The system and method are used to convert images on motion picture film or slides to video signals. Color corrections in the video signals are made by adjusting not only the color balance, but also the color hue and saturation, as well as the separate component parts of the luminance signal. During the first phase of operation, the "load" mode, a "standard" set of color correction values is selected so as to provide a video picture which is pleasing to the eye. Then the whole film is color-corrected by providing incremental adjustment signals to be added to or subtracted from the "standard" values for each different scene on the film. The incremental adjustment values are stored in the memory of a digital computer. A frame counter provides a count of the frame at which a color correction is made. Furthermore, each color correction of a frame is given an "event" number. The event and frame numbers are stored together with the adjustment values for each scene or frame. During the second phase of operation, the "run" mode, a video tape recording of the color-corrected video signals is produced by re-running the motion picture film through the system, while reference values for the color corrections, together with incremental values previously stored, are read out, added together, and sent through a film chain. The color-corrected video signals from the film chain are sent to a video tape recorder which records them in a continuous record on tape. If desired, the adjustment values for the color components can be read out of the digital computer memory and stored in a more permanent storage medium such as punched paper tape. Then, at a later date, the signals can be read back into the digital computer, so that the color corrections can be used again. At this time, a new reference signal can be selected and stored in the computer to be combined with the adjustment signals. This permits adjusting the reference signal to compensate for changes due to aging of components in the film chain and elsewhere in the system, thus making it practical to store color correction information for relatively long periods of time without significant degradation of quality of the resulting tape recording. The system will color-correct motion picture film or still slides. Moreover, the speeds of the projectors are variable. Also, during color correction, the motion picture film is stopped so as to provide a stationary display of the images from a selected frame. In order to prevent degradation of the sharpness of the images due to these speed variations, an image enhancement circuit is provided which produces image enhancement in an amount which varies directly with the projector speed.
A method and apparatus for colorimetric evaluation of photographic film by passing light through the film to form a visual image, determining corrections to be made to provide a desired color corrected version of the image, and providing such corrections by adjusting the intensities of separate light beams of different primary colors which are used to form the visual image.
In order to achieve color correction of color television signal generated by a film scanner which includes a scanning device and a digital frame store, correction means are arranged before and after a frame store. Correction data are stored during a first film run and reproduced during a second film run, e.g. when the film is televised. The correction may be performed during motion and still motion of the film without increasing of quantization errors.
An editing system and method for editing, which may include two or more video signal sources, a storage and retrieval device, color correction circuits, and equipment for combining video signals. Two or more sets of color correction values may be stored in the storage and retrieval device. The sets of color correction values are retrieved from the storage and retrieval device and applied to the color correction circuits which then respond to the sets of color correction values in order to color correct the video signals produced by the video signal sources. The equipment for combining video signals combines the color corrected video signals to produce edited video signals, which may be recorded with a video recorder. In this fashion, a color corrected edited master is made. Such an editing system advantageously includes a control mechanism that automatically controls the various components of the system in response to a predetermined set of instructions. Furthermore, the control mechanism may permit one or more of the components of the system to be selectively controlled by an operator. One set of color correction values may contain a color balance correction, a hue correction, a sauration correction, and a luminance correction. Other corrections may be included, too. The same set of color correction values may be employed for every scene, or different sets of color correction values may be used for different scenes.
In a device for producing corrected color chromatic components for multicoloring printing in which an original is scanned and recorded and selectively displayed on a television monitor in which a switching arrangement is provided for producing an one-color frame which surrounds the color picture on the picture screen so as to allow improved color corrections to be made.
This invention is an improvement upon the system and method shown in the "Rainbow" U.S. Pat. No. 4,096,523. A special luminance compensation signal is formed by combining the color derivative signals (yellow, green, red, blue, cyan and magenta) with one another. The compensation signal so formed is combined with the luminance signal from a standard luminance matrix. The overall luminance signal is used in the usual way to form video picture signals. The individual color derivative components of the luminance signal can be varied independently of one another. This provides an improved degree of control and correction of video color signals, and corrects for some film errors which previously have not been adequately corrected. Preferably, the gain, pedestal and gamma factors of the overall luminance signal also can be controlled independently. It also is preferred that the primary color component signals delivered to the standard luminance matrix be taken from the output of the gain section of the signal processor for each of the primary color component signals. A special gamma control circuit is provided by means of which it is possible to provide continuous variation of the gamma factor from values substantially less than one to values substantially greater than one. This is done by means of a single circuit which also has excellent noise suppression properties.
