Method of and device for generating an image having a desired brightness

Abstract

The present invention relates to a method of generating an image having a desired brightness, which image is generated by means of a device provided with at least one light source, at least one electro-optical light modulation panel and at least one light-control device. The light from the light source is converted into an image having a desired brightness via at least the electro-optical light modulation panel and the light-control device. The image to be projected is analyzed in a regulator, whereafter the electro-optical light modulation panel and the light-control device are driven, while a too bright image is generated by means of the electro-optical light modulation panel, which image is converted by means of the light-control device into an image having a desired brightness and a desired contrast.

1. A method of generating a desired image, comprising:
 analyzing a first image to determine a desired brightness and a desired contrast for said first image;   providing an illumination beam from a constant intensity light source;   modulating said illumination beam to produce an image beam having said desired contrast; and   optically adjusting a one of said illumination beam and said image beam to form said desired image having said desired brightness.   
     
     
       2. The method as claimed in  claim 1 , wherein the analyzing is performed by a regulator. 
     
     
       3. The method as claimed in  claim 1 , wherein the step of modulating is performed by a light modulator panel. 
     
     
       4. The method as claimed in  claim 1 , wherein the step of optically adjusting is performed by a light control device. 
     
     
       5. The method as claimed in  claim 1 , wherein a brightness and a contrast of said desired image are adjusted substantially independently of each other. 
     
     
       6. The method as claimed in  claim 1 , wherein a contrast of said desired image is independent from a background illumination level. 
     
     
       7. The method of  claim 1 , wherein
 the first image does not cover a complete range of gray levels producible by an image processing apparatus performing said step of modulating;   the image beam covers a larger range of gray levels than the first image, while being within said complete range; and   whereby, the desired image has the larger range of gray levels with the desired brightness.   
     
     
       8. The method of  claim 7 , wherein the image processing apparatus comprises at least one light modulation panel and wherein the image beam comprises image modulation information within the at least one modulation panel. 
     
     
       9. The method of  claim 7 , wherein the step of modulating results in a brightness level that causes the image beam to lie within parameters achieving a maximum dynamic range of at least a portion of the image processing apparatus. 
     
     
       10. The method of  claim 9 , wherein the step of optically adjusting relates to a second portion of the image proceasing apparatus. 
     
     
       11. A method for producing an output image in a device comprising a constant intensity light source and at least one light modulator, the output image resulting from passing light from the constant intensity light source through the light modulator, the method comprising:
 analyzing an input image to derive a desired contrast and desired brightness; 
 adjusting the light modulator to a setting which would normally not result in the desired brightness, but would result in the desired contrast; 
 optically adjusting the brightness of the output image to retain the desired contrast achieved by the light modulator while attaining the desired brightness. 
 
     
     
       12. An image producing device for generating an output image, the image producing device comprising:
 a video input; 
 at least one constant intensity light source, having a given normal brightness value; 
 at least one light modulator, responsive to the video input for adding image data from the video input to light from the light source; means for 
 a video signal analyzer performing video signal processing including:  
 analyzing the video input to derive a desired contrast and a desired brightness; 
 supplying at least one first control signal to cause the light modulator to be adjusted to achieve the desired contrast, but a brightness other than the desired brightness with the constant intensity light source at the given normal brightness value; and  
 supplying at least one second control signal to cause an optical a brightness adjustment optically or by varying a time interval of flashing of the at least one constant intensity light source in order to achieve the desired brightness in the output image in view of the adjustment of the light modulator; so such that the output image has both the desired contrast and the desired brightness. 
 
     
     
       13. The image producing device of claim 12, further comprising: a light source controlling device, the video signal analyzer supplying the at least one second control signal to cause the light source controlling device to vary a time interval of flashing of the at least one constant intensity light source.  
     
     
       14. The image producing device of claim 12, wherein the output image is an output color image, and the at least one constant intensity light source comprises:
 a red constant intensity light source, having a normal red brightness value;   a green constant intensity light source having a normal green brightness value; and   a blue constant intensity light source having a normal blue brightness value, wherein the adjusting includes independently varying time intervals of flashing of the red, green, and blue constant intensity light sources to form said output color image such that that the output color image has both the desired contrast and the desired brightness for each of red, green, and blue components.    
     
     
       15. The image producing device of claim 12, wherein said desired contrast is maximal contrast.  
     
     
       16. The image producing device of claim 12, wherein the video signal analyzer supplies the at least one second control signal to one of a diaphragm and the light modulator to cause said brightness adjustment such that that the output image has both the desired contrast and the desired brightness.  
     
     
       17. The image producing device of claim 12, wherein the analyzing of the video input derives a desired contrast and a desired brightness for a part of the output image.  
     
     
       18. The image producing device of claim 12, further comprising:
 A light control device receiving the at least one second control signal and adjusting brightness of a part of the output image.