Computer-based method for designing more efficient lenses

Abstract

This invention relates to a method (100) for designing optical objectives using computer-aided design software, the method comprising a step (102) of designing a current design, and at least one iteration of a phase (104) referred to as an improvement phase, the improvement phase comprising the steps of: - performing a simulation using design software, on the current design, measuring (106-110) the optical transfer function (OTF) for light selected from the following colors: red, green, and blue light individually; - determining (112) a quality indicator depending on at least one measured OTF; and - modifying (116) the current design when the quality indicator is unsatisfactory to obtain a design referred to as a final design, which has a satisfactory quality indicator. The invention also relates to a computer program for implementing this method.

Description

[0001] This invention relates to a method for computer-aided design of optical objectives with improved optical quality. The invention also relates to a computer program for implementing this method. Furthermore, the invention relates to an apparatus and vehicle equipped with an optical objective designed for this method.

[0002] The field of this invention is generally the field of computer-based optical objective design, particularly for imaging. Existing technology

[0003] The design of optical objectives used for imaging is performed using design software, such as Zemax®. In short, a digital model of the objective is designed in this software. Its expected efficiency is then estimated by measuring the modulation transfer function (MTF) under white light using the design software. The measured MTF is compared to a predetermined threshold MTF to determine whether the objective's quality is considered satisfactory. The digital model of the objective is iteratively modified to improve the measured MTF until it is satisfactory.

[0004] The MTF measured under white light represents all optical aberrations of the optical objective, namely chromatic aberration, geometric aberration, and third-order and higher-order aberrations (hereinafter referred to as "third-order aberrations" for the sake of brevity).

[0005] However, the inventors have discovered that certain aberrations, such as lateral chromatic aberration and geometric aberration, can be effectively corrected through calculation. Therefore, a new approach is needed for designing optical objectives.

[0006] One object of the present invention is to solve at least one of the above-mentioned disadvantages.

[0007] Another objective of this invention is to provide a simpler and less time-consuming method for designing optical objectives.

[0008] Another objective of this invention is to propose a design for an optical objective lens that achieves a simpler architecture compared to existing solutions while maintaining the same quality.

[0009] Another objective of this invention is to propose a design for an optical objective lens that achieves improved efficiency compared to current designs with the same architectural complexity.

[0010] Another object of the present invention is to propose a design for an optical objective lens that has a simpler architecture and improved efficiency.

[0011] Invention disclosure

[0012] This invention aims to achieve at least one of the aforementioned objectives by means of a method for designing an optical objective using computer-executed design software, the optical objective comprising a plurality of optical elements, the method comprising a step of designing a design of the optical objective (referred to as the current design), and at least one iteration of a phase referred to as an improvement phase, the improvement phase comprising the following steps:

[0013] - By using design software for simulation, the optical transfer function (OTF) of at least one color of light selected from the following colors is measured for the current design: red, green, and blue light;

[0014] - Determine the quality indicator based on at least one measured OTF; and

[0015] - When the quality indicator is unsatisfactory, modify the current design to achieve a satisfactory quality indicator design (referred to as the final design).

[0016] The inventors have noted that displacement optical aberrations caused by optical objectives can be corrected very effectively through computation, i.e., by digitally processing the acquired image, while diffusion aberrations are very difficult to correct, and sometimes even impossible to correct, depending on the scene being imaged.

[0017] Based on this observation, this invention proposes using a quality indicator to design optical objectives. This quality indicator is not the MTF measured using white light as is currently the case, but rather at least one OTF measured individually for at least one of the red, green, and blue components. Such an indicator allows for the design of optical objectives in a manner that reduces or even minimizes diffusion aberrations, while displacement aberrations can be corrected through digital processing. In this way, the present invention provides a more efficient approach to designing optical objectives, resulting in optical objectives with improved optical quality.

[0018] Furthermore, in existing technologies, the goal of the optical objective design process is to achieve a design that minimizes all optical aberrations caused by the objective (i.e., displacement and diffusion aberrations). However, choosing to reduce one of these aberrations during the design phase can lead to an increase in another aberration: this complicates and time-consuming the optical objective design process, ultimately resulting in objectives with increasingly complex architectures and the use of more lenses. Moreover, this approach leads to choosing an architecture that corresponds to a trade-off between all optical aberrations, which limits the optical efficiency of the objective, particularly regarding diffusion aberrations, which are difficult to correct computationally.

[0019] In a different way, the method according to the invention provides a faster and less time-consuming approach for designing optical objectives because it does not seek to optimize all optical aberrations, but only primarily optimizes diffusion aberrations. Furthermore, the solution proposed by the invention enables the design of optical objectives with reduced complexity while maintaining the same image quality. Moreover, the solution proposed by the invention enables the design of optical objectives with better image quality at the same level of complexity because these objectives will have fewer diffusion aberrations that are difficult (if not impossible) to correct digitally, while other aberrations can be effectively corrected digitally when using the optical objectives.

[0020] "Optical aberration" refers to the concept that the image of points in a scene becomes a spot of light, either wide or narrow, at the location where the image is formed (usually on a plane). Aberrations result in various types of effects: some aberration effects have the characteristic of displacing the average position of the spot of light produced by points in the scene relative to the ideal position where the light should be produced. These aberrations are called displacement aberrations. Other effects are that the spot has a spatially expanded rather than point-like energy distribution in the image trajectory. These aberrations are called diffusion aberrations.

[0021] Aberrations caused by optical objectives are commonly referred to as chromatic aberration, geometric aberration, and third-order aberration.

[0022] "Third-order aberrations" refer to all aberrations introduced into an image acquired using an optical objective, excluding chromatic aberration and geometric aberrations. These third-order (and higher-order) aberrations include, for example, spherical aberration, coma, astigmatism, field curvature, and distortions (of the spot shape and energy distribution). These third-order aberrations are diffusion-type aberrations.

[0023] Chromatic aberration is caused by the decomposition of light into multiple color bands, referring to the optical aberration that produces different focal positions in space according to wavelength. In the case of lateral chromatic aberration, it consists of the shift of the focal point along the image trajectory according to wavelength. The result is an image with iridescent edges, or colored stripes around objects of a uniform color (e.g., white). In the case of axial chromatic aberration, it consists of the focal point being far from the image trajectory because the focal point is shifted along an axis perpendicular to the image trajectory (or an axis corresponding to the central ray reaching the image point, which may be tilted relative to the image trajectory). The result is that some colors in the image are blurred. As long as lateral chromatic aberration is quantifiable, i.e., measurable during the design / manufacturing of optical objectives, it can be corrected by digitally processing the image captured by the optical objectives. Lateral chromatic aberration is a displacement aberration. On the other hand, axial chromatic aberration is a diffusion aberration because, for example, if green is focused on the image plane sensor, red may be focused upstream, and it will broaden as the red beam reaches the sensor located outside the focal point.

[0024] "Geometric aberration" refers to the deviation between paraxial rays as defined in the Gaussian approximation and their corresponding actual rays. Geometric aberration can also be characterized by the deviation between the paraxial wavefront and the actual wavefront. For example, geometric aberration distorts the shape of the resulting image. For instance, a square might become shaped like a barrel (corners concave) or a pincushion (corners convex). Similarly, the straight, vertical edges of a building might become curved and not perpendicular. As long as this aberration is quantifiable—that is, measurable during the design / manufacturing of optical objectives—it can be corrected by digitally processing the captured image. Geometric aberration is a type of displacement aberration.

