CN115988300B - A miniaturized imaging device for space cooperation targets - Google Patents

Abstract

The invention relates to a miniaturized imaging device of a space cooperation target, which comprises a fixed-focus optical system, a high-resolution CMOS image sensor chip, an FPGA main control chip, a high-speed data cache chip and display equipment, wherein the fixed-focus optical system and the high-resolution CMOS image sensor chip complete photoelectric conversion of the space cooperation target and output high-resolution image data to the FPGA main control chip; the FPGA main control chip is used for imaging driving of the high-resolution CMOS image sensor, acquisition of high-resolution image data, read-write control of an off-chip cache chip, gray level histogram statistics, automatic dimming parameter calculation, digital zooming of the cache high-resolution image data according to an asynchronous serial port instruction, and the like. The imaging device provided by the invention can realize clear imaging of the space cooperative target under a plurality of view fields, and can show the size suitable for human eyes to observe, and has the advantages of small volume and high reliability.

Description

A miniaturized imaging device for space cooperation targets

Technical Field

The present invention relates to the technical field of space target imaging detection, and in particular to a miniaturized imaging device for space cooperative targets.

Background Art

In recent years, my country's space launch missions have become more and more frequent. Among them, the imaging device of space cooperation targets has played an important role in multiple space application scenarios such as automatic rendezvous and docking of spacecraft and attitude measurement of space targets. Due to the particularity of the space environment, the imaging device of space cooperation targets is required to work normally under high dynamic range imaging conditions to meet the imaging requirements of the sun-illuminated area and the shaded area; at the same time, under the premise of meeting the requirements of imaging technical indicators, the imaging device is required to be lightweight and miniaturized.

In many application scenarios, such as when spacecraft automatically rendezvous and dock, the imaging distance range of space cooperation targets is very large, with the closest distance being within 1 meter and the farthest distance exceeding 100 meters. At the same time, under the condition that the resolution of the display device remains unchanged, it is necessary to ensure that the image size of the target in the display device is suitable for human eye observation. The space cooperation target imaging equipment currently developed either uses multiple fixed-focus lenses, using a large-field-of-view fixed-focus lens for imaging long-distance targets and a small-field-of-view fixed-focus lens for imaging close-range targets, but this method greatly increases the volume and weight and cannot meet the requirements of lightweight and miniaturization; or uses a zoom lens to solve the problem of target imaging at different distances by zooming, but this method requires the addition of a manual focus step for astronauts, or the addition of an autofocus algorithm, which increases the complexity of the system, reduces the reliability of the system, and cannot meet the requirements of high reliability in the space environment.

Summary of the invention

In order to solve the problems in the prior art of space cooperative target imaging equipment that the use of multiple fixed-focus lenses leads to increased volume and weight, and the use of autofocus algorithms reduces system reliability, the present invention provides a miniaturized space cooperative target imaging device.

The present invention adopts the following technical solution:

A miniaturized imaging device for space cooperation targets, comprising a fixed-focus optical system, a high-resolution CMOS image sensor chip, an FPGA main control chip, a high-speed data cache chip and a display device, wherein the fixed-focus optical system and the high-resolution CMOS image sensor chip are used to complete the photoelectric conversion of space cooperation targets, and the FPGA main control chip comprises a CMOS drive module, a data acquisition module, a high-speed cache control module, a digital zoom and display module and an automatic dimming module;

The CMOS driving module performs imaging driving on the high-resolution CMOS image sensor chip;

The data acquisition module acquires, processes and performs serial-to-parallel conversion on the high-speed multi-channel serial image data output by the high-resolution CMOS image sensor chip, and then outputs the parallel image data to the cache control module;

The cache control module writes the parallel image data into the high-speed data cache chip according to the generated read and write timing;

After the digital zoom and display module and the automatic dimming module respectively read out the parallel image data cached in the high-speed data cache chip through the high-speed cache control module, the digital zoom and display module performs a digital zoom operation on the read parallel image data according to the asynchronous serial port instruction, generates a display timing according to the requirements of the display device, and outputs the zoomed fixed-resolution image data to the display device for display according to the display timing; the automatic dimming module performs grayscale histogram statistics on the parallel image data to obtain a grayscale mean, and compares the grayscale mean with a preset threshold range, and sets the automatic dimming parameters specified by the CMOS driver module for the high-resolution CMOS image sensor chip according to the comparison result.

