Image pickup apparatus, solid-state image pickup device, and control method for image pickup apparatus
Decrease of the frame rate is suppressed in a solid-state image pickup device that generates a frame having an increased dynamic range. A measurement section measures a reception light amount in each of a plurality of regions to generate a measurement result. A selection section selects one of a plurality of exposure periods different from each other based on the measurement result in each of the plurality of regions. An image data generation section performs exposure for each of the plurality of regions over the selected exposure period to generate image data. An image processing section adjusts a value of the image data generated for each of the plurality of regions based on the measurement result.
1. An image pickup apparatus, comprising:
a measurement section configured to measure a reception light amount in each of a plurality of regions to generate a measurement result, wherein the measurement section decides whether or not the reception light amount is higher than a given value and generates and retains a decision flag indicative of a result of the decision as the measurement result,
a selection section configured to select one of a plurality of exposure periods different from each other based on the measurement result in each of the plurality of regions;
a digital signal generation section configured to perform exposure for each of the plurality of regions over the selected exposure period to generate a digital signal,
an image processing section configured to adjust a value of the digital signal generated for each of the plurality of regions based on the measurement result;
a counting section configured to count a count value in synchronism with a given clock signal;
a photodiode configured to generate charge according to the reception light amount; and
a comparator configured to compare a given ramp signal and a voltage according to an amount of the charge with each other and output a result of the comparison as a comparator output signal,
wherein the digital signal generation section retains, in a case where the comparator output signal is inverted, the count value as the digital signal, and
wherein the measurement section includes
a decision flag generation section configured to compare the count value and a given set value according to the given value with each other and output a result of the comparison as a latch input signal, and
a decision flag retention section configured to retain, in the case where the comparator output signal is inverted, a value of the latch input signal as the decision flag.
2. The image pickup apparatus according to claim 1 , wherein
each of the plurality of regions is configured from one pixel.
3. The image pickup apparatus according to claim 1 , wherein
each of the plurality of regions is configured from a plurality of pixels.
4. The image pickup apparatus according to claim 1 , wherein
the counting section first performs one of an incrementing process and a decrementing process of the count value and then performs an another of the processes.
5. The image pickup apparatus according to claim 1 , wherein
the image processing section executes at least one of a process of amplifying the digital signal in any region in which the reception light amount is higher than the given value from among the plurality of regions and another process of attenuating the digital signal in any region in which the reception light amount does not exceed the given value from among the plurality of regions.
6. The image pickup apparatus according to claim 1 , wherein
for each of a plurality of given image pickup cycles, the measurement section retains the measurement result every time a given image pickup cycle elapses, and
the selection section selects, in each of the given image pickup cycles, one of the plurality of exposure periods based on the measurement result retained before the image pickup cycle.
7. The image pickup apparatus according to claim 1 , wherein
the selection section selects, in each of a plurality of given image pickup cycles, one of the plurality of exposure periods based on the measurement result generated in the given image pickup cycle.
8. The image pickup apparatus according to claim 1 , wherein
the measurement section, the selection section and the digital signal generation section are provided in a solid-state image pickup device, and
a circuit in the solid-state image pickup device is distributed to a plurality of stacked semiconductor substrates.
9. A solid-state image pickup device, comprising:
a measurement section configured to measure a reception light amount in each of a plurality of regions to generate a measurement result, wherein the measurement section decides whether or not the reception light amount is higher than a given value and generates and retains a decision flag indicative of a result of the decision as the measurement result;
a selection section configured to select one of a plurality of exposure periods different from each other based on the measurement result in each of the plurality of regions;
a digital signal generation section configured to perform exposure for each of the plurality of regions over the selected exposure period to generate a digital signal indicative of an exposure light amount;
a counting section configured to count a count value in synchronism with a given clock signal;
a photodiode configured to generate charge according to the reception light amount; and
a comparator configured to compare a given ramp signal and a voltage according to an amount of the charge with each other and output a result of the comparison as a comparator output signal,
wherein the digital signal generation section retains, in a case where the comparator output signal is inverted, the count value as the digital signal, and
wherein the measurement section includes
a decision flag generation section configured to compare the count, value and a given set value according to the given value with each other and output a result of the comparison as a latch input signal, and
a decision flag retention section configured to retain, in the case where the comparator output signal is inverted a value of the latch input signal as the decision flag.
10. A control method for an image pickup apparatus, comprising:
a measurement procedure for measuring a reception light amount in each of a plurality of regions to generate a measurement result, wherein the measurement procedure includes deciding whether or not the reception light amount is higher than a given value and generating and retaining a decision flag indicative of a result of the decision as the measurement result;
a selection procedure for selecting one of a plurality of exposure periods different from each other based on the measurement result in each of the plurality of regions;
a digital signal generation procedure for performing exposure for each of the plurality of regions over the selected exposure period to generate a digital signal indicative of an exposure light amount;
an image processing procedure for adjusting a value of the digital signal generated for each of the plurality of regions based on the measurement result;
a counting procedure that one of increments or decrements a count value in synchronism with a given clock signal;
a charge generation procedure, wherein a photodiode generates charge according to the reception light amount; and
a comparison procedure, wherein a given ramp signal and a voltage are compared with each other according to an amount of the charge and a result of the comparison is provided as a comparator output signal,
wherein the digital signal generation procedure retains, in a case where the comparator output signal is inverted, the count value as the digital signal, and
wherein the measurement procedure includes
a decision flag generation procedure that compares the count value and a given set value according to the given value with each other and outputs a result of the comparison as a latch input signal, and
a decision flag retention procedure that retains, in the case where the comparator output signal is inverted, a value of the latch input signal as the decision flag.