James S Burkhardt, 695 Angela St, Canton, MA 02021

4468637, Aug 28, 1984

Aug 26, 1981

6/296351

William R. Wray - Sudbury MA
James Burkhardt - Watertown MA

Polaroid Corporation - Cambridge MA

H03K 3023

331143

An oscillator unit having a charge storage device periodically rapidly charged through a small resistor and slowly discharged through a large resistor under control of a comparator for producing an oscillatory output and a switch actuatable by means of a frequency controlled zero-crossing multiplier to selectively discharge the storage device and thereby repeatedly resynchronize the oscillator unit with the frequency input to the multiplier.

4839721, Jun 13, 1989

Aug 28, 1984

6/645093

Munib Abdulwahab - East Boston MA
James L. Burkhardt - Watertown MA
John J. McCann - Belmont MA

Polaroid Corporation - Cambridge MA

G03F 308

358 80

A color transform enables color-image information to be recorded, displayed and otherwise processed with exacting control of color relative to a selected display. Apparatus implementing the transform enables a single-exposure photographic print of image information produced in pre-press equipment to predict with accuracy an ink-on-paper print of that information. Color-image information is transformed with a technique that produces output information for each output color component or other parameter at each point in response to up to all input parameters at that point. The technique includes scaling, normalizing and linearizing steps, and may include selecting a uniform color space for mapping the color response of the object (film) medium with the color response of the reference (print) medium. The output information may include approximate transform values and finalizing values. The technique can be implemented for real-time conversion with look-up tables storing approximate transform values and storing interpolation factors, including gradient values, for computing finalizing values.

4520403, May 28, 1985

Jun 22, 1984

6/623518

James L. Burkhardt - Watertown MA
John J. McCann - Belmont MA

Polaroid Corporation - Cambridge MA

H04N 584
H04N 592

358332

A signal processor for selective use with a conventional color television receiver for modifying the color image displayed on the screen of the receiver in order to enable a color photograph to be made by directly exposing a photosensitive material to the modified color image displayed on the screen of the receiver such that the photographic image is of an appearance substantially corresponding to the appearance of the image otherwise displayed on the screen of the receiver when the signal processor is not in use.

4307946, Dec 29, 1981

Jul 7, 1980

6/166101

William R. Wray - Sudbury MA
James Burkhardt - Watertown MA

Polaroid Corporation - Cambridge MA

G03B 2150
G03B 3102

352 5

Flutter in an audio signal recorded on a magnetic tape is reduced by sampling the audio at a rate determined by the frequency of a reference signal also recorded on the tape, reading the samples into respective cells of a memory, and reading out respective cells of the memory at a substantially constant rate that is independent of rapidly changing short duration variations in tape speed. The read-out rate is isolated from tape speed by introducing a time delay between the read-in and read-out of the same sample, the amount of the delay changing in accordance with differences in speed between the tape and a fixed reference. Changes in the delay between read-in and read-out of the same sample generate an error signal that is used to control the speed of the capstan motor that drives the tape past a transducer.

4492987, Jan 8, 1985

Mar 22, 1982

6/360468

James L. Burkhardt - Watertown MA
John J. McCann - Belmont MA

Polaroid Corporation - Cambridge MA

H04N 576

358332

A signal processor for selective use with a conventional color television receiver for modifying the color image displayed on the screen of the receiver in order to enable a color photograph to be made by directly exposing a photosensitive material to the modified color image displayed on the screen of the receiver such that the photographic image is of an appearance substantially corresponding to the appearance of the image otherwise displayed on the screen of the receiver when the signal processor is not in use.