High resolution automotive lenses and sensors

Abstract

A camera for automotive applications comprises a lens system having a modulation transfer function (MTF) tuned to process light in a spectral range from red to green with a higher resolution than light in a spectral range from blue to violet. The camera further comprises an imager having a matrix of pixel sensors and a color filter matrix comprising a plurality of color filter elements, each color filter element corresponding to a pixel sensor of the imager. The color filter matrix comprises red filter elements and yellow filter elements, and the number of yellow filter elements is greater than the number of red filter elements.

Description

[0001] Cross-reference to related applications This patent application is based on the benefit of priority to U.S. Provisional Application Serial No. 62 / 682,082, filed June 7, 2018, entitled “COST EFFECTIVE LENS AND SENSOR DESIGN FOR HIGHRESOLUTION AUTOMOTIVE APPLICATIONS”, 35 U.S. SC §119(e), the entire contents of which are hereby incorporated herein by reference. Technical Field

[0002] The embodiments described herein generally relate to image capture systems, and more specifically, to lenses, color filters, and imager assemblies for automotive applications. Background Technology

[0003] Autonomous or semi-autonomous vehicle technologies (often referred to as "autonomous driving" or "driver assistance" operations in automobiles) are being rapidly developed and deployed in commercial and consumer vehicles. These systems use arrays of sensors to continuously observe the vehicle's movement and surroundings. These sensors can be used to observe the vehicle's surroundings, such as road surfaces and boundaries, lane markings, other vehicles, pedestrians, objects and hazards, signage, and other relevant items. Image-capturing sensors, including one or more cameras, are particularly useful for detecting and identifying objects, monitoring other vehicles, and reading signs and road markings. Camera-based systems have been applied to measure three-dimensional structures, such as the vertical profile of a road, to identify lane markings and curbs, as well as to detect objects or hazards. Practical sensor systems are expected to reliably provide high-resolution imagery across a wide field of view under varying weather and road conditions. Summary of the Invention

[0004] This application proposes a camera module having a modulation transfer function (MTF) tuned to be better in the green-to-red spectral range than in the blue-to-violet spectral range. The camera module includes: a lens system preferentially configured for the green-to-red spectral range relative to the blue-to-violet spectral range; and an imager including a plurality of pixel sensors arranged in a matrix, and a color filter matrix located between the lens system and the imager. The color filter matrix has a plurality of filter elements positionally corresponding to the plurality of pixel sensors of the imager, the filter elements including a greater number of yellow filter elements than red filter elements. The imager is configured relative to the lens system such that the MTF of the camera module is enhanced for the green-to-red portion of the spectrum. This application also proposes a camera module having a modulation transfer function (MTF) tuned to be better in the green to red spectral range than in the blue to violet spectral range. The camera module includes: a lens system preferentially configured for the green to red spectral range relative to the blue to violet spectral range; an imager including a plurality of pixel sensors arranged in a matrix, and a color filter matrix located between the lens system and the imager, the color filter matrix having a plurality of filter elements positionally corresponding to the plurality of pixel sensors of the imager, the filter elements including a greater number of transparent filter elements than red filter elements; and a cutoff filter located between the lens system and the color filter matrix, the cutoff filter being configured to attenuate light in the blue to ultraviolet spectral range projected by the lens system onto the color filter matrix and the imager; wherein the imager is configured relative to the lens system such that the MTF of the camera module is enhanced for the green to red portion of the spectrum. Attached Figure Description

[0005] In accompanying drawings that are not necessarily drawn to scale, similar numerals may describe similar components in different views. Similar numerals with different letter suffixes may represent different instances of similar components. The accompanying drawings generally illustrate the various embodiments discussed in this document by way of example and not limitation.

[0006] Figure 1 It is a side view of a vehicle including a car camera according to an example embodiment.

[0007] Figure 2 This is a cut-out side view showing the components of a car camera according to an example embodiment.

[0008] Figure 3A This is a top view of the color filter matrix according to an example embodiment.

[0009] Figure 3B This is a graph of quantum efficiency (QE) relative to wavelength, which illustrates the characteristics of the imager according to an example embodiment.