[0025] "Displacement aberration" or "displacement aberration" refers to lateral chromatic aberration and geometric aberration.

[0026] "Diffusion aberration" or "diffusion aberration" refers to axial chromatic aberration and third-order aberration.

[0027] "Colored light" refers to red light, green light, or blue light.

[0028] According to some embodiments, the optical transfer function (OTF) can be the modulation transfer function (MTF).

[0029] According to some embodiments, for a given measurement point, MTF can be measured in the design software as follows.

[0030] Consider an image plane that corresponds to the plane that the objective lens will assemble with an image sensor to form an imaging module once manufactured. According to an example embodiment, the optical objective lens is illuminated by simulating a test pattern arranged at a specific distance, which is the distance from the scene. This distance can be set to infinity to obtain a so-called infinity distance from the scene. The simulated test patterns alternate:

[0031] - So-called dark patterns, which do not allow light to pass through, and

[0032] - The so-called bright pattern corresponds to the color of the light used to measure its MTF.

[0033] Dark patterns should form patterns without light in the image plane because they do not allow any light to pass through. Bright patterns should form patterns with the same color as the light on the image sensor, seemingly because they allow light to pass through.

[0034] In this configuration, the MTF of a point (x, y) on the sensor is calculated as follows. For a region centered at point (x, y) and comprising multiple alternating patterns, multiple contrast values ​​are calculated based on values ​​received by “pixels” in the image plane, each contrast value corresponding to one alternating pattern in that region. The MTF value of the point (x, y) on the image plane is calculated based on the measured values ​​(e.g., by averaging the values). Thus, for a given color of light, the MTF value for that light and for the point (x, y) on the image plane is obtained through simulation measurements.

[0035] By repeating this simulation measurement on multiple points of the image sensor, the MTF for the light measurement can be obtained, which is then represented by a domain of multiple discrete values.

[0036] Of course, MTF can also be measured in other ways.

[0037] According to some embodiments, the optical transfer function (OTF) can be the point spread function (PSF).

[0038] According to some embodiments, for a given measurement point, the PSF can be measured in the design software as follows.

[0039] Consider an image plane that corresponds to the plane that the objective lens will be assembled with an image sensor to form an imaging module once it is manufactured. According to an example embodiment, the optical objective lens is illuminated by simulating a test pattern arranged at a specific distance, which is a distance from the scene. This distance can be set to infinity to obtain a so-called infinity distance from the scene. The simulated test pattern comprises multiple points through which colored light, for which the PSF is measured, passes. The rest of the test pattern is opaque and does not allow any light to pass through. Each point at position (x, y) forms a spot of light in the image plane that is more or less different in shape and wider or narrower. When the spot is perfectly circular, the PSF value at point (x, y) corresponds to the radius of the spot captured on the sensor. When the spot has other shapes, the PSF can be calculated, for example, as the average radius of the spot. The average radius can be calculated as follows: First, for example, by determining the centroid of the point where the spot is formed, the center of the spot is extracted based on the intensity detected at each position. Next, the sum of the detected amplitudes multiplied by the square of the distance to the centroid is calculated. Divide this sum by the sum of the detected amplitudes. Calculate the square of the average radius of the light spot. Take the square root of this square root. This gives the effective average radius of the light spot.

[0040] By repeating this simulation measurement at multiple points on the image sensor, the PSF for the color light measurement can be obtained, which is then represented by a domain of multiple discrete values.

[0041] Of course, PSF can also be measured in other ways.

[0042] According to some embodiments, the improvement phase can be repeated until, for at least one point used to measure the at least one OTF, and in particular for each point used to measure the at least one OTF, the value of the obtained quality indicator reaches a predetermined target value or a predetermined target value range.

[0043] In this scenario, one or more iterations in the improvement phase aim to improve the OTF measured by the current design to at least reach a predetermined threshold. Thus, the resulting final design for the optical objective has diffusion aberrations below the predetermined threshold.

[0044] In these embodiments, the improvement phase includes the step of comparing the measured OTF with at least one predetermined threshold OTF. For each measurement point, the improvement phase is repeated as long as the measured OTF does not reach the threshold OTF. The current design where the OTF reaches at least one predetermined threshold OTF is stored as the final design for manufacturing the actual optical objective.

[0045] According to some embodiments, the improvement phase can be repeated until the value of the quality indicator reaches the optimal value for at least one OTF measurement point, and more particularly for each OTF measurement point.

[0046] In this context, the iterations in the improvement phase aim to optimize the measured OTF, i.e., minimize diffusion aberration. Thus, the final design for the optical objective is optimized in terms of diffusion aberration.

[0047] In these embodiments, the improvement phase includes a step of comparing the measured OTF with the best OTF value measured in previous iterations. If the measured OTF does not improve over multiple consecutive iterations (e.g., 10 consecutive iterations), the iteration of the improvement phase is stopped because the measured OTF of the current design is considered optimized and may not be able to be improved further. Of course, other example embodiments for determining whether the optimal value of the OTF has been reached are also possible.

[0048] When the OTF is the MTF, the improvement phase can be repeated until the quality indicator value reaches its maximum value.

[0049] When the OTF is a PSF, the improvement phase can be repeated until the quality indicator value reaches its minimum.

[0050] According to some embodiments, for at least one color of light, and especially for each color of light, the measurement step can measure the OTF value at multiple measurement points (e.g., at the center of the objective lens, the edge of the objective lens, etc.).

[0051] In this configuration, each measured OTF can be represented by OTF values ​​measured at multiple measurement points. Preferably, the measured OTF can be represented by a domain of values, including multiple measured OTF values, each corresponding to a location (x, y) in the image plane, and more specifically, to a pixel location (x, y) in the image plane, in order to perform this measurement. The image plane corresponds to the plane of the image sensor that will be assembled with the image sensor to form the imaging module once the objective lens is manufactured. In this case, the measured OTF is represented by discrete values, each corresponding to a measurement point.

[0052] Alternatively, a mathematical relationship can be derived from the measured values, which takes the position (x, y) of the image sensor as input and the measured OTF value as output.

[0053] Of course, at least one measured OTF can be provided in other forms, such as a matrix, vector, etc.

[0054] According to some embodiments, the measurement steps may be performed only for measuring OTF for a single color of light, and the quality indicator is determined based on the OTF measured for said light.

[0055] In this configuration, the measurement process can be performed more quickly. Furthermore, because the quality indicator depends solely on the OTF of that single color light, obtaining the final design is also faster, and improving the quality indicator becomes easier.

[0056] In some embodiments, the only color of light used to measure OTF can be green light. In fact, the inventors have discovered that green light is more representative of the aberrations of optical objectives than red and blue light.

[0057] If OTF is measured for a single color of light, the quality indicator can be the measured OTF.

[0058] Optionally, the quality indicator can correspond to the measured OTF, where different weights can be assigned to the measured OTF values ​​at different measurement points. For example, at least one measurement point at the center of the optical objective can be given a higher weight, and at least one measurement point at the periphery of the optical objective can be given a lower weight.

