This paper presents a simple and effective method for image contrast enhancement called spatially weighted histogram equalization. Spatially weighted histogram not only considers the times of each grey value appears in a certain image, but also takes the local characteristics of each pixel into account. In the homogeneous region of an image, the spatial weights of pixels tend to zero, whereas a...

A model for computing image ow in image sequences containing a very wide range of instantaneous ows is proposed. This model integrates the spatio-temporal image derivatives from multiple temporal scales to provide both reliable and accurate instantaneous ow estimates. The integration employs robust regression and automatic scale weighting in a generalized brightness constancy framework. In addi...

Disoriented animals from ants to humans reorient in accord with the shape of the surrounding surface layout: a behavioral pattern long taken as evidence for sensitivity to layout geometry. Recent computational models suggest, however, that the reorientation process may not depend on geometrical analyses but instead on the matching of brightness contours in 2D images of the environment. Here we ...

This paper presents a photometric invariant called reeectance ratio that can be computed from a single brightness image of a scene. The brightness variation in an image of a surface depends on several factors; the three-dimensional shape of the surface, its reeectance properties, and the illumination conditions. Since neighboring points on a smoothly curved surface have similar surface orientat...

Within the scope of a common evaluation of brightness and range images, this article introduces a new area based approach to achieve the simultaneous orientation of both data types. The actual innovation is the combined least-squares adjustment. The adjustment is an extension of object space image matching with ranges as additional observations. The complete mathematic model is specified and di...

Auto exposure is an important part of digital image signal processing. We studied the detection of the exposure status in this paper, and fast and parallel detection method was presented. The method comprises the following steps: first obtaining the current image, counting the numbers of pixels in bright and dark regions of the image and obtaining these pixels brightness; then determining expos...

Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digita...

An image fusion is from a combination of two or more source images corresponding to the image information into a single process. The information displayed in the modified image of the combination shows a higher quality. The quality of an image depends on its perception quality, resolution and contrast. In this paper, we have applied Pyramid Decomposition based on image fusion techniques, which ...

The drawback of using a global operator is its inability in revealing image details of local luminance variation. On the contrary, the advantage of a local operator is its capability of revealing the details of luminance level information in an image. In the image enhancement technology, we have proposed local contrast enhancement based on Adaptive Inverse Hyperbolic Tangent Algorithm (AIHT), a...

The basic difference between human and machine vision systems may be briefly summarized as "humans recognize, machines measure" [1]. However, it is not possible to simply transfer or copy the capability of human biological vision to machine vision systems. So, it is a very difficult task to design an artificial system to segment an image, based on the information supplied by the gray-level of t...