[0010] Figure 4A , 4B 4C is a graph of the modulation transfer function (MTF) relative to the field of view of the lens system according to the example embodiment.

[0011] Figure 5A , 5B 5C, 6A, 6B, 6C, 7A, 7B, and 7C are graphs of MTF relative to the focus shift distance of the lens system according to the example embodiment. Detailed Implementation

[0012] The following detailed description is with reference to the accompanying drawings. The same reference numerals may be used to identify the same or similar elements in different drawings. In the following description, specific details, such as particular structures, architectures, interfaces, technologies, etc., are set forth for purposes of explanation and not limitation in order to provide a thorough understanding of various aspects of the various embodiments. However, it will be apparent to those skilled in the art, who will benefit from this disclosure, that various aspects of the various embodiments may be practiced in other examples that depart from these specific details. In some instances, descriptions of well-known devices, circuits, and methods have been omitted so as not to obscure the description of the various embodiments with unnecessary detail.

[0013] The embodiments described below implement a camera lens and color filter matrix tuned to light in the red to green spectral range, disregarding light in the blue spectral range. The red to green spectral range is used in automotive applications to perform numerous sensing functions, including but not limited to sensing red, yellow, and green traffic signals, sensing the activation of brake lights on other vehicles, recognizing and reading road signs and lane markings, and identifying obstacles. These tasks do not depend on light in the blue spectral range. Furthermore, a lens system that ignores the blue spectral range can produce a more focused image in the red, yellow, and green spectral range, thereby improving the resolution of the image captured by the camera.

[0014] Active pixel sensor (APS) imagers (such as complementary metal-oxide-semiconductor (CMOS) imagers) are sensitive to a wide range of wavelengths in the visible spectrum, from 400 nm to 700 nm. Images captured by an APS imager represent all wavelengths in the visible spectrum as well as wavelengths in the infrared (IR) and ultraviolet (UV) spectra. To capture color images, an APS imager may employ one or more cut filters to attenuate wavelengths in the IR and UV spectra, and a color filter matrix arranged in a specific pattern in front of the individual pixel sensors of the imager. The pattern includes multiple color pixel filter elements to deliver light from different portions of the visible spectrum to the different pixel sensors of the APS imager. While the embodiments described herein use APS imagers, other embodiments may use other types of imagers, such as charge-coupled device (CCD) imagers.

[0015] The color filter elements may include red (R), green (G), and blue (B) pixel filter elements arranged in a repeating pattern both vertically and horizontally across all pixel sensor positions of the APS imager. Signals captured by the pixel sensors are combined to generate an image with good resolution and proper color reproduction, even in low-light conditions. For example, a Bayer filter uses twice the number of green pixel filters as red and blue filters arranged in an RGGB 2×2 (two-by-two) matrix pattern, such that one row of the pattern includes alternating R and G filters, and the next row includes alternating G and B filters. Alternative filter patterns use complementary color filter elements, such as cyan (Cy), yellow (Y), and magenta (M). The R, G, and B pixel filters each reduce the amount of light reaching their respective pixel sensors by approximately two-thirds, while the Cy, Y, and M pixel filters reduce the amount of light reaching the pixel sensors by approximately one-third.

[0016] Monochrome sensors, which lack color filters and thus allow all incident light to reach the pixel sensor, exhibit significantly better low-light performance compared to imagers with color filter matrices. One filter matrix that achieves good low-light performance while still retaining some color information uses only red and transparent color filter elements. For example, an RCCC (red, transparent, transparent, transparent) filter matrix has been developed for automotive applications. This filter lacks G or B filter elements and has R filter elements that cover only every other pixel sensor in every other row. The R filter elements allow camera systems using this filter to detect red traffic signals and brake lights from other vehicles. However, the lack of G filters makes it difficult for optical systems including RCCC filter matrices to sense other colors, such as yellow traffic signs and / or yellow and green traffic signals.

