0271] An embodiment of the present application also provides an electronic device, which includes an image processing chip and the camera device involved in the above-mentioned embodiment, and the image processing chip is used to process the image acquired by the camera device.

[0272] Exemplarily, the image processing chip may be the image processor mentioned in the aforementioned embodiment.

[0273] In some embodiments, the camera device also includes at least one second camera module, which is a three-channel camera, and the image processing chip is used to correct the color of the target object acquired by the second camera module based on the spectral information of the target object acquired by the multi-spectral camera module.

[0274] Fig.10 A schematic flow chart of a camera module design method provided by an embodiment of the present application is shown. Fig.10 The number of color channels sensed by the multi-spectral camera module (hereinafter also referred to as the first camera module) designed by the method 400 shown is greater than the number of color channels sensed by the three-channel camera module (hereinafter also referred to as the second camera module). For example, the number of channels of the multi-spectral camera module is greater than 3. The method 400 includes steps S410 to S420, which are described below in conjunction with the accompanying drawings.

[0275] S410, obtaining an initial spectral response matrix of the multi-spectral camera module, a spectral response matrix of a human eye, and a spectral response matrix of each second camera module in at least one second camera module.

[0276] S420, based on the optimization target, optimizing the initial spectral response matrix of the multi-spectral camera module to obtain the target spectral response matrix of the multi-spectral camera module.

[0277] In the embodiment of the present application, the multispectral camera module is a C-channel camera, where C is an integer greater than 3. Exemplarily, on the image sensor of the multispectral camera module, each photosensitive unit includes C different filter channels, where C>3. That is, the number of channels of the image sensor of the multispectral camera module is greater than 3.

[0278] In the embodiment of the present application, the multi-spectral camera module includes an optical lens, a filter and an image sensor. The optical lens and the filter are both optical elements, which will affect the spectrum reaching the image sensor. Therefore, the spectral response characteristics of the multi-spectral camera module need to comprehensively consider the transmittance curve of the optical lens, the transmittance curve of the filter and the spectral response curve of the image sensor.

[0279] The spectral response characteristics of the entire multi-spectral camera module can be expressed as the spectral response matrix Q N×C (can also be expressed as Q) means, specifically it can be expressed as Q N×C =M N×C ⊙T N×1 ⊙L N×1 .

[0280] M N×C is a matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the image sensor; T N×1 is a matrix obtained by sampling N points based on the transmittance curve of the filter; L N×1 is the matrix obtained by N-point sampling based on the transmittance curve of the optical lens; ⊙ is the dot product.

[0281] It can be understood that the spectral response curve of the image sensor includes the spectral response curve corresponding to each of the C channels. It can also be said that the spectral response curve of the image sensor is a collection of spectral response curves of the C channels.

[0282] It can be seen that by adjusting the spectral response curve of the image sensor (corresponding to M N×C ), filter transmittance curve (corresponding to T N×1 ) and the transmittance curve of the optical lens (corresponding to L N×1 ) can adjust the spectral response characteristics of the multi-spectral camera module (corresponding to Q N×C ).

[0283] For example, taking the transmittance curve of the optimized filter as an example, before optimization, the filter has an initial transmittance matrix T′ N×1 , the multi-spectral camera module has an initial spectral response matrix Q′ N×C , where Q′ N×C =M N×C ⊙T′ N×1 ⊙L N×1 After optimizing the transmittance curve of the filter, the filter has a target transmittance matrix T″ N×1 , the multi-spectral camera module has a target spectral response matrix Q″ N×C , where Q″ N×C =M N×C ⊙T″ N×1 ⊙LN×1 . The spectral response matrix of the image sensor and the transmittance matrix of the optical lens remain unchanged.

[0284] In the embodiment of the present application, the second camera module is a three-channel camera. It can be understood that on the image sensor of the second camera module, each photosensitive unit includes three different filter channels, for example, red, green, and blue filter channels or red, yellow, and blue filter channels. Each filter channel corresponds to a spectral response curve. That is, the number of channels of the image sensor of the second camera module is 3.

[0285] In the embodiment of the present application, similar to the multi-spectral camera module, the human eye and the second camera module also have corresponding spectral response curves (or spectral response characteristics), wherein the spectral response curve corresponding to the human eye includes the response curve of the human eye to red, green and blue light, and the spectral response curve corresponding to the second camera module includes its response curve to three different wavelengths of light (such as red, green and blue light).

