A macro camera array cis device

Abstract

The application discloses a macro camera array CIS device, which comprises a plurality of macro cameras 4 with short-focus low-distortion lenses 3 arranged in a line array and a main control driving board 5, the macro cameras 4 are used for scanning and imaging the object 1 with a distance of less than or equal to 30 mm through the short-focus low-distortion lenses 3, the macro cameras 4 are electrically and mechanically connected to the main control driving board 5 in a plug-in mode, and the images of the plurality of macro cameras 4 are processed through software splicing to realize wide-width high-resolution scanning imaging with a resolution of not less than 1000 dpi. The device has the characteristics of low cost, easy maintenance and easy expansion, and is suitable for wide-width imaging fields such as industrial detection.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging and detection technology, and in particular to a macro camera array (CIS) device for wide-format high-resolution scanning imaging. Background Technology

[0002] Traditional contact image sensors (CIS) use a rod lens for 1:1 imaging, followed by backend processing to form a digital image. The term "contact" essentially refers to macro imaging, meaning the distance between the scanned object and the front surface of the lens is very short, typically within 10mm. CIS technology is widely used in fax machines, scanners, and industrial inspection due to its high-quality image reproduction. However, when the area to be inspected is wide (e.g., exceeding 1 meter), rod lens-based CIS cameras become expensive and difficult to maintain.

[0003] As an alternative, existing technologies employ area array or line array CMOS cameras for suspended shooting at a certain distance and achieve wide-area scanning by stitching together images from multiple cameras. For example, patent CN201710815307 uses a line array CMOS camera array to detect glass surfaces, but this solution is still costly when detecting wide areas (such as those exceeding 1 meter). Patent CN202020271501 uses a mobile phone lens module array to detect express parcels, but due to the nature of the object being detected and the suspended shooting characteristics, the spatial resolution of the image is relatively low. Summary of the Invention

[0004] This utility model aims to provide a low-cost, easy-to-maintain, and easily expandable CIS device that possesses the wide-field imaging quality of existing cylindrical lens CIS cameras, specifically a macro camera array CIS device. The technical solution is as follows: A macro camera array (CIS) device is characterized by comprising a plurality of macro cameras 4 with short-focal-length, low-distortion lenses 3 arranged in a dense linear array, and a main control drive board 5. The macro cameras 4 are electrically and mechanically connected to the main control drive board 5 via plug-in connection. The macro cameras 4 scan and image the object 1 at a distance of ≤30mm from the object being inspected through the short-focal-length, low-distortion lenses 3. The overlap rate of the imaging areas of adjacent macro cameras 4 is not less than 10%. The images of the plurality of macro cameras 4 are processed and stitched together by software to achieve wide-area, high-resolution imaging with a resolution of not less than 1000dpi.

[0005] Furthermore, the macro camera 4 uses a global shutter CMOS chip with a pixel count of no less than 600,000.

[0006] Furthermore, the focal length of the short-focal-length, low-distortion lens 3 is no greater than 4mm.

[0007] The main control drive board 5 synchronously triggers all macro cameras 4 to acquire images, outputs the images to the main control system, and performs distortion correction and redundancy cropping on the images through image processing software, and finally stitches them together to form a CIS wide-format scan image. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of a macro camera array (CIS) device. Specific Implementation

[0009] like Figure 1 Taking a scanning swath of 1 meter and 50 macro cameras 4 arranged in a linear array as an example, the system layout is described below. The macro cameras 4 are electrically and mechanically connected to the main control drive board 5 via a plug-in method. The main control drive board 5 triggers the macro cameras 4 to acquire and output images. Subsequent image correction, cropping, and stitching are existing technologies; this section only describes the specific layout and implementation of the optical system. Fifty macro cameras 4 are arranged in a linear array. Each macro camera 4 uses a global shutter CMOS chip, and the pixel count is no less than 600,000, depending on usage requirements and cost considerations. In this embodiment, the image pixel count is 1280×1024. Short focal length lenses are suitable for close-up photography. The choice of lens focal length must consider distortion. This application recommends a low-distortion lens 3 with a focal length no greater than 4mm. In this embodiment, the lens focal length is f=2.8mm, which achieves zero distortion.

[0010] The recommended object distance (approximately the height of lens 3 from the scanned surface 1) is no more than 30mm. In this example, it is set to u=25mm. This 25mm distance is similar to the scanning style of contact image sensing CIS. According to the lens imaging formula, the image distance v=3.15mm, and the imaging magnification β=v / u=0.126.

[0011] The selected CMOS sensor has a pixel size of 2.2µm. The image width corresponding to 1280 pixels is 2.816mm. Therefore, the corresponding object scanning width is 2.816 / 0.126=22.35mm, which means that the corresponding object scanning resolution is 1280*25.4 / 22.35=1454dpi. The scanning resolution exceeds 1000dpi, which meets the high-resolution scanning requirements.

[0012] The center spacing of the 50 macro cameras 4 is set to d=20mm. Since 22.35mm is greater than 20mm, there is an overlapping area 2 in the imaging areas of adjacent macro cameras 4. The redundancy generated by the coverage of a single camera is: (22.35 / 20-1)*100%=11.7%. For the low distortion lens 3, this redundancy exceeds 10%, which is beneficial to the subsequent image stitching process.

[0013] Based on the object width and object distance, the field of view θ of a single macro camera 4 is 48°.

[0014] It should be noted that this imaging system has a shallow depth of field (usually less than 1mm), which is consistent with the characteristics of traditional CIS. Clear imaging can be guaranteed by the precise focusing of the lens.

[0015] In terms of mechanical dimensions, the outer diameter of the low-distortion lens 3 and the macro camera 4 is less than 15mm, which is compatible with a 20mm spacing, resulting in a compact structure.

[0016] Since each camera 4 and lens 3 can be independently plugged into and removed from the main control drive board 5, it is easy to replace camera modules that are malfunctioning locally, making maintenance easier and reducing overall operating costs. Furthermore, the length of the CIS array in this application can be flexibly increased or decreased, easily meeting the scanning requirements for larger swaths, and the system has strong scalability. The dense array constructed in this embodiment achieves the performance of a traditional CIS camera at the hardware level, while commercial low-distortion macro cameras have the advantage of low cost.

[0017] The embodiments of the present invention have been shown and described above. Those skilled in the art may make modifications, substitutions and variations to the embodiments without departing from the principles and spirit of the present invention, as needed, without contributing any inventive step. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A macro camera array (CIS) device, characterized in that: The system includes several macro cameras (4) with short focal length and low distortion lenses (3) arranged in a dense linear array, and a main control drive board (5). The macro cameras (4) are electrically and mechanically connected to the main control drive board (5) by plugging and unplugging. The macro cameras (4) scan and image the object (1) at a distance of ≤30mm from the object being inspected by using the short focal length and low distortion lenses (3). The overlap rate of the imaging areas of adjacent macro cameras (4) is not less than 10%. After the images of several macro cameras (4) are processed and stitched together by software, a wide-area high-resolution imaging with a resolution of not less than 1000dpi is achieved.

2. The macro camera array (CIS) device according to claim 1, characterized in that: The macro camera (4) uses a global shutter CMOS chip with a pixel count of no less than 600,000.

3. The macro camera array (CIS) device according to claim 1, characterized in that: The focal length of the short-focal-length, low-distortion lens (3) is no more than 4mm.

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