[0017] In addition to the imager, an automotive camera includes a lens system that focuses light from the scene onto the imager. The desired outcome is that this lens system provides high-resolution images over a wide field of view. The resolution of the image projected by the lens system is a function of the spatial frequency response of the lens system. The spatial frequency response of an optical system can be specified by the system's modulation transfer function (MTF). The MTF is the modulus of the optical transfer function (OTF), which specifies how the optical system influences the amplitude and phase of the light projected from the scene onto the detector array. The OTF is the Fourier transform of the point spread function (PSF). The PSF is the impulse response of the optical system (e.g., an image generated from an ideal point source). Because the OTF is a Fourier transform, it is a complex function with values ​​in both the real and imaginary planes. The MTF is the modulus of the complex OTF (e.g., its absolute value). The MTF ignores the phase part of the transfer function and provides a measurement of how the amplitude of the projected light varies across the correlated spectrum. Both the OTF and MTF specify the response of the optical system to periodic sinusoidal modes passing through the optical system. This response is a function of both the spatial frequency or period and the orientation of the sinusoidal mode.

[0018] The OTF and MTF measurements described herein can be specified at a particular resolution. Resolution can be specified as cycles per millimeter (CYC / mm) or line pairs per millimeter (lp / mm). A lens system capable of resolving 10 μm features has a resolution of 100 lp / mm. Therefore, a lens system with 80% MTF at 100 lp / mm can project an image with 200 lines per millimeter, which is slightly blurred compared to the original image.

[0019] Figure 1 This is a block diagram of an example vehicle 104 having a camera 102 including processing circuitry 108. The camera 102 is mounted on the vehicle 104 and monitors the environment of the vehicle 104. In this example, the processing circuitry 108 is integrated into the camera 102. Figure 1 A camera is shown as an example of a forward-facing camera mounted behind the windshield. However, the camera assembly described herein can be used for rear-facing or side-facing cameras mounted inside or outside the vehicle 104.

[0020] In the example system, processing circuitry 108 performs vehicle environment modeling using images acquired from camera 102. Figure 1In the example shown, vehicle environment modeling may include modeling the road surface 106, obstacles, obstructions, and moving entities (e.g., other vehicles, pedestrians, animals, etc.). However, it is conceivable that camera 102 or other cameras (not shown) may be used to model traffic signals, road signs, and environmental conditions. These models may be used directly by processing circuitry 108 or by means of another management system (not shown) to adjust the operating parameters of vehicle 104 based on the sensed environmental conditions. For example, processing circuitry may use camera 102 to monitor lane markings on road surface 106 and warn the driver when it detects that vehicle 104 is crossing a lane marking. For example, to perform modeling of road surface 106, processing system 108 is arranged to obtain a temporal sequence of images representing road surface 106.

[0021] Figure 2 It can be used as Figure 1 The diagram illustrates the components of an example camera 102. The example camera 102 includes a lens system 200 coupled to an imager system 220. The lens system 200 is contained within a lens barrel 202 having a front cover glass 204 and a rear cover glass 218. The example lens system 200 includes a first biconvex lens 206, a second biconvex lens 208, a combined lens including a positive meniscus lens 210 and a biconvex lens 212, and a second positive meniscus lens 214. The lens system 200 also includes a cutoff filter 216 that attenuates light in the IR and UV spectral ranges projected from the lens system 200 onto the imager system 220. Because the lens system 200 is configured to provide a relatively large MTF for light in the red to green spectral range, the cutoff filter 216 can be configured to attenuate at least a portion of light in the blue spectral range in addition to attenuating light in the IR and UV spectral ranges. Any of the lens elements 206, 208, 210, 212, and / or 214 can be a spherical or aspherical element. Lenses 210 and 212, which form the combined lens, can be bonded together with an optical adhesive or separated by air. This lens configuration is one possible arrangement. Other configurations that meet the design rules described below with reference to Tables 1, 2, and 3 can be used instead of lens system 200.

[0022] Imager system 220 includes housing 222, color filter matrix 224, and APS image sensor 226, which may be a CMOS sensor. The relative dimensions of color filter matrix 224 and imager 226 are magnified to aid in the description of imager system 220. Imager 226 is positioned relative to lens system 200 within housing 222 such that an image from a scene is focused through color filter matrix 224 onto the top surface of imager 226. Pixel data captured by imager 226 is provided to processing circuitry 108, which also controls the operation of imager 226.

