Image sensor including real-time automatic exposure control and swallowable pill including the same
First Claim
Patent Images
1. An image sensor comprising:
- an array of pixels comprising a plurality of rows and columns;
a plurality of comparison circuits, each comparison circuit receiving a reference signal value and being coupled to a respective column, each comparison circuit comparing a pixel signal value to the reference signal value and having an output that indicates if the pixel signal value is greater than the reference signal value;
a first circuit connected to and counting a number of outputs from the comparison circuits that indicate the pixel signal value is greater than the reference signal value, said first circuit outputting the number of outputs; and
a logic circuit that receives the number of outputs from the first circuit, wherein during an exposure period said logic circuit compares the number received from the first circuit to a predetermined number of pixels that may have a pixel signal value greater than the reference signal value and, if the number received from the first circuit is greater than the predetermined number of pixels and a current exposure time is less than a maximum exposure time, the logic circuit adjusts automatic exposure control parameters for a remaining portion of the exposure period by setting a readout gain of the image sensor to a minimum gain value and adjusting the reference signal value to a value of a full scale pixel signal.
9 Assignments
0 Petitions
Accused Products
Abstract
An imager and a method for real-time, non-destructive monitoring of light incident on imager pixels during their exposure to light. Real-time or present pixel signals, which are indicative of present illumination on the pixels, are compared to a reference signal during the exposure. Adjustments, if necessary, are made to programmable parameters such as gain and/or exposure time to automatically control the imager'"'"'s exposure to the light. In a preferred exemplary embodiment, only a selected number of pixels are monitored for exposure control as opposed to monitoring the entire pixel array.
142 Citations
12 Claims
-
1. An image sensor comprising:
-
an array of pixels comprising a plurality of rows and columns; a plurality of comparison circuits, each comparison circuit receiving a reference signal value and being coupled to a respective column, each comparison circuit comparing a pixel signal value to the reference signal value and having an output that indicates if the pixel signal value is greater than the reference signal value; a first circuit connected to and counting a number of outputs from the comparison circuits that indicate the pixel signal value is greater than the reference signal value, said first circuit outputting the number of outputs; and a logic circuit that receives the number of outputs from the first circuit, wherein during an exposure period said logic circuit compares the number received from the first circuit to a predetermined number of pixels that may have a pixel signal value greater than the reference signal value and, if the number received from the first circuit is greater than the predetermined number of pixels and a current exposure time is less than a maximum exposure time, the logic circuit adjusts automatic exposure control parameters for a remaining portion of the exposure period by setting a readout gain of the image sensor to a minimum gain value and adjusting the reference signal value to a value of a full scale pixel signal. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A swallowable pill comprising:
an image sensor, said image sensor comprising; an array of pixels comprising a plurality of rows and columns; a plurality of comparison circuits, each comparison circuit receiving a reference signal value and being coupled to a respective column, each comparison circuit comparing a pixel signal value to the reference signal value and having an output that indicates if the pixel signal value is greater than the reference signal value; a first circuit connected to and counting a number of outputs from the comparison circuits that indicate the pixel signal value is greater than the reference signal value, said first circuit outputting the number of outputs; and a logic circuit that receives the number of outputs from the first circuit , wherein during an exposure period said logic circuit compares the number received from the first circuit to a predetermined number of pixels that may have a pixel signal value greater than the reference signal value and, if the number received from the first circuit is greater than the predetermined number of pixels and a current exposure time is less than a maximum exposure time, the logic circuit adjusts automatic exposure control parameters for a remaining portion of the exposure period by setting a readout gain of the image sensor to a minimum gain value and adjusting the reference signal value to a value of a full scale pixel signal.
-
7. An image sensor comprising:
-
an array of pixels comprising a plurality of rows and columns; a plurality of comparison circuits, each comparison circuit receiving a reference signal value and being coupled to a respective column, each comparison circuit comparing a pixel signal value to the reference signal value and having an output that indicates if the pixel signal value is greater than the reference signal value; a first circuit connected to and counting a number of outputs from the comparison circuits that indicate the pixel signal value is greater than the reference signal value, said first circuit outputting the number of outputs; and a logic circuit that receives the number of outputs from the first circuit, wherein during an exposure period said logic circuit compares the number received from the first circuit to a predetermined number of pixels that may have a pixel signal value greater than the reference signal value and, if the number received from the first circuit is greater than the predetermined number of pixels and a current exposure time is within a predetermined time interval, the logic circuit adjusts automatic exposure control parameters for a remaining portion of the exposure period by setting a readout gain to a gain value between a maximum gain value and a minimum gain value and setting the reference signal value to a value of a full scale pixel signal divided by the readout gain value set to be between the maximum gain and the minimum gain value. - View Dependent Claims (8, 9, 10, 11)
-
-
12. A swallowable pill comprising:
an image sensor, said image sensor comprising; an array of pixels comprising a plurality of rows and columns; a plurality of comparison circuits, each comparison circuit receiving a reference signal value and being coupled to a respective column, each comparison circuit comparing a pixel signal value to the reference signal value and having an output that indicates if the pixel signal value is greater than the reference signal value; a first circuit connected to and counting a number of outputs from the comparison circuits that indicate the pixel signal value is greater than the reference signal value, said first circuit outputting the number of outputs; and a logic circuit that receives the number of outputs from the first circuit, wherein during an exposure period said logic circuit compares the number received from the first circuit to a predetermined number of pixels that may have a pixel signal value greater than the reference signal value and, if the number received from the first circuit is greater than the predetermined number of pixels and a current exposure time is within a predetermined time interval, the logic circuit adjusts automatic exposure control parameters for a remaining portion of the exposure period by setting a readout gain to a gain value between a maximum gain value and a minimum gain value and setting the reference signal value to a value of a full scale pixel signal divided by the readout gain value set to be between the maximum gain and the minimum gain value.
Specification