Method for performing ultra long integration time control on CCD image sensor

Abstract

The invention discloses a method for performing ultra long integration time control on a CCD image sensor. The involved hardware comprises a full-frame transfer CCD, a control circuit, a signal processing circuit, an image collection device, a shutter and an upper computer. The method comprises the following steps: controlling an exposure time through the shutter, only performing an optical integral operation by a light sensing pixel element of the full-frame transfer CCD in an exposure process, performing no signal read-out, and meanwhile continuously reading out internal dark signals by a horizontal transfer area; and after the exposure is terminated, reading out the accumulated signals within a frame period by the light sensing pixel element to form a frame of complete image. The method for performing the ultra long integration time control on the CCD image sensor provided by the invention has the beneficial effects that, after the method is adopted, the full-frame transfer CCD can perform the optical integral operation with an ultra long integral time.

Description

technical field [0001] The invention relates to a CCD image sensor control technology, in particular to a method for controlling a CCD image sensor with an ultra-long integration time. Background technique [0002] In astronomical observation, due to the dim brightness of some stars, it is difficult to observe them directly. Therefore, after imaging the area where the stars are located, these stars can only be observed through images, and when imaging, the imaging device A long exposure operation is required, otherwise it will be difficult to feed back enough light signals. [0003] Compared with other imaging technologies, CCD image sensor is one of the most widely used imaging technologies because of its many advantages. However, when using CCD image sensor for imaging of dim stars, the following problems arise: [0004] At present, the integration time of most cameras using CCD as imaging means is generally less than 1 second, and the integration time exceeding 1 second ...

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Problems solved by technology

[0004] At present, the integration time of most cameras using CCD as imaging means is generally less than 1 second, and the integration time exceeding 1 second is generally called long-time integration. When the CCD image sensor is used for long-time integration, the integration time Generally, it will not exceed 10 seconds, and in the field of astronomical observation, sometimes it is necessary to perform a longer exposure operation to feed back the light signal enough to make the stars appear on the image (generally implemented by a film camera). In the prior art, There are few cases where CCD image sensor is used for ultra-long integration time (that is, the integration time is greater than 10 seconds). The difficulties mainly include the following two points. The image acquisition card) can be processed by the host computer after acquisition. During the acquisition process, a frame synchronization discrimination operation needs to be performed between the image acquisition device and the CCD image sensor. During the frame synchronization determination operation, the built-in counter of the image acquisition device needs to pass The counting method performs frame synchronization discrimination on the output signal of the CCD image sensor. The counting time of the current image acquisition device can only be adapted to the time length of the long-time integration operation. A simple idea is to combine the CCD image sensor The integration time is adjusted to a super-long integration time, and the counting time of the image acquisition device is also adjusted to the corresponding time length. However, since the time length of the super-long integration time is particularly large, performing such a long frame synchronization discrimination operation will cause the counter to There is a large number of counting redundancy. Second, there are dark signals in the integration process of the CCD image sensor. After the integration operation with a long integration time, a large number of dark signals will accumulate inside it, resulting in the obliteration of effective signals and imaging failure.

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