The beneficial effects of the present invention are as follows: the optical system of a miniaturized imaging device for space cooperation targets proposed by the present invention adopts a fixed-focus optical system, and uses electronic digital zoom to achieve clear imaging of space cooperation targets under multiple fields of view under the condition of the fixed-focus optical system, so that the space cooperation targets can appear in a size suitable for human eye observation under different field conditions, avoiding both the increase in volume caused by multiple fixed-focus optical systems and the reduction in reliability caused by the use of zoom optical systems, and fully meeting the requirements of miniaturization and high reliability of imaging devices for imaging space cooperation targets. At the same time, the high-resolution CMOS image sensor chip used in the imaging device of the present invention has the advantages of a wide imaging range and convenient window opening, and is very suitable for imaging space cooperation targets in digital zoom scenarios.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic structural diagram of a miniaturized imaging device for space cooperative targets provided by the present invention.

DETAILED DESCRIPTION

The present invention proposes a miniaturized imaging device for space cooperation targets, which is mainly composed of a fixed-focus optical system, a field programmable gate array (FPGA) main control chip, a high-resolution complementary metal oxide semiconductor (CMOS) image sensor chip, a high-speed data cache chip and a display device. The FPGA main control chip completes the imaging drive of the high-resolution CMOS image sensor; the fixed-focus optical system and the high-resolution CMOS image sensor chip are used to complete the photoelectric conversion of the space cooperation target and output the high-resolution image data to the FPGA main control chip; the FPGA main control chip completes the acquisition of the high-resolution image data and the read-write control of the off-chip high-speed data cache chip; the FPGA main control chip completes the histogram statistics of the cached high-resolution image data, and calculates the automatic dimming parameters according to the preset threshold range, and controls the automatic dimming parameters of the high-resolution CMOS image sensor chip, that is, the exposure time, according to the automatic dimming parameters, so as to realize automatic and clear imaging of the space cooperation target under different lighting conditions; according to the asynchronous serial port instruction, the FPGA main control chip completes the digital zoom of the cached high-resolution image data, and realizes clear imaging of space cooperation targets in multiple fields of view under the condition of the fixed-focus optical system. Finally, the FPGA main control chip outputs the image data with a fixed resolution to the display device according to the display timing, and the display device displays the image data in high definition.

As shown in Figure 1, an embodiment of the present invention provides a miniaturized imaging device for space cooperation targets, which includes a fixed-focus optical system, a high-resolution CMOS image sensor chip 1, an FPGA main control chip 2, a high-speed data cache chip 3 and a display device 4, wherein the FPGA main control chip 2 is the logic control core of the entire imaging device, and the internal logic of the FPGA main control chip includes a CMOS drive module 21, a data acquisition module 22, a high-speed cache control module 23, a digital zoom and display module 24 and an automatic dimming module 25.

The fixed-focus optical system and the high-resolution CMOS image sensor chip 1 are used to complete the photoelectric conversion of the space cooperation target and realize the imaging of the space cooperation target. The high-resolution CMOS image sensor chip 1 requires external input of the correct timing drive signal when working, and the CMOS drive module 21 in the FPGA main control chip 2 completes the imaging drive of the high-resolution CMOS image sensor chip 1. In particular, the CMOS drive module 12 specifies the imaging parameters such as exposure time, window area and gain of the high-resolution CMOS image sensor chip 1. Optionally, the high-resolution CMOS image sensor chip 1 adopts a CMOS image sensor with a resolution of 5120*5120. The high-resolution CMOS image sensor chip used in the imaging device of this embodiment has the advantages of a wide imaging range and convenient window opening, and is very suitable for imaging of space cooperation targets in digital zoom scenarios.