[0059] Alternatively or additionally, a value range can be used to calculate a single quality indicator value by using a predetermined mathematical relation (with the values ​​contained in that value range as input). This mathematical relation can be the sum, mean, variance, etc., of the values ​​contained in the value range, or the square of each value.

[0060] Other exemplary embodiments that do not depart from the scope of the invention are also possible.

[0061] According to some embodiments, the measurement steps can be performed by measuring OTF separately for multiple colors of light (especially for each color of light), and the quality indicator is determined based on the OTF measured for said light.

[0062] For example, the measurement steps can measure OTF for green, red, and blue light. Thus, the measurement steps provide simulation-based measurements of OTF for green light, OTF for red light, and OTF for blue light.

[0063] Each measured OTF can include multiple OTF values, each OTF value for a given measurement point (x, y) in the image plane.

[0064] If multiple OTFs are measured for various colors of light, a quality indicator can be calculated for at least one measurement point using a mathematical relation that takes into account the value of each OTF measured for that measurement point.

[0065] For example, for a given measurement point, the quality indicator could be the average, squared average, sum, or sum of squares of the OTF values ​​measured for different colors at that measurement point. Of course, these examples are by no means limiting, and other mathematical relationships can be used to calculate the quality indicator.

[0066] Alternatively, different weights can be applied to different colors. For example, at a given measurement point, it might be beneficial to give a higher weight to the OTF value for green than to the OTF value for red, and so on.

[0067] Alternatively, different weights can be applied to different measurement points. For example, at least one measurement point at the center of the optical objective can be given a higher weight, while at least one measurement point at the periphery of the optical objective can be given a lower weight.

[0068] Alternatively or additionally, a value range can be used to compute a single quality indicator value by using a predetermined mathematical relation (with the values ​​contained in that value range as input). This mathematical relation can be the sum, mean, variance, etc., of the values ​​contained in the field of that value, or the square of each value.

[0069] Other exemplary embodiments that do not depart from the scope of the invention are also possible.

[0070] According to some embodiments, the current design can be improved without taking lateral chromatic aberration into account. In this case, lateral chromatic aberration is completely relaxed when designing the optical objective.

[0071] According to some embodiments, the improvement phase may include the step of measuring the lateral color difference function LCAF on the current design.

[0072] When designing optical objectives, this LCAF can be compared to a lateral chromatic aberration threshold that should not be exceeded. This allows for improvements to the current design of the optical objective while maintaining limits on lateral chromatic aberration. In this case, lateral chromatic aberration is not completely relaxed when designing the optical objective.

[0073] According to some embodiments, the current design can be improved without taking geometric aberrations into account. In this case, geometric aberrations are completely relaxed when designing the optical objective.

[0074] According to some embodiments, the improvement phase may include the step of measuring the geometric aberration function (GAF) on the current design.

[0075] When designing optical objectives, this GAF can be compared to a geometric aberration threshold that should not be exceeded. This allows for improvements to the current design of the optical objective while maintaining constraints on geometric aberrations. In this case, lateral chromatic aberration is not fully relaxed when designing the optical objective.

[0076] According to some embodiments, the method according to the invention may include determining at least one correction function for the final design to correct for the following:

[0077] - Lateral color difference, and / or

[0078] - Geometric aberrations.

[0079] According to some embodiments, a lateral color difference correction function (LCACF) can be provided to correct lateral color differences separately.

[0080] According to some embodiments, a geometric aberration correction function (GACF) can be provided to correct geometric aberrations individually.

[0081] According to some embodiments, a single aberration correction function (ACF) can be provided to correct both lateral chromatic aberration and geometric aberration simultaneously.

[0082] At least one correction function can be derived from the previously measured LCAF and GAF.

[0083] If LCAF and / or GAF were measured on the current design that was adopted as the final design during the improvement phase, then they are known.

[0084] If the improvement phase does not include measuring LCAF and / or GAF, then one or more of these functions can be measured on the final design.

[0085] LCAF can be measured in a variety of ways.

[0086] According to some embodiments, consider an image plane corresponding to the plane that the objective lens will be assembled with an image sensor to form an imaging module once manufactured. According to one example embodiment, the optical objective lens is illuminated by simulating a test pattern arranged at a specific distance, which is a distance from the scene. This distance can be set to infinity to obtain a so-called infinity distance from the scene. The test pattern can be illuminated with white light or sequentially with green, red, and blue light. The pattern corresponding to position (x, y) in the image plane generates a spot for each color on the image plane. The position of each color spot can be detected. The detected positions of the three colors of spots are then used to calculate a displacement vector relative to a reference position. The reference position can be the position of one of the three spots, for example, the position of the green spot. Alternatively, the reference position can be another position, such as the position of the optical axis of the optical objective lens in the image plane.

[0087] LCAF can then be determined by simultaneously or sequentially measuring multiple positions (x, y) in the image plane.

[0088] GAF can be measured in a variety of ways.

[0089] According to some embodiments, consider an image plane corresponding to the plane that the objective lens will be assembled with an image sensor to form an imaging module once manufactured. According to one example embodiment, the optical objective lens is illuminated by simulating a test pattern arranged at a specific distance, which is the distance from the scene. This distance can be set to infinity to obtain a so-called infinity distance from the scene. The test pattern is illuminated with white light or sequentially with green, red, and blue light. The angle (θ) relative to the optical objective lens axis... i γ i (where θ) i It is the tilt angle relative to the optical objective axis, γ i A pattern (the rotation angle about the optical objective axis) generates spots on the image plane for each of the three colors: red, green, and blue. The position of each color spot can be detected. The detected positions of the three spots are then used to calculate the displacement distance of each color relative to the center of the optical objective. Optionally, the displacement distance can be divided by the focal length to obtain the angle (θ) of the light beam entering the optical objective relative to the axis of the optical objective. i γ i Angular quantities of a function of ).

[0090] By targeting multiple angles (θ) of the optical axis of the optical objective lens i γ i By performing measurements simultaneously or sequentially, the GAF can be determined.

[0091] According to some embodiments, the lateral chromatic aberration correction function (LCACF) can take the form of a range that includes at least one displacement vector to be applied to correct lateral chromatic aberration at each of a plurality of locations (x, y) on the image plane. For at least one location (x, y) of the sensor, LCACF may include:

[0092] - A single displacement vector for each of the red, green, and blue colors; or

[0093] - For at least one color, a displacement vector specifically for that color.

[0094] Alternatively, LCACF can be a mathematical function that takes the position (x, y) of the image sensor as input and provides one or more displacement vectors to be applied to correct aberrations at said position (x, y).

[0095] According to another alternative, LCACF can take the form of a mapping table for each of multiple pixels in the image plane, indicating the correction position of that pixel, and performed individually for the following:

[0096] - Each color, or

[0097] - When using green as a reference, this applies to red and blue.

[0098] According to some embodiments, the geometric aberration correction function GACF can be presented in the form of a range, which includes values ​​for multiple angles (θ). i γ i For each of the following, at least one distance vector is applied to correct geometric aberrations. For at least one angle (θ) i γ i ), GACF can include:

[0099] - Individual distance correction values ​​for each of the red, green, and blue colors; or

[0100] - For at least one color, a distance correction value specifically for that color.

