Precise CMOS imager transfer function control for expanded dynamic range imaging using variable-height multiple reset pulses

A method for measuring a sense node voltage associated with a light detecting element, the sense node voltage being related to light intensity incident upon the light detecting element, comprising:

• (a) initiating an integration period for the light-detecting element;
• (b) resetting, a plurality of times, the voltage level of the sense node after initiating the integration period;
• and
• (c) measuring, only once during the integration period, the sense node voltage generated in response to incident light intensity, the sense node voltage being measured subsequent to the plural resettings of the voltage level of the sense node and prior to initiating a next integration period.

A method for capturing a frame of image data associated with a scene using an array of light-detecting elements, each light-detecting element having an associated sense node, comprising:

• (a) initiating an integration period for the array of light-detecting elements, the integration period being associated with the frame of image data;
• (b) generating a plurality of intra-period reset pulses during the integration period such that voltage levels of the sense nodes associated with a portion of the array of light-detecting elements are enabled to be set a plurality of times during the integration period;
• and
• (c) measuring, only once during the integration period, the voltage levels of the sense nodes voltages generated in response to incident light intensities, the sense node voltages being measured subsequent to a final resetting of the voltage levels of the sense nodes associated with the portion of the array of light-detecting elements and prior to initiating a next integration period.

A method for measuring a sense node voltage associated with a light detecting element, the sense node voltage being related to light intensity incident upon the light detecting element, comprising:

• (a) initiating an integration period for the light-detecting element;
• (b) resetting, a first number of times during the integration period, the voltage level of the sense node after initiating the integration period;
• and
• (c) measuring the sense node voltage generated in response to incident light intensity, the sense node voltage being measured a second number of times during the integration period, the second number of times being less than the first number of times.

A method for measuring a sense node voltage associated with a light-detecting element, the sense node voltage being related to light intensity incident upon the light-detecting element, the light-detecting element having a reset switch associated therewith so as to set a voltage level of the sense node, comprising:

• (a) generating a first integration reset pulse to enable a resetting of the sense node voltage to a voltage value substantially equal to a reset voltage value associated with the first integration reset pulse, an edge of the first integration reset pulse triggering a beginning of a first integration period;
• (b) generating a second integration reset pulse to enable a resetting of the sense node voltage to a voltage value substantially equal to a reset voltage value associated with the second integration reset pulse, an edge of the second integration reset pulse triggering a beginning of a second integration period;
• (c) generating, subsequent to the generation of the first integration reset pulse and prior to the generation of the second integration reset pulse, a train of progressively decreasing intra-period reset pulses to enable resetting of the sense node voltage to a plurality of voltage values, each voltage value being substantially equal to a reset voltage value associated with the generated intra-period reset pulse;
• and
• (d) measuring, only once during an integration period, the sense node voltage generated in response to incident light intensity, the sense node voltage being measured subsequent to the generation of the train of progressively decreasing intra-period reset pulses and prior to the generation of the second integration reset pulse.

A method for measuring a sense node voltage associated with a light-detecting element, the sense node voltage being related to light intensity incident upon the light-detecting element, comprising:

• (a) generating a first integration reset pulse to enable a resetting of the sense node voltage to a voltage value substantially equal to a reset voltage value associated with the first integration reset pulse, an edge of the first integration reset pulse triggering a beginning of a first integration period;
• (b) generating a second integration reset pulse to enable a resetting of the sense node voltage to a voltage value substantially equal to a reset voltage value associated with the second integration reset pulse, an edge of the second integration reset pulse triggering a beginning of a second integration period;
• (c) generating, subsequent to the generation of the first integration reset pulse and prior to the generation of the second integration reset pulse, a plurality of intra-period reset pulses to selectively reset the sense node voltage to a plurality of voltage values, each voltage value being substantially equal to a reset voltage value associated with the generated intra-period reset pulse;
• and
• (d) measuring, only once during an integration period, the sense node voltage generated in response to incident light intensity, the sense node voltage being measured subsequent to the generation of the plurality of intra-period reset pulses and prior to the generation of the second integration reset pulse.