[0023] According to an example embodiment, the color filter matrix 224 of the imager system 220 is an RYYCy filter matrix. An example layout of the color filter matrix 224 is shown in... Figure 3A The image is shown in the diagram. Conventional color filters (such as an RGGB filter matrix or a CyYYM filter matrix) produce images spanning the spectrum from red to blue. However, as described above, these filters reduce the amount of light reaching the pixel sensor by 1 / 3 or 2 / 3. This reduction in light quantity results in a reduced quantum efficiency (QE) for the imager. The QE of an imager is the ratio of electrons generated by the imager from photons striking it; therefore, QE is a measure of the efficiency with which the imager converts photons into electrons. The RYYCy filter matrix is ​​an example matrix. Other filter matrices that can be used include RYYB, RYYY, RYYG, and RYYC. Other example filter matrices can be used if the cutoff filter 216 is tuned to attenuate light in the blue spectral range as well as light in the IR and UV spectral ranges. In this instance, when used with a lens system such as lens system 200 as described above, the RCCC or RCCB filter matrix can produce an acceptable image, with the MTF of said lens system 200 configured for the red to green spectral range.

[0024] As discussed in this article, for automotive applications, image data from the blue spectral range may be less important than image data from the red to green spectral range. One approach to increasing the quantum efficiency of an imager without increasing the lens aperture is to design a lens configured to produce sharper images in the red to green spectral range than in the blue spectral range, and to provide a color filter that matches the lens.

[0025] When mixed, yellow light is a combination of red and green light. In the example embodiment, the imager color filter matrix 224 is designed to match the lens system 200, and both the lens system 200 and the color filter matrix 224 are configured to emphasize the red to green spectrum over the blue to violet spectrum. As mentioned above, RCCC filter matrices are currently used in many automotive applications. The color filter matrix 224 according to the example embodiment uses yellow filter elements instead of transparent filter elements, such that the imager pixel position under the yellow filter element provides most of the information from the imager. The processing circuit 108 uses red filter elements in the RCCC filter matrix to detect taillights. Because the difference between the yellow filter element and the red filter element is not as strong as the difference between the transparent filter element and the red filter element, the example color filter matrix 224 also uses cyan filter elements. Cyan filter elements also help the processing system 108 distinguish between red and orange. The example color filter matrix 224 is an RYYCy filter matrix, an example of which is shown in Figure 3A The imager 226 is shown in the diagram. As shown, the filter comprises a pattern of R, Y, and Cy filter elements repeated horizontally and vertically. The pattern comprises four filter elements arranged in a 2×2 submatrix: R filter 302, first Y filter 304, second Y filter 306, and Cy filter 308. The 2×2 submatrix is ​​repeated horizontally and vertically across the surface of the imager 226.

[0026] Figure 3B An example QE of a sensor using the RYYCy filter matrix 224 is shown. The QE depends on the characteristics of the dye used to implement the filter and the APS imager without the filter matrix 224. Therefore, the QE of a particular sensor may vary with... Figure 3B The QE values ​​shown are significantly different. Curve 322 represents the sensor's QE for photons in the cyan spectral range. Curves 324 and 326 represent the sensor's QE for photons in the yellow to green spectral range, while curve 328 represents the sensor's QE for photons in the red spectral range. Figure 3B Each of the curves shown corresponds to Figure 3A The pixel positions in the 2×2 submatrix shown. The four pixel positions of the submatrix generate separate signals, which are combined by processing circuitry 108 to generate, for example, three-color signals of red, green, and blue, or magenta, yellow, and cyan. Figure 3B The diagram shows that the QE drops from a peak of approximately 70% near 525 nm (corresponding to yellow light) to approximately 50% at 800 nm (corresponding to near-infrared light). Note that the yellow peak is higher than the red and cyan peaks. Additionally, Figure 3BThis shows that the QE of the yellow pixel drops to half at 475nm, ensuring that the blue-to-violet spectral range from 400nm to 500nm does not significantly affect the sensing of light in the red-to-green spectral range. This is because the RYYCy filter matrix uses a red filter instead of the magenta filter in the CyYYM filter matrix. Figure 3B The shapes of the red, yellow, and cyan curves shown may differ from the corresponding curves of the CyYYM filter. However, the cutoff wavelengths for different spectral ranges are similar.