[0101] Alternatively, GACF can be the angle (θ) relative to the axis of the optical objective. i γ i A mathematical function that takes one or more distance correction values ​​as input.

[0102] According to another alternative, GACF can take the form of a mapping table, which indicates the correction position of each of the multiple pixels on the image sensor, and is performed individually for each color.

[0103] According to some embodiments, for at least one iteration, modifying the current design may include performing at least one of the following steps on the current design:

[0104] - Replace at least one optical element;

[0105] - Add or remove at least one optical element;

[0106] - Modify the geometry of at least one optical interface of at least one optical element;

[0107] - Modify the refractive index of at least one optical element;

[0108] - Modify the wavelength dependence of the refractive index of at least one optical element;

[0109] - Modify the distance between at least two optical elements;

[0110] - Modify the position of at least one optical element.

[0111] Of course, these examples are illustrative and do not limit the scope of the invention in any way.

[0112] According to another aspect of the invention, a computer program is provided that includes executable instructions that, when executed by a computer device, carry out all the steps of the method according to the invention.

[0113] Computer programs can be written in any computer language, such as machine language, C, C++, JAVA, Python, etc.

[0114] Computer programs can be integrated into design software used to design optical objectives.

[0115] Alternatively, the computer program may include design software, or the computer program may be independent of the design software.

[0116] According to another aspect of the present invention, a camera module is provided, comprising:

[0117] - An optical objective lens designed using the method according to the invention; and

[0118] - An image sensor associated with an optical objective.

[0119] The image sensor can be any type of image sensor associated with an optical objective, such as a CMOS or CCD image sensor, but is not limited to these image sensors.

[0120] According to another aspect of the present invention, a method for manufacturing an optical objective lens is provided, comprising the following steps:

[0121] - Designing optical objectives using the method according to the invention; and

[0122] - Manufacture at least one optical objective lens according to the final design obtained.

[0123] According to some embodiments, the manufacturing method according to the present invention may include the step of measuring the following functions using at least one measuring device for at least one manufactured objective lens:

[0124] - Lateral color difference function LCAF; and

[0125] - Lateral geometric aberration function LGAF.

[0126] One or more functions measured on the manufactured objective lens can be used for:

[0127] - Check whether the manufactured optical objectives conform to the final design obtained during the design phase; and / or

[0128] - Corrects lateral chromatic aberration and / or geometric aberration when taking images using optical objectives.

[0129] According to some embodiments, measurement steps can be performed on each manufactured optical objective.

[0130] Alternatively, the measurement steps can be performed on a subset of the manufactured optical objectives. For example, within the same batch of optical objectives, the measurement steps can be performed on a single optical objective or a small number of optical objectives. One or more aberration functions measured can then be used for all objectives in the same batch.

[0131] A batch of optical objectives can correspond to objectives with the same design. Alternatively, a batch of optical objectives can correspond to objectives with the same design and assembled according to the same assembly process.

[0132] According to another aspect of the present invention, an apparatus for manufacturing optical objectives is provided, comprising:

[0133] - A design apparatus configured to implement the design method according to the invention; and

[0134] - Optical objective lens production line.

[0135] The facility according to the invention may include, in terms of hardware and / or configuration, any combination of features disclosed above in reference to the method according to the invention, which will not be mentioned further herein for the sake of brevity.

[0136] Specifically, the manufacturing facility is configured to implement the manufacturing method according to the invention.

[0137] According to another aspect of the invention, an apparatus is also proposed, which includes at least one optical objective lens designed using the method according to the invention.

[0138] In particular, the device according to the invention may include at least one camera module according to the invention.

[0139] Specifically, the device can be a user device, such as a smartphone, tablet, etc.

[0140] User devices may optionally include a display screen, especially a touch screen.

[0141] Specifically, the device can be a virtual reality headset or an augmented reality headset designed to be worn by a user.

[0142] Head-mounted devices may optionally include displays, especially touchscreens.

[0143] Specifically, the device can be a user device, such as a camera or video camera.

[0144] Camera-type user devices may optionally include a display screen, especially a touch screen.

[0145] In particular, the device can be a computer-type user device.

[0146] Computer-type user devices may optionally include a display screen, especially a touch screen.

[0147] The computer-type user device may optionally include a keyboard or any other device integrated into or associated with the device.

[0148] In particular, the device can be a television set.

[0149] Televisions may optionally include a display screen, especially a touch screen.

[0150] In particular, the device can be a medical imaging device.

[0151] Medical imaging devices can be, for example, endoscopes, ultrasound equipment, etc.

[0152] Of course, the apparatus according to the present invention is not limited to the example apparatus disclosed above.

[0153] According to another aspect of the invention, a vehicle is also proposed, which includes at least one optical objective lens designed using the method according to the invention.

[0154] In particular, the device according to the invention may include at least one camera module according to the invention.

[0155] According to some embodiments, the vehicle can be a land vehicle, such as a car, for example a car with non-autonomous driving, semi-autonomous driving or fully autonomous driving.

[0156] According to some embodiments, the vehicle can be a flying vehicle, such as a drone, airplane, or helicopter, for example, a drone, airplane, or helicopter with non-autonomous, semi-autonomous, or fully autonomous driving capabilities.

[0157] According to some embodiments, the vehicle can be a waterborne or underwater vehicle, such as a boat or submarine, for example a waterborne or underwater vehicle with non-autonomous, semi-autonomous, or fully autonomous driving capabilities.

[0158] According to another aspect of the present invention, a method for acquiring a scene image is proposed, the method comprising the following steps:

[0159] - Acquire images using an optical objective designed according to the method of the present invention, and

[0160] - Perform digital processing on the image to correct it.

[0161] According to some embodiments, digital processing may include a step of correcting chromatic aberration introduced into an image by an optical objective, such as using a correction function provided during the optical objective design process and / or the optical objective manufacturing process to correct chromatic aberration introduced into an image by an optical objective.

[0162] According to some embodiments, digital processing may include steps to correct geometric aberrations introduced into an image by an optical objective, such as using a correction function provided during the optical objective design process and / or the optical objective manufacturing process to correct geometric aberrations introduced into an image by an optical objective.

[0163] In some embodiments, the optical objective lens can be used for 2D or 3D imaging.

[0164] According to some embodiments, optical objectives can be used for image acquisition to image a scene at a given moment, or to acquire an image stream or video of the scene.

[0165] Description of the accompanying drawings and embodiments

[0166] Other advantages and features will become apparent from a study of the detailed description of the non-limiting embodiments and the accompanying drawings, in which:

[0167] - Figure 1-3 These are illustrative depictions of three non-limiting example embodiments of the method according to the present invention;

[0168] - Figure 4 This is a schematic depiction of a non-limiting example embodiment of a method for manufacturing one or more optical objectives according to the present invention;

[0169] - Figure 5This is a schematic depiction of a non-limiting example embodiment of a facility for manufacturing one or more optical objectives according to the present invention;

[0170] - Figure 6 This is a schematic depiction of a non-limiting example embodiment of a camera module according to the present invention;

[0171] - Figure 7 This is an illustrative depiction of a non-limiting example embodiment of a method for acquiring images according to the present invention;

[0172] - Figures 8a-8c This is an illustrative depiction of a non-limiting example embodiment of a device according to the invention; and

[0173] - Figure 9 This is a schematic depiction of a non-limiting example embodiment of a vehicle according to the present invention.

