TDI system with dual-stage independently controllable timing drive

Abstract

The TDI system with dual-segment independent controllable timing drive is suitable for TDI type devices for space remote sensing push-scan or swing-scan applications. Its main application feature is that the pixels of the TDI device can be divided into several segments, each of which can be driven by an independent timing drive circuit, so that each segment of pixels can work under different timing control. The present invention overcomes the disadvantage that the traditional TDI device introduces a large image shift deviation due to the control of a single timing drive for the entire row of pixels, resulting in a serious deterioration of the dynamic MTF index of the device. The control method of segmented independent timing drive is adopted to reduce the original image shift deviation to half of the traditional drive architecture, greatly improving the dynamic MTF index of the device.

Description

Technical Field

[0001] The present invention relates to a TDI system with dual-segment independently controllable timing drive, which is suitable for TDI type devices for space remote sensing push-scan or swing-scan applications. Its main application feature is that the pixels of the TDI device can be divided into several segments, each of which can be driven by an independent timing drive circuit, so that each segment of the pixels can work under different timing control. Background Art

[0002] In modern space remote sensing applications, especially in the field of earth observation, TDI detectors (including TDICCD or CMOS-TDI devices) are widely used. As the requirements for width and spatial resolution of earth observation remote sensing become higher and higher, the requirements for the array size and speed of TDI detectors are getting higher and higher.

[0003] Limited by the characteristics of TDI applications, only when the transfer speed of the accumulated charge in the pixel is consistent with the relative movement speed of the imaged scene, can a clear image be obtained. Otherwise, when there is a mismatch between the two speeds, that is, when there is image motion, an important indicator of the imaging system, dynamic MTF_Dyn, will decay. Assume that the difference between the charge transfer speed and the speed of the imaged scene is ΔV, the time for each line transfer is T, the number of lines transferred is M, and the pixel size is d, then

[0004]

[0005] Therefore, in order to reduce the dynamic MTF attenuation caused by image shift, the charge transfer speed should be kept consistent with the speed of the imaged scene. In the case of push-scan, the relative speed of the imaged scene is determined by the satellite's operating speed in a certain altitude orbit, while in the case of swing-scan, it is determined by the satellite's operating speed, the swing angular velocity of the actuator, and the distance from the imaging target. The charge transfer speed is determined by the period of the TDI device's drive signal. Therefore, in order to ensure the consistency of the two speeds, the corresponding timing of the TDI device's drive signal needs to be adjusted according to the orbital altitude or the swing speed and the corresponding distance.

[0006] Since the pixel array size of the TDI device in the cross-track direction is generally large, when the space remote sensing camera is imaging the ground, the speed of the imaged scene projected onto each pixel varies to a certain extent. In order to completely eliminate the MTF attenuation introduced by image motion, in theory, each pixel in the cross-track direction needs to be driven to transfer charge according to an independent timing sequence to match the speed of the imaged scene on the pixel. However, existing traditional TDI devices (such as Figure 1As shown in the figure, in the cross-track direction, the entire row of pixels is controlled by a single drive timing, that is, the charge in each pixel can only be transferred at the same speed. In this way, most pixels have image shift, and the larger the pixel array, the greater the image shift. This architecture of driving the entire row of pixels with a single timing cannot meet the application requirements of higher-resolution earth observation remote sensing. Summary of the invention

[0007] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a TDI system with dual-stage independently controllable timing drive, to solve the problem that the traditional TDI device introduces a large image shift deviation due to the control of a single timing drive for the entire row of pixels, resulting in a serious degradation of the device's dynamic MTF index

[0008] The technical solution of the present invention is: a TDI system with dual-stage independently controllable timing drive, including a pixel array, a timing signal module, and a driving signal module;

[0009] The pixel array includes pixels divided into two sections according to the cross-track direction; the number of pixels in the two sections is set according to needs;

[0010] The two segments of pixels are respectively connected to two driving signal modules, and the driving signals generated by the two driving signal modules are respectively connected to the electrodes of the corresponding pixels through contact points, and the driving signal modules are used to generate a pulse signal for charge transfer, and the pulse signal has a high level and a low level that meet the charge transfer requirements;

[0011] The two driving signal modules are respectively connected to a timing signal module, and the timing signal module is used to generate a pulse signal for charge transmission, and the pulse signal has a period and a pulse width that meet the charge transmission requirements.