[0286] The method 400 regards the human eye as a special three-channel camera module. Set i=0, 1, 2, 3, ..., n, where n is an integer greater than or equal to 1. When i is 0, it represents the human eye, and when i is 1, 2, 3, ..., n, it represents a different second camera module. Based on the spectral response curve of the three-channel camera module, the spectral response matrix X of the three-channel camera module can be discretely sampled. i , whose order is N×3 (i.e., N rows and 3 columns). In some embodiments, X i It can also be expressed as That is, the spectral response matrix of the human eye is expressed as The spectral response matrices of different second camera modules are expressed as

[0287] In the embodiment of the present application, There are many ways to obtain X′, for example, refer to the X′ introduced in the above formula (2): N×3 and The method of obtaining the information is not limited in this application.

[0288] Based on the above introduction, in step S410, the initial spectral response matrix Q′ of the multi-spectral camera module can be obtained. N×C , the spectral response matrix of the human eye and the second camera module Among them, Q′ N×C Specifically through the transmittance matrix L of the optical lens N×1 , filter transmittance matrix T N×1 , the spectral response matrix M of the image sensor N×C Dot product.

[0289] For example, the L N×1 、T N×1 、M N×C , Directly input into the device executing method 400. Exemplarily, L N×1 、M N×C 、T N×1 or (i>0) can be obtained from data recorded in the specification corresponding to the corresponding hardware, or obtained through manufacturer's test data, or obtained through self-test data, etc. It can be obtained by sampling the tristimulus value curve of the human eye.

[0290] For another example, the spectral response curve of the human eye, the spectral response curve of the second camera module, the transmittance curve of the optical lens in the multi-spectral image sensor module, the transmittance curve of the filter, and the spectral response curve of the image sensor can be input into the device for executing method 400, and the device performs discrete sampling to obtain the corresponding And by L N×1 、T N×1 、M N×C The dot product of the three is Q′ N×C That is, the device for executing method 400 is used for both sampling and acquiring the corresponding matrix and executing the optimization process of method 400 .

[0291] In the embodiment of the present application, the optimization objectives involved in step S420 include:

[0292] The similarity between the spectral response matrix of the multispectral camera module and the spectral response matrix of the human eye is greater than or equal to a first preset threshold;

[0293] The similarity between the spectral response matrix of the multi-spectral camera module and the spectral response matrix of each second camera module is greater than or equal to a second preset threshold.

[0294] Exemplarily, the first preset threshold is greater than or equal to 0.93. For example, the first preset threshold may be 0.95, 0.96, or 0.97.

[0295] Exemplarily, the second preset threshold is greater than or equal to 0.93. For example, the second preset threshold may be 0.95, 0.96, or 0.97.

[0296] The first preset threshold and the second preset threshold may be the same or different, and may be determined as needed in practical applications, and this application does not limit this.

[0297] It can be understood that the similarity between the spectral response matrix of the multispectral camera module and the spectral response matrix of the human eye is used to characterize the similarity or equivalence between the spectral response curve of the multispectral camera module and the spectral response curve of the human eye, and is specifically used to characterize the degree of closeness between the spectral response matrix (or spectral response curve) of the multispectral camera module and the spectral response matrix (or spectral response curve) of the human eye after dimensionality reduction from a high dimension.

[0298] It can be understood that the similarity between the spectral response matrix of the multi-spectral camera module and the spectral response matrix of each second camera module is used to characterize the similarity or equivalence between the spectral response curve of the multi-spectral camera module and the spectral response curve of the second camera module, and is specifically used to characterize the degree of closeness between the spectral response matrix (or spectral response curve) of the multi-spectral camera module and the spectral response matrix (or spectral response curve) of the second camera module after dimensionality reduction from a high dimension.

[0299] In some embodiments, the similarity between the spectral response matrix of the multi-spectral camera module and the spectral response matrix of the three-channel camera module is expressed as v i Specifically, it can be:

[0300]

[0301] The operator P{} is specifically:

[0302] P{Q N×C =Q N×C [Q N×C T Q N×C ] -1 Q N×C T , whose order is N×N, Q N×C =M N×C ⊙T N×1 ⊙L N×1

[0303] Its order is N×N.