[0174] It should be clearly understood that the embodiments described below are by no means limiting. In particular, variations of the invention are conceivable that include only selections of features disclosed below independently of other disclosed features, if such selection is sufficient to impart a beneficial technical effect or distinguish the invention from the prior art. Such selections include at least one preferably functional feature that has no structural details, or only a portion of structural details, if that portion alone is sufficient to impart a beneficial technical effect or distinguish the invention from the prior art.

[0175] In particular, all the described variations and embodiments can be combined with each other if there are no technical obstacles to such combinations.

[0176] In the following description of the accompanying drawings and specification, the same reference numerals are used for features common to multiple drawings.

[0177] Figure 1 This is a schematic depiction of a non-limiting example embodiment of the method according to the present invention.

[0178] Figure 1 Method 100 can be used to design optical objectives for imaging (i.e., for acquiring images or videos). Such optical objectives can be associated with image sensors to form imaging modules and integrated into various devices.

[0179] Optical objectives typically consist of multiple optical elements, such as the objective lens element and spacers. When designing an optical objective, technical specifications define its efficiency during image acquisition. This efficiency is usually quantified using the MTF (modulation transfer function).

[0180] The optical objective design process is performed using design software that enables the definition of a digital model of the optical objective (also known as the digital design of the optical objective), simulation of wave propagation through the design, and measurement of various quantities. One of the most well-known design software packages is, for example, ZEMAX®.

[0181] Figure 1 Method 100 includes step 102, in which a design for the objective lens is created using design software (e.g., ZEMAX® design software), referred to as the current design. This design is achieved by stacking multiple optical elements along a stacking direction that also corresponds to the axis of the optical objective. Each optical element of the optical objective is modeled digitally: in other words, each optical element is represented by digital data describing that element, namely the shape of each optical interface of the element, the position of the element, the position of the vertices of the element (if applicable), the optical index of the element, the orientation of the element in the XY plane perpendicular to the Z-axis of the optical objective, the tilt of the element relative to the Z-axis, etc. All this data is used to simulate the propagation of light waves through the optical elements. Thus, it is possible to simulate the propagation of light waves of a given wavelength within each optical element of the optical objective by calculation, and therefore simulate the propagation of light waves through the stack of optical elements forming the optical objective.

[0182] By simulating the propagation of light waves through a digitally modeled optical objective lens, the light waves are detected at an image plane that simulates the plane of the image sensor. This allows for the simulation of measurements on the propagating light waves at the image sensor level.

[0183] After step 102, method 100 includes at least one iteration of phase 104 for improving the current design of the optical objective.

[0184] This improvement phase 104 includes determining the value of the quality indicator on the current design of the optical objective.

[0185] According to the present invention, the quality indicator denoted as Q is determined based on the optical transfer function (OTF) measured by simulation for at least one color of light selected from red, green, and blue in the current design.

[0186] exist Figure 1 In the example shown, the quality indicator Q is calculated based on a function of the OTF for each type of light measurement (i.e., the OTF for red light measurement, the OTF for green light measurement, and the OTF for blue light measurement) through simulation.

[0187] In addition, Figure 1In the example shown (by no means a limitation), OTF is the modulation transfer function (MTF). Alternatively, OTF can be the point spread function (PSF). Generally, OTF can be any function representing the optical behavior of an optical objective.

[0188] Phase 104 includes step 106, which involves measuring the MTF for green light in the current design using simulation.

[0189] For example, green light can be green light with a wavelength of 500 nm to 570 nm, especially green light with a wavelength of 535 nm.

[0190] MTF can be measured using the techniques described above. According to one example embodiment, an optical objective is illuminated by simulating a test pattern arranged at a specific distance, which is the distance from the scene. This distance can be set to infinity to obtain a so-called infinity distance from the scene. The simulated test patterns alternate:

[0191] - So-called dark patterns, which do not allow light to pass through, and

[0192] - The so-called bright pattern corresponds to the color of light: green.

[0193] Dark patterns should form patterns without light in the image plane because they do not allow any light to pass through. Light patterns should form patterns with the same color as the light (i.e., green) in the image plane because they allow light to pass through.

[0194] In this configuration, the MTF of the sensor point (x, y) is calculated as follows. For a region centered at point (x, y) and comprising multiple alternating patterns, multiple contrast values ​​are calculated based on values ​​received by “pixels” of the simulated image plane, each contrast value corresponding to one alternating pattern in the region. The MTF value of the point (x, y) in the image plane is calculated based on the measured values ​​(e.g., by averaging the values).

[0195] Step 106 performs multiple MTF value measurements on multiple points on the image plane and provides an MTF for green light, which is represented by the field of the measured MTF values, each value corresponding to a position (x, y) on the image plane.

[0196] Phase 104 includes step 108, which measures the MTF for red light in the current design through simulation. Step 108 is similar to the method described in step 106 for green light, except that green light is replaced with red light.

[0197] For example, red light can be red light with a wavelength of 570 nm to 730 nm, especially red light with a wavelength of 650 nm.

[0198] Step 108 provides the MTF for red light, which is represented by the field of the measured MTF values, each value corresponding to a position (x, y) in the image plane.

[0199] Phase 104 includes step 110, which measures the MTF for blue light in the current design through simulation. Step 110 is similar to the method described in step 106 for green light, except that green light is replaced with blue light.

[0200] For example, blue light can be blue light with a wavelength of 400 nm to 500 nm, especially blue light with a wavelength of 450 nm.

[0201] Step 110 provides an MTF for blue light, which is represented by a field of measured MTF values, each value corresponding to a location (x, y) in the image plane.

[0202] Phase 104 includes step 112, which determines the quality indicator Q for iteration i of the improvement phase based on the MTF measured in steps 106-110.

[0203] Quality indicators can be calculated in several ways.

[0204] For example, for a given measurement point, the quality indicator could be the average, squared average, sum, or sum of squares of the OTF values ​​measured for different colors at that measurement point. Optionally, different weights could be used for different colors. For example, at a given measurement point (x, y), it might be beneficial to give higher weight to the MTF value for green than to the MTF values ​​for red and blue, and so on. In this example, the quality indicator takes the form of a range, giving a quality indicator value for each point (x, y) in the image plane.

[0205] According to another example embodiment, the previously obtained value range for the quality indicator can be used to calculate a single quality indicator value using a predetermined mathematical relation that takes the values ​​contained in the value range as input. This mathematical relation can be the sum, average, variance, etc., of the values ​​contained in the value range, or the square of each value. Optionally, different weights can be used for different measurement points. For example, at least one measurement point at the center of the optical objective can be given a higher weight, and at least one measurement point at the periphery of the optical objective can be given a lower weight. In this example, the quality indicator takes the form of a single value specific to the current design.

[0206] Phase 104 includes step 114, which tests the quality indicator obtained in step 112 to determine whether the quality indicator is satisfactory.

