Charles Lewis Coleman

US Patent:

44320264, Feb 14, 1984

Filed:

Aug 10, 1981

Appl. No.:

6/291344

Inventors:

Charles H. Coleman - Redwood City CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

G11B 500
G11B 2110

US Classification:

360 77

Abstract:

A system is described for determining the position of a magnetic read head relative to the center of a selected data track on a magnetic recording medium moving with respect to the read head. Tracking signals of equal frequency, but out of phase a predetermined fixed amount, are recorded on adjacent data tracks. The tracking signal frequency is selected to be a long enough wavelength such that a single read head positioned over a selected data track also detects the tracking signal recorded on adjacent data tracks. A phase comparator compares the phase of the tracking signal detected by the read head with respect to the phase of a reference signal of equal frequency, and a resultant signal is generated which is indicative of any deviation of the read head from the center of the selected track.

US Patent:

53010183, Apr 5, 1994

Filed:

Aug 16, 1993

Appl. No.:

8/106968

Inventors:

Peter Smidth - Menlo Park CA
Charles H. Coleman - Redwood City CA
Sidney D. Miller - Mt. View CA

Assignee:

Ampex Systems Corporation - Redwood City CA

International Classification:

H04N 712

US Classification:

348420

Abstract:

In a data compression process such as employed to compress video or other data, it is preferable not to compress the image data representative of the video image in a sequential format, or to take the data from the same area of the image. To equalize the information content of the data prior to compression, the present shuffling/deshuffling technique divides the video image into a multitude of image representing blocks, and selects a predetermined number of the image blocks from different spatial locations in the image, to form a succession of data sets representative of the video image information. That is, the selection of the image representing blocks is such that the information content (complexity) in each data set is similar to the information content in each other data set and further similar to the average information content of the entire video image. Thus, the subsequent quantizing factor used in the compression process will tend to be similar for successive data sets, thereby reducing any distortion introduced by the compression process. The image representing blocks may be formed of sequentially scanned blocks of the video image, or of transform coefficients representing similar blocks of the video image.

US Patent:

44802749, Oct 30, 1984

Filed:

Apr 15, 1983

Appl. No.:

6/485159

Inventors:

Charles H. Coleman - Redwood City CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

G11B 2736
G11B 1502

US Classification:

360 31

Abstract:

A method and apparatus are disclosed for enabling the continuous monitoring of recording circuit performance and the automatic optimization of the recording process in a rotary head recorder having a plurality of recording heads. A calibration signal is recorded by each recording head onto the overlap area of a moving magnetic tape medium. A fixed monitor head subsequently detects components of the recorded signal, the magnitudes of which are squared and retained in sample and hold units. The sampled and held values are periodically used to construct an outputted value commensurate with recording circuit performance. Optimization is accomplished by varying the recording drive level of a recording head about a predetermined point during a series of successive overlap periods. A DC error voltage is derived from the respective outputs resulting from such variation, and used to shift the recording drive level of that head towards a point of optimum playback output.

US Patent:

44687087, Aug 28, 1984

Filed:

Oct 30, 1981

Appl. No.:

6/316756

Inventors:

Charles H. Coleman - Redwood City CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

H04N 949

US Classification:

358310

Abstract:

A method and apparatus are disclosed for performing a reduction of the data rate of a data stream for transmission through a transmission channel or recording and for subsequently reconstructing the original data stream upon receipt or during reproducing. The method and apparatus utilizes a combination of two processes, one of which eliminates or drops digital samples from the data stream to reduce the data rate for transmission and which subsequently reconstructs the original data stream using the unaltered and recovered digital samples to generate an interpolated value for each of the samples that had been dropped. The second process utilizes differential pulse code modulation for reducing the number of data bits per sample before sending the data stream through the transmission channel and for subsequently restoring the data to its original multi-bit form.

US Patent:

51463245, Sep 8, 1992

Filed:

Jul 31, 1990

Appl. No.:

7/560606

Inventors:

Sidney D. Miller - Mt. View CA
Peter Smidth - Menlo Park CA
Charles H. Coleman - Redwood City CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

H04N 712

US Classification:

358133

Abstract:

An image data compression technique is described which utilizes calculating means and a selected series of bit calculating stages having delays, to estimate one or more quantization parameters for such data. The estimation process preferably is iterated a number of times, with the values found through each estimation being used as the trial values for subsequent estimations. In addition, an initial trial value is selected by a data look ahead technique, which assures that its value is within range of the final quantization parameter used to quantize the data. The final quantization parameter insures that the compressed data fits within a predetermined number of encoded data bits to be transmitted or recorded, for example, in a recording medium.

US Patent:

RE288233, May 18, 1976

Filed:

Aug 20, 1971

Appl. No.:

5/173705

Inventors:

Charles H. Coleman - Belmont CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

H04N 944

US Classification:

358 18

Abstract:

A time-base correcting system primarily adapted for use in video tape recording equipment and providing synchronous lockup and time base corrected operation of the video-tape recorder in the playback mode. The system includes circuitry receiving phase alternating line (PAL) composite television signals and which determines the burst switching sequence of the recorded signal before stable lockup is achieved.

US Patent:

44802714, Oct 30, 1984

Filed:

Nov 2, 1981

Appl. No.:

6/316978

Inventors:

Charles H. Coleman - Redwood City CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

H04N 949

US Classification:

358310

Abstract:

A method and apparatus are disclosed for eliminating or dropping digital samples from a data stream of samples to reduce the data rate for transmission of the data stream through a transmission channel, such as a data record and reproduce system or the like, and for subsequently reconstructing the original data stream by using the unaltered and recovered digital samples to generate an interpolated value for each of the samples that has been dropped. A finite impulse response multi-term digital filter is used to generate the interpolated value for the samples that have been dropped. Advantages reside in the fact that errors are not propagated during multiple generation recording or transmission, since unaltered sample values are always used to produce the interpolated value for the dropped sample that is being reconstructed. The invention has particular use in video recording and reproducing wherein it is desirable to record a digital data stream at the lowest practicable data rate.

US Patent:

54346231, Jul 18, 1995

Filed:

Dec 20, 1991

Appl. No.:

7/811486

Inventors:

Charles H. Coleman - Redwood City CA
Sidney D. Miller - Mountain View CA
Peter Smidth - Menlo Park CA

Assignee:

Ampex Corporation - Redwood City CA

International Classification:

H04N 730

US Classification:

348405

Abstract:

A technique is provided for a color imaging system having a luminance component and two color difference (chrominance) components, which allots more space in the compressed data stream to the signal component of greater information content or complexity; that is, which combines the encoding of the components of the data representing a common portion of an image in response to the actual needs of the component, prior to encoding the combined data. To this end, the calculation of the quantizing factors considers the combined information content of both the luminance and chrominance components for the same image location. Thus, low chrominance complexity allows the transmission of more of the luminance information, and vice versa. The system also provides for predetermining the relative complexity of the signal components to thus pre-allot the amount of space for each signal component in the compressed data stream in proportion to its measured complexity.