Panoramic Camera With Multiple Image Sensors Using Timed Shutters

Abstract

The present invention relates to the field of panoramic still and motion photography. In a first embodiment, a camera apparatus for panoramic photography includes a first image sensor positioned to capture a first image. The first image sensor has a rolling-shutter readout arranged in portrait orientation. The camera apparatus also includes second image sensor positioned to capture a second image. The second image sensor has a rolling-shutter readout arranged in portrait orientation. Finally, the camera apparatus includes a controller configured to signal the second image sensor to start capturing the second image before the first image sensor finishes capturing the first image. At least a portion of the first image is in front of the second image relative to a forward direction of the camera apparatus.

What is claimed is: 
     
         1 . A camera apparatus for panoramic photography, comprising:
 a first image sensor positioned to capture a first image, the first image sensor having a rolling-shutter readout arranged to sequentially activate columns of converters that each convert an optical signal into an electrical signal;   a second image sensor positioned to capture a second image, the second image sensor having a rolling-shutter readout arranged to sequentially activate columns of converters that each convert an optical signal into an electrical signal; and   a controller configured to signal the second image sensor to start capturing the second image before the first image sensor finishes capturing the first image,   wherein a delay time between when the second image sensor starts capturing the second image and when the first image sensor finishes capturing the first image corresponds to an amount of overlap between a field of view of the first image sensor and a field of view of the second image sensor,   wherein at least a portion of the first image is in front of the second image relative to a forward direction of the camera apparatus.   
     
     
         2 . The camera apparatus of  claim 1 , wherein the controller is configured to signal the second image sensor to start capturing the second image approximately when the first image sensor starts to capture an overlap of the fields of view of the first and second image sensors. 
     
     
         3 . The camera apparatus of  claim 1 , wherein the delay time is offset according to a velocity value of the camera apparatus to use motion parallax resulting from motion of the camera apparatus to cancel out spatial parallax between the first and second image sensors. 
     
     
         4 . The camera apparatus of  claim 3 , wherein the velocity value of the camera apparatus is an approximate or average velocity of the camera apparatus. 
     
     
         5 . The camera apparatus of  claim 4 , wherein the delay time is offset by a time between when an entrance pupil of the first image sensor passes a location and when an entrance pupil of the second image sensor passes the location during forward motion of the camera apparatus. 
     
     
         6 . The camera apparatus of  claim 4 , wherein the delay time approximately satisfies the following equation: 
       
         
           
             
               
                 t 
                 = 
                 
                   
                     
                       R 
                       1 
                     
                     · 
                     
                       F 
                       1 
                     
                   
                   - 
                   
                     
                       D 
                       12 
                     
                     v 
                   
                 
               
               , 
             
           
         
         wherein t is the delay time,
 wherein R 1  is a rolling-shutter readout time of the first image sensor, 
 
         wherein F 1  is a percentage of the field of view of the first image sensor which does not overlap with the field of view of the second image sensor, 
         wherein D 12  is a distance between an entrance pupil of the first image sensor and an entrance pupil of the second image sensor, and 
         wherein v is a speed of the camera apparatus. 
       
     
     
         8 . The camera apparatus of  claim 1 , wherein the first and second image sensors are attached to a vehicle. 
     
     
         9 . The camera apparatus of  claim 1 , wherein the first image sensor exposes at least a first and second column of the first image sensor, the first column capturing a more rearward portion of the first image and the second column capturing a more forward portion of the first image relative to forward motion of the camera apparatus,
 wherein the first column of the first image sensor starts exposure before the second column of the first image sensor,   wherein the second image sensor exposes at least a first and second column of the second image sensor, the first column capturing a more rearward portion of the second image and the second column capturing a more forward portion of the second image relative to the forward motion of the camera apparatus, and   wherein the first column of the second image sensor starts exposure before the second column of the second image sensor.   
     
     
         10 . The camera apparatus of  claim 1 , further comprising at least six additional image sensors, wherein a computer is able to stitch together images taken from the at least eight total cameras to create a panoramic image. 
     
     
         11 . The camera apparatus of  claim 1 , wherein the first and second image sensors are CMOS image sensors. 
     
     
         12 . The camera apparatus of  claim 1 , wherein the controller determines the delay time between when the second image sensor starts capturing the second image and when the first image sensor finishes capturing the first image to prevent ghosting between the first and second images. 
     
     
         13 . The camera apparatus of  claim 1 , wherein each converter is a photodiode. 
     
     
         14 . A method for panoramic photography, comprising:
 (a) capturing a first image with a first image sensor, the first image sensor having a rolling-shutter readout arranged to sequentially activate columns of converters that each convert an optical signal into an electrical signal; and   (b) starting to capture a second image with a second image sensor at a delay time prior to completion of the capturing in (a), the delay time corresponding to an amount of overlap of a field of view of the first image sensor and a field of view of the second image sensor, wherein the second image sensor has a rolling-shutter readout arranged in to sequentially activate columns of converters that each convert an optical signal into an electrical signal,   wherein at least a portion of the first image is in front of the second image relative to a forward direction of a camera apparatus comprising the first and second image sensors.   
     
     
         15 . The method of  claim 14 , wherein the delay time is offset according to a velocity value of the camera apparatus to use motion parallax resulting from motion of the camera apparatus to cancel out spatial parallax between the first and second image sensors. 
     
     
         16 . The method of  claim 15 , wherein the delay time is offset by a time between when an entrance pupil of the first image sensor passes a location and when an entrance pupil of the second image sensor passes the location during forward motion of the camera apparatus. 
     
     
         17 . The method of  claim 15 , wherein the delay time approximately satisfies the following equation: 
       
         
           
             
               
                 t 
                 = 
                 
                   
                     
                       R 
                       1 
                     
                     · 
                     
                       F 
                       1 
                     
                   
                   - 
                   
                     
                       D 
                       12 
                     
                     v 
                   
                 
               
               , 
             
           
         
         wherein t is the delay time,
 wherein R 1  is a rolling-shutter readout time of the first image sensor, 
 
         wherein F 1  is a percentage of the field of view of the first image sensor which does not overlap with the field of view of the second image sensor, 
         wherein D 12  is a distance between an entrance pupil of the first image sensor and an entrance pupil of the second image sensor, and 
         wherein v is a speed of the camera apparatus. 
       
     
     
         18 . The method of  claim 14 , wherein further comprising:
 (c) determining the delay time between when the second image sensor starts capturing the second image and when the first image sensor finishes capturing the first image to prevent ghosting between the first and second images.   
     
     
         19 . The method of  claim 14 , wherein each converter is a photodiode.