Multispectral image output device and multispectral image output method

Abstract

The invention provides a multispectral image output device which comprises a narrowband filter, an image sensor and an image processor, the narrowband filter is provided with narrowband filtering channels with 2-4 wave bands, the range of the wave bands is from 400nm to 1000nm, and the range of the image sensor is from 400nm to 1000nm. The spectral response ratios of different channels of the image sensor in different wavebands of the narrow-band filter meet the condition that the ratio of the spectral response value of any channel in the peak waveband of the narrow-band filter to the spectral response value of any channel in other wavebands of the narrow-band filter is greater than a preset value, and the preset value is not less than 6. According to the multi-spectral image output method, through reasonable cooperation of the filter and the RGB image sensor and specific value condition setting of spectral response values of the image sensor under different wave bands, 2-4 spectral image output meeting requirements can be achieved, a de-mixing algorithm is not needed, a complex technology is not needed, and the method is suitable for large-scale popularization and application. The structure is simple and cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of hyperspectral imaging, and particularly to an output device for multi-spectral images, a method for outputting multi-spectral images, and a method for outputting multi-spectral images. Background Art

[0002] Since the response ranges of the conventional RGB image sensors for R, G, and B are wide, it is impossible to directly output narrow-band images. Currently, there are three methods for outputting multiple narrow-band images. One is to provide a single-wavelength light source to achieve imaging at different wavelengths respectively; this method requires a light source, has a large volume, and a slow imaging speed. The second is to rotate a filter wheel and output an image of one band each time it rotates, and the speed is also slow, which cannot meet the requirements of some applications. The last one is a multi-spectral imaging device with a coated mosaic filter, where different filter films are coated on different pixels to achieve multi-spectral imaging. In order to achieve precise pixel alignment, the filter films cover the surface of the image sensor, lacking flexibility, having high requirements for the coating process, being difficult to implement, and at the same time reducing the spatial resolution. Summary of the Invention

[0003] In order to solve the above technical problems existing in the prior art, the present invention provides an output device for multi-spectral images and a method for outputting multi-spectral images to achieve the output of narrow-band images of multiple bands quickly and at low cost.

[0004] According to a first aspect of the present invention, there is provided an output device for multi-spectral images, including a narrow-band filter, an image sensor, and an image processor. The narrow-band filter is provided with narrow-band filtering channels in 2 to 4 bands, and the range of the bands is taken from 400 nm to 1000 nm. Moreover, the spectral response ratios of different channels of the image sensor at different bands of the narrow-band filter satisfy that the ratio of the spectral response value of any channel in the peak band of the narrow-band filter to its spectral response values in other bands of the narrow-band filter is greater than a preset value, and the preset value is not less than 6. By providing a narrow-band filter with narrow-band filtering channels in 2 to 4 band ranges, cooperating with an image sensor that meets specific spectral response ratio conditions, and an image processor, the output of multi-spectral images can be achieved. The spectral response ratio conditions of different channels of the image sensor at different bands of the narrow-band filter ensure that the response differences of the image sensor to lights of different bands reach a certain degree, which helps to more clearly distinguish spectral information of different bands.

[0005] In some specific embodiments, 2 to 4 narrowband filter channels are defined as wavelength bands W1, W2, W3, and W4, and the ranges of the wavelength bands satisfy 400nm ≤ W1 ≤ 500nm, 500nm ≤ W2 ≤ 600nm, 600nm ≤ W3 ≤ 700nm, and 700nm ≤ W4 ≤ 1000nm. The specific wavelength band ranges of the narrowband filter channels are clarified, enabling the device to obtain spectral information in specific wavelength intervals. These wavelength band ranges cover the visible light and part of the near-infrared light regions, which is conducive to capturing the unique spectral characteristics of different substances in these wavelength bands.

[0006] In some specific embodiments, the image sensor is a Bayer array image sensor. This image sensor can efficiently perform color perception and signal conversion on the light passing through the narrowband filter.

[0007] In some specific embodiments, wavelength band W1 is the peak position of the spectral response of the blue channel.

[0008] In some specific embodiments, wavelength band W2 is the peak position of the spectral response of the green channel, or the intersection position of the spectral responses of the blue channel and the red channel.

[0009] In some specific embodiments, wavelength band W3 is the peak position of the spectral response of the red channel, or the valley position of the spectral response of the green channel.