The high-resolution CMOS image sensor chip 1 uses a high-speed multi-channel serial output method to input high-resolution image data into the FPGA main control chip 2. The data acquisition module 22 in the FPGA main control chip 2 completes the acquisition, processing and serial-to-parallel conversion of the high-speed multi-channel serial image data. Due to wiring delays and other reasons, it is impossible to ensure that the serial image data of different channels are completely aligned, which will inevitably cause the problem of inconsistent image data of multiple channels. The data acquisition module 22 in the FPGA main control chip 2 uses a dynamic contrast correction code to perform multi-channel data consistency correction processing, thereby ensuring the accurate acquisition of digital image data. Specifically, in each channel of the high-resolution CMOS image sensor chip 1, there will be a correction code with a fixed value before a row of image data. If the data of a certain channel is not aligned with the data of other channels, the correction code of the channel collected by the data acquisition module 22 at the start of a row is inconsistent with other channels. Based on this feature, the data acquisition module 22 first determines the correction code that is inconsistent with other channels, and then calculates the number of delayed clocks based on this erroneous correction code, and uses the calculated number of clocks to delay the image data of the channel where the correction code is located, thereby ensuring the correctness of the data of the channel. After the data acquisition module 22 completes the acquisition and processing of the multi-channel serial image data, it performs serial-to-parallel conversion of the data according to the data bit width of the off-chip high-speed data cache chip 3 to obtain parallel image data, and then outputs the parallel image data to the cache control module 23.

The cache control module 23 in the FPGA main control chip 2 generates the read and write timing of the high-speed data cache chip 3, and writes the parallel image data after serial-to-parallel conversion into the high-speed data cache chip 3. Correspondingly, the back-end data magnification and display module 24 reads out the cached data.

Due to the need for miniaturization and high reliability of the imaging device, this embodiment uses a fixed-focus optical system and a high-resolution CMOS image sensor chip 1 to complete the photoelectric conversion of the space cooperation target. Under the condition of the fixed-focus optical system, clear imaging of the space cooperation target in multiple fields of view is achieved, so that the space cooperation target always presents a size suitable for human eye observation on the display device. In this way, the increase in volume caused by multiple fixed-focus optical systems is avoided, and the reduction in reliability caused by the use of zoom optical systems is avoided. Therefore, the imaging device of this embodiment has the advantages of small size and high reliability, and fully meets the needs of miniaturization and high reliability of the imaging device for imaging the space cooperation target. After the digital zoom and display module 24 in the FPGA main control chip 2 reads out the parallel image data cached in the high-speed data cache chip 3, it performs a digital zoom operation according to the asynchronous serial port instruction. The digital zoom operation includes 1x, 2x and 5x, a total of 3 output modes, which are performed when the output resolution is fixed. In this embodiment, the resolution of 1024*1024 is taken as an example. When the zoom is 1x, the field of view range of 5120*5120 remains unchanged, and the image with a resolution of 5120*5120 is output at a resolution of 1024*1024; when the zoom is 2x, the field of view range is changed to 5120*5120 with a middle window area of 2560*2560, and the image with a resolution of 2560*2560 is output at a resolution of 1024*1024; when the zoom is 5x, the field of view range is changed to 5120*5120 with a middle window area of 1024*1024, and the resolution of 1024*1024 is directly output. At the same time, the digital zoom and display module 24 generates a display timing according to the requirements of the display device 4, and outputs the image data with a fixed resolution of 1024*1024 after zooming to the display device 4 according to the display timing, and the display device 4 performs high-definition display.

