Image sensor control method
A method for acquiring images using at least one CMOS-type sensor with four transistors including an acquisition node and a read node, where the read node can receive a compression signal, including a step of reading a reference state of the sensor; a reset step; an integration step, during which the sensor is exposed and during part of which the compression signal is applied to the read node; and a step of reading the data acquired during the integration step; the read node being, during the integration step, isolated from the acquisition node, except immediately before the application of the compression signal, at which time the acquisition node is connected to the read node long enough to enable a transfer of the charges present at the acquisition node to the read node.
1. A method for acquiring images by means of at least one CMOS-type sensor with four transistors comprising an acquisition node and a sense node, where the sense node can receive a compression signal, the method comprising:
a step of reading a reference state of the sensor;
a reset step;
an integration step, during which the sensor is exposed and during part of which the compression signal is applied to the sense node; and
a step of reading the data acquired during the integration step;
wherein, during the integration step, the sense node is isolated from the acquisition node, except immediately before the application of the compression signal, at which time the acquisition node is connected to the sense node long enough to enable a transfer of signal charges present at the acquisition node to the sense node.
2. The method of claim 1 , wherein the compression signal is a pulse train, the acquisition node being connected to the sense node before application of each compression pulse to the sense node.
3. The method of claim 1 , wherein the compression signal is applied during the last half of the integration step.
4. The method of claim 1 , wherein the compression signal is applied during the last quarter of the integration step during which the sensor is exposed.
5. The method of claim 1 , wherein the compression signal is applied during the last eighth of the integration step.
6. The method of claim 1 , wherein the step of reading a reference state of the sensor is implemented immediately after the reset step.
7. The method of claim 1 , wherein the step of reading a reference state of the sensor is implemented during the integration step immediately before the first charge transfer.
8. An image acquisition device of rolling shutter type implementing the method of claim 1 .
9. An image acquisition device of global shutter type implementing the method of claim 1 .
10. An image acquisition device including a CMOS-type sensor comprising a photosensor, a plurality of transistors, and an acquisition node and a sense node,
wherein the CMOS-type sensor is configured to operate in an integration phase during which the photosensor is exposed and during part of which a compression signal is applied to the sense node, and is further configured to isolate the sense node from the acquisition node during the integration phase except immediately before the application of the compression signal, wherein the acquisition node is configured to be connected to the sense node long enough to enable transfer of signal charges present at the acquisition node to the sense node and then disconnected from the sense node.
11. The image acquisition device of claim 10 , wherein the compression signal is a pulse train and the CMOS-type sensor is configured to temporarily connect the acquisition node to the sense node before application of each compression pulse to the sense node.
12. The image acquisition device of claim 11 , further configured to apply the compression signal within a last half of the integration phase.
13. The image acquisition device of claim 11 , further configured to reset the sense node and read a reference state of the sense node.
14. The image acquisition device of claim 13 , wherein the reading a reference state of the sense node is configured to occur immediately before a first transfer of charges present at the acquisition node to the sense node during the integration phase.
15. The image acquisition device of claim 11 , further configured to operate in rolling shutter mode.
16. The image acquisition device of claim 11 , further configured to operate in global shutter mode.
17. A method of acquiring a signal from at least one CMOS-type sensor comprising a photosensor, a plurality of transistors, and an acquisition node and a sense node, the method comprising acts of:
operating the CMOS-type sensor in an integration phase during which the photosensor is exposed to illumination;
applying a compression signal to the sense node during part of the integration phase;
isolating the sense node from the acquisition node during the integration phase except immediately before the application of the compression signal, wherein the acquisition node is connected to the sense node long enough to enable transfer of signal charges present at the acquisition node to the sense node and is then disconnected from the sense node.
18. The method of claim 17 , further comprising:
resetting the sense node; and
reading a reference state of the sense node before applying the compression signal to the sense node.
19. The method of claim 17 , wherein the compression signal is a pulse train and the isolating of the sense node occurs during the integration phase except immediately before each compression pulse wherein the acquisition node is temporarily connected to the sense node long enough to enable transfer of charges present at the acquisition node to the sense node before each compression pulse.
20. The method of claim 19 , wherein the compression signal is applied within a last half of the integration phase.
21. The method of claim 19 , further comprising reading a reference state of the sense node immediately before a first charge transfer from the acquisition node to the sense node.