CN107367885A - A kind of super spectrum camera based on linear optical filter - Google Patents

Abstract

The invention belongs to the field of image processing, in particular to a hyperspectral camera based on a linear filter. The invention consists of a camera lens, a linear optical filter, a CCD image sensor and an image processing system. After the reflected light of the object is split by the lens and the linear filter, the CCD image sensor generates the signal of each pixel of the object under a specific spectrum and transmits it to the image processing system; by adjusting the position of the linear filter, the image processing The system obtains the full-spectrum information of all pixels of the object, and finally uses the image processing system to synthesize, so as to realize the hyperspectral imaging of the object. The invention is easy to operate, can realize rapid and portable measurement, can realize full-spectrum imaging of any object, and avoids imaging errors caused by metamerism.

Description

A Hyperspectral Camera Based on Linear Filter

technical field

The invention belongs to the field of image processing, in particular to a hyperspectral camera based on a linear filter.

Background technique

Full-spectrum camera technology is now widely used in medical, agricultural, military, tourism and other directions. As a small, portable, linearly variable central wavelength spectroscopic device, linear optical filters have a very broad prospect in spectral analysis. In the field of image processing, it is a practical technical solution to use spectral analysis technology to realize full-spectrum imaging of the subject. Hyperspectral imaging technology refers to the use of this linear filter and camera lens to not only obtain the three-dimensional spatial information of the object information, but also obtain the spectral energy distribution information of each pixel in the full spectral range per 1~10nm. The innovation of this camera technology lies in the ability to quickly analyze the reflection spectrum of the object under different wavelengths. The spectroscopic system based on the grating device of the traditional hyperspectral camera will make the whole instrument very large, and it is difficult to achieve rapid analysis under continuous spectrum.

Therefore, it is technically possible to consider replacing the grating device with a linear variable optical filter. This linear variable filter is a thin-film filter with a wedge-shaped thickness distribution along one direction and a uniform thickness in the other direction. Therefore, if it is designed as a bandpass filter and its thickness distribution is optimized, the center wavelength of its passband will vary linearly in one direction. The hyperspectral camera based on this linear variable optical filter can quickly obtain the full spectrum information of all pixels of the object by using the CCD image sensor. Compared with the grating, the advantage of this instrument is that it is very compact, low cost, high light transmission, high stability, wider spectral range, and can solve the imaging error caused by metamerism.

More importantly, the camera lens of the mobile phone can be used, and through the design of special software, only a small number of components such as CCD image sensor and linear filter can be added to realize full-spectrum imaging of the subject. The camera is placed on the UAV, and the hyperspectral camera is remotely controlled by using a wired or wireless network.

Therefore, this linear filter-based hyperspectral camera has broad application prospects.

Contents of the invention

The invention belongs to the field of image processing, and aims at proposing a hyperspectral camera based on a linear optical filter that can realize fast imaging and has small measurement errors.

A hyperspectral camera based on a linear optical filter proposed by the present invention is composed of a camera lens, a sliding rod, a linear optical filter, a CCD image sensor and an image processing system;

The camera lens is erected and fixed on the central axis of the hyperspectral camera;

The slide bar is located between the camera lens and the CCD image sensor, and is perpendicular to the central axis of the hyperspectral camera;

The linear optical filter is placed on the sliding rod, and can move arbitrarily along the direction perpendicular to the central axis of the hyperspectral camera on the sliding rod; adjust the axis of the linear optical filter by controlling the sliding rod Different directions can display images of different colors at different positions of the CCD image sensor;

Described CCD image sensor is fixed behind described linear optical filter, erects perpendicular to the central axis of described hyperspectral camera, can receive the light that sends out from each point of photographed object after refracting through camera lens;

The image processing system is placed at the end of the hyperspectral camera, or placed outside the hyperspectral camera;

The light outlet of the subject is aligned with the light inlet of the camera lens, the light outlet of the camera lens is aligned with the light inlet of the linear filter, the light outlet of the linear filter is aligned with the CCD image sensor, and the CCD image sensor is connected to the image processing system.

In the present invention, the camera lens is a digital camera lens or a mobile phone camera lens. It is mainly used to present the full-spectrum monochromatic image produced by the subject passing through the linear filter on different positions of the CCD image sensor.

In the present invention, by adjusting the position of the sliding rod on the central axis of the hyperspectral camera, the axial position of the linear filter on the sliding rod is controlled, thereby changing the relative position of the linear filter and the camera lens , to obtain the full spectrum information of all the pixels of the object, and realize the hyperspectral imaging of the object.