[0207] According to some embodiments, the quality indicator can be compared with at least one threshold quality indicator or a range of threshold quality indicators. When the quality indicator is in the form of a range, where each value in the range corresponds to a position (x, y) in the image plane, the threshold quality indicator or each threshold quality indicator can also be in the form of a range, where each value in the range corresponds to a position (x, y) in the image plane. A position-by-position comparison can then be performed. When the quality indicator is in the form of a single value, the quality indicator or each threshold quality indicator can also be in the form of a single value.

[0208] According to some embodiments, the quality indicator can be compared with at least one quality indicator previously measured during previous iterations in the improvement phase.

[0209] Of course, other embodiments are possible, and the examples given are by no means limiting.

[0210] If the quality indicator is deemed unsatisfactory in step 114, improvement stage 104 includes step 116 of modifying the current design. This modification of the current design may include at least one of the following operations:

[0211] - Replace at least one optical element;

[0212] - Add or remove at least one optical element;

[0213] - Modify the geometry of at least one optical interface of at least one optical element;

[0214] - Modify the refractive index of at least one optical element;

[0215] - Modify the distance between at least two optical elements;

[0216] - Modify the position of at least one optical element;

[0217] - etc.

[0218] Then a new iteration of optimization phase 104 can be performed until a satisfactory quality indicator is obtained.

[0219] If the quality indicator is deemed satisfactory in step 114, then improvement phase 104 terminates.

[0220] Method 100 then includes step 118 of storing the current design as the final design of the optical objective.

[0221] Method 100 may also include an optional step 120, which measures the lateral color difference function LCAF representing the lateral color difference LCA of the final design.

[0222] For a given measurement point, LCA can be measured in several ways. According to one example embodiment, an optical objective is illuminated by simulating a test pattern arranged at a specific distance, which is the distance from the scene. This distance can be set to infinity to obtain a so-called infinite distance from the scene. The test pattern can be illuminated with white light or sequentially with green, red, and blue light. The pattern corresponding to the position (x, y) in the image plane generates a spot for each color on the image plane. The position of each color spot can be detected. The detected positions of the three colors of spots are then used to calculate a displacement vector relative to a reference position, which can be the position of one of the three spots or another position.

[0223] The LCAF can then be determined by simultaneously or sequentially measuring multiple positions (x, y) in the image plane. In this case, the LCAF takes the form of a range, where each value corresponds to a position (x, y) in the image plane, and each value includes one or more displacement vectors.

[0224] Method 100 may also include an optional step 120, which measures the geometric aberration function GAF representing the geometric aberration GA of the final design.

[0225] For a given measurement point, GAF can be measured in several ways. According to one example embodiment, the optical objective is illuminated by simulating a test pattern arranged at a specific distance, which is the distance from the scene. This distance can be set to infinity to obtain a so-called infinite distance from the scene. The test pattern is illuminated with white light or sequentially with green, red, and blue light. An angle (θ) is made with the axis of the optical objective. i γ i The pattern generates spots on the image plane for each of the three colors: red, green, and blue. The position of each color spot can be detected. The detected positions of the three spots are then used to calculate the displacement distance of each color relative to the center of the optical objective. Optionally, the displacement distance can be divided by the simulated focal length to obtain the angle (θ) of the light beam entering the optical objective relative to the axis of the optical objective. i γ i Angular quantities of a function of ).

[0226] By targeting multiple angles (θ) of the optical axis of the optical objective lens i γ i By performing measurements simultaneously or sequentially, the GAF can be determined.

[0227] Method 100 may also include an optional step 124, which determines and provides at least one lateral chromatic aberration correction function and / or geometric aberration correction function based on the LCAF measured in step 120 and / or the GAF measured in step 122.

[0228] Figure 1 Method 100 involves designing optical objectives without considering lateral chromatic aberration and geometric aberrations in the resulting design. In other words, these aberrations are completely relaxed in the design of the optical objectives.

[0229] Alternatively, it can be expected that these aberrations are kept at an acceptable level without optimizing the optical objective design process for these aberrations.

[0230] Figure 2 This is an illustrative depiction of another non-limiting example embodiment of the method according to the present invention.

[0231] Figure 2 Method 200 enables the design of optical objectives while keeping lateral chromatic aberration (LCA) and / or geometric aberration (GA) at acceptable levels. In other words, method 200 enables the design of optical objectives without completely relaxing LCA and / or GA.

[0232] Figure 2 Method 200 includes Figure 1 All steps of Method 100, except for the differences noted below.

[0233] exist Figure 2 In method 200, when the quality indicator is deemed satisfactory in step 114, improvement phase 104 further includes an optional step 202, which measures the lateral color difference function LCAF for the current design, for example, performing step 202 on the current design in a similar / identical manner to that described with reference to step 120.

[0234] In step 204, the LCAF is compared with a predetermined threshold to maintain an acceptable lateral color difference level. If the LCAF does not meet the predetermined threshold, step 116, modifying the current design, is performed to continue the improvement phase.

[0235] If the LCAF meets a predetermined threshold in step 204, then improvement phase 104 includes an optional step 206, which measures the geometric aberration function GAF for the current design, for example, performing step 206 on the current design in a similar / identical manner to that described with reference to step 122.

[0236] In step 208, the GAF is compared with a predetermined threshold to maintain an acceptable level of geometric aberration. If the GAF does not meet the predetermined threshold, step 116, modifying the current design, is performed to continue the improvement phase. Otherwise, improvement phase 104 is terminated.

[0237] Method 200 continues to execute step 118, where the current design is stored as the final design.

[0238] Method 200 does not include steps 120 and 122 because LCAF and GAF ​​are measured during the last iteration of improvement phase 104.

[0239] Method 200 may optionally include step 124, which provides at least one aberration correction function based on the LCAF and GAF ​​for the final design measurement.

[0240] Figure 1 Method 100 and Figure 2 Method 200 takes into account the OTF for each color of light when designing optical objectives, and in particular the MTF for each color of light.

[0241] Alternatively, optical objectives for OTFs can be designed to take into account only a single color of light (such as green, red, or blue).

[0242] Figure 3 This is an illustrative depiction of another non-limiting example embodiment of the method according to the present invention.

[0243] Figure 3 Method 300 enables the design of optical objectives with an MTF that only considers a single color of light (e.g., green light).

[0244] Method 300 includes all the steps of method 100 except for steps 108 and 110.

[0245] The quality indicator used can be the MTF for green light measurement. In this case, steps 112 and 106 are performed together, or not at all.

[0246] Alternatively, the quality indicator can correspond to the MTF for green light measurements, where different weights can be assigned to different measurement points. For example, at least one measurement point at the center of the optical objective can be given a higher weight, and at least one measurement point at the periphery of the optical objective can be given a lower weight.

[0247] Alternatively or additionally, the value range of the MTF for green light measurements can be used to calculate a single quality indicator value, using a predetermined mathematical relation that takes as input the values ​​contained in the value range of the MTF for green light measurements. This mathematical relation can be the sum, mean, variance, etc., of the values ​​contained in the value range, or the square of each value.

[0248] In method 300, red or blue light can be used instead of green light.