[0010] In some specific embodiments, the ratio of the spectral response value of any channel in the peak wavelength band of the narrowband filter to its spectral response value in other wavelength bands of the narrowband filter is greater than a preset value, which specifically includes: the ratio of the spectral response value QBw1 of the blue channel in wavelength band W1 of the narrowband filter to the spectral response value QBw2 in wavelength band W2 is greater than the preset value; the ratio of the spectral response value QBw1 of the blue channel in wavelength band W1 to the spectral response value QBw3 in wavelength band W3 is greater than the preset value, the ratio of the spectral response value QGw2 of the green channel in wavelength band W2 to the spectral response value QGw1 in wavelength band W1 is greater than the preset value; the ratio of the spectral response value QGw2 of the green channel in wavelength band W2 to the spectral response value QGw3 in wavelength band W3 is greater than the preset value, the ratio of the spectral response value QRw3 of the red channel in wavelength band W3 to the spectral response value QRw1 in wavelength band W1 is greater than the preset value; the ratio of the spectral response value QRw3 of the red channel in wavelength band W3 to the spectral response value QRw2 in wavelength band W2 is greater than the preset value. This ensures the response differences of the image sensor to light in different wavelength bands from multiple dimensions, enabling the device to more accurately capture and distinguish the spectral information of each wavelength band.

[0011] In some specific embodiments, the preset value is taken as 7. With the setting of this preset value, the spectral information of different bands can be effectively distinguished, and the difficulties in equipment debugging or cost increase caused by excessive ratio requirements can be avoided, which helps the popularization and use of the equipment in actual production and application.

[0012] In some specific embodiments, the image sensor is an RGBIR image sensor, and the spectral response values of the blue channel, the green channel, the red channel, and the infrared channel under the band W4 of the narrowband filter are basically equal.

[0013] According to the second aspect of the present invention, a method for outputting a multispectral image is proposed. Using the above-mentioned multispectral image output device, it includes the following steps:

[0014] S1: Filter the incident light using a narrowband filter to divide the light into 2 - 4 narrowband lights of different bands, where the band range of the narrowband filter is taken from 400nm to 1000nm;

[0015] S2: Receive the narrowband light filtered by the narrowband filter through the image sensor. Different channels of the image sensor generate different spectral responses to the narrowband lights of different bands, and satisfy that the ratio of the spectral response value of any channel in the peak band of the narrowband filter to its spectral response value in other bands of the narrowband filter is greater than the preset value, and the preset value is not less than 6;

[0016] S3: Transmit the signal received by the image sensor to the image processor;

[0017] S4: Process the received signal using the image processor to obtain a multispectral image.

[0018] The multispectral image output device of the present invention can effectively distinguish the optical signals of different bands, reduce spectral aliasing, clearly capture the spectral information of each band, improve the spectral resolution ability, and provide reliable data for subsequent accurate analysis. Through the reasonable setting of the bands, the information capture of each color channel in the corresponding band is more sensitive. Through the reasonable cooperation of the narrowband filter and the image sensor, the output of the multispectral image is realized, avoiding complex de - mixing algorithms and high - difficulty coating processes. The overall system structure is simple, easy to implement and maintain, and while ensuring the multispectral imaging function, the system cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments and, together with the description, are used to explain the principles of the invention. Other embodiments and many of the intended advantages of the embodiments will be readily apparent, as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with each other. The same reference numerals refer to corresponding like parts.

[0020] Figure 1 It is a schematic cross-sectional view of an output device for a multi-spectral image of an embodiment;

[0021] Figure 2 It is an effect diagram of the output of three narrow-band images of an output device for a multi-spectral image of a specific embodiment;

[0022] Figure 3 It is an effect diagram of the output of four narrow-band images of an output device for a multi-spectral image of a specific embodiment;

[0023] Figure 4 It is a schematic flowchart of a method for outputting a multi-spectral image of an embodiment. Detailed Description of Specific Embodiments

[0024] In the following detailed description, reference is made to the accompanying drawings, which form a part of the detailed description and in which are shown illustrative specific embodiments by which the invention may be practiced. In this regard, directional terms, such as "top", "bottom", "left", "right", "up", "down", etc., are used with reference to the orientation of the described figures. Since the components of the embodiments can be positioned in several different orientations, the directional terms are used for purposes of illustration and are in no way limiting. It should be understood that other embodiments may be utilized or logical changes may be made without departing from the scope of the invention. Accordingly, the following detailed description should not be taken in a limiting sense, and the scope of the invention is defined by the appended claims.