[0027] The RYYCy color filter matrix 224 differs from existing models such as RGGB, CyYYM, and RCCC. The filter matrix 224, combined with a lens system 200 designed to disregard the blue-to-violet spectral range, achieves... Figure 1 The camera 102 shown. According to an example embodiment, the lens system 200 can be focused to achieve a good MTF value for light in the red to green spectral range, but a relatively lower MTF for light in the blue to violet spectral range. Because the imager system 220 uses a color filter matrix 224 with red filter elements instead of magenta filter elements in a standard CyYYM filter matrix, the red-filtered pixels provided by the imager array 226 are in good focus just like the yellow-filtered pixels. Since the color filter elements covering these pixels include a significant blue component and the MTF of the lens system is designed to produce a higher MTF for light in the red to green spectral range than for light in the blue to violet spectral range, the out-of-focus pixels are only the cyan-filtered pixels. If the image of a monochrome resolution target is captured using a lens system (designed as described below), and the RYYCy color matrix is ​​as shown below... Figure 3A As shown, a subsampled image that includes only red pixel data will be significantly sharper than a subsampled image that includes only cyan pixel data, even if the imager includes the same number of pixels with both red and cyan filter elements.

[0028] Such as Figure 2The example lens system 200 shown can be designed according to the design rules shown in Tables 1, 2, and 3 below. Table 1 shows the wavelength weighting for the lens design. Table 2 shows the multicolor MTF for a lens design with the wavelength weighting shown in Table 1, and Table 3 shows the parameters of a cutoff filter 216 configured to attenuate UV light with wavelengths smaller than the cutoff wavelengths that can be in the range of 410 nm to 395 nm, and to attenuate IR light with wavelengths larger than the cutoff wavelengths that can be in the range of 690 nm to 705 nm. As described above, in some embodiments, the cutoff filter 216 may be configured to attenuate light with wavelengths smaller than about 500 nm to attenuate light in the blue to violet spectral range and light in the UV spectral range.

[0029] These design rules specify lens systems in which the focal point of light in the red to green spectral range is emphasized across a 60-degree field of view. The weighted design rules shown in Table 1 assign more weight to yellow wavelengths than to red or blue wavelengths. Therefore, the field-of-view design rules shown in Tables 1-3 specify a relatively high MTF across the lens system for light in at least the red to green spectral range. Such a lens system can be used by the processing system 108 of camera 102 to identify items of interest across the field of view of camera 102.

[0030] Figure 4A It shows that in such Figure 3A The design MTF (e.g., the module of the design OTF) over a 60-degree field of view for lenses in the 510 nm to 660 nm wavelength range associated with yellow filter elements 304 and 306 is shown. Curve 412 represents the MTF in the tangential plane, while curve 414 represents the MTF in the sagittal plane. The tangential response pertains to light in the propagation direction, while the sagittal response pertains to light perpendicular to the propagation direction. Curves 412 and 414 represent the spatial frequency response of an example lens system at a resolution of 120 lp / mm. Figure 4A As shown, for 120 lp / mm, the design MTF is not less than 0.8 (80 percent) in the center of the FOV, and the design MTF has a FOV greater than 0.5 across 60 degrees.

[0031] Figure 4B The MTF is shown for wavelengths in the blue range (around 450 nm). Curve 422 shows the tangential response, while curve 424 shows the sagittal response. Figure 4BAs shown, at the same resolution of 120 lp / mm, the MTF through-FOV is less than 0.5 or even less than 0.4.

[0032] Figure 4C The design MTF using a standard weighted lens for the visible spectrum from 436 nm to 656 nm is shown. Figure 4C As shown, at the center of the FOV, the tangential MTF is less than 0.8, while at many other angles within the FOV, the FOV is less than 0.5.

