According to this invention, a sharpness emphasis is carried out by multiplying a sharpness emphasis signal of an original image by a function of a look-up table which is accessed based on an output from an edge detecting filter performing detections, in accordance with only the edge portions of the original image. Since the edge detecting filter for detecting edges of the image is equipped in order to emphasize the sharpness only in the edge portions of the image, it is possible to prevent the image grains from being sharpness-emphasized. In addition, although the edge detecting filter may have a same size of a mask with that of the unsharpness mask, it is possible, if required, to modify freely both sizes of the masks, in order to perform a proper process in accordance with each image variation.

Method and apparatus for emphasizing sharpness of image by detecting the edge portions of the image

A digital camera with video input is disclosed. An image sensor is provided to capture an image and convert the captured image into R/G/B image signals the are processed by a video signal processing unit for being converted into pixel data having a first format. A TV decoder converts input analog video signals into pixel data having a second format. A scaling unit performs aspect ratio processing and zoom/pan function to pixel data. A TV interface unit converts pixel data having the second format into pixel data having the first format for being selectively output to the scaling unit directly and output to the scaling unit after transferring to the video signal processing unit for performing edge enhancement. A compressing and storage unit performs compress operation to the pixel data output from the video signal processing unit and the scaling unit. An USB unit converts pixel data after being compressed into serial data for output.

Digital camera with video input

An enhancing circuit wherein a color difference signal (b) is enhanced by utilizing the change of a luminance siganal (a). The luminance signal (a) is sent, via a low-pass filter (2), a first delay circuit (3), a first differentiation circuit (4), a detector (5), a slicer (6), and a second differentiation circuit (7), to a comparator set (8) to produce two signals (i and j). The two signals (i and j) are sent to first and second sample-and-hold circuits (11 and 12). Meanwhile, the color difference signal (b) is delayed in a second delay circuit (10). In thses two sample-and-hold circuit (11 and 12), such a delayed color difference signal (c) and color difference signal (b) are respectively held in response to the two signals (i and j). Then, such two held signals (I' and II') and the delayed color difference signal (d) are sent to a switching circuit (13) for selecting one of these three signals (I', II', III') in accordance with the combination of the two signals (i and j) thereby producing an enhanced color difference signal (k). Since the luminance signal (a) has a wide frequency band, color-ringing of an image can be satisfactorily reduced.

Circuit for enhancing a color difference signal by utilizing the change of a luminance signal

A transition enhancing circuit includes a tapped delay line which provides successively delayed replicas of the signal to be processed. A multiplexer, responsive to a signal transition, sequentially couples delayed signal from the center tap and taps more distant from the input of the delay line to an output terminal to effectively hold the initial value of the transition for approximately half the transition period. The taps at the input end of the delay line up to and including the center tap are then sequentially coupled to the output terminal to effectively advance, in time, the end value of the signal transition. The signal transition is thereby reduced to a time equivalent to the switching interval between taps.

Signal transient improvement circuit

In a method of obtaining an improved perceived color transient, an artificial transient signal is inserted (50) into a luminance signal (Yin) when it is detected (10, 20, 30) that there is an edge in a chrominance signal (Cin) in the absence of an edge in the luminance signal (Yin).

Perceived color transient improvement

The invention relates to a circuit arrangement for increasing the resolution of color contours. A slope detector detects the slope of the luminance signal and, when a predetermined slope value is exceeded, produces a detection signal for energizing a counter. The counter controls an edge enhancement circuit for a color difference signal, in which, as soon as the counter is energizing, the value of the color difference signal is stored and is available as an output signal. After a predetermined number of equidistant clock pulses has been counted, the edge enhancement circuit (7, 16) supplies the actual color difference signal value. If before the end of the counting operation, a new detection signal is produced, then the edge enhancement circuit briefly receives and stores the actual color difference signal value, and the counter starts a new counting cycle.

Circuit arrangement for increasing the definition of color contours of a color television signal using selective edge enhancement

Schaltungsanordnung zum Erhoehen der Schaerfe von Farbkanten

In einer Schaltungsanordnung zum Erhohen der Scharfe von Farbkanten detektiert ein Steilheitsdetektor (2l) die Steilheit des Helligkeitssignals und gibt ein Detektionssignal bei Uberschreitung eines bestimmten Steilheitsbetrages zur Aktivierung eines Zahlers (28) ab. In a circuit arrangement for enhancing the sharpness of color edge a slope detector (2l) detects the slope of the luminance signal and outputs a detection signal if it exceeds a certain slope amount for activating a counter (28) from. Der Zahler (28) steuert eine Versteilerungsschaltung (7, l6) fur ein Farbdifferenzsignal, in der zu Beginn der Aktivierung des Zahlers (28) der Wert des Farbdifferenzsignals gespeichert wird und als Ausgangssignal verfugbar ist. The counter (28) controls a peaking (7, l6) of the value of the color difference signal is stored for a color difference signal in which the start of activation of the counter (28) and is available as an output signal. Nach der Zahlung einer bestimmten Anzahl von aquidistanten Takten gibt die Versteilerungsschaltung (7, l6) wieder den aktuellen Farbdifferenzsignalwert aus. After the counting of a certain number of equidistant strokes are the peaking (7, l6) again the current color difference signal value. Wird vor Ende der Zahlung ein neues Detektionssignal erzeugt, so beginnt der Zahler (28) mit einer neuen Zahlung. If a new detection signal is generated before the end of the count, the counter (28) starts a new count.

Martin Schmidt

Papers

Circuit arrangement for increasing the definition of color contours of a color television signal using selective edge enhancement

Schaltungsanordnung zum Erhoehen der Schaerfe von Farbkanten

Circuitry for increasing the sharpness of colour edges