[0012] Furthermore, the numbers of the two segments of pixels are equal.

[0013] Furthermore, the left half pixel and the right half pixel work under the independent control of the driving signal module and the timing signal module connected thereto.

[0014] Furthermore, when the numbers of the two segments of pixels are not equal, each of the N pixels at the connection of the two segments of pixels has two electrode contacts respectively connected to one end of the two selection switches; the other ends of the two selection switches are respectively connected to the two drive signal modules.

[0015] Furthermore, the middle N optional picture elements are set to work under the control of any driving signal module and timing signal module through a selection switch.

[0016] The advantages of the present invention compared with the prior art are:

[0017] 1) To overcome the drawback of traditional TDI devices that the whole row of pixels is driven by a single timing drive, which introduces a large image shift deviation, resulting in serious degradation of the device's dynamic MTF index, the control method of segmented independent timing drive is adopted to reduce the original image shift deviation to half of the traditional drive architecture, greatly improving the device's dynamic MTF index;

[0018] 2) The drive signal is input from both sides, which reduces the load of the drive signal and ensures the signal integrity of the drive signal. The signal quality of the drive signal is better than that of the traditional drive architecture;

[0019] 3) The adjustable segmented structure can flexibly configure the number of pixels in different segments and can be applied to different application modes;

[0020] 4) For applications with low MTF indicators, through timing design, the TDI device can realize the working mode of the traditional driving architecture, that is, the entire row of pixels is driven according to the same timing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0022] Figure 1 It is the driving architecture of traditional TDI devices;

[0023] Figure 2 A schematic diagram of a fixed-segment drive architecture proposed by the present invention;

[0024] Figure 3 A schematic diagram of the adjustable segmented driving architecture proposed by the present invention;

[0025] Figure 4 The working timing of the fixed segment driving architecture proposed by the present invention;

[0026] Figure 5 The working timing of the adjustable segmented driving architecture proposed by the present invention. DETAILED DESCRIPTION

[0027] In order to better understand the above technical scheme, the technical scheme of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0028] The following is a further detailed description of the TDI system with dual-stage independently controllable timing drive provided by the embodiment of the present application in conjunction with the accompanying drawings. The specific implementation method may include (such as Figures 1 to 5 As shown in Figure 1, the pixels in the cross-track direction are divided into two independent segments, each of which has a corresponding timing signal module and a driving module. This driving architecture can independently control the driving timing of each segment of pixels, so that the charge transfer speed of each segment of pixels matches the relative motion of the scene projected onto each segment of pixels, thereby maximizing the dynamic MTF index of the TDI device.

[0029] The present invention is divided into two structures according to whether the number of each segmented pixel is adjustable. One is a fixed segmented structure, which divides the pixels in the cross-track direction into two equal segments. If the number of pixels in the cross-track direction is N, then the number of independently controllable segmented pixels is N / 2.

[0030] Another structure is an adjustable segmented structure, whose main feature is that the middle N pixels in the cross-track direction are designed to be able to select any of two timing drives, while the pixels on the other two sides are each controlled by a fixed timing drive signal.

[0031] The solution provided in the embodiment of the present application includes two methods:

[0032] 1. Fixed segmentation

[0033] The fixed segmented dual-segment independently controllable timing driven TDI architecture is mainly composed of a pixel array, a first timing signal module, a second timing signal module, a first drive signal module and a second drive signal module. The pixels in the cross-track direction are divided into two equal segments (for example, there are N pixels in the entire row of the cross-track direction, so the left and right N / 2 pixels are divided into two independent segments), wherein the N / 2 pixels on the left side of the cross-track direction are connected by the first drive signal module, and the drive signal generated by the first drive signal module is connected to the electrodes of the N / 2 pixels on the left side of the cross-track direction through the contact point, and the drive signal generated by the second drive signal module is connected to the electrodes of the N / 2 pixels on the right side of the cross-track direction through the contact point. After the first timing signal module generates the timing signal of the N / 2 pixels on the left side of the cross-track direction, it is transmitted to the first drive signal module, and after the second timing signal module generates the timing signal of the N / 2 pixels on the right side of the cross-track direction, it is transmitted to the second drive signal module. When working, the N / 2 pixels on the left side of the cross-track direction and the N / 2 pixels on the right side of the cross-track direction are independently controlled by their own timing signal modules and driving signal modules.