[0033] Figure 5A , 5B Tables 1 and 5C show the MTF for light in the 510 nm to 660 nm range (e.g., light in the red to green spectral range) as a function of the focal displacement of an example lens system 200 designed according to the design rules shown in Tables 1, 2 and 3. Figure 5A , 5B The MTF values ​​shown in 5C are at a resolution of 120 lp / mm. Figure 5A The focus response at 0 degrees in the field of view is shown. Figure 5B The image shows the focus response at 30 degrees within the field of view (FOV), while the image 5C shows the focus response at 60 degrees within the FOV. Because... Figure 5A The response at 0 degrees is shown, with the tangential and sagittal curves overlapping, and represented by curve 502. Figure 5B and 5C In the diagram, curves 512 and 522 show the corresponding tangential focus responses, while curves 514 and 524 show the corresponding sagittal focus responses. Figure 5A , 5B 5C shows approximately 0 mm of focal displacement for light in the spectral range of 510 nm to 660 nm.

[0034] Figure 6A , 6B Figures 6C and 6C illustrate the focal response (e.g., MTF relative to focal displacement) of a lens system 200 designed according to the design rules shown in Tables 1, 2 and 3 for light (e.g., blue light) at approximately 450 nm. Figure 6A , 6B Both the 6C and 6C operate at a resolution of 120 lp / mm. Figure 6A Curve 602 in the figure shows the tangential and sagittal focal response of blue light at 0 degrees in the field of view. Figure 6B Curves 612 and 614 show the tangential and sagittal focal responses of lens system 200 to blue light at a 30-degree field of view (FOV), respectively. Figure 6C Curves 622 and 624 show the tangential and sagittal focal response of the lens system 200 pairs of blue light at a 60-degree FOV. Figure 6A , 6BCorresponding to 6C Figure 5A , 5B Compared to 5C, it shows that the focal point of blue light is shifted by approximately 0.01 mm at 0 degrees within the FOV relative to the focal point of light in the red to green spectral range. Note that the shift in focal point is even greater for angles further out of the FOV (e.g., 30 degrees and 60 degrees).

[0035] Figures 5A-6C The lens system designed according to the design rules shown in Tables 1, 2, and 3 demonstrates poor performance for light in the blue to violet spectral range. However, for light in the red to green spectral range, the peaks of the MTF for various angles of the FOV are concentrated around the same focal displacement region. Therefore, light in the red to green spectral range can reach focus across the entire FOV in the same amount of time.

[0036] Figures 7A-7C The focal response of the production lens system 200 for light in the red to green spectral range (e.g., from approximately 430 nm to approximately 660 nm) is shown. As... Figures 5A-6C The situation is the same as shown. Figures 7A-7C The MTF shown is at a resolution of 120 lp / mm and at FOV angles of 0 degrees, 30 degrees, and 60 degrees respectively. Figure 7A In the diagram, curve 702 represents the focal response of lens system 200 in both the tangential and sagittal planes. Figure 7B and 7C In the figure, curves 712 and 722 represent the corresponding focal response of lens system 200 in the tangential plane, while curves 714 and 724 represent the corresponding focal response of lens system 200 in the sagittal plane. Figures 7A-7C The example MTF value shown is lower than the reference value mentioned above. Figures 5A-5C The design values ​​are taken into account because the production response reflects manufacturing tolerances. However, it is noted that at a focal displacement of 0 mm, the MTF of lens system 200 is still greater than 0.60 at the center of the FOV, and greater than 0.55 at both 30 and 60 degrees within the FOV. Although not shown, in some parts of the FOV, for light in the blue to violet spectral range at 120 lp / mm, the production MTF of lens system 200 can be between 50% and 60% of the MTF for light in the red to green spectral range. For example, at the center of the FOV, the MTF for light in the blue to violet spectral range can be less than 0.35, at 30 degrees the MTF can be less than 0.33, and at 60 degrees the MTF for light in the blue to violet spectral range can be less than 0.30. These values ​​assume that lens system 200 is focused to obtain a relatively high MTF for light in the red to green spectral range.