[0304] In formula (4), i = 0, 1, 2, 3, ..., n, where n is an integer greater than or equal to 1. When i is 0, it represents the human eye, and the corresponding spectral response matrix is When i is 1, 2, 3, ..., n, it represents different second camera modules, and the corresponding spectral response matrices are

[0305] The above v i The value of may be greater than or equal to a preset value. For example, the preset value may be greater than or equal to 0.93.

[0306] In the embodiment of the present application, in order to enable the multi-spectral camera module to assist the second camera module to achieve the effect closest to the human eye, v i Should be as close to 1 as possible. For example, v i The value of must be increased to at least 0.93.

[0307] Based on the above formula (4), it can be seen that before optimization, the initial spectral response matrix Q′ of the multi-spectral camera module is N×C Substituting into formula (4), we can obtain the equivalence between the spectral response curve of the multi-spectral camera module and the spectral response curves of the human eye and the second camera module. N×C ), filter transmittance curve (corresponding to T N×1 ) and the transmittance curve of the optical lens (corresponding to L N×1 ), can be used to determine Q' N×C Optimize, and accordingly make v i changes. When v i When the value of meets the optimization goal, the obtained spectral response matrix is ​​the target spectral response matrix Q″ of the multi-spectral camera module. N×C The target spectral response matrix Q″ N×C Spectral response matrix with three-channel camera module (including human eye and second camera module) Suitable.

[0308] For example, taking the optimization of the transmittance curve of the filter as an example, by adjusting the transmittance curve of the filter, the transmittance matrix of the filter can be adjusted. Accordingly, the spectral response matrix of the multi-spectral camera module changes, thereby making v i changes. When v i When the value of meets the optimization target, for example, when it is greater than or equal to 0.93, the optimization design of the multi-spectral camera module can be considered to be completed. The corresponding filter parameter setting can improve the color restoration ability and color correction accuracy of the multi-spectral camera module.

[0309] In some embodiments, for different v i You can also set the corresponding weight F i , for example, 0 , v 1 , v 2 , v 3 , …, v n The corresponding weights are F 0 , F 1 , F 2 , F 3 , …, F n Among them, F i≥0, The optimization objectives in step S420 also include: The value of is greater than or equal to a third preset threshold.

[0310] Exemplarily, the third preset threshold is greater than or equal to 0.93. For example, the third preset threshold may be 0.95, 0.96, or 0.97.

[0311] Determine v by setting the weight i The value of can ultimately select a multispectral camera module that meets actual needs (such as the importance of each camera module, color balance strategy, etc.).

[0312] Understandably, Expanded to F 0 / m*v 0 +F 1 / m*v 1 +…+F n / m*v n For example, taking m=1 as an example, the above optimization goal can be concretized as:

[0313] In some embodiments, the weight allocation principle can be determined according to the importance of each second camera module and / or the color balance strategy.

[0314] For example, the higher the importance of the second camera module, the greater the corresponding weight value. For example, if a second camera module is a main camera module, the weight corresponding to the v value calculated based on the spectral response matrix of the camera module can be F 0 , F 1 , F 2 , F 3 , …, F n The maximum value in .

[0315] For another example, if the color balance strategy emphasizes the color restoration capability of the multi-spectral camera module, the weight corresponding to the v value calculated by the spectral response matrix of the human eye can be set to the maximum.

[0316] For another example, if some second camera modules are not considered in the color balance strategy, their corresponding weights may be set to 0.

[0317] For another example, if the second camera modules have no priority, the weights corresponding to the second camera modules may be set to be equal.

[0318] In some embodiments, in step S420, based on the optimization target, a nonlinear optimization algorithm may be used to optimize the initial spectral response matrix of the multi-spectral camera module.

[0319] Exemplary, nonlinear optimization algorithms include, but are not limited to: dividing rectangles (DIRECT) algorithm, controlled random search (CRS) algorithm, multi-level single-linkage (MLSL) algorithm, improved stochastic ranking evolution strategy (ISRES), evolutionary algorithm (ESCH), etc.

[0320] As mentioned above, in the design of the multispectral camera module, by adjusting T N×1 、M N×C and L N×1 At least one of them can achieve the above optimization goal, thereby obtaining the target spectral response matrix of the multi-spectral camera module.

