Correcting digitized signals to achieve specified output results for an image

• US 5,467,412 A
• Filed: 08/02/1994
• Issued: 11/14/1995
• Est. Priority Date: 03/05/1992
• Status: Expired due to Term

• Current Assignee: Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Capitant, Patrice J., Collier, David C.
• Primary Examiner(s): Raeavi, Michael T.
• Assistant Examiner(s): Chang, Jon
• Application Number:
  US08/285,642
• Time in Patent Office: 469 Days
• Field of Search: 382/41, 382/54, 382/57, 382/17, 382/167, 382/254, 358/518, 358/519, 358/520, 358/527, 358/530, 348/453, 348/708, 348/97, 348/96, 348/577, 348/520, 348/104
• US Class Current: 382/167
• CPC Class Codes: H04N 1/6027 Correction or control of colour gradation or colour contrast H04N1/6058 takes precedence

Abstract

An operator input subsystem and an image signal processing subsystem are provided to a digital image processing system. The operator input subsystem comprises a CPU, a display device and an input device, whereas the image signal processing subsystem comprises a digital signal processor having a number of digitized signal correctors. For cases where the output results are expressible as smoothly differentiable continuous functions of the digitized input signal values and the processing parameters, the CPU receives the specified output results from the input device and the digitized input signal values and the current processing parameters from the digitized signal correctors. In response, the CPU determines the most optimal processing parameters for the digitized signal correctors to achieve the specified output results. The CPU provides the determined optimal processing parameters to the digitized signal correctors, which in turn use the parameters to correct the digitized signals. The CPU makes the determination by performing a standard non-linear optimization of the smoothly differentiable continuous function. As a result, the increasingly difficult task of providing processing parameters to the image signal correctors is done automatically for the operator, thereby making the image processing system more efficient and user friendly.

Claims

1. A method for converting a source image from a first medium to a second medium, said method comprising the following steps:

generating source image signals representative of the source image on the first medium;

displaying a plurality of reference output images associated with the second medium;

selecting a desired one of the reference output images;

generating optimal values for a set of image processing parameters, by performing a Levenberg-Marquardt non-linear optimization on a smoothly differentiable continuous function, the value of the smoothly differentiable continuous function being approximately the desired reference output image, and the source image signals and the image processing parameters being variables of the smoothly differentiable continuous function;

correcting the source image signals so as to closely approximate the desired reference output image, using the optimal values for the image processing parameters;

reconstructing the source image on the second medium using the corrected source image signals.

2. The method as set forth in claim 1, wherein, said source image signals comprise digitized color signals, and wherein said step of correcting said source image signals is performed by a digitized signal color corrector.

3. The method as set forth in claim 2, wherein, said digitized color signals comprise digitized red, blue and green signals.

4. The method as set forth in claim 2, wherein, said processing parameters comprise gain and offset adjustment parameters, said color corrector performing gain and offset adjustments to said digitized color signals.

5. The method as set forth in claim 2, wherein, said processing parameters comprise interimage masking parameters, said color corrector performing interimage masking transforms on said digitized color signals.

6. The method as set forth in claim 2, wherein, said processing parameters are film characteristic gamma parameters, said color corrector performing film characteristic gamma transforms on said digitized color signals.

7. The method as set forth in claim 2, wherein, said processing parameters are video cross-talk parameters, said color corrector performing video cross-talk transforms on said digitized color signals.

8. The method as set forth in claim 1, wherein, said method is a film to video conversion digital image processing method, said first and second medium being film and video respectively.

9. The method as set forth in claim 8, wherein, said film to video conversion digital image processing method is a film to video conversion digital image processing method for HDTV video.

10. A digital image processing system for converting a source image from a first medium onto a second medium, comprising:

image sampling means for generating source image signals representative of the source image on the first medium;

operator input means for displaying a plurality of reference output images associated with the second medium, and for selecting a desired one of said reference output images;

processor means, being coupled to the operator input means and the image sampling means, for generating optimal values for a set of image processing parameters by performing a Levenberg-Marquardt non-linear optimization on a smoothly differentiable continuous function the value of the smoothly differentiable continuous function being approximately the desired reference output image, and the source image signals and the image processing parameters being variables of the smoothly differentiable continuous function;

image signal correction means, being coupled to the image sampling means and the processor means, for generating a corrected version of the source image signals so as to closely approximate the desired reference output image, using the optimal values for the image processing parameters;

image reconstruction means for using the corrected version of the source image signals to reconstruct the source image on a second medium.

11. The digital image processing system as set forth in claim 10, wherein, said source image signals comprise digitized color signals, and said image signal correction means comprise a color corrector.

12. The digital image processing system as set forth in claim 11, wherein, said digitized color signals comprise digitized red, blue and green signals.

13. The digital image processing system as set forth in claim 11, wherein, said processing parameters comprise gain and offset adjustment parameters, said color corrector performing gain and offset adjustments to said digitized color signals.

14. The digital image processing system as set forth in claim 11, wherein, said processing parameters comprise interimage masking parameters, said color corrector performing interimage masking transforms on said digitized color signals.

15. The digital image processing system as set forth in claim 11, wherein, said processing parameters are film characteristic gamma parameters, said color corrector performing film characteristic gamma transforms on said digitized color signals.

16. The digital image processing system as set forth in claim 11, wherein, said processing parameters are video cross-talk parameters, said color corrector performing video cross-talk transforms on said digitized color signals.

17. The digital image processing system as set forth in claim 10, wherein, said digital image processing system is a film to video conversion digital image processing system, said first and second media being film and video respectively.

18. The digital image processing system as set forth in claim 17, wherein, said film to video conversion digital image processing system is a film to video conversion digital image processing system for HDTV video.