An image processing device includes a memory and a processor configured to calculate a reference black level and a reference illumination light component based on pixel values of peripheral pixels located around a target pixel for image processing using image data acquired by an imaging device, correct a black level of the target pixels based on the reference black level calculated by the processor, and perform a tone correction of the target pixels with the black level corrected based on the reference illumination light component calculated by the processor. Accordingly, even when a large gain is applied to a dark portion of an image in a local tone correction, it is possible to generate an image with high visibility in which an occurrence of raised black levels is suppressed.

To enable a good quality optimization of the luminances of an image, so that they are not only optimized for a particular maximum displayable luminance of a display, but also a particular amount of light in the viewing environment in which the display is watched, the inventor has invented a method of processing an input image to obtain an output image, wherein the input image has pixels which have input luminances which fall within a first luminance dynamic range (DR 1), which first luminance dynamic range has a first maximum luminance (PL_V_HDR), wherein a reference luminance mapping function (F_L) is received as metadata associated with the input image, wherein the reference luminance mapping function specifies a relationship between luminances of a first reference image and luminances of a second reference image, wherein the first reference image has a first reference maximum luminance and the second reference image has a second reference maximum luminance, wherein the input image is equal to one of the first reference image and the second reference image, wherein the output image is not equal to the first reference image nor the second reference image; wherein the processing comprises applying an adapted luminance mapping function (FL_DA) to the input pixel luminances, to obtain the output luminances, wherein the adapted luminance mapping function (FL_DA) is calculated based on the reference luminance mapping function (F_L) and a maximum luminance value (PLA), wherein the calculation involves finding a position on a metric which corresponds to the maximum luminance value (PLA), wherein a first endpoint of the metric corresponds to the first maximum luminance (PL_V_HDR) and a second endpoint of the metric corresponds to a maximum luminance of one of the first reference image and the second reference image not being equal to the input image, characterized in that maximum luminance value (PLA) is calculated based on a maximum luminance (PL_D) of a display which is to be supplied with the output image, and a black level value (b) of the display, wherein the calculation comprises applying an inverse of an electro-optical transfer function to the maximum luminance (PL_D), subtracting from the resulting value the black level value (b), and applying the electro-optical transfer function to the subtraction to obtain the maximum luminance value (PLA).

An image sensor includes a pixel array including at least one light-shielded area where no light enters and an imaging area where light enters, wherein each pixel includes a photoelectric conversion element, a black level processing unit that corrects an output of each pixel in the imaging area, and a memory that stores a predetermined black level reference for each pixel in the imaging area. The processing unit calculates a Slope, which is determined by an average output value at imaging of pixels in the at least one light-shielded area taken during imaging and a reference average output value of pixels in the at least one light-shielded area under certain conditions taken prior to imaging, and correct an output of each pixel in the imaging area using the predetermined black level reference and the Slope.

A method for black level correction, including determining whether the first image sensor and/or the second image sensor triggers a calibration mode based on a calibration signal, performing, in response to the first image sensor triggering the calibration mode and the second image sensor not triggering the calibration mode, first image acquisition through the first image sensor based on a first automatic exposure configuration, and obtaining a calibration result by performing black level calibration, obtaining, in response to the first image sensor not triggering the calibration mode and the second image sensor triggering the calibration mode, an image to be processed by performing second image acquisition through the first image sensor based on a second automatic exposure configuration, and performing black level correction on the image to be processed based on the second automatic exposure configuration and the calibration result.

Image processing devices and methods thereof use different color conversion data of an image obtained in a black-and-white mode under a low illuminance condition than that of an image obtained in a color mode.

Image processing devices and methods thereof use different color conversion data of an image obtained in a black-and-white mode under a low illuminance condition than that of an image obtained in a color mode.

A camera unit includes an image sensor having a light-receiving surface in which pixels are two-dimensionally arranged, the pixels having a photodiode for converting input light into an electrical signal and outputting an analog signal and an AD conversion unit for converting the analog signal into a digital signal based on a dark offset value indicating a black level of an image, and an image processing circuit having a clip value set in accordance with the dark offset value and configured to perform a conversion process of converting a digital value of a digital signal having a digital value that is smaller than the clip value into the clip value and output image data based on a digital signal after the conversion process.

A camera unit includes an image sensor having a light-receiving surface in which pixels are two-dimensionally arranged, the pixels having a photodiode for converting input light into an electrical signal and outputting an analog signal and an AD conversion unit for converting the analog signal into a digital signal based on a dark offset value indicating a black level of an image, and an image processing circuit having a clip value set in accordance with the dark offset value and configured to perform a conversion process of converting a digital value of a digital signal having a digital value that is smaller than the clip value into the clip value and output image data based on a digital signal after the conversion process.

In an imaging array having a plurality of pixel sensors arranged in a plurality of rows and columns, pixel data being read out on column lines of the array, a column line voltage clamp circuit for column lines of the array includes a master voltage clamp circuit coupled to provide a reference voltage clamp level on a reference node, and a slave voltage clamp circuit coupled to each column line in the imaging array, each slave voltage clamp circuit configured to clamp voltage on the column line to a column voltage clamp level derived from the reference voltage level.

Methods and systems to improve the operation of graphic's system are described. In general, techniques are disclosed for compensating for an image sensor's non-zero black-level output. More particularly, a image sensor noise model may be used to offset an image's signal prior to clipping so that the image's dark signal exhibits a linear or near linear mean characteristic after clipping. In one implementation the noise model may be based on calibration or characterization of the image sensor prior to image capture. In another implementation the noise model may be based on an evaluation of the image itself during image capture operations. In yet another implementation the noise model may be based on analysis of an image post-capture (e.g., hours, days, . . . after initial image capture).