[0025] Figure 1 It shows a schematic cross-sectional structure diagram of an output device for a multi-spectral image of an embodiment of the present application. As Figure 1As shown in the figure, the output device of the multispectral image includes a narrow-band filter 1, an image sensor 3, and a circuit board 4. Among them, the narrow-band filter 1 is placed above the image sensor 3 through a filter holder 2. The narrow-band filter 1 includes narrow-band filtering channels in 2 to 4 bands, and the band range is taken from 400nm - 1000nm. Its function is to filter the incident light, divide the light into narrow-band light of different bands, so that the image sensor can receive the light signals of specific bands to meet the requirements of multispectral imaging. The image sensor 3 is installed above the circuit board 4. It is the core component of the device to obtain image information. By responding to light of different bands, it converts the light signals into electrical signals, providing the original data for generating multispectral images subsequently. And the spectral response ratio of different channels of the image sensor 3 in different bands of the narrow-band filter 1 satisfies: the ratio of the spectral response value of any channel in the peak band of the narrow-band filter to its spectral response value in other bands of the narrow-band filter is greater than a preset value, and the preset value is not less than 6, which ensures that the response difference of the image sensor 3 to light of different bands reaches a certain degree, helps to more clearly distinguish the spectral information of different bands, and improves the quality and recognition rate of multispectral images. The circuit board 4 carries the circuit system, is responsible for transmitting the electrical signals generated by the image sensor to the image processor, and then performs a series of operations such as noise filtering, enhancement processing, and feature extraction on these signals, and finally generates multispectral images.

[0026] In a specific embodiment, the bands of the narrow-band filter 1 can be divided into Wi, where i = 2 to 4; specifically, 400nm ≤ W1 ≤ 500nm, 500nm ≤ W2 ≤ 600nm, 600nm ≤ W3 ≤ 700nm, 700nm ≤ W4 ≤ 1000nm. These band ranges cover the visible light and part of the near-infrared light regions, which is beneficial to capturing the unique spectral characteristics of different substances in these bands, and improves the pertinence and effectiveness of the device in related field applications.

[0027] In a specific embodiment, the image sensor 3 adopts a Bayer array image sensor. This sensor is mature and has a low cost, and can be widely used in various imaging devices. With its existing color filter array structure and working principle, it can efficiently perform color perception and signal conversion on the light passing through the narrow-band filter. Cooperating with the narrow-band filter 1, it can reduce the device cost on the premise of ensuring a certain image quality, making the multispectral image output device more competitive in the market, and is suitable for application scenarios that are sensitive to cost but have certain multispectral imaging requirements.

[0028] In a specific embodiment, the ratio of the spectral response value of any channel in the peak band of the narrowband filter to its spectral response value in other bands of the narrowband filter being greater than a preset value is specifically manifested as: the ratio of the spectral response value QBw1 of the blue channel in the image sensor 3 at the band W1 of the narrowband filter 1 to the spectral response value QBw2 at the band W2 being greater than the preset value; the ratio of the spectral response value QBw1 of the blue channel at the band W1 to the spectral response value QBw3 at the band W3 being greater than the preset value; the ratio of the spectral response value QGw2 of the green channel at the band W2 to the spectral response value QGw1 at the band W1 being greater than the preset value; the ratio of the spectral response value QGw2 of the green channel at the band W2 to the spectral response value QGw3 at the band W3 being greater than the preset value; the ratio of the spectral response value QRw3 of the red channel at the band W3 to the spectral response value QRw1 at the band W1 being greater than the preset value; the ratio of the spectral response value QRw3 of the red channel at the band W3 to the spectral response value QRw2 at the band W2 being greater than the preset value. That is, the ratios of QBw1 / QBw2, QBw1 / QBw3, QGw2 / QGw1, QGw2 / QGw3, QRw3 / QRw1, and QRw3 / QRw2 are greater than the preset value. Preferably, the preset value is 7, which can not only effectively distinguish the spectral information of different bands but also avoid difficulties in equipment debugging or cost increase due to overly high ratio requirements, facilitating the popularization and use of the equipment in actual production and applications.

[0029] In a specific embodiment, the band W1 is the peak position of the spectral response of the blue channel, optimizing the capture ability of the blue channel for light in this band.

[0030] In a specific embodiment, the band W2 is the peak position of the spectral response of the green channel, or the intersection position of the spectral responses of the blue and red channels, which helps to better distinguish and utilize the information of different color channels in this band. When it is the intersection position of the blue and red channels, it can balance the responses of the blue and red channels in this band, avoiding the information of a certain channel being too strong or too weak, making the color performance of the multi-spectral image in this band more accurate, and being beneficial to subsequent image processing and analysis, such as improving the accuracy in color image fusion, target recognition, etc.

