A system and process for determining the vignetting function of an image and using the function to correct for the vignetting is presented. The image can be any arbitrary image and no other images are required. The system and process is designed to handle both textured and untextured segments in order to maximize the use of available information. To extract vignetting information from an image, segmentation techniques are employed that locate image segments with reliable data for vignetting estimation. Within each image segment, the system and process capitalizes on frequency characteristics and physical properties of vignetting to distinguish it from other sources of intensity variation. The vignetting data acquired from segments are weighted according to a presented reliability measure to promote robustness in estimation.

The present invention discloses a test method for image sharpness, which can instantly determine the sharpness of a captured image, wherein a captured image is firstly divided into multiple blocks with each block composed of multiple pixels; in each block of the captured image, the pixels having higher sharpnesses are selected, and the sharpnesses of those pixels are summed up to be the sharpness of the related block; the estimated sharpness of the captured image is also obtained similarly; and the estimated sharpness is compared with a threshold value to determine whether the captured image is sharp enough. Thereby, the present invention can test the sharpness of an image fast and correctly and inform the user of the status of the captured image and provide the user with corresponding suggestions.

The invention provides a system and method for processing a video stream having at least one video signal contained therein. The invention utilizes a computer, a video card connected to the computer and a frame processing card connected to the computer. The video card generates a digital video signal by inserting the video signal into the digital video signal. The digital video signal is transmitted from the video card to the frame processing card through a video output port of the video card. A video synchronization signal relating to the digital video signal is provided to the frame processing card. For the system and method, the frame processing card extracts the video signal from the digital video signal utilizing the video synchronization signal to maintain a frame rate for extracting the video signal.

An apparatus for controlling a stereo video display with non-stereo video source includes a memory, a read/write controller and a motion analyzer. The memory stores a current frame, a previous frame of the current frame, and a next frame for the current frame that is in preparation. The current frame and the previous frame are for a dextral image and a sinistral image of a stereoscopic image respectively. The read/write controller controls the addresses to write the current frame and the next frame into the memory, and the reading order of the current frame and the previous frame. The motion analyzer calculates an overall motion direction of the next frame in relation to the current frame, and compares the next overall motion direction to a previous overall motion direction of the current frame in relation to the previous frame, to control the action of the read/write controller to read from or write into the memory, so that when the horizontal relation between the next overall motion direction and the previous overall motion direction is changed, the corresponding relation between the current and the next frames and the dextral and the sinistral images is also changed.

A plurality of known markers is disposed in a specific district. A marker detection section detects the known markers existing in the image photographed by an image pickup device. A position/orientation relation calculation section identifies the detected known marker to calculate position and orientation relations between the identified known marker and the image pickup device. An associated information obtaining section obtains predetermined information associated with the identified known marker. An information processing section processes the obtained predetermined information based on the calculated position and orientation relations. A display device superimposes and displays the processed information on the photographed image. At least the image pickup device and display device are disposed in a portable information terminal, and the other sections are disposed in a server which can perform radio communication with the portable information terminal.