US 7,679,660 B2Granted

Solid-state image pickup apparatus for compensating for deterioration in horizontal charge transfer efficiency

AssigneeFUJIFILM Corporation

InventorHirokazu Kobayashi

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Abstract

An solid-state image pickup apparatus compensates for deterioration in horizontal transfer efficiency conspicuous in an image captured in, e.g. a high ISO sensitivity mode. A horizontal transfer efficiency calculator in a transfer efficiency compensator of a signal processor calculates in advance a local horizontal transfer efficiency for signal charge transfer in a concentrating portion of an image sensor, for each value of ISO sensitivity, to store a resultant value. The signal processor processes a digital image signal representing a photographed subject. In main shooting with a value of ISO sensitivity for image pickup set, a subject field is captured, and a horizontal transfer efficiency detector detects a local horizontal transfer efficiency consistent with the value of ISO sensitivity for image pickup. A horizontal transfer efficiency corrector corrects a digital image signal based on the consistent local horizontal transfer efficiency.

Claims40

Dependent claims

A solid-state image pickup apparatus comprising:

an image sensor for transducing light incident on an image sensing surface, which has a plurality of pixels arranged in rows and columns, to electric signal charges on a pixel-by-pixel basis, shifting the signal charges on the rows transferred from said image sensing surface in a horizontal direction along a horizontal transfer path, concentrating the signal charges at a local portion, and transferring the concentrated signal charges to an output circuit, which converts the concentrated signal charges to an electric signal;
an analog signal processor and an analog-to-digital converter for converting the electric signal to a digital image signal;
and
a signal processor for executing digital signal processing on the digital image signal;
wherein, for main shooting, a predetermined value of ISO sensitivity, among a plurality of different values of the ISO sensitivity, is set as a value of ISO sensitivity for image pickup;
said image sensor photographing a subject field in keeping with the value of ISO sensitivity for image pickup;
said signal processor comprising:
a horizontal transfer efficiency calculator for calculating in advance the horizontal transfer efficiency information, representing the horizontal transfer efficiency for signal charge transfer in said image sensor, in keeping with predetermined one of the different values of the ISO sensitivity, and storing the horizontal transfer efficiency information calculated;
a horizontal transfer efficiency detector for acquiring the horizontal transfer efficiency information from said horizontal transfer efficiency calculator and for detecting the horizontal transfer efficiency for image pickup, consistent with the value of ISO sensitivity for image pickup, based on the horizontal transfer efficiency information;
and
a horizontal transfer efficiency corrector for correcting the digital image signal for compensating the horizontal transfer efficiency for image pickup, and
wherein said horizontal transfer efficiency calculator calculates, as the horizontal transfer efficiency information, the local horizontal transfer efficiency for signal charge transfer in said concentrating portion and/or the horizontal transfer efficiency for all stages for signal charge transfer in said horizontal transfer path.

9 more elements

An image correcting method comprising:

an image sensing step of photo-electrically converting incident light to generate signal charges on an image sensing surface, on which a plurality of pixels are arrayed in a row direction and in a column direction, shifting the signal charges of each row transferred from said image sensing surface in the horizontal direction on a horizontal transfer path, concentrating the signal charges in a concentrating portion to transfer the charges to an output circuit, converting the signal charges, transferred to said output circuit, into an electric signal and outputting the electric signal;
a signal processing step of analog-signal processing and analog-to-digital converting the electric signal to produce a digital image signal, and of digital-signal processing the digital image signal;
and
a step of setting, for main shooting, a predetermined value of ISO sensitivity, among a plurality of different values of the ISO sensitivity, as value of ISO sensitivity for image pickup, said image sensing step photographing a field in keeping with the value of ISO sensitivity for image pickup;
said signal processing step includes:
a horizontal transfer efficiency calculation substep of calculating in advance the horizontal transfer efficiency information, representing the horizontal transfer efficiency for signal charge transfer in said image sensing step, in keeping with predetermined one of the different values of the ISO sensitivity, and storing the horizontal transfer efficiency information calculated;
a horizontal transfer efficiency detection substep of acquiring the horizontal transfer efficiency information from said horizontal transfer efficiency calculation substep and of detecting the horizontal transfer efficiency for image pickup, consistent with the value of ISO sensitivity for image pickup, based on the horizontal transfer efficiency information;
and
a horizontal transfer efficiency correction substep of correcting the digital image signal for compensating the horizontal transfer efficiency for image pickup, and
wherein said horizontal transfer efficiency calculation substep calculates, as the horizontal transfer efficiency information, the local horizontal transfer efficiency for signal charge transfer in the concentrating portion and/or the horizontal transfer efficiency for all stages for signal charge transfer in the horizontal transfer path.

7 more elements

Dependencies are inferred from the claim text.