[0249] Alternatively, and not shown in this document, the optical objective design process may take into account two colors of light selected from green, red, and blue.

[0250] Alternatively, and not shown in this paper, the optical objective design process can be based on Figure 2 Method 200, but using a single color of light or two colors of light.

[0251] Figure 4 This is a schematic depiction of a non-limiting example embodiment of a method for manufacturing an optical objective lens according to the present invention.

[0252] Figure 4 Method 400 can be used to manufacture optical objectives for imaging (i.e., for acquiring images or videos).

[0253] Method 400 includes methods according to the present invention, and in particular according to... Figure 1-3 Step 402 of any of methods 100, 200, and 300 designs the optical objective. Step 402 provides the final design and optionally provides at least one of the following functions:

[0254] - LCAF (Lateral Color Difference Function) for the final design;

[0255] - Geometric aberration function (GAF) for the final design;

[0256] - The lateral color difference correction function LCACF for the final design; and

[0257] - Geometric aberration correction function GACF for the final design.

[0258] Method 400 includes step 404 of manufacturing an optical objective. The manufacturing of optical objectives is a conventional and well-known method, and therefore will not be described in detail herein.

[0259] Method 400 may optionally include a stage 406, which characterizes the optical objective OO manufactured in step 404.

[0260] Characterization stage 406 may include an optional step 408, which uses a measuring device to measure the lateral chromatic aberration function LCAF for the optical objective lens OO.

[0261] Characterization stage 406 may include an optional step 410, which uses a measuring device to measure the geometric aberration function (GAF) for the optical objective lens OO manufactured in step 404.

[0262] Characterization stage 406 may include optional step 412, which determines and provides at least one lateral chromatic aberration correction function and / or geometric aberration correction function for the optical objective lens OO manufactured in step 404.

[0263] According to some embodiments, a characterization phase 406 may be performed for each manufactured optical objective.

[0264] Alternatively, characterization phase 406 can be performed on a subset of the manufactured optical objectives. For example, within the same batch of optical objectives, characterization phase 406 can be performed on a single optical objective or a small number of optical objectives. One or more aberration functions measured and / or one or more correction functions determined can be used for all objectives in the same batch.

[0265] A batch of optical objectives can correspond to objectives with the same design. Alternatively, a batch of optical objectives can correspond to objectives with the same design and assembled according to the same assembly process.

[0266] Figure 5 This is a schematic depiction of a non-limiting example embodiment of an apparatus for manufacturing optical objectives according to the present invention.

[0267] Figure 5 The manufacturing equipment 500 is capable of manufacturing optical objectives for imaging (i.e., for acquiring images or videos).

[0268] The apparatus 500 can be configured to implement the manufacturing method according to the invention, in particular to realize... Figure 4 Manufacturing method 400.

[0269] The apparatus 500 includes a means for implementing the method according to the invention, in particular by realizing Figure 1-3 The design apparatus 502 is a device 502 for designing optical objectives using any of methods 100, 200, or 300. The design apparatus 502 provides a final design for the optical objective and may optionally provide at least one of the following functions:

[0270] - LCAF (Lateral Color Difference Function) for the final design;

[0271] - Geometric aberration function (GAF) for the final design;

[0272] - The lateral color difference correction function LCACF for the final design; and

[0273] - Geometric aberration correction function GACF for the final design.

[0274] Design device 502 can be any type of device, such as a computer. Design device 502 can perform:

[0275] - The computer program according to the present invention, or

[0276] - Design software for designing optical objectives, which integrates a computer program according to the invention, or implements a method according to the invention.

[0277] Equipment 500 includes optical objective lens production line 504. Production line 504 is a known conventional optical objective lens production line, and therefore will not be described in detail here.

[0278] Optionally, the apparatus 500 may include at least one measuring device 506 for characterizing at least one optical objective lens OO manufactured in step 504. Specifically, the at least one measuring device 506 is configured to implement... Figure 4 Step 406 of manufacturing method 400.

[0279] Figure 6 This is an illustrative depiction of a non-limiting example embodiment of a camera module.

[0280] Figure 6 The camera module 600 includes, according to the present invention, particularly by means of... Figure 1-3 Characterized or through any of the methods 100, 200, and 300 Figure 4 The optical objective 602 is manufactured using method 400. The optical objective 602 can be... Figure 4-5 The optical objective lens OO shown is shown.

[0281] exist Figure 6 In the non-limiting example shown, the optical objective 602 includes four lenses 604-610 stacked in the lens barrel 612 along a stacking direction 614, which also corresponds to the axis 614 of the optical objective 602.

[0282] The camera module 600 also includes an image sensor 616 associated with the optical objective lens 602. The image sensor 616 can be any type of image sensor, such as a CCD or CMOS sensor.

[0283] Of course, camera module 600 may include other components / assemblies. Figure 4 Not shown, such as mechanisms for modifying the imaging angle or other mechanisms for modifying the imaging sharpness distance.

[0284] Camera module 600 may optionally include module 618 for digitally processing data captured by image sensor 616. Such a digital processing module 618 may be arranged, for example, to correct the image captured by image sensor 616, such as by correcting lateral chromatic aberration and / or geometric aberrations. Module 618 may, for example, integrate one or more previously determined aberration correction functions, such as the one or more correction functions determined in steps 124 and 412 described above.

[0285] The processing module 618 can be a standalone module. Alternatively, the processing module 618 can be integrated into another module or another application, such as a photo application for image acquisition, for example.

[0286] Module 618 may be a hardware unit, such as a processor, chip, computer, server, etc. Alternatively, module 618 may be a software unit, such as a computer application or program. Alternatively, module 618 may be any combination of at least one hardware unit and at least one software unit. Module 618 may be a standalone module. Alternatively, module 618 may be integrated into an existing module within a device, such as a photo application for a device equipped with camera module 600.

[0287] Figure 7 This is a schematic depiction of a non-limiting example embodiment of a method for acquiring images according to the present invention.

[0288] Method 700 includes step 702, which is to use an optical objective lens characterized by the present invention or a camera module according to the present invention (especially...) Figure 6 The camera module 600 acquires images.

[0289] Method 700 further includes step 704, which digitally processes the acquired image. This digital processing can correct the acquired image, for example, by aiming to at least partially correct lateral chromatic aberration and / or geometric aberrations caused by the optical objectives in the acquired image. Such aberration correction can be achieved, for example, using at least one aberration correction function, such as those obtained in steps 124 and 412 described above.

[0290] Figure 8a This is a schematic depiction of a non-limiting example embodiment of the device according to the invention.

[0291] Figure 8a The device 810 includes at least one imaging module according to the invention, in particular Figure 6 The imaging module 600.

[0292] exist Figure 8a In the example shown, device 810 is a smartphone or tablet.

[0293] Optionally, the device 810 may also include a display screen 812 equipped with a touch-sensitive surface 814 (e.g., a capacitive touch-sensitive surface).

[0294] The imaging device 810 may also include an imaging application 816, such as a photo and / or video application, mounted on and executed by the device 810. The application 816 may, for example, be integrated with the processing module 618 of the imaging module. Alternatively, the processing module 618 may be independent of the application 816.