[0321] Generally, there are relatively more factors to consider when designing optical lenses and image sensors. For example, when designing optical lenses, it is necessary to consider depth of field, lens focal length, field of view angle, optical resolution, maximum aperture, tolerance precision design, aberration control, etc.; when designing image sensors, it is necessary to consider pixel size, target size, resolution, filter material process feasibility, etc. Therefore, the design of optical lenses and image sensors must give priority to basic design requirements. In this way, after the basic design of optical lenses and image sensors is completed, on the premise of meeting basic design requirements, there is less room for adjustment when optimizing the spectral response curve of the multi-spectral camera module, and the adjustment cost is high and the cycle is long.

[0322] The main function of the filter is to filter light to improve the accuracy of color reproduction, the utilization rate of the effective visible light band, etc. Therefore, by adjusting the parameters of the filter to optimize the spectral response curve of the multi-spectral camera module, the adjustable space is large and the adjustment method is flexible. N×1 The spectral response curve of the multi-spectral camera module can be optimized.

[0323] In the present application embodiment, T N×1 The transmittance value is a relative value, which only constrains the relative relationship between transmittances of different wavelengths. In practical applications, according to the actual process capability of the filter, it can be achieved by changing T N×1 Multiplying by a constant gives the true transmittance matrix. The transmittance matrix of a filter can be converted into a transmittance curve.

[0324] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A camera device, characterized in that: The first camera module comprises an optical lens, a filter and an image sensor which are sequentially arranged along an optical axis direction, wherein the optical lens is used to receive light from a target object, the filter is used to allow visible light in the light to pass through, and the image sensor is used to receive the visible light to obtain spectral information of the target object, and the number of channels of the image sensor is greater than 3; The optical filter has a first transmittance curve and a second transmittance curve, the first transmittance curve is a curve of corresponding relationship between the wavelength of light incident on the optical filter and the transmittance, the second transmittance curve is a curve of corresponding relationship between the wavelength of light incident on the optical filter at a first angle and the transmittance, and the first angle is greater than 0° and less than or equal to 35°; On the first transmittance curve, the wavelength corresponding to 50% transmittance includes a first wavelength, and the first wavelength is greater than or equal to 600 nm and less than or equal to 660 nm; On the second transmittance curve, the wavelength corresponding to 50% transmittance includes the second wavelength, and the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 20 nm.

2. The camera device according to claim 1, characterized in that On the first transmittance curve, the wavelength corresponding to 50% transmittance includes a third wavelength, and the third wavelength is greater than or equal to 400 nm and less than or equal to 440 nm; On the second transmittance curve, the wavelength corresponding to 50% transmittance includes a fourth wavelength, and the difference between the third wavelength and the fourth wavelength is greater than or equal to 0 and less than or equal to 20 nm.

3. The imaging device according to claim 1 or 2, characterized in that: A difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 10 nm.

4. The imaging device according to any one of claims 1 to 3, characterized in that: On the first transmittance curve, the average transmittance in the 350nm-395nm band is less than or equal to 3%, and the average transmittance in the 700nm-780nm band is less than or equal to 2%; On the second transmittance curve, the average transmittance in the wavelength range of 350 nm to 395 nm is less than or equal to 4%, and the average transmittance in the wavelength range of 700 nm to 780 nm is less than or equal to 3%.

5. The imaging device according to any one of claims 1 to 4, characterized in that: On the first transmittance curve, the minimum transmittance in the 440nm-580nm band is greater than or equal to 70%, and the average transmittance in the 440nm-580nm band is greater than or equal to 80%; On the second transmittance curve, the minimum transmittance in the 440nm-580nm band is greater than or equal to 70%, and the average transmittance in the 440nm-580nm band is greater than or equal to 80%.

6. The imaging device according to any one of claims 2 to 5, characterized in that: The first wavelength and the second wavelength belong to a red light band, and the third wavelength and the fourth wavelength belong to a blue light band.

7. The imaging device according to any one of claims 1 to 6, characterized in that: The camera device further comprises at least one second camera module, the second camera module is a three-channel camera, the first camera module is a C-channel camera and C is greater than 3, and the similarity v between the spectral response curve of the first camera module and the spectral response curve of the human eye is 0 is greater than or equal to 0.93, and the similarity v′ between the spectral response curve of the first camera module and the spectral response curve of the second camera module is greater than or equal to 0.93; in Q N×C is a spectral response matrix obtained by sampling N points in each of the C channels based on the spectral response curve of the first camera module, P{Q N×C =Q N×C [Q N×C T Q N×C ]- 1 Q N×C T ; is a spectral response matrix obtained by sampling N points in each of the three channels based on the spectral response curve of the human eye, X′ N×3 is a spectral response matrix obtained by sampling N points in each of the three channels based on the spectral response curve of the second camera, P{X′ N×3 } = X′ N×3 [X′ N×3 T X′ N×3 ]- 1 X′ N×3 T ; Tr() is the trace.

