Image pickup apparatus and image pickup method

• US 20040175053A1
• Filed: 03/01/2004
• Published: 09/09/2004
• Est. Priority Date: 03/05/2003
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kawamata, Shinya, Hagisato, Yasuo
• Granted Patent: US 7,577,299 B2
• Time in Patent Office: Days
• US Class Current: 382/260
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 5/10 using non-spatial domain filtering
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement

Abstract

A form of the image pickup apparatus of the invention is characterized by including an image pickup portion that receives a incident light from an image-pickup object and performs a photoelectric conversion of the light, and an image processing portion that performs a spatial filter process of removing a predetermined low-frequency component from a picked-up image output by the image pickup portion.

Claims

1. An image pickup apparatus comprising:

an image pickup portion that receives a incident light from an image-pickup object and performs a photoelectric conversion of the light; and

an image processing portion that performs a spatial filter process of removing a predetermined low-frequency component from a picked-up image output by the image pickup portion.

2. The image pickup apparatus according to claim 1, wherein the image processing portion performs a discrete Fourier transform of the picked-up image, and removes the low-frequency component from the discrete Fourier transformed-image, and then performs an inverse discrete Fourier transform of the image.

3. The image pickup apparatus according to claim 1, wherein the image processing portion performs the spatial filter process by using a one-dimensional digital filter or a two-dimensional digital filter.

4. The image pickup apparatus according to claim 1, wherein due to the spatial filter process performed by the image processing portion, a pixel brightness value of the picked-up image of a range of at least a predetermined distance from the image pickup portion becomes relatively greater than a pixel brightness value of the picked-up image of a range of less than the predetermined distance from the image pickup portion.

5. The image pickup apparatus according to claim 4, wherein with regard to the range of less than the predetermined distance from the image pickup portion in the picked-up image, the image processing portion increases the pixel brightness value with increases in the distance from the image pickup portion.

6. The image pickup apparatus according to claim 4, wherein the image processing portion performs the spatial filter process with a cutoff frequency set based on a ratio between a pixel region of the image-pickup object at the predetermined distance and a pixel region of the entire picked-up image.

7. The image pickup apparatus according to claim 1, wherein the image processing portion performs the spatial filter process via a spatial filter of a predetermined cutoff frequency that is set in accordance with an ambient environment.

8. The image pickup apparatus according to claim 7, wherein the image processing portion sets the cutoff frequency based on a brightness of the ambient environment.

9. The image pickup apparatus according to claim 8, wherein the image processing portion sets the cutoff frequency higher the brighter the ambient environment.

10. The image pickup apparatus according to claim 8, further comprising an illuminance sensor that detects the brightness of the ambient environment,

wherein the image processing portion sets the cutoff frequency based on the brightness of the ambient environment detected by the illuminance sensor.

11. The image pickup apparatus according to claim 7, wherein the image processing portion sets the cutoff frequency based on a weather condition.

12. The image pickup apparatus according to claim 11, wherein the image processing portion sets the cutoff frequency for a rainy weather lower than the cutoff frequency for clear weather.

13. The image pickup apparatus according to claim 11, further comprising a raindrop sensor that detects the weather condition,

wherein the image processing portion sets the cutoff frequency based on the weather condition detected by the raindrop sensor.

14. The image pickup apparatus according to claim 1, wherein the image pickup portion is disposed in a vehicle and takes an image of the image-pickup object present in a traveling direction of the vehicle.

15. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is used in a visual recognition support system that assists a driver of a vehicle in visual recognition during a nighttime run of the vehicle.

16. An image pickup method for an image pickup apparatus having an image pickup portion that receives a incident light from an image-pickup object and performs a photoelectric conversion of the light and an image processing portion that performs an image processing of a picked-up image, comprising the steps of:

outputting the picked-up image, and

performing a spatial filter process of removing a predetermined low-frequency component from the picked-up image output by the image pickup portion.