[0295] Figure 8bThis is an illustrative depiction of another non-limiting example embodiment of the device according to the invention.

[0296] Figure 8b The device 820 includes at least one imaging module according to the invention, in particular Figure 6 The imaging module 600.

[0297] exist Figure 8b In the example shown, device 820 is a virtual reality headset (VR) or an augmented reality headset (VA).

[0298] Optionally, the head-mounted device 820 may also include a display screen 822. Optionally, the head-mounted device 820 may also include a sensor (not shown) for detecting the position of one or both of the user's eyes on the display screen 822.

[0299] The head-mounted device 820 may also include an imaging application (not shown), such as a photo and / or video application, mounted on and executed by the device 820. The imaging application may, for example, be integrated into the processing module 618 of the imaging module. Alternatively, the processing module 618 may be an imaging application independent of the head-mounted device 820.

[0300] Figure 8c This is an illustrative depiction of another non-limiting example embodiment of the device according to the invention.

[0301] Figure 8c The device 830 includes at least one imaging module according to the invention, in particular Figure 6 The imaging module 600.

[0302] exist Figure 8c In the example shown, device 830 is a medical imaging device, such as an endoscope or ultrasound equipment.

[0303] Optionally, the medical imaging device 830 may also include a display screen 832.

[0304] Optionally, the medical imaging device 830 may also be equipped with a sensing surface 834, such as a capacitive sensing surface.

[0305] Optionally, the medical imaging device 830 may also include a distal objective lens 836 for collecting light, which may or may not be part of the imaging module 600.

[0306] The imaging device 830 may also include an imaging application (not shown), such as a photo and / or video application, mounted on and executed by the device 830. The imaging application may, for example, be integrated into the processing module 618 of the imaging module. Alternatively, the processing module 618 may be an imaging application independent of the device 830.

[0307] Figure 9 This is a schematic depiction of a non-limiting example embodiment of a vehicle according to the present invention.

[0308] Figure 9 The vehicle 900 includes at least one imaging module according to the invention, in particular Figure 6 An imaging module 600, such as an imaging module 600 integrated in a camera 902.

[0309] In vehicle 900, camera module 902 may be positioned, for example, behind the windshield of vehicle 900, at the top of the windshield of vehicle 900, or above the front windshield of vehicle 900. Of course, this positioning is given as a non-limiting example, and camera 902 may be positioned elsewhere.

[0310] exist Figure 9 In the example shown, vehicle 900 is a land vehicle, particularly an automobile. Vehicle 900 may also include a display screen 904 arranged in the passenger compartment of vehicle 900 and equipped with a touch-sensitive surface 906 (e.g., a capacitive touch-sensitive surface).

[0311] The vehicle 900 may also include an imaging application 908, such as a photo and / or video application. The imaging application 908 may, for example, integrate with the processing module 618 of the imaging module. Alternatively, the processing module 618 may be independent of the imaging application 908.

[0312] Of course, this invention is not limited to land vehicles. Vehicles according to the invention can be aircraft, such as unmanned aerial vehicles, airplanes, helicopters, etc. Vehicles according to the invention can be waterborne or underwater vehicles, such as seaplanes, boats, submarines, etc.

[0313] This invention is not limited to the examples of devices and vehicles given with reference to the accompanying drawings. This invention can be used with all types of devices and vehicles.

[0314] Of course, the present invention is not limited to the examples disclosed above.

Claims

1. A method (100; 200; 300) for designing an optical objective (OO; 600) using computer-executed design software, the optical objective (OO; 600) comprising a plurality of optical elements (604-610), the method (100; 200; 300) comprising a design step (102) of designing the optical objective (OO; 600) referred to as a current design, and at least one iteration of a phase (104) referred to as an improvement phase, the improvement phase comprising the following steps: - By using design software for simulation, at least individually measure the optical transfer function (OTF) for light selected from the following colors: red, green, and blue light; - Determining (112) depends on at least one measured quality indicator of the OTF; as well as - When the quality indicator is unsatisfactory, modify (116) the current design to obtain a design known as the final design, which has the quality indicator satisfactory.

2. The method according to the preceding claim (100; 200; 300), characterized in that, The optical transfer function is: - Modulation transfer function (MTF), or - Point spread function (PSF).

3. The method according to any one of the preceding claims (100; 200; 300), characterized in that, Repeat the improvement phase (104) until the value of the quality indicator obtained for at least one point used to measure the at least one OTF, and in particular for each point used to measure the at least one OTF, reaches a predetermined target value or a predetermined target value range.

4. The method (100; 200; 300) according to claim 1, characterized in that, Repeat the improvement phase (104) until the value of the quality indicator reaches the optimal value for at least one OTF measurement point, and in particular the optimal value for each OTF measurement point.

5. The method (100; 200; 300) according to any one of the preceding claims, characterized in that, For at least one color of light, the measurement steps (106, 108, 110) measure the OTF value at multiple measurement points.

6. The method (300) according to any one of the preceding claims, characterized in that, The measurement step (106) measures the OTF only for a single color of light, and the determination of the quality indicator depends on the OTF measured for that light.

7. The method according to claims 1 to 5 (100; 200), characterized in that, The measurement steps (106, 108, 110) measure the OTF for multiple colors of light, especially for each color of light individually, and the determination of the quality indicator depends on the OTF measured for these lights.

8. The method according to the preceding claim (100; 200; 300), characterized in that, For at least one measurement point, the quality indicator is calculated using a mathematical relation that takes into account the value of each OTF measured for that measurement point.

9. The method (200) according to any one of the preceding claims, characterized in that, It includes the steps (202; 206) of measuring the following items on the current design: - Lateral color difference function LCAF; and / or - Geometric aberration function (GAF).

10. The method according to the preceding claim (100; 200; 300), characterized in that, It includes the step (124) of determining at least one correction function for the final design to correct for the following: - Lateral color difference, and / or - Geometric aberrations.

11. The method (100; 200; 300) according to any one of the preceding claims, characterized in that, The step (116) of modifying the current design includes performing at least one of the following steps on the current design: - Replace at least one optical element; - Add or remove at least one optical element; - Modify the geometry of at least one optical interface of at least one optical element; - Modify the refractive index of at least one optical element; - Modify the wavelength dependence of the refractive index of at least one optical element; - Modify the distance between at least two optical elements; - Modify the position of at least one optical element.

12. A computer program comprising executable instructions that, when executed by a computer device, perform all the steps of the method (100; 200; 300) according to any one of the preceding claims.

13. A method (400) for manufacturing an optical objective (OO) comprising a plurality of optical elements, the method (400) comprising the following steps: - Obtain (402) the final design for the optical objective by the method (100; 200; 300) according to any one of claims 1 to 11; and - The optical objective (OO) is manufactured (404) according to the final design.

14. An imaging module (600), comprising: - An optical objective (OO) designed using the method (100; 200; 300) according to any one of claims 1 to 11; and - An image sensor (601) is associated with the optical objective (OO).

15. A method (700) for acquiring a scene image, the method (700) comprising the following steps: - To acquire (702) an image using an optical objective (OO) designed by any one of the methods (100; 200; 300) according to any one of claims 1 to 11, and - The image is digitally processed (704) to correct the image.

Images