[0031] In a specific embodiment, the band W3 is the peak position of the spectral response of the red channel, or the valley position of the spectral response of the green channel. When the band W3 is the peak position of the spectral response of the red channel, it can enhance the display of red-related substances or features in the image; when it is the valley position of the spectral response of the green channel, it further highlights the difference between the red and green channels in this band, enabling more clear distinction of red- and green-related objects or regions in the multi-spectral image and improving the contrast and recognition rate of the image.

[0032] In a specific example, taking the output of three narrow-band images as an example, the narrow-band channels of the narrow-band filter 1 are W1, W2, and W3 respectively, and the spectral responses of the RGB image sensor 3 are QB, QG, and QR respectively, and the ratios of QBw1 / QBw2, QBw1 / QBw3, QGw2 / QGw1, QGw2 / QGw3, QRw3 / QRw1, and QRw3 / QRw1 are greater than T, where T is taken as 7. Figure 2 The figure shows the effect diagram of the output of three narrow-band images of the multi-spectral image output device in a specific embodiment, as Figure 2 shown. In the figure, the blue, green, and red curves represent the spectral response curves of the blue, green, and red channels in the image sensor 3 respectively. The abscissa represents the wavelength, and the ordinate may represent the spectral response intensity. The pink rectangular frames in the figure represent the band ranges of the narrow-band filters, corresponding to the bands W1, W2, and W3 respectively, visually presenting the positions and approximate ranges of different bands on the wavelength axis, and showing the selective transmission characteristics of the narrow-band filter 1 for light of different bands. In this embodiment, W1 = 460; W2 = 545; W3 = 655; the values of QBw1 / QBw2, QBw1 / QBw3, QGw2 / QGw1, QGw2 / QGw3, QRw3 / QRw1, and QRw3 / QRw2 are 11.2524, 29.1558, 8.1932, 14.8391, 21.1695, and 18.8232 respectively.

[0033] In another specific example, taking the output of four narrow-band images as an example, the narrow-band channels of the filter 1 are W1, W2, W3, and W4 respectively, and the image sensor 3 is an RGBIR image sensor. The spectral response values of the blue channel, green channel, red channel, and infrared channel of the RGBIR image sensor in the band of the narrow-band channel W4 of the narrow-band filter are the same (or basically the same). The spectral response curves of its different channels are QB, QG, QR, and QIR respectively, and QBw4 = QGw4 = QRw4 = QIRw4, and the ratios of QBw1 / QBw2, QBw1 / QBw3, QGw2 / QGw1, QGw2 / QGw3, QRw3 / QRw1, and QRw3 / QRw2 are greater than T, with a value of 7. Figure 3 The figure shows the effect diagram of the output of four narrow-band images of the multi-spectral image output device in a specific embodiment, as Figure 3As shown, the blue, green, red, and black curves respectively represent the spectral response curves of the blue, green, red, and infrared channels in the RGBIR image sensor 3. The abscissa represents the wavelength, and the ordinate may represent the spectral response intensity. The pink rectangular frames in the figure represent the band ranges of the narrowband filters, corresponding to bands W1, W2, and W3 respectively, intuitively presenting the positions and approximate ranges of different bands on the wavelength axis, and demonstrating the selective transmission characteristics of the narrowband filter 1 for light of different bands. In this embodiment, w1 = 460; w2 = 545; w3 = 655; w4 = 830; the values of QBw1 / QBw2, QBw1 / QBw3, QGw2 / QGw1, QGw2 / QGw3, QRw3 / QRw1, and QRw3 / QRw2 are respectively: 11.2524, 29.1558, 8.1932, 14.8391, 21.1695, 18.8232.

[0034] Continue to refer to Figure 4 , Figure 4 which is a schematic flowchart of the output method of a multi-spectral image of an embodiment. As Figure 4 shown, the method includes:

[0035] S1: Filter the incident light using a narrowband filter to divide the light into 2 to 4 narrowband lights of different bands, where the band range of the narrowband filter is taken from 400nm to 1000nm.

[0036] S2: Receive the narrowband light filtered by the narrowband filter through an image sensor. Different channels of the image sensor generate different spectral responses to the narrowband light of different bands, and satisfy that the ratio of the spectral response value of any channel in the peak band of the narrowband filter to its spectral response value in other bands of the narrowband filter is greater than a preset value; the preset value is not less than 6, and the preferred value is 7.

