IMAGE PROCESSING APPARATUS ADAPTED TO RECOGNIZE OBJECT IN ACQUIRED IMAGE

• US 20100091106A1
• Filed: 10/09/2009
• Published: 04/15/2010
• Est. Priority Date: 10/09/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: KIMURA, Takayuki
• Granted Patent: US 8,310,546 B2
• Time in Patent Office: Days
• US Class Current: 348/148
• CPC Class Codes: G06V 10/147 Details of sensors, e.g. sensor lenses fingerprint or palmprint sensors G06V40/13; vascular sensors G06V40/145; eye sensors G06V40/19
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road

Abstract

An image processing apparatus communicates with an image acquisition apparatus provided with an image acquisition region comprising light-shielded pixels and effective pixels. Data of an image are acquired based on output signals from the effective pixels. An edge of an object is extracted in the acquired image data using a preset edge threshold, and the object is recognized based on the extracted edge. Output signals are acquired from the light-shielded pixels and a degree of variations in noise contained in the output signals from the effective pixels is estimated based on the output signals acquired. The edge threshold is set based on the degree of variations in noise which is estimated, such that the noise having a level which exceeds the edge threshold occurs at a probability lower than a preset value.

Claims

1. An image processing apparatus that communicates with an image acquisition apparatus provided with an image acquisition region comprising both a light-shielded region where a plurality of light-shielded solid-state image acquisition elements are arrayed as light-shielded pixels and a non-light-shielded region where a plurality of exposed solid-state image acquisition elements are arrayed two-dimensionally as effective pixels for acquiring an image of an object, the image processing apparatus comprising:

image data acquiring means for acquiring data of the image based on output signals from the effective pixels which are provided by the solid-state image acquisition elements in the non-light-shielded region of the image acquisition apparatus;

edge extracting means for extracting an edge in the image, the is edge being composed of pixels whose values differ from values of adjacent pixels in the effective pixels by differences each being equal to or larger than a preset edge threshold;

object recognizing means for recognizing the object based on the extracted edge;

output acquiring means for acquiring output signals from the light-shielded pixels which are provided by the solid-state image acquisition elements in the light-shielded region;

noise estimating means for estimating a degree of variations in noise contained in the output signals from the effective pixels, based on the output signals acquired by the output acquiring means; and

threshold setting means for setting the edge threshold based on the degree of variations in noise which is estimated by the noise estimating means, such that the noise having a level which exceeds the edge threshold occurs at a probability lower than a preset value.

2. The image processing apparatus of claim 1, wherein the noise estimating means is configured to estimate, as the degree of variations in noise, a standard deviation of levels of the output signals from the light-shielded pixels.

3. The image processing apparatus of claim 2, wherein the threshold setting means is configured to set the edge threshold at a value which is calculated by multiplying the standard deviation by a magnification larger than 1 which is previously set.

4. The image processing apparatus of claim 1, wherein the threshold setting means is configured to set the edge threshold at a value which is smaller than a difference between a maximum and a minimum among levels of the output signals from the effective pixels.

5. The image processing apparatus of claim 1, wherein

the output acquiring means is configured to acquire the output signals from the light-shielded pixels every time the image data acquiring means acquires the output signals from the effective pixels, and

the threshold setting means is configured to set the edge threshold every time the output acquiring means acquires the output signals from the light-shielded pixels.

6. The image processing apparatus of claim 1, wherein

the image acquisition apparatus is mounted in a vehicle so as to allow the image acquisition apparatus to acquire forward images of a road on which the vehicle runs, and

the object is composed of white lines on the road.

7. The image processing apparatus of claim 2, wherein the threshold setting means is configured to set the edge threshold at a value which is smaller than a difference between a maximum and a minimum among levels of the output signals from the effective pixels.

8. The image processing apparatus of claim 2, wherein

the output acquiring means is configured to acquire the output signals from the light-shielded pixels every time the image data acquiring means acquires the output signals from the effective pixels, and

the threshold setting means is configured to set the edge threshold every time the output acquiring means acquires the output signals from the light-shielded pixels.

9. The image processing apparatus of claim 2, wherein

the image acquisition apparatus is mounted in a vehicle so as to allow the image acquisition apparatus to acquire forward images of a road on which the vehicle runs, and

the object is composed of white lines on the road.

10. The image processing apparatus of claim 3, wherein the threshold setting means is configured to set the edge threshold at a value which is smaller than a difference between a maximum and a minimum among levels of the output signals from the effective pixels.

11. The image processing apparatus of claim 3, wherein

the output acquiring means is configured to acquire the output signals from the light-shielded pixels every time the image data acquiring means acquires the output signals from the effective pixels, and

the threshold setting means is configured to set the edge threshold every time the output acquiring means acquires the output signals from the light-shielded pixels.

12. The image processing apparatus of claim 3, wherein

the image acquisition apparatus is mounted in a vehicle so as to allow the image acquisition apparatus to acquire forward images of a road on which the vehicle runs, and

the object is composed of white lines on the road.