In the present invention, the image processing system adopts any one of computer image processing module, mobile phone image processing software or image processing chip of digital camera, and is connected with the CCD image sensor through a wired network or a wireless network. It only needs to add a very small number of components such as CCD image sensor and linear filter to realize the spectral test and analysis of the sample under the conditions of common camera equipment, so it can realize portable operation.

In the present invention, hyperspectral cameras are placed on various unmanned machines including unmanned aerial vehicles and planetary surface detectors, and hyperspectral photography is performed automatically or by remote control.

In the present invention, the linear optical filter is a linear filter with equidistant central wavelengths of the passband in one direction after optimizing the thickness distribution, and the adjacent central wavelengths are densely distributed with an interval of only 1 to 10 nm. A linear filter.

The hyperspectral imaging technology proposed in the present invention refers to the use of this linear filter and camera lens not only to obtain the three-dimensional space information of the object information, but also to obtain the 1-10nm of each pixel in the full spectrum range. Spectral energy distribution information.

The linear optical filter of the present invention includes areas through which light of various wavelengths corresponding to the full spectrum passes, and each area is arranged one-dimensionally along a direction perpendicular to the central axis of the hyperspectral camera.

The linear optical filter placed on the sliding rod described in the present invention, by changing the relative position of the linear optical filter and the camera lens, obtains the full spectrum information of all the pixels of the object in sequence; the reflected light of the object passes through After the lens and the linear filter split the light, the CCD image sensor generates the signal of each pixel of the object under a specific spectrum and transmits it to the image processing system. Then, by adjusting the position of the linear filter, the image processing system can obtain all the images of the object. The full-spectrum information of the pixels is finally synthesized by the image processing system, so as to realize the hyperspectral imaging of the subject.

The beneficial effect of the present invention is: the present invention can place described hyperspectral camera on various unmanned machinery including unmanned aerial vehicle, star surface detector through the communication means of wired and wireless network, Automatically or by means of remote control, hyperspectral photography is performed in some places that humans cannot reach; through the miniaturization advantages of linear filters compared to traditional gratings, the size of the camera is greatly reduced, and the cost of space transportation is reduced. Provide high-definition color video.

Description of drawings

Fig. 1 is a schematic diagram of a hyperspectral camera system based on a linear filter in the present invention.

Fig. 2 is a schematic structural view of the linear filter of the present invention.

Numbers in the figure: 1 is the subject, 2 is the camera lens, 3 is the linear filter, 4 is the sliding rod, 5 is the CCD image sensor, 6 is the image processing system, 7 is the upper reflective film layer, 8 is the spacer layer , 9 is the lower reflection film layer, and 10 is the base.

detailed description

The present invention will be further illustrated below by means of embodiments in conjunction with the accompanying drawings.

Example 1:

As shown in Figure 1, described device is made up of camera lens 2, slide bar 4, linear optical filter 3, CCD image sensor 5 and image processing system 6; Described camera lens 2 is erected and fixed on described hyperspectral camera on the central axis; the slide bar 4 is placed between the camera lens 2 and the CCD image sensor 5, perpendicular to the central axis of the hyperspectral camera; the linear filter 3 Placed on the sliding rod 4, it can move arbitrarily along the direction perpendicular to the central axis of the hyperspectral camera on the sliding rod 4; the CCD image sensor 5 is fixed on the linear filter 3 Afterwards, it is erected perpendicular to the central axis of the hyperspectral camera, and can receive the light emitted from each point of the subject after being refracted by the camera lens 2; the image processing system 6 can be placed in the hyperspectral end inside the camera, or outside the hyperspectral camera. Image processing system 6 described in the present invention is by the image acquisition card (such as Pro Capture Dual DVI acquisition card, RS-644 (LVDS) digital image acquisition card, Levin-M205 high-precision image acquisition card etc.) An image processing system composed of image processing hardware and image processing software for stereoscopic imaging. Its functions include but are not limited to 3D CT (computer tomography) in medicine, and 3D geographic and topographic maps in military simulation.

Example 2:

As shown in Figure 2, it is a schematic structural diagram of a linear filter. The linear filter is distributed in a wedge shape in the x direction, and the passband can be adjusted by adjusting the thickness change between the upper reflective film layer 7 and the lower reflective film layer 9. The central wavelength of the light changes linearly, so when the incident light is vertically incident from the y direction, the central wavelength of the transmitted light can be changed linearly in the x direction, so as to obtain the full spectral distribution of each pixel.