[0037] S3: Transmit the signal received by the image sensor to an image processor.

[0038] S4: Process the received signal using the image processor to obtain a multi-spectral image.

[0039] Through the reasonable cooperation of the filter and the RGB image sensor, the present application overcomes the technical problems that due to the overlap of the quantum curves of the RGB image sensor in wavelength, there is a certain spectral aliasing in the obtained spectrum, and when the extracted spectral information exceeds 3, the difficulty of spectral calculation and purification is high. It can not only realize the output of 2 to 4 spectral images that meet the requirements, but also does not require a de-mixing algorithm, does not require complex processes, and has a simple structure and low cost.

[0040] Obviously, those skilled in the art can make various modifications and changes to the embodiments of the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and changes are within the scope of the claims of the present invention and their equivalent forms, the present invention also aims to cover these modifications and changes. The word "comprising" does not exclude the presence of other elements or steps not listed in the claims. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An output device for multi-spectral images, characterized in that, It includes a narrowband filter, an image sensor and an image processor. There are 2 to 4 narrowband filtering channels on the narrowband filter, and the range of the bands is taken from 400nm to 1000nm. Moreover, the spectral response ratios of different channels of the image sensor at different bands of the narrowband filter satisfy that the ratio of the spectral response value of any channel in the peak band of the narrowband filter to its spectral response values in other bands of the narrowband filter is greater than a preset value, and the preset value is not less than 6.

2. The output device for a multi-spectral image according to claim 1, wherein The 2 to 4 narrowband filtering channels are defined as band W1, band W2, band W3 and band W4, and the range of the bands satisfies 400nm ≤ W1 ≤ 500nm, 500nm ≤ W2 ≤ 600nm, 600nm ≤ W3 ≤ 700nm, 700nm ≤ W4 ≤ 1000nm.

3. The output device for multi-spectral images according to claim 1, wherein The image sensor is a Bayer array image sensor.

4. The output device for multi-spectral images according to claim 2, characterized in that, The band W1 is the peak position of the spectral response of the blue channel.

5. The output device for a multi-spectral image according to claim 2, characterized in that, The band W2 is the peak position of the spectral response of the green channel, or the intersection position of the spectral responses of the blue channel and the red channel.

6. The output device for a multi-spectral image according to claim 2, wherein The band W3 is the peak position of the spectral response of the red channel, or the valley position of the spectral response of the green channel.

7. The output device for multi-spectral images according to claim 2, characterized in that, That the ratio of the spectral response value of any channel in the peak band of the narrowband filter to its spectral response values in other bands of the narrowband filter is greater than a preset value specifically includes: the ratio of the spectral response value QBw1 of the blue channel in the image sensor at band W1 of the narrowband filter to the spectral response value QBw2 at band W2 is greater than the preset value, and the ratio of the spectral response value QBw1 of the blue channel at band W1 to the spectral response value QBw3 at band W3 is greater than the preset value; the ratio of the spectral response value QGw2 of the green channel at band W2 to the spectral response value QGw1 at band W1 is greater than the preset value, and the ratio of the spectral response value QGw2 of the green channel at band W2 to the spectral response value QGw3 at band W3 is greater than the preset value; the ratio of the spectral response value QRw3 of the red channel at band W3 to the spectral response value QRw1 at band W1 is greater than the preset value; the ratio of the spectral response value QRw3 of the red channel at band W3 to the spectral response value QRw2 at band W2 is greater than the preset value.

8. The output device for multi-spectral images according to claim 1, wherein The preset value is taken as 7.

9. The output device for a multi-spectral image according to claim 2, characterized in that, The image sensor is an RGBIR image sensor, and the spectral response values of the blue channel, the green channel, the red channel and the infrared channel at the band W4 of the narrowband filter are basically equal.

10. A method for outputting a multi-spectral image, characterized in that, Using the multispectral image output device according to any one of claims 1 to 9, includes the following steps: S1: Filter the incident light by using the narrowband filter to divide the light into narrowband light of 2 to 4 different bands, wherein the band range of the narrowband filter is taken from 400nm to 1000nm; S2: Receive the narrowband light filtered by the narrowband filter through the image sensor. Different channels of the image sensor have different spectral responses to narrowband light of different bands, and satisfy that the ratio of the spectral response value of any channel in the peak band of the narrowband filter to its spectral response value in other bands of the narrowband filter is greater than a preset value, and the preset value is not less than 6; S3: Transmit the signal received by the image sensor to the image processor; S4: Use the image processor to process the received signal to obtain a multispectral image.

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