Due to the particularity of the space application environment, the imaging device of the space cooperation target needs to work normally in both the sun-illuminated area and the shaded area, that is, it needs to have an automatic dimming function under high dynamic range conditions. The high-resolution CMOS image sensor chip 1 sets the exposure time according to the initial automatic dimming parameters, and the exposure time determines the grayscale value of the output image data. After the automatic dimming module 25 in the FPGA main control chip 2 reads out the parallel image data cached in the high-speed data cache chip 3, it performs grayscale histogram statistics on the image data to obtain the grayscale mean of the parallel image data, compares the grayscale mean with the preset threshold range, and sets the automatic dimming parameter specified by the CMOS driving module 21 for the high-resolution CMOS image sensor chip 1 according to the comparison result. The specific steps are as follows: if the grayscale value is within the preset threshold range, the automatic dimming parameter is kept unchanged, that is, the exposure time of the CMOS image sensor is not changed; if the grayscale value is less than the minimum value of the preset threshold range, the automatic dimming parameter is increased, that is, the exposure time of the CMOS image sensor chip 1 is increased; if the grayscale value is greater than the maximum value of the preset threshold range, the automatic dimming parameter is reduced, that is, the exposure time of the CMOS image sensor chip 1 is reduced. The exposure time of the CMOS image sensor is controlled by using the automatic dimming parameter to realize automatic and clear imaging of the space cooperation target under different lighting conditions, so that the image grayscale value clock of the space cooperation target is within a range suitable for human eye observation.

The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims (4)

1. The miniaturized imaging device of the space cooperation target is characterized by comprising a fixed-focus optical system, a high-resolution CMOS image sensor chip (1), an FPGA main control chip (2), a high-speed data cache chip (3) and a display device (4), wherein the fixed-focus optical system and the high-resolution CMOS image sensor chip (1) are used for completing photoelectric conversion of the space cooperation target, and the FPGA main control chip (2) comprises a CMOS driving module (21), a data acquisition module (22), a cache control module (23), a digital zoom and display module (24) and an automatic dimming module (25);

the CMOS driving module (21) performs imaging driving on the high-resolution CMOS image sensor chip (1);

The data acquisition module (22) acquires, processes and converts serial-parallel serial image data of a high-speed multichannel output by the high-resolution CMOS image sensor chip (1), and outputs parallel image data to the cache control module (23);

the high-speed buffer control module (23) writes parallel image data into the high-speed data buffer chip (3) according to the generated read-write time sequence;

After the digital zoom and display module (24) and the automatic dimming module (25) read out parallel image data cached in the high-speed data cache chip (3) through the high-speed cache control module (23), the digital zoom and display module (24) performs digital zoom operation on the read-out parallel image data according to an asynchronous serial port instruction, generates a display time sequence according to the requirement of the display equipment (4), and outputs the image data with fixed resolution after zoom into the display equipment (4) for display according to the display time sequence; the automatic dimming module (25) performs gray histogram statistics on the parallel image data to obtain a gray average value, compares the gray average value with a preset threshold range, and sets the automatic dimming parameters designated by the CMOS driving module (21) for the high-resolution CMOS image sensor chip (1) according to a comparison result.

2. A space cooperation object-miniaturization imaging apparatus according to claim 1, wherein the data acquisition module (22) performs a consistency correction process on the high-speed multi-channel serial image data by using a dynamic contrast correction code, comprising the steps of:

determining correction codes inconsistent with other channels;

And calculating the number of delayed clocks according to the correction code, and delaying the image data of the channel where the correction code is positioned by using the calculated number of clocks.

3. The space cooperation object miniaturized imaging apparatus according to claim 1, wherein the automatic dimming module (25) compares the gray-scale average value with a preset threshold range, sets the automatic dimming parameters designated by the CMOS driving module (21) for the high-resolution CMOS image sensor chip (1) according to the comparison result, comprising the steps of:

When the gray average value is smaller than the minimum value of a preset threshold range, the automatic dimming module (25) increases an automatic dimming parameter;

When the gray average value is within a preset threshold value range, the automatic dimming module (25) keeps the automatic dimming parameter unchanged;

the automatic dimming module (25) decreases the automatic dimming parameter when the gray average value is greater than a maximum value of a preset threshold range.

4. The spatially-collaborative target miniaturized imaging device of claim 1, wherein digital zoom operations include 1x, 2x, and 5x zoom.