The hyperspectral camera based on the linear filter can be used to realize the full-spectrum imaging function. Its specific working steps are:

(1) The reflected light generated by the subject 1 being irradiated by sunlight or any external light source reaches the linear filter 3 through the refraction of the camera lens 2;

(2) After the light reaches the linear filter 3, the light of a specific wavelength in the corresponding area passes through the linear filter and presents an image of the specific color on the CCD image sensor 5;

(3) By controlling the sliding rod 4 to adjust the axial position of the linear filter 3, images of different specific colors can be presented at different positions of the CCD image sensor 5;

(4) After the collection of images on the CCD image sensor 5 is processed and calculated by the image processing system 6 , a hyperspectral image of the subject 1 can be obtained.

The advantages of the present invention are:

1) By specifically limiting the wavelength region corresponding to the linear filter, cameras with different color resolution capabilities can be obtained in different price ranges, and all pixels can be integrated under the condition of extremely refining the wavelength region corresponding to the linear filter. Reflected light information at all wavelengths, so as to realize hyperspectral imaging of the subject and avoid imaging errors caused by metamerism;

2) Full-spectrum scanning is realized by simply controlling the lateral displacement of the sliding rod, which simplifies the control method of the camera, so that it can be applied to various applications including unmanned aerial vehicles and planetary surface detectors through wired and wireless network communication methods. On unmanned machinery, hyperspectral photography is performed in places that humans cannot reach by means of automatic or remote control; by using linear filters instead of traditional gratings, the volume of products is greatly reduced, and the cost of space transportation is reduced. Provide high-definition color video recording under the condition of volume.

Claims (7)

1. A hyperspectral camera based on a linear optical filter, characterized in that it is made up of a camera lens, a slide bar, a linear optical filter, a CCD image sensor and an image processing system; The camera lens is erected and fixed on the central axis of the hyperspectral camera; The slide bar is located between the camera lens and the CCD image sensor, and is perpendicular to the central axis of the hyperspectral camera; The linear optical filter is placed on the sliding rod, and can move arbitrarily along the direction perpendicular to the central axis of the hyperspectral camera on the sliding rod; adjust the axis of the linear optical filter by controlling the sliding rod Different directions can display images of different colors at different positions of the CCD image sensor; Described CCD image sensor is fixed behind described linear optical filter, erects perpendicular to the central axis of described hyperspectral camera, can receive the light that sends out from each point of photographed object after refracting through camera lens; The image processing system is placed at the end of the hyperspectral camera, or placed outside the hyperspectral camera; The light outlet of the subject is aligned with the light inlet of the camera lens, the light outlet of the camera lens is aligned with the light inlet of the linear filter, the light outlet of the linear filter is aligned with the CCD image sensor, and the CCD image sensor is connected to the image processing system. 2. a kind of hyperspectral camera based on linear filter according to claim 1, is characterized in that its camera lens is a digital camera lens or a mobile phone camera lens. 3. a kind of hyperspectral camera based on linear optical filter according to claim 1, it is characterized in that by adjusting the position of sliding bar on the central axis of described hyperspectral camera, control described linear optical filter in The axial position on the sliding rod can change the relative position between the linear filter and the camera lens, obtain the full spectrum information of all pixels of the object, and realize the hyperspectral imaging of the object. 4. a kind of hyperspectral video camera based on linear optical filter according to claim 1, it is characterized in that image processing system adopts any in the image processing chip of computer image processing module, mobile phone image processing software or digital camera, and It is connected with the CCD image sensor through a wired network or a wireless network. 5. A kind of hyperspectral camera based on linear optical filter according to claim 1, it is characterized in that hyperspectral camera is placed and comprises unmanned aerial vehicle, on various unmanned machinery including planetary surface probe, Hyperspectral shooting automatically or by remote control. 6. A kind of hyperspectral camera based on linear optical filter according to claim 1, it is characterized in that described linear optical filter is a kind of passband center wavelength equidistant in one direction by optimizing the thickness distribution It is a kind of linear filter with a linear distribution, and the adjacent central wavelengths are densely distributed, and the interval is only 1~10nm. 7. A kind of hyperspectral camera based on linear optical filter according to claim 1, it is characterized in that said linear optical filter corresponds to the area through which light of various wavelengths of the full spectrum passes, and each area is perpendicular to said The direction of the central axis of the hyperspectral camera is arranged in one dimension.