Sensor Overview

Table of Contents

• CMOS sensors
  • Sony Pregius
  • Sony Starvis
• Output sequence of color sensors (RGB Bayer)
• Bilinear interpolation of color sensors (RGB Bayer)

By default, the steps exposure and readout out of an image sensor are done one after the other. The pipelined CMOS sensors only support the overlapped mode. Even less CMOS sensors support the overlapped mode combined with trigger. Please check the sensor summary. In overlapping mode, the exposure starts the exposure time earlier during readout.

Figure 1: Overlapping / pipelined exposure and readout

CMOS sensors

The CMOS sensor modules incorporate the following features:

Sony Pregius

Sensors:	1.6 Mpixels resolution CMOS sensor (-0016A)
Sensor supplier	Sony
Sensor name	IMX296
Resolution	1448 x 1088 gray scale or RGB Bayer mosaic
Indication of sensor category to be used	1/2.9"
Pixel clock	74.25 MHz
Max. frames per second (in free-running full frame mode)	21.8
Binning	H+V, AverageH+V (frame rate unchanged)
Exposure time	10 us - 1 s
ADC resolution	10 bit (10 / 8 bit transmission)
SNR	TBD dB
DR (normal / HDR)	TBD dB
Progressive scan sensor (no interlaced problems!)	X
Rolling shutter	-
Global shutter	X
Trigger (Hardware / Software)	X / X
Pipelined in continuous / triggered mode	X / -
High color reproductivity (for color version)	X
Programmable readout timing with free capture windows and partial scan	X
Flash control output, synchronous to exposure period	X
More specific data

Sony Starvis

Sensors:	5.1 Mpixels resolution CMOS sensor (-0051H)
Sensor supplier	Sony
Sensor name	IMX335
Resolution	2592 x 1944 gray scale or RGB Bayer mosaic
Indication of sensor category to be used	1/2.8"
Pixel clock	74.25 MHz
Max. frames per second (in free-running full frame mode)	7.24
Binning	H+V, AverageH+V (frame rate unchanged)
Exposure time	10 us - 0.3 s
ADC resolution	10 bit (10 / 8 bit transmission)
SNR	TBD dB
DR (normal / HDR)	TBD dB
Progressive scan sensor (no interlaced problems!)	X
Rolling shutter	X
Global shutter	-
Trigger (Hardware / Software)	X / -
Pipelined in continuous / triggered mode	X / -
High color reproductivity (for color version)	X
Programmable readout timing with free capture windows and partial scan	X
Flash control output, synchronous to exposure period	X
More specific data

Note

For further information about image errors of image sensors, please have a look at

For further information about image errors of image sensors, please have a look at Correcting image errors of a sensor.

Output sequence of color sensors (RGB Bayer)

Figure 2: Output sequence of RAW data

Bilinear interpolation of color sensors (RGB Bayer)

For Bayer demosaicing in the camera, we use bilinear interpolation:

Figure 3: Bilinear interpolation

1. Interpolation of green pixels: the average of the upper, lower, left and right pixel values is assigned as the G value of the interpolated pixel.
   For example:

             (G3+G7+G9+G13)
   G8     =  --------------
                   4 
   

   
   For G7:

                               (G1+G3+G11+G13)
   G7_new =  0.5 * G7 + 0.5 *  ---------------
                                      4
   

2. Interpolation of red/blue pixels:
   Interpolation of a red/blue pixel at a green position: the average of two adjacent pixel values in corresponding color is assigned to the interpolated pixel.
   For example:

            (B6+B8)           (R2+R12)
   B7     = ------- ; R7    = --------
               2                 2
   

   
   Interpolation of a red/blue pixel at a blue/red position: the average of four adjacent diagonal pixel values is assigned to the interpolated pixel.
   For example:

            (R2+R4+R12+R14)             (B6+B8+B16+B18)
   R8     = --------------- ;  B12    = ---------------
                  4                           4
   

Any colored edge which might appear is due to Bayer false color artifacts.

Note

There are more advanced and adaptive methods (like edge sensitive ones) available if the host is doing this debayering.