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AssigneeSTMicroelectronics S.r.l.
InventorsAlfio Castorina, Massimo Mancuso, Sebastiano Battiato
Estimating the term…
A method of processing digital source images, each represented by pixel matrices, to obtain from two or more source images, representing one and the same real scene and acquired by utilizing different exposure levels, a final digital image capable of reproducing the real scene with an exposure latitude greater than that of each of the source images. The method, which can be advantageously used in digital still cameras, produces the final image by combining the source images with the help of a weighted average constructed pixel by pixel. Thanks to a special filtering to which the weighting coefficients are subjected before the weighted mean operation, the method obtains a final image in which the source images are harmoniously combined with each other.
A method, comprising:
A system, comprising:
A method, comprising:
A system, comprising:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
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Image enhancement or restoration: using two or more images, e.g. averaging or subtraction
Image enhancement details: high dynamic range [HDR] image processing
Image data processing or generation, in general
Term ended 19 Feb 2023 (estimated)
The present invention generally concerns the acquisition and processing of images in digital format and, more particularly, a method that can be advantageously used in digital still cameras, where, combining several images representative of one and the same real scene, the method generates a final image of a quality superior to that of the source or input images.
The digital still camera, often referred to by the abbreviation DSC, is at present one of the most common devices employed for acquiring digital images. The fact that both sensors of ever greater resolution and low-priced digital signal processors (DSPS) of low power consumption are readily available in commerce has led to the development of digital still cameras capable of acquiring images of very high resolution and quality.
Just like their traditional counterparts, however, these cameras still have a rather limited response when it comes to acquiring real scenes containing zones differing from each other by considerable illumination contrasts.
The invention will be understood more readily from the detailed description given below of a particular embodiment, the said embodiment being merely an example and should not therefore be regarded as in any way limitative, together with the accompanying drawings, of which:
FIG. 1 shows the logic scheme in the form of a block diagram of an acquisition system that utilizes the method in accordance with an embodiment of the invention,
FIG. 2a shows the response curve of a photoelectric cell in accordance with an embodiment of the invention,
The following discussion is presented to enable a person skilled in the art to make and use the invention. The general principles described herein may be applied to embodiments and applications other than those detailed below without departing from the spirit and scope of the present invention. The present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed or suggested herein.
As can be seen from FIG. 1, a system that applies the method in accordance with the an embodiment of the invention includes four principal logic blocks. A non-reductive assumption for the purposes of the description is to suppose initially that the system shown in FIG. 1 acquires and processes monochromatic images, for example, in a gray scale represented by means of pixels digitized with N=8 bits.
Block 1 analyzes the scene at a point that in a digital still camera could be, for example, at the output of the sensor (not shown) and, applying an algorithm of a type known to a person skilled in the art, decides whether or not the scene is critical in terms of exposure.