JP2582269B2 - High sensitivity camera device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-sensitivity camera device.

[Prior art] Conventionally, as a method of reducing fixed pattern noise caused by dark current of a solid-state imaging device, for example, an imager,
A method has been proposed for keeping the imager cool by an auxiliary device.

[Problems to be solved by the invention]

The conventional high-sensitivity camera apparatus has the following problems because the imager is kept at a low temperature by the auxiliary device. That is, it takes time from when the power switch is turned on to when the imager reaches a predetermined temperature.

Large cooling heat treatment mechanism.

Countermeasures against condensation must be taken.

Power consumed for cooling is large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to increase the ratio between a signal and fixed pattern noise caused by dark current.

[Means for solving the problem]

A high-sensitivity camera device according to the present invention includes a shift unit that relatively shifts the solid-state image sensor and the optical input image for each frame, and a space between the image obtained after the shift from the solid-state image sensor and the image in the memory space. Address correcting means for correcting the address of the memory so that the target position matches, and adding the pixel information from the memory with the corrected address and the pixel information from the solid-state imaging device having the same address as the pixel information And writing means for writing the pixel information after addition at the same address as described above.

[Action]

According to the high sensitivity camera device of the present invention, the solid-state imaging device including a plurality of pixels and the light input image are relatively shifted by the shift unit for each frame, and after the shift, the image obtained from the solid-state imaging device and the memory space are shifted. The address of the memory is corrected by the address correcting means so that the spatial position of the image coincides with that of the image, and the pixel information with the corrected address and the pixel information from the solid-state imaging device having the same address as the pixel information are Are added by the adding means, and the pixel information after the addition is written to the same address as the above by the writing means.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In the figure, 1
Is an imaging lens which forms an incident image on an imager (solid-state imaging device) 2. The imager 2
Converts an optical signal into an electric signal, and its effective area is made larger than the effective screen _Fref shown in FIG. An imager driver 3 drives the imager 2. Reference numeral 4 denotes a positioner (shift means), which is composed of an electrostrictive element or the like, and shifts the imager 2 for each frame so that the effective screen _Fref falls within its effective area. A positioner driver 5 drives the positioner 4. 6
Is a positioner position detecting circuit for detecting the shift amount of the positioner 4. Reference numeral 7 denotes an address correction circuit (address correction means) which is a shifted imager 2
The address of the FM (frame memory) 12 is corrected so that the spatial position of the image from the memory and the image in the memory space match. An amplifier 8 amplifies the electric signal from the imager 2. Reference numeral 9 denotes signal processing for performing signal processing such as pedestal level clamping and gamma correction in the same manner as in the conventional example. An ADC 10 converts an analog signal from the signal processing circuit 9 into a digital signal. Reference numeral 11 denotes an addition circuit (addition means) which adds pixel information from the FM 12 having the corrected address and pixel information from the solid-state imaging device having the same address as the pixel information. A read / write circuit (writing means) 13 reads out image information from the FM 12 and writes the pixel information after addition into an address before correction. A clock generator 14 outputs a clock signal to the imager driver 3, the positioner driver 5, the address correction circuit 7, and the ADC 10.

 Next, the operation will be described.

The imager 2 is in the i-th frame F (i), and the head of the effective screen F _ref is the coordinates of the imager 2 (m _i , n _i )
Is located at

From this state, when shifted by the positioner 4 the imager 2 to (i + l) th frame F (i + l), the head of the effective screen F _ref is position in the coordinates imager _{2 (m i + l, n} i + l) I come to. However, 1 = 0-8.

When the imager 2 receives an image from the i-th frame F (i) (i +
When the frame is shifted to the (l) -th frame F (i + 1), the shift amount is detected by the positioner position detection circuit 6, and based on the detected shift amount, the address correction circuit 7
Thereby, the address of the FM12 is corrected so that the spatial position of the image from the imager 2 and the image of the FM12 space coincide.

On the other hand, pixel information of the imager 2 is output to the addition circuit 11 via the amplifier 8, the signal processing circuit 9, and the ADC 10.

Then, the addition circuit 11 adds the pixel information from the FM 12 having the corrected address and the pixel information from the imager 2 having the same address as the pixel information,
The pixel information after addition is read by the read / write circuit 13 into FM12.
At the same address as described above.

 Thereafter, the above operation is repeated for each shift.

In this embodiment, since the imager 2 is shifted nine times as shown in FIG. 3, the signal components are added in the same phase and become nine times, but the dark current is added by nine pixels, and the variance is nine. That is, the ratio is reduced to 1/3, and the ratio between the signal and the dark current fixed pattern noise, that is, the S / N ratio is tripled.

From this, in general, It can be seen that the ratio is improved. In this case, all the states of l need to be different.

Therefore, the sensitivity of the camera is increased, and the low-speed shutter can be released.

In this embodiment, the example in which the imager 2 is shifted has been described. However, the intended purpose can be achieved by shifting the light input image.

〔The invention's effect〕

As described above, according to the present invention, there is an effect that it is possible to obtain a high-sensitivity camera device capable of increasing the ratio between a signal and fixed pattern noise caused by dark current.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram for explaining the principle of the present invention, and FIG. 3 is a diagram showing an example of displacement of an imager. 2 ... Imager 4 ... Positioner 7 ... Address correction circuit 11 ... Addition circuit 13 ... Read / write circuit

Claims (1)

(57) [Claims] 1. A solid-state imaging device having a plurality of pixels, a shift means for relatively shifting the solid-state imaging device and an optical input image for each frame, an image obtained after shifting from the solid-state imaging device and a memory space Address correcting means for correcting the address of the memory so that the spatial position of the image coincides with that of the image, and the pixel information from the memory with the corrected address and the pixel information from the solid-state imaging device having the same address as the pixel information. A high-sensitivity camera device comprising: an adding unit that adds pixel information; and a writing unit that writes the pixel information after the addition at the same address as described above.