8. The imaging device according to claim 7, wherein: The spectral response matrix of the first camera module Q N×C =M N×C ⊙T N×1 ⊙L N×1 M N×C A matrix obtained by sampling N points in each of C channels based on the spectral response curve of the image sensor; T N×1 A matrix obtained by performing N-point sampling based on the transmittance curve of the optical filter; L N×1 is a matrix obtained by performing N-point sampling based on the transmittance curve of the optical lens.

9. A filter, characterized in that: Applied in a camera module, the camera module further includes an optical lens and an image sensor, the filter is arranged between the optical lens and the image sensor, the optical lens is used to receive light from a target object, the filter is used to allow visible light in the light to pass, the image sensor is used to receive the visible light to obtain spectral information of the target object, and the number of channels of the image sensor is greater than 3; The optical filter has a first transmittance curve and a second transmittance curve, the first transmittance curve is a curve of corresponding relationship between the wavelength of light incident on the optical filter and the transmittance, the second transmittance curve is a curve of corresponding relationship between the wavelength of light incident on the optical filter at a first angle and the transmittance, and the first angle is greater than 0° and less than or equal to 35°; On the first transmittance curve, the wavelength corresponding to 50% transmittance includes a first wavelength, and the first wavelength is greater than or equal to 600 nm and less than or equal to 660 nm; On the second transmittance curve, the wavelength corresponding to 50% transmittance includes the second wavelength, and the difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 20 nm.

10. The optical filter according to claim 9, characterized in that: On the first transmittance curve, the wavelength corresponding to 50% transmittance includes a third wavelength, and the third wavelength is greater than or equal to 400 nm and less than or equal to 440 nm; On the second transmittance curve, the wavelength corresponding to 50% transmittance includes a fourth wavelength, and the difference between the third wavelength and the fourth wavelength is greater than or equal to 0 and less than or equal to 20 nm.

11. The optical filter according to claim 10, characterized in that: A difference between the first wavelength and the second wavelength is greater than or equal to 0 and less than or equal to 10 nm.

12. The optical filter according to any one of claims 9 to 11, characterized in that: On the first transmittance curve, the average transmittance in the 350nm-395nm band is less than or equal to 3%, and the average transmittance in the 700nm-780nm band is less than or equal to 2%; On the second transmittance curve, the average transmittance in the wavelength range of 350 nm to 395 nm is less than or equal to 4%, and the average transmittance in the wavelength range of 700 nm to 780 nm is less than or equal to 3%.

13. The optical filter according to any one of claims 8 to 10, characterized in that: On the first transmittance curve, the minimum transmittance in the 440nm-580nm band is greater than or equal to 70%, and the average transmittance in the 440nm-580nm band is greater than or equal to 80%; On the second transmittance curve, the minimum transmittance in the 440nm-580nm band is greater than or equal to 70%, and the average transmittance in the 440nm-580nm band is greater than or equal to 80%.

14. The optical filter according to any one of claims 10 to 13, characterized in that: The first wavelength and the second wavelength belong to a red light band, and the third wavelength and the fourth wavelength belong to a blue light band.

15. A camera module, characterized in that: It comprises an optical lens, an image sensor and a filter as described in any one of claims 9 to 14, wherein the filter is arranged between the optical lens and the image sensor, the optical lens is used to receive light from a target object, the filter is used to allow visible light in the light to pass, the image sensor is used to receive the visible light to obtain spectral information of the target object, and the number of channels of the image sensor is greater than 3.

16. An electronic device, characterized in that: The invention comprises an image processing chip and the camera device according to any one of claims 1 to 8, wherein the image processing chip is used to process images acquired by the camera device.

17. The electronic device according to claim 16, characterized in that: The camera device also includes at least one second camera module, which is a three-channel camera. The image processing chip is used to correct the color of the target object acquired by the second camera module based on the spectral information of the target object acquired by the first camera module.

18. The electronic device according to claim 17, characterized in that: The second camera module is a wide-angle camera, a telephoto camera or an ultra-wide-angle camera.

Images