[0034] 2. Adjustable segmentation

[0035] The TDI architecture of the adjustable segmented dual-segment independently controllable timing drive is mainly composed of a pixel array, a first timing signal module, a second timing signal module, a first drive signal module, a second drive signal module and a selection switch. The N pixels in the middle area of ​​the cross-track direction are designed to be a configurable and selectable structure, and the drive signal of the first drive signal module is connected to the contact of the electrode through the first selection switch, and the drive signal of the second drive signal module is connected to another contact of the electrode of the pixel through the second selection switch. In this way, through the configuration of the selection switch, the pixel can be configured to be driven by the first drive signal module or by the second drive signal module. For the remaining M pixels on the left, the drive signal of the first drive signal module is connected to its electrode through the contact, and the M pixels on the right are connected to its electrode through the contact by the drive signal of the second drive signal module. After the first timing signal module generates the timing signal of the left pixel in the cross-track direction, it is transmitted to the first drive signal module, and after the second timing signal module generates the timing signal of the right pixel in the cross-track direction, it is transmitted to the second drive signal module. When working, it can be set to be divided into two equal sections according to actual needs (for example, there are N pixels in the whole row of the cross-track direction, then the left and right N / 2 pixels are divided into two independent sections), wherein the N / 2 pixels on the left side of the cross-track direction are connected by the first drive signal module, and the drive signal generated by the first drive signal module is connected to the electrodes of the N / 2 pixels on the left side of the cross-track direction through the contact point, and the drive signal generated by the second drive signal module is connected to the electrodes of the N / 2 pixels on the right side of the cross-track direction through the contact point. After the first timing signal module generates the timing signal of the N / 2 pixels on the left side of the cross-track direction, it is transmitted to the first drive signal module, and after the second timing signal module generates the timing signal of the N / 2 pixels on the right side of the cross-track direction, it is transmitted to the second drive signal module. When working, the middle M pixels can be configured by switches to set whether they are driven by the first drive signal module or by the second drive signal module.

[0036] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0037] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A TDI system with dual-stage independently controllable timing drive, characterized in that: It includes a pixel array, a timing signal module, and a driving signal module; The pixel array includes pixels divided into two sections according to the cross-track direction; the number of pixels in the two sections is set according to needs; The two segments of pixels are respectively connected to two driving signal modules, and the driving signals generated by the two driving signal modules are respectively connected to the electrodes of the corresponding pixels through contact points, and the driving signal modules are used to generate a pulse signal for charge transfer, and the pulse signal has a high level and a low level that meet the charge transfer requirements; The two driving signal modules are respectively connected to a timing signal module, and the timing signal module is used to generate a pulse signal for charge transmission, and the pulse signal has a period and a pulse width that meet the charge transmission requirements; When the number of the two segments of pixels is not equal, each of the N pixels at the connection of the two segments of pixels has two electrode contacts respectively connected to one end of the two selection switches; the other ends of the two selection switches are respectively connected to the two drive signal modules; After the first timing signal module generates the timing signal of the left pixel in the cross-track direction, it is transmitted to the first driving signal module. After the second timing signal module generates the timing signal of the right pixel in the cross-track direction, it is transmitted to the second driving signal module.

2. The TDI system with dual-stage independently controllable timing drive according to claim 1, characterized in that: The numbers of picture elements in the two segments are equal.

3. The TDI system with dual-stage independently controllable timing drive according to claim 2, characterized in that: The left half pixel and the right half pixel work under the independent control of the driving signal module and the timing signal module connected thereto.

4. The TDI system with dual-stage independently controllable timing drive according to claim 1, characterized in that: The middle N optional picture elements are set to work under the control of any driving signal module and timing signal module through the selection switch.

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