[0037] Example Example 1 is a camera module having a modulation transfer function (MTF) tuned to be better in the green-to-red spectral range than in the blue-to-violet spectral range. The camera module includes: a lens system preferentially configured for the green-to-red spectral range relative to the blue-to-violet spectral range; an imager including a plurality of pixel sensors arranged in a matrix; and a color filter matrix located between the lens system and the imager, the color filter matrix having a plurality of filter elements positionally corresponding to the plurality of pixel sensors of the imager, the filter elements including a greater number of yellow filter elements than red filter elements, wherein the imager is configured relative to the lens system such that the MTF of the camera module is enhanced for the green-to-red portion of the spectrum.

[0038] In Example 2, the subject of Example 1 includes the filter matrix comprising multiple 2×2 sub-matrices that are repeated horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising two yellow filter elements, a red filter element, and a cyan filter element.

[0039] In Example 3, the subject of Examples 1-2 includes the filter matrix comprising multiple 2×2 sub-matrices that are repeated horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising three yellow filter elements and one red filter element.

[0040] In Example 4, the subject of Examples 1-3 includes the filter matrix comprising multiple 2×2 sub-matrices that are repeated horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising two yellow filter elements, a red filter element, and a green filter element.

[0041] In Example 5, the subject of Examples 1-4 includes the filter matrix comprising multiple 2×2 sub-matrices that are repeated horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising two yellow filter elements, a red filter element, and a transparent filter element.

[0042] In Example 6, the subject of Examples 1-5 includes the filter matrix comprising multiple 2×2 sub-matrices that repeat horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising two yellow filter elements, a red filter element, and a blue filter element.

[0043] In Example 7, the subject matter of Examples 1-6 includes the lens system being designed to weight light in the yellow spectral range more than light in the red and blue spectral ranges.

[0044] In Example 8, the subject matter of Examples 1-7 includes the lens system comprising a plurality of optical elements, the plurality of optical elements including a composite optical element having two optical sub-elements bonded together by an optical adhesive.

[0045] In Example 9, the subject of Example 8 includes, wherein at least one of the plurality of optical elements comprises an aspherical lens.

[0046] In Example 10, the subject of Examples 1-9 includes a lens system comprising a cutoff filter located between the lens system and the color filter matrix, the cutoff filter being configured to attenuate light in the ultraviolet spectral range projected by the lens system onto the color filter matrix and the imager.

[0047] In Example 11, the subject of Example 10 includes the fact that the cutoff filter is also configured to attenuate light in the blue to violet spectral range.

[0048] In Example 12, the subject of Examples 10-11 includes the fact that the cutoff filter is also configured to attenuate light in the infrared (IR) spectral range.

[0049] Example 13 is a camera module having a modulation transfer function (MTF) tuned to be better in the green-to-red spectral range than in the blue-to-violet spectral range, the camera module comprising: a lens system preferentially configured for the green-to-red spectral range relative to the blue-to-violet spectral range; an imager including a plurality of pixel sensors arranged in a matrix, and a color filter matrix located between the lens system and the imager, the color filter matrix having a plurality of filter elements positionally corresponding to the plurality of pixel sensors of the imager, the filter elements including a greater number of transparent filter elements than red filter elements; and a cutoff filter located between the lens system and the color filter matrix, the cutoff filter being configured to attenuate light in the blue-to-ultraviolet spectral range projected by the lens system onto the color filter matrix and the imager; wherein the imager is configured relative to the lens system such that the MTF of the camera module is enhanced for the green-to-red portion of the spectrum.

[0050] In Example 14, the subject of Example 13 includes the fact that the cutoff filter is also configured to attenuate light in the infrared (IR) spectral range.

[0051] In Example 15, the subject of Examples 13-14 includes the filter matrix comprising multiple 2×2 sub-matrices repeated horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising three transparent filter elements and a red filter element.

[0052] In Example 16, the subject of Examples 13-15 includes the filter matrix comprising multiple 2×2 sub-matrices that are repeated horizontally and vertically across the pixel sensor of the imager, each sub-matrix comprising two transparent filter elements, a red filter element, and a green filter element.

[0053] In Example 17, the subject matter of Examples 13-16 includes the lens system being designed to weight light in the yellow spectral range more than light in the red and blue spectral ranges.

[0054] In Example 18, the subject matter of Examples 13-17 includes the lens system comprising a plurality of optical elements, the plurality of optical elements including a composite optical element having two optical sub-elements bonded together by an optical adhesive.

[0055] In Example 19, the subject matter of Example 18 includes that at least one of the plurality of optical elements comprises an aspherical lens. The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in accordance with the above teachings, or may be obtained from practice of various implementations of the embodiments.

[0056] An abstract is provided to comply with Section 1.72(b) of 37C.FR, which requires that the abstract allow the reader to determine the nature and essence of the technical disclosure. The abstract is submitted on the understanding that it will not be used to limit or interpret the scope or meaning of the claims.

Claims

1. An image capture device for vehicle enhancement, the image capture device comprising: A color filter matrix, the color filter matrix comprising a plurality of filter elements, each of the plurality of filter elements corresponding to each of a plurality of pixel sensors of an image sensor, the plurality of filter elements including a greater number of yellow filter elements than red filter elements; as well as A lens system having an increased spatial frequency response relative to the blue-to-violet spectral range for the green-to-red spectral range, the lens system focusing light from the scene onto the image sensor through the color filter matrix.

2. The image capture device according to claim 1, wherein, The lens system is designed to provide higher wavelength weighting for light in the yellow spectral range than for light in the red and blue spectral ranges.

3. The image capture device according to claim 1, wherein, The lens system includes multiple optical elements, including a combined optical element having two optical sub-elements joined by an optical adhesive.

4. The image capture device according to claim 3, wherein, At least one of the plurality of optical elements includes an aspherical lens.

5. The image capture device according to claim 1, wherein, The lens system includes a cutoff filter located between the lens system and the color filter matrix, the cutoff filter being configured to attenuate light in the ultraviolet spectral range projected by the lens system onto the color filter matrix and the image sensor.

6. The image capture device according to claim 5, wherein, The cutoff filter is further configured to attenuate light in the blue to violet spectral range.

7. The image capture device according to claim 5, wherein, The cutoff filter is also configured to attenuate light in the infrared (IR) spectral range.

8. The image capture device of claim 1, wherein the color filter matrix comprises a plurality of 2×2 sub-matrices repeated horizontally and vertically across the plurality of pixel sensors of the image sensor, each sub-matrix comprising two yellow filter elements, a red filter element and a cyan filter element.

9. The image capture device of claim 1, wherein the color filter matrix comprises a plurality of 2×2 sub-matrices repeated horizontally and vertically across the plurality of pixel sensors of the image sensor, each sub-matrix comprising three yellow filter elements and three red filter elements.

10. The image capture device of claim 1, wherein the color filter matrix comprises a plurality of 2×2 sub-matrices repeated horizontally and vertically across the plurality of pixel sensors of the image sensor, each sub-matrix comprising two yellow filter elements, a red filter element and a green filter element.

11. The image capture device of claim 1, wherein the color filter matrix comprises a plurality of 2×2 sub-matrices repeated horizontally and vertically across the plurality of pixel sensors of the image sensor, each sub-matrix comprising two yellow filter elements, a red filter element, and a transparency filter element.

12. The image capture device of claim 1, wherein the color filter matrix comprises a plurality of 2×2 sub-matrices repeated horizontally and vertically across the plurality of pixel sensors of the image sensor, each sub-matrix comprising two yellow filter elements, a red filter element and a blue filter element.

13. An image capture method for vehicle enhancement, the image capture method comprising: Light from the scene is focused onto a color filter matrix at a lens system, which includes an increased spatial frequency response for the green to red spectral range relative to the blue to violet spectral range. as well as The light from the lens system to the image sensor is filtered at the color filter matrix, which includes a plurality of filter elements, each of which corresponds to each of a plurality of pixel sensors of the image sensor, and the plurality of filter elements includes a greater number of yellow filter elements than red filter elements.

14. The image capture method of claim 13, further comprising attenuating light at a cutoff filter located between the lens system and the color filter matrix, the cutoff filter being configured to attenuate light in the ultraviolet spectral range projected by the lens system onto the color filter matrix and the image sensor.

15. The image capture method according to claim 14, wherein, The cutoff filter is also configured to attenuate light in at least one of the blue to violet spectral range and